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BACKGROUND: Energy‐saving and low‐carbon baking processes, as well as the need to determine the flavor‐forming mechanisms of baked dried tofu, are becoming increasingly necessary. The application of emerging catalytic infrared radiation (CIR) technology in baking of dried tofu is considered of high interest due to the low energy consumption and high baking efficiency compared to traditional baking methods. Hence, this study aimed to investigate the evolution of aroma compounds in baked dried tofu during the CIR baking process and reveal relevant relationships between physical qualities, potential flavor precursors and key volatile compounds. RESULTS: The results showed that the surface color of dried tofu gradually turned an appetizing golden yellow color during the rapid heating process, caused by the uniform infrared radiation from the radiant emitters. Meanwhile, the moisture of dried tofu experienced minimal reduction and the hardness of dried tofu gradually increased with the formation of crust on the surface. In addition, 49 volatile compounds were identified by headspace solid‐phase microextraction–gas chromatography–mass spectrometry and 13 substances – 1‐hexanol, 1‐octen‐3‐ol, 1‐pentanol, heptanal, nonanal, hexanal, (E,E)‐2,4‐decadienal, (E,Z)‐2,4‐decadienal, octanal, (E)‐2‐octenal, (E)‐2‐nonenal, 2‐heptanone and 2‐pentylfuran – were confirmed as key aroma compounds. Moreover, the amino acids aspartic acid, glutamic acid, isoleucine, lysine and arginine, and the fatty acids butyric, caprylic, capric, tridecanoic, stearic, oleic and linolenic were responsible for the unique flavor of CIR‐baked dried tofu. CONCLUSION: Consequently, the findings can provide a scientific basis for manufacturers to achieve precise quality control and large‐scale production of CIR‐baked dried tofu products. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Rice wine (RW) fermentation is limited by its long fermentation time, weak taste and unpleasant flavors such as oil and odor. In this study, a novel ultrasound technology of Saccharomyces cerevisiae was used with the aim of improving fermentation efficiency and volatile flavor quality of RW. RESULTS: The results showed that fixed‐frequency ultrasonic treatment (28 kHz, 45 W L−1, 20 min) of S. cerevisiae seed culture at its logarithmic metaphase significantly increased the biomass and alcohol yield by 31.58% and 26.45%, respectively, and reduced fermentation time by nearly 2 days. Flavor analysis indicated that the flavor compounds in RW, specifically the esters and alcohols, were also increased in quantity after the ultrasonic treatment of S. cerevisiae seed liquid. Isobutyl acetate, ethyl butyrate, ethyl hexanoate and phenethyl acetate contents were increased by 78.92%, 129.19%, 7.79% and 97.84%, respectively, as compared to the control. CONCLUSION: Ultrasonic treatment of S. cerevisiae reduced fermentation time and enhanced the flavor profile of RW. This study could provide a theoretical and/or technological basis for the research and development of RW. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: The pickling process with NaCl is an essential step for pork preservation. This study aimed to investigate the effect of different ultrasonic intensities of tri‐frequency simultaneous ultrasound (TSIU) pickling on the NaCl content and quality of pork (longissimus dorsi). After 30 min pickling, the NaCl content, moisture content, pickling yield, cooking loss, textural properties, color, pH, moisture migration and distribution as well as microstructure of pork were assessed. RESULTS: Results showed that among all the ultrasonic treatment intensities (85–150 W L−1), the NaCl content of the sample pickled by an intensity of 101.3 W L−1 was higher than that of other intensities. TSIU 101.3 W L−1 showed 59.95% higher NaCl content than the control sample. In addition, the sample treated with TSIU of 101.3 W L−1 had higher pickling yield and moisture content, better textural properties of pork (including hardness and chewiness), and less cooking loss. The results of the low‐field nuclear magnetic resonance showed that, compared with the control group, the relaxation time T21 of the ultrasound‐assisted pickling samples increased, while the proportion of T22 (A22) reduction ranged from 175.0% to 379.9%. The microstructure designated that the ultrasonic treatment could facilitate changes in meat texture. CONCLUSION: Ultrasound marination of different intensities promoted the diffusion of NaCl and affected the quality of pork tenderloins. The TSIU at 101.3 W L−1 could better accelerate NaCl transport and homogeneous distribution on meat, thereby improving the sample quality. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Surfactin, usually produced by microbial metabolism, has many advantages including low toxicity, high biodegradability, and stability at extreme pH levels and temperatures, making it suitable for industry. However, its commercial production has not yet been achieved. RESULTS: A strain with a strong surfactin‐producing ability was isolated and identified as Bacillus subtilis SOPC5, based on the appearance of colonies, microscopic observation, and 16S rDNA sequencing. The isolate exhibited significant tolerance to acid, bile, gastric, and intestinal juices, and was sufficiently susceptible to antibiotics. Bacillus subtilis SOPC5 showed high levels of auto‐aggregation and surface hydrophobicity, and a strong capacity to secrete protease, amylase, and cellulase. The strain also exhibited antibacterial activity against Staphylococcus aureus 10 306 with a antibacterial circle diameter of 18.0 ± 1.1 mm. The maximal yield of surfactin (1.32 mg mL−1) was obtained by fermenting soybean meal (SBM) using the isolate under the following conditions: SBM 86 g L−1, inoculation 1.5 × 107 CFU mL−1, FeSO4 1.2 mg L−1, MnSO4 2.6 mg L−1, MgSO4 0.5 mg mL−1, L‐Glu 4 mg L−1, temperature 33 °C, duration 120 h, and shaking at 210 rpm. The purity of surfactin was 97.42% as measured by high‐performance liquid chromatography (HPLC). The half inhibitory concentration (IC50) values for surfactin to scavenge 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2‐azino‐bis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cation (ABTS·+) were 1.275 ± 0.11 and 0.73 ± 0.08 mg mL−1, respectively. CONCLUSION: This study provides a scientific basis for the application of B. subtilis SOPC5 (as a potential probiotic) and the preparation of its metabolic product (surfactin). © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Power ultrasound is a kind of green and environmentally friendly processing technology. Still, because of its uneven distribution of acoustic pressure in the propagation medium, the large‐scale industrial application of ultrasound is limited. In order to make more effective use of ultrasound waves, this paper uses a counter‐current ultrasound‐assisted extraction container as the geometric model of simulation, calculates the distribution of the acoustic pressure field in the container by COMSOL Multiphysics software, and investigates the effect of acoustic pressure on the fluid field, and temperature field. The simulation results showed that the acoustic pressure increased with the increase of ultrasound power and frequency, tended to balance with the rise of propagation distance, and the cavitation effect was more likely to occur. The propagation of ultrasound in the fluid medium increased the velocity and vorticity of the fluid, which was conducive to the generation of mixing effects. Under the ultrasound pulse working mode for 4 min, the fluid temperature on the central axis increased in a stepped order, with a maximum increase of 19.3°C. We can see that the establishment of the simulation model provides some theoretical guidance for the more practical application of ultrasound in the food industry. Practical Applications: The limitation of ultrasound application mainly lies in the nonuniform distribution of acoustic pressure when ultrasound propagates in the fluid medium. Therefore, mastering the distribution of multiple physical fields in the reaction zone through simulation has important technical support and theoretical guiding significance for designing efficient ultrasound‐assisted extraction equipment and large‐scale industrial production of ultrasound. [ABSTRACT FROM AUTHOR]

BACKGROUND: There has been a significant growth in demand for plant‐derived protein, and this has been accompanied by an increasing need for sustainable animal‐feed options. The aim of this study was to investigate the effect of magnetic field‐assisted solid fermentation (MSSF) on the in vitro protein digestibility (IVPD) and functional and structural characteristics of rapeseed meal (RSM) with a mutant strain of Bacillus subtilis. RESULTS: Our investigation demonstrated that the MSSF nitrogen release rate reached 86.3% after 96 h of fermentation. The soluble protein and peptide content in magnetic field feremented rapeseed meal reached 29.34 and 34.49 mg mL−1 after simulated gastric digestion, and the content of soluble protein and peptide in MF‐FRSM reached 61.81 and 69.85 mg mL−1 after simulated gastrointestinal digestion, which significantly increased (p > 0.05) compared with the fermented rapeseed meal (FRSM). Studies of different microstructures – using scanning electron microscopy (SEM) and atomic force microscopy (AFM) – and protein secondary structures have shown that the decline in intermolecular or intramolecular cross‐linking leads to the relative dispersion of proteins and improves the rate of nitrogen release. The smaller number of disulfide bonds and conformational alterations suggests that the IVPD of RSM was improved. CONCLUSIONS: Magnetic field‐assisted solid fermentation can be applied to enhance the nutritional and protein digestibility of FRSM. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bacillus amyloliquefaciens has excellent protease production ability and holds great prospects for application in the solid‐state fermentation of soybean meal (SBM). RESULTS: Among eight strains of bacteria, Bacillus amyloliquefaciens subsp. plantarum CICC 10265, which exhibited higher protease production, was selected as the fermentation strain. The protease activity secreted by this strain reached 106.41 U mL−1. The microbial community structure differed significantly between natural fermentation and inoculation‐enhanced fermented soybean meal (FSBM), with the latter showing greater stability and inhibition of miscellaneous bacterial growth. During fermentation, the temperature inside the soybean meal increased, and the optimal environmental temperature for FSBM was found to be between 35 and 40 °C. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis analysis and nitrogen solubility index (NSI) results demonstrated that solid‐state fermentation had a degrading effect on highly denatured proteins in SBM, resulting in an NSI of 67.1%. CONCLUSION: Bacillus amyloliquefaciens subsp. plantarum CICC 10265 can enhance the NSI of SBM in solid‐state fermentation and inhibit the growth of miscellaneous bacteria. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Our previous studies have shown that ultrasound‐treated γ‐aminobutyric acid (GABA)‐rich coffee leaves have higher angiotensin‐I‐converting enzyme inhibitory activity than their untreated counterpart. However, whether they have antidiabetic activity remains unknown. In this study, we aimed to investigate the inhibitory activities of coffee leaf extracts (CLEs) prepared with ultrasound (CLE‐U) or without ultrasound (CLE‐NU) pretreatment on α‐amylase and α‐glucosidase. Subsequently, we evaluated the binding interaction between CLE‐U and both enzymes using multi‐spectroscopic and in silico analyses. Results: Ultrasound pretreatment increased the inhibitory activities of CLE‐U against α‐amylase and α‐glucosidase by 21.78% and 25.13%, respectively. CLE‐U reversibly inhibits both enzymes, with competitive inhibition observed for α‐amylase and non‐competitive inhibition for α‐glucosidase. The static quenching of CLE‐U against both enzymes was primarily driven by hydrogen bond and van der Waals interactions. The α‐helices of α‐amylase and α‐glucosidase were increased by 1.8% and 21.3%, respectively. Molecular docking results showed that the key differential compounds, including mangiferin, 5‐caffeoylquinic acid, rutin, trigonelline, GABA, caffeine, glutamate, and others, present in coffee leaves interacted with specific amino acid residues located at the active site of α‐amylase (ASP197, GLU233, and ASP300). The binding of α‐glucosidase and these bioactive components involved amino acid residues, such as PHE1289, PRO1329, and GLU1397, located outside the active site. Conclusion: Ultrasound‐treated coffee leaves are potential anti‐diabetic substances, capable of preventing diabetes by inhibiting the activities of α‐amylase and α‐glucosidase, thus delaying starch digestion. Our study provides valuable information to elucidate the possible antidiabetic capacity of coffee leaves through the inhibition of α‐amylase and α‐glucosidase activities. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Emulsion systems are extensively utilized in the food industry, including dairy products, such as ice cream and salad dressing, as well as meat products, beverages, sauces, and mayonnaise. Meanwhile, diverse advanced technologies have been developed for emulsion preparation. Compared with other techniques, high‐intensity ultrasound (HIUS) and high‐pressure homogenization (HPH) are two emerging emulsification methods that are cost‐effective, green, and environmentally friendly and have gained significant attention. HIUS‐induced acoustic cavitation helps in efficiently disrupting the oil droplets, which effectively produces a stable emulsion. HPH‐induced shear stress, turbulence, and cavitation lead to droplet disruption, altering protein structure and functional aspects of food. The key distinctions among emulsification devices are covered in this review, as are the mechanisms of the HIUS and HPH emulsification processes. Furthermore, the preparation of emulsions including natural polymers (e.g., proteins‐polysaccharides, and their complexes), has also been discussed in this review. Moreover, the review put forward to the future HIUS and HPH emulsification trends and challenges. HIUS and HPH can prepare much emulsifier‐stable food emulsions, (e.g., proteins, polysaccharides, and protein–polysaccharide complexes). Appropriate HIUS and HPH treatment can improve emulsions' rheological and emulsifying properties and reduce the emulsions droplets' size. HIUS and HPH are suitable methods for developing protein–polysaccharide forming stable emulsions. Despite the numerous studies conducted on ultrasonic and homogenization‐induced emulsifying properties available in recent literature, this review specifically focuses on summarizing the significant progress made in utilizing biopolymer‐based protein–polysaccharide complex particles, which can provide valuable insights for designing new, sustainable, clean‐label, and improved eco‐friendly colloidal systems for food emulsion. Practical Application: Utilizing complex particle‐stabilized emulsions is a promising approach towards developing safer, healthier, and more sustainable food products that meet legal requirements and industrial standards. Moreover, the is an increasing need of concentrated emulsions stabilized by biopolymer complex particles, which have been increasingly recognized for their potential health benefits in protecting against lifestyle‐related diseases by the scientific community, industries, and consumers. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of ultrasound (US) combined with mild heat (T) and potassium sorbate (PS) on Pichia membranaefaciens in soy sauce and the quality of soy sauce. The maximum reduction of P. membranaefaciens was 5.34 ± 0.15 log after thermoultrasound (TS, 300 W, 10/3 s, 20 + 40 kHz, 60°C) + PS (0.1 mg/mL) treatment for 20 min. Physicochemical properties, including pH and total acid of soy sauce, did not change significantly after TS + PS treatment. Electronic nose analysis showed changes in the flavour of soy sauce after different treatments. A total of 122 and 125 volatile compounds were detected by SPME‐GCMS before and after TS + PS treatment respectively. T90 (soy sauce processed at 90°C) treatment decreased the content of the flavour compounds greatly, while TS + PS decreased the content of the flavour compounds slightly in soy sauce. TS + PS treatment inactivated P. membranaefaciens effectively in soy sauce and maintained and partially improved the sensory and flavour characteristics of soy sauce, which indicates that this combination technology has potential application in the commercial processing of soy sauce. [ABSTRACT FROM AUTHOR]

Background: Soybean meal, a by‐product of the soybean oil production industry, has a high protein content but the compact globular structure of the protein from soybean meal limits its wide application in food processing. Allicin has been found to have numerous functional properties. In this study, allicin was interacted with soy protein isolate (SPI). The functional properties of the adducts were investigated. Results: Binding with allicin significantly quenched the fluorescence intensity of SPI. Static quenching was the main quenching mechanism. The stability of adducts decreased with increasing temperature. The greatest extent of binding between allicin and sulfhydryl groups (SH) of SPI was obtained at an allicin/SH molar ratio of 1:2. The amino groups of SPI did not bind with allicin covalently. Soy protein isolate was modified by allicin through covalent and non‐covalent interactions. Compared with SPI, the emulsifying activity index and foaming capacity of adducts with a ratio of 3:1 were improved by 39.91% and 64.29%, respectively. Soy protein isolate‐allicin adducts also exhibited obvious antibacterial effects. The minimum inhibitory concentrations (MICs) of SPI‐allicin adducts on Escherichia coli and Staphylococcus aureus were 200 and 160 μg mL−1, respectively. Conclusion: The interaction of allicin with SPI is beneficial for the functional properties of SPI. These adducts can be used in different food formulations as emulsifiers, foamers, and transport carriers. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Ultrasonic washing has been widely applied to the postharvest storage of fruits and vegetables as a residue‐free physical washing technology, which plays an important role in improving shelf‐life, safety, and nutritional value. Phenolics are a large group of phytochemicals widespread in fruits and vegetables, and they have been considered potential protective factors against some diseases because of potent antioxidative properties. Previous studies have shown that ultrasonic washing can increase the phenolic content of fruits and vegetables immediately or during storage through the induction of plant stress responses, which is of great significance for improving the functional and nutritional value of fruits and vegetables. However, the mechanisms of ultrasound as an elicitor to improve the phenolic content remain controversial. Therefore, this review summarizes the applications of ultrasonic washing to increase the phenolic content in fruits and vegetables. Meanwhile, the corresponding physiological stress response mechanisms of the phenolic accumulation in terms of immediate stress responses (i.e., higher extractability of phenolics) and late stress responses (i.e., metabolism of phenolics) are expounded. Moreover, a hypothetical model is proposed to explain phenolic biosynthesis triggered by signaling molecules produced under ultrasound stress, including primary signal (i.e., extracellular adenosine triphosphate) and secondary signals (e.g., reactive oxygen species, Ca2+, NO, jasmonates, and ethylene). Additionally, the techno‐economic feasibility of ultrasonic washing technology is also discussed. Further, challenges and trends for further development of ultrasonic washing as an abiotic elicitor applied to the postharvest storage of fruits and vegetables are presented. [ABSTRACT FROM AUTHOR]

BACKGROUND: Thermophiles can thrive at 50–80 °C and produce some enzymes with special promise for biocatalysis. A thermophilic protease‐producing strain YYC4 was isolated from Yunyan cigarette and employed in solid‐state fermentation (SSF) of unsterilized soybean meal (SBM). RESULTS: The isolate was identified as Bacillus licheniformis based on appearance of colonies, microscopic observation and 16S rDNA sequencing. After SSF, soluble and crude protein contents in SBM increased from 49.24 to 185.73 g kg−1 and from 404.18 to 479.46 g kg−1, respectively, under the fermentation conditions of 107 cfu g−1 inoculation of strain YYC4, 1:1.8 (g mL−1) SBM to distilled water, 1.2 g kg−1 magnesium sulphate addition, 55 °C and 48 h. During fermentation, pH of the medium increased from 6.30 to 9.09 and protease activity especially neutral protease increased significantly from 13.5 to 181.31 U g−1. Meanwhile, trypsin inhibitor (TI) activity was decreased from 8.19 to 3.19 mg g−1. The safety of fermented SBM (FSBM) was verified by acute toxicity animal experiment. Analysis of microbial community in FSBM showed that Bacillus licheniformis YYC4 as a dominant strain inhibited most of the other microorganisms pre‐existing in the materials during fermentation. CONCLUSION: Increments of soluble and crude protein by 277.19% and 18.63% and decrement of harmful TI by 61.05% in SBM were achieved using thermophilic SSF by Bacillus licheniformis YYC4, providing a basis for the application of thermophiles in fermentation industry in an environmentally friendly and energy‐saving way. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This review assesses the nonthermal physical processing technologies for protein modification. The review also discusses the structural, functional, and digestibility attributes of protein following nonthermal physical processing. Applications of ultrasonication, ultrahigh pressure, and pulsed electric field (PEF) can induce the conformational changes of protein via the creation of free radicals and/or larger/smaller protein molecules, damaging the primary, secondary, tertiary, and quaternary structure of protein, and thus influence the functional properties. Some key achievements in using nonthermal physical technologies to process protein‐rich foods include improved enzymatic hydrolysis, solubility, emulsification, foaming, gelatinization, digestion properties, and reduced allergenicity. Therefore, nonthermal physical technologies are useful methods to modify food protein structure and functionality for the food industry. Practical Application: The demand for protein with desirable functional properties and nutritional value makes it imperative to find suitable processing technologies that could conserve or yield high quality proteins from both conventional and nonconventional sources. Since thermal processing (including microwave, radiofrequency heating, etc.) could possibly reduce the quality attributes of proteins, many researchers have focused their investigations on nonthermal physical processing to improve the functional properties of proteins. To this regard, this review discusses nonthermal techniques, including ultrasonication, high‐pressure processing, PEFs, cold plasma, and ultraviolet. [ABSTRACT FROM AUTHOR]

BACKGROUND Surfactin, a good biological surfactant, is derived from the metabolites of microorganisms. However, the ability of natural strains to produce surfactin is low, and so the presented study aimed to use a novel mutagenesis technology to increase their yields. RESULTS: Atmospheric and room temperature plasma (ARTP) was used to conduct mutation breeding of Bacillus subtilis CICC 10721, and a mutant strain M45 with a higher surfactin yield of 34.2% and a stable subculture was screened out. From the fermentation kinetics study, it was found that the maximum cell dry weight, maximum growth rate and surfactin synthesis parameters of the mutant strain M45 were all greater than that of the original strain. Scanning electron microscope and laser scanning confocal microscope observations showed that the spore morphology changed after ARTP treating, and the intracellular Ca2+ concentration of the mutant increased. Genome resequencing analysis showed that 66 single nucleotide poymorphism non‐synonymous mutation sites occurred in M45, and the identification results of the fermentation broth extract from M45 showed that it is composed of C12‐C16 surfactin. CONCLUSION: ARTP mutagenesis was found to change the morphology of bacteria, membrane permeability and genes related to the synthesis and secretion of surfactin. The present study provides a basis for industrial production of surfactin and an understanding of the mutagenesis mechanism. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Fermentation efficiency of thermophiles of Bacillus licheniformis YYC4 and Geobacillus stearothermophilus A75, and mesophilic Bacillus subtilis 10 160 on soybean meal (SBM), was evaluated by examining the nutritional and protein structural changes. RESULTS: SBM fermentation by B. licheniformis YYC4, B. subtilis 10 160 and G. stearothemophilus A75 increased significantly the crude and soluble protein from 442.4 to 524.8, 516.1 and 499.9 g kg−1, and from 53.9 to 203.3, 291.3 and 74.6 g kg−1, and decreased trypsin inhibitor from 8.19 to 3.19, 2.14 and 5.10 mg g−1, respectively. Bacillus licheniformis YYC4 and B. subtilis 10 160 significantly increased phenol and pyrazine content. Furthermore, B. licheniformis YYC4 fermentation could produce abundant alcohols, ketones, esters and acids. Surface hydrophobicity, sulfhydryl groups and disulfide bond contents of SBM protein were increased significantly from 98.27 to 166.13, 173.27 and 150.71, from 3.26 to 4.88, 5.03 and 4.21 μmol g−1, and from 20.77 to 27.95, 29.53 and 25.5 μmol g−1 after their fermentation. Fermentation induced red shifts of the maximum absorption wavelength (λmax) of fluorescence spectra from 353 to 362, 376 and 361 nm, while significantly reducing the fluorescence intensity of protein, especially when B. subtilis 10 160 was used. Moreover, fermentation markedly changed the secondary structure composition of SBM protein. Analyses by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and atomic force microscopy showed that macromolecule protein was degraded into small‐sized protein or peptide during fermentation of SBM. CONCLUSION: Bacillus licheniformis YYC4 fermentation (without sterilization) improved nutrition and protein structure of SBM as B. subtilis 10 160, suggesting its potential application in the SBM fermentation industry. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Fresh shiitake mushrooms are rich in nutrients, but have high water content, a fast metabolism after harvest, and deteriorate extremely easily. Therefore, the drying of shiitake mushrooms has become a research direction. However, the role of different drying techniques on shiitake mushroom quality is limited. Therefore, the purpose of this study was to investigate the effect of thermal and non‐thermal drying on the drying kinetics, and the physicochemical properties of the end product. RESULTS: Results showed that shiitake mushroom treated with non‐thermal drying (vacuum freeze‐drying) had an attractive color, low shrinkage, and uniform honeycomb structure, while the drying time was the longest and not conducive to the formation of shiitake mushroom aroma. But shiitake mushroom treated with thermal drying presents an attractive fragrance. In thermal processing technology, compared with hot air convection drying (HAD), infrared hot air convection drying (IRHAD) shortens the drying time by 37.5%, and had the highest oxidation resistance, polysaccharide content and the lowest color change. Relative‐humidity drying (RHD) samples had the lowest shrinkage compared with other thermal processing technology. The five polysaccharides exhibited similar preliminary structural characteristics, but the polysaccharides obtained by IRHAD have the highest antioxidant properties. CONCLUSION: These results showed that compared with thermal drying technology, non‐thermal drying technology is not suitable for shiitake mushroom processing. In thermal processing technology, IRHAD is a potential drying method to obtain high‐quality dried shiitake mushrooms and shiitake mushroom polysaccharide (SMP). However, it is necessary to increase the pretreatment technology to achieve the attractive appearance of non‐thermal drying technology. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND The change of surface color caused by browning during the drying process of shiitake mushrooms seriously affects its market circulation. Intensive pulsed light (IPL) as a non‐heat‐treatment method can reduce enzyme activity by changing the enzyme structure. Therefore, in this study, the use of IPL pretreatment before drying was aimed to reduce the adverse reactions caused by the browning reaction during the drying processing of shiitake mushrooms. RESULTS: Shiitake mushrooms pretreated with 25 pulses of IPL energy of 400 J reduced the initial polyphenol oxidase enzyme activity, the browning index, and browning degree values by 42.83%, 43.02%, and 47.54% respectively. The IPL pretreatment enhanced the polysaccharides and reducing sugars contents and it reduced 5‐hydroxymethylfurfural generation in the dried shiitake mushrooms. The pretreatment also improved the surface color, the antioxidant activity, and retained the umami taste characteristics in the dried shiitake mushroom. CONCLUSION: The IPL pretreatment combined with controlled temperature and humidity for convection drying could be a suitable method to improve the quality of dried shiitake mushrooms. Therefore, this study provides a new pretreatment method for materials that are prone to browning during drying. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND The increase of peptide yield contributed to reducing the usage of antibiotics in solid‐state fermented feed. Ultrasound technology is used in the field of liquid‐state fermentation to improve yield of fermented products but has not been utilized in the field of solid‐state fermentation (SSF). The main objective of this study was to investigate the feasibility of improving peptide yield in SSF products through ultrasound‐treated bacterial strain. RESULTS: The highest peptides content in soybean meal SSF products reached 153.28 mg g−1, which increased by 15.05% compared with the control. This content value was acquired through treating the bacteria of Bacillus amyloliquefaciens by ultrasound before inoculating into soybean meal under the optimized mode and parameters (simultaneous dual‐frequency ultrasound mode, frequency combination of 40/60 kHz, total power density of 40 W L−1, time of 20 min, pulse‐on and pulse‐off times of 40 and 60 s, delayed inoculation time of 0 h). Fermenting with ultrasound‐treated bacterial strain can effectively increase peptide yield, biomass and protease activity of soybean meal fermented products during the SSF prophase. After treating by ultrasound, the latent phase and logarithmic phase of the bacterial strain shortened by 1 and 3 h while the generation time reduced by 23.64%. In qualitative test of protease activity, diameter ratio (DR) value of ultrasound‐treated bacterial cells enlarged by 12.0% compared with the control. CONCLUSION: Peptide yield of soybean meal SSF products can be improved through ultrasound‐treated bacterial inoculum, which attributed to the promoting effect of ultrasound treatment on growth activity and protease production capability of bacterial cells. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Ultrasonic pretreatment is a novel physical method that can be used in the extraction process of okra pectin. Real‐time online monitoring technologies were introduced in time and frequency domains when okra was pretreated. Preparation time of dried okra and yield of okra pectin were studied; and physicochemical properties of okra pectin were analyzed at the optimum ultrasonic parameter. RESULTS: Results showed that ultrasonic intensity of sweeping‐frequency ultrasonic (SFU) pretreatment was stronger than that of fixed‐frequency ultrasonic pretreatment (FFU). SFU pretreatment (60 ± 1 kHz) at 30 min had a strong ultrasonic voltage peak of 0.05387 V and signal power peak of −6.62 dBm. The preparation time of dried okra was 160 ± 14.14 min in the pretreated group, 44.83% lower than control without SFU pretreatment. The intercellular space was 56.03% higher than control. Water diffusion coefficient increased from 1.41 × 10−9 to 2.14 × 10−9 m2 s−1. Monobasic quadratic equations were developed for the monitored ultrasonic intensity and pectin yield. Compared to control, extraction yield (16.70%), pectin content (0.564 mg mg−1), solubility (0.8187 g g−1) and gel strength (30.91 g) were improved in the pretreated group. Viscosity decreased, and values of G′ and G″ crossing at 63 rad s−1 revealed the viscoelastic behavior and the beginning of viscous behavior with a sol state. CONCLUSION: Decrement of dried preparation time and increment of yield were achieved by ultrasonic pretreatment during the extraction process of okra pectin, and the relationship of ultrasonic intensity monitored by real‐time online technologies and yield was given. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: The main objective of this study was to evaluate the safety and antihypertensive activity of rapeseed peptides and to investigate their potential synergy with captopril. RESULTS: The peptides were nontoxic with the maximum tolerated dose exceeding 25 g kg−1 BW d−1 for mice and they had angiotensin converting enzyme (ACE) inhibitory activity with IC50 value of 1.27 mg mL−1. Rapeseed peptides did not have a synergistic effect with captopril on inhibiting ACE activity in simulated digestion tests in vitro. But in vivo they could synergistically augment the amplitude range of lowering blood pressure with captopril by approximately 9% and prolong the antihypertensive effect duration time by over 20% in antihypertension tests of spontaneously hypertensive rats. In addition, the inhibiting effect of rapeseed peptides on ACE activity was noticeable in some rat organs in vivo. Nevertheless, when compared to captopril group, the potential synergy of rapeseed peptides with captopril did not cause a further decrease in ACE activity in the organs but their synergy further improved levels of NO (12.7%) and endothelial nitric oxide synthase (74.1%) in rat serum. Further studies of some peptides identified from rapeseed peptides showed that some of the rapeseed peptides (Cys‐Leu, Val‐Ala‐Pro) could markedly increase contents of NO and endothelial nitric oxide synthase. CONCLUSIONS: Rapeseed peptides have antihypertensive activity and they showed potential synergy with captopril in antihypertensive performance in vivo. The synergy was not from ACE inhibition but from other pathways, like improvement in endogenous vasodilator contents. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Having short drying time and attractive product quality are important in fruit and vegetable dehydration processing. In this work, tri‐frequency (20, 40 and 60 kHz) ultrasound‐ethanol pretreatment, ultrasound‐water pretreatment and ethanol pretreatment were employed before infrared convection drying (ICD) of scallion stalks, which was aimed at improving the drying process and quality of the end products. The mass transfer, drying characteristics (moisture ratio and drying rate and quality properties of scallion (rehydration, color, flavor, optical microscope image, moisture distribution and microbiological quality) were analyzed. RESULTS: All pretreatments have decreased the drying time by 33.34–83.34% compared to the control, while ultrasound‐ethanol pretreatment provided the highest time reduction (83.34%). The reason is that the volatility of ethanol have replaced air in the tissue, which produced a better osmotic dehydration effect and the cavitation effect of ultrasound changed the cell function of the material, so that the food tissue was rapidly compressed and expanded, resulting in damage to the cell structure. Ultrasonic‐ethanol pretreatment has greatly reduced the water loss and dry matter of fresh scallion, improved the rehydration effect of dried scallion, better retained the color and flavor of scallion and effectively reduced the microbiological quality of the scallion. CONCLUSION: The tri‐frequency ultrasound‐ethanol pretreatment has effectively improved the drying process and quality characteristics of the dried scallion. Therefore, this research has a great contribution to the drying technology, as evident in the remarkable reduction in drying time and the improvement in the quality of the end product. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Sweeping frequency ultrasonic (SFU) pretreatment was utilized to promote pulsed vacuum drying (PVD) process of okra. Drying characteristics and microstructure of okra were studied. Then mechanism of SFU pretreatment was revealed by acoustic signal monitoring technologies in time and frequency domains and bubble oscillations. Results showed that core temperature (57–58°C) of PVD, rehydration ratio (3.16%), hardness (23.90 N) and, fracturability (3.15 mm) were the highest, while moisture ratio was the smallest in SFU pretreated okra group at 30 min during the ultrasonic pretreatment process. It was related to changes of microstructure. SFU pretreated okra cells got folded, intercellular space was large, and the tunnel structure was generated until 30 min. However, excessive ultrasound caused the structural collapse of cells; the tunnel structure was congested, which was not beneficial to moisture transfer during PVD process. Effects of SFU pretreatment were further explained by monitored data of acoustic signals in time and frequency domains. The maximum voltage amplitude (40.6 mV) and space peak temporal peak acoustic intensity (2.76 × 106 W/m2) were the highest at 30 min during the pretreatment process. The corresponding SFU signals had a wide frequency domain and fluctuation range of energy, and cavitation effects of ultrasonic bubbles was facilitated. Practical applications: PVD is an innovative drying technology. However, okra structure is complex, which is against moisture transfer during the process of drying. Hence, SFU pretreatment was added before drying. The tunnel structure of okra generated by the pretreatment could support moisture transfer suggesting a rapid rate of drying. The best quality of dried okra was obtained at 30 min during the pretreatment process, which makes for long storage and preparation of functional snacks. Acoustic signals were analyzed by real‐time monitoring technique during pretreatment of okra, and the cavitation intensity of SFU fields was revealed. Thus, the fundamental basis for accurate ultrasonic processing is provided. [ABSTRACT FROM AUTHOR]

The use of ultrasound has the potential of improving the production of valuable substances in Ganoderma lucidum (G. lucidum)—a well‐known fungus rich in bioactive compounds. The effect of different ultrasonic parameters on the fermentation of G. lucidum was studied. The results showed that under optimal ultrasonic conditions, the mycelium biomass and triterpenoids production increased by 26.99 and 33.62%, respectively (p <.05). Compared with the control, ultrasonication notably increased (p <.05) the content of intracellular and extracellular polysaccharides (by 18.48 and 35.90%) and flavonoids (by 30.27 and 12.00%) in mycelium. Ultrasonic treatment promoted growth, and increased metabolism of G. lucidum. Scanning electron microscopy images showed that ultrasonic treatment caused moderate breakages in mycelium leading to leaked content at recovery time of 0.5 hr. When the recovery time lasted for 3 hr, the mycelium was recovered with increased branches and tighter winding. The findings of Fluo‐4/AM suggested that the intracellular calcium ion concentration of the mycelium improved after ultrasound treatment, demonstrating the altering‐influence of sonication on the cell membrane permeability of mycelium. These results suggest that ultrasound is an efficacious approach to produce more biomass and metabolites of G. lucidum in liquid fermentation. Practical Applications: Ultrasonic technology has been widely used in the field of food fermentation. By changing the ultrasonic time, power density or frequency or other conditions, the ultrasonic energy entering the cell suspension can be changed, thereby controlling the effect of ultrasound on microbial activity. The outcome of this work indicated that the use of ultrasonication in fermentation process of G. lucidum promoted its growth and metabolism. This study provides a theoretical basis for the application of ultrasonication technology in the microbial fermentation industry. [ABSTRACT FROM AUTHOR]

This study was aimed to enhance the extraction yield of propolis samples using ultrasound technology, analyze the volatile compounds, and compare the antioxidant and antimicrobial effect of propolis extracts of different areas. Four propolis samples were collected from different regions of China, namely: Linqing, Shandong Province (LSP); Yingchun, Heilongjiang Province (YHP); Changge, Henan Province (CHP); and Raohe, Heilongjiang Province (RHP). The ultrasound extracts of CHP and RHP showed a higher total phenolic content (TPC) of 201.78 ± 4.60 mgGAE/g and 166.071 ± 1.53 mgGAE/g, total flavonoid content (TFC) of 519.77 ± 29.90 and 341.227 ± 10.82 mg quercetin/g respectively, as well as high antioxidant and antibacterial activity. Conventional extraction showed 15%–20% lower yield for TPC ranging from 72.02 ± 1.99 to 155.95 ± 3.69 mg GAE/g, TFC ranges from 129.675 ± 6.82 to 412.83 ± 12.14 mg quercetin/g, with lower antibacterial activity. The antioxidant activity of propolis extracts was determined by assays of reducing power, DPPH*, FRAP*, TEAC*, hydroxyl radical scavenging activity and superoxide anion scavenging activity. Collectively, the antioxidant activities of extracts from CHP and RHP were higher than those of the other two extracts(YHP and LSP). All the extracts showed high antimicrobial activity on Staphylococcus aureus, Listeria monocytogenes, and Bacillus subtilis, but no effect on Escherichia coli. A total of 150 compounds in propolis were detected by GC/MS. Terpenes (RHP 34%, YHP 5%, LSP 18%, and CHP 12%) and alcohols (RHP 12%, YHP 13%, LSP 12%, and CHP 10%) showed the highest relative content among all other extracts. [ABSTRACT FROM AUTHOR]

This work aims at investigating effect of different pretreatments and varied temperature on the drying kinetics, bioactive compounds, antioxidant activity, microstructure and functional group of apple slices using pulsed vacuum dryer. Pretreated apple slices (Ethanol, US + W, and US + E) dried at varied temperature (60, 70, and 80°C) were analyzed to determine total phenolic content (TPC), total flavonoid content (TFC), 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH+), 2,2‐azino‐bis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS+), color, microstructure and FT‐IR spectroscopy. The findings revealed that US + E pretreatment significantly (p <.05) decreased drying time (20–33.33%). Activation energy and moisture effective diffusivity were 17.60–29.86 kJ/mol and 1.52–3.60 × 10−8 m2/s, respectively. Microstructure evaluation showed disruption of cells structure and microchannels formation but was more prominent in US + E pretreatment with noticeable larger pores and several microchannels. US + E pretreatment retained TPC (64.89–75.75 mg/100 g GAE dw), TFC (45.96–56.25 mg/100 g ER dw), DPPH+ (66.85–73.34%) and ABTS+ (62.58–71.17%) than Ethanol, US + W, and control and was further corroborated by the observed peaks as revealed by the FT‐IR spectroscopy. Color (L*, a*, b*, whiteness) was better retained by Ethanol and US + E pretreatments. US + E pretreatment decreased drying time and also preserved bioactive compounds, antioxidant activity and color of apple slices. Practical application: Apples are popularly consumed fruits and confer various nutritional and health benefits to humans. Drying is the most common approach for apple processing and shelf life extension. However, drying often leads to a reduction in quality parameters as well as degradation of nutritional components of the apple. Novel pretreatment techniques like ultrasonic aided ethanolic pretreatment preceding to apple drying provides an added advantage over conventional drying methods in that it reduces dehydration time as a result of faster moisture removal, lowers energy consumption, improves process efficiency leading to industrial competiveness and it also preserves the nutritional and sensorial parameters of dried apple slices. [ABSTRACT FROM AUTHOR]

In this study, an in situ 7.5 L ultrasonic fermentation tank was used to culture Saccharomyces cerevisiae at 30°C for 36 hr to explore the effects of low intensity ultrasound on the production of glutathione (GSH). Ultrasonic conditions of 28 kHz frequency, 28 W/L power density for fermentation time of 0–12 hr, 280 W/L power density for fermentation time of 12–36 hr, 3 s of interval and fixed frequency mode were used for the set‐up and a nonsonicated set‐up served as the control for the experiment. Results showed that ultrasound treatment increased total GSH production by 15.60% from a maximum value of 45.52 mg/L in the control to a maximum value of 52.62 mg/L in the sonicated sample. Also, intracellular and extracellular GSH productions in the sonicated sample increased by 5.60% and 42.92% respectively. Regular detection of the changes of biomass yield, residual sugar, dissolved oxygen and pH showed that sonication resulted in biomass increased by 7.25%, glucose consumption rate increased by 53.08% and dissolved oxygen content decreased by 41.67%. The biomass models of sonication and nonsonication treatments were established according to growth of S. cerevisiae showed that the model fitted well with Logistic regression in which the strain specific growth rate increased by 60.95% after sonication. GSH production model agreed with Luedeking‐Piret regression in which GSH synthesis parameters of sonication, α and β increased by 1.96% and 19.64% in comparison to the nonsonicated sample. This study clearly demonstrated that ultrasonic stimulation could improve the biosynthesis of GSH during fermentation. Practical Applications: In this study, the GSH was producted by microbial fermentation in in situ 7.5 L ultrasonic fermentation tank. During the fermentation, sonication was applied to increasing yield of GSH. The results show that the study provides a theoretical basis for manufacture GSH combined with sonication industrialization. The fermentation kinetic model was established, which provided experimental basis for continous fermentation. [ABSTRACT FROM AUTHOR]

Aims: The objective of this study was to optimize thermosonication conditions under different processing conditions of temperature, pretreatment time, and ultrasound frequencies and to study its influence on the inactivation behavior of Bacillus cereus and also to predict the conditions that will result in the best qualities of the pork meat regarding color, texture, moisture content loss, and fat content loss. Methods: To evaluate the influence of temperature (50–70°C), ultrasound frequency (20–60 kHz), and processing time (10–20 min) on color retention, lowest hardness, fat content loss, moisture content loss, and maximizing inactivation of B. cereus spores suspended in sterilized distilled water (SDW), as well as B. cereus inoculated in pork meat, response surface methodology was employed. Result: The findings from the study showed that thermosonication treatment had a significant effect on color, texture, fat content loss, B. cereus spores suspended in SDW, B. cereus inoculated in pork, and moisture content loss. The optimum operating conditions to accomplish the best inactivation behavior of B. cereus and physicochemical properties of pork meat were ultrasound frequency of 20 kHz, temperature of 70°C, and processing time of 13.56 min. Considering the abovementioned conditions, the predicted results obtained include B. cereus in SDW (0.79 CFU/g), B. cereus in pork (0.47 CFU/g), moisture content loss (22.42%), color (45.48), texture (134.38 N), and fat content (68.63%). These outcomes were in line with the experimental values and the overall desirability was 0.534. Conclusions: The results of our study confirm that thermosonication has a better way of enhancing the quality of pork meat under the application of the suitable parameters. This can advance the processing and production of pork meat by the meat industries. Practical Applications: Pork meat is one of the most extensively consumed products in the world particularly in Asia and some parts of Africa. This product is in high consumer demand, but it is easily contaminated by microorganism, which leads to high deterioration and loss of quality. Thermosonication could be used as an effective and efficient technique for the meat industry. Its application will enhance the inactivation of deteriorative microorganisms and improve the physiochemical properties of pork meat. [ABSTRACT FROM AUTHOR]

This study sought to establish an optimized procedure for extraction of protein from microwave‐dried larvae of an edible insect, Hermetia illucens (HIL), and to determine and compare the amino acid (AA) component, intrinsic fluorescence (IF), and physicochemical/functional properties (PFPs) of protein isolates. Box–Behnken's design with the Box–Wilson methodology was applied in the optimization process. Following single‐factor investigations, the relational analysis indicated that the polynomial model could be used to illustrate the influence of extraction parameters on protein yield. Response–surface plots showed that extraction variables influenced (p <.05) protein yield of HIL. The optimized extraction (optimized protocol [OP]) conditions with highest yield (64.44%) were time—59.43 min, alkaline solution to sample ratio—24.85:1.00, and temperature—52.23°C. The protein extract obtained using the OP, compared with a modified protocol (MP) (with conditions: 60 min, 15:1 alkaline solution to sample ratio, and 40°C) showed content of 80.42 ± 0.90% and 76.91 ± 0.91%, respectively (p <.05). The AA‐scores were above that recommended by FAO. Variations existed between OP and MP extracts regarding PFPs, consistent with IF/AA‐values. The optimized extraction process was feasible, and the functional properties of HIL protein could be enhanced/modified for different food formulations. Practical applications: Hermetia illucens (HIL), an edible insect rich in protein, is one most promising insect species for food applications with extra benefits to the environment. Consumption, however, is limited by many due to association of insects to vermin/dirt. The need to increase consumption globally is paramount, as there is high demand on the already scarce protein sources available worldwide. Extracting the constituents of edible insects for novel/food applications is a promising approach to upturn global consumption in the next 2–3 decades where humans may rely on insect protein. The success of scale‐up processing in this regard depends on process conditions for better yields. Therefore, determining an optimized technique for extraction of protein from HIL larvae was investigated as well as physicochemical/technofunctional properties, and fluorescence attribute. The extraction approach was feasible and the outcome of the study may benefit industry in extraction and/or modification of edible insect protein in novel applications. [ABSTRACT FROM AUTHOR]

The main objective of this research was to monitor variety in the content of Bacillus subtilis 10160 during solid‐state fermentation (SSF) of rapeseed meal by near infrared (NIR) spectroscopy and chemometrics. Observations showed the coefficient of determination (R2) value was 0.9401 and root‐mean‐square deviation was 0.639 log (CFU/g) for viable cell content by synergies between four intervals 5,203.003–5,600.267, 5,604.124–6,001.388, 6,807.487–7,204.751 and 8,411.972–8,809.235 cm−1. The determination coefficient of prediction (Rp2) and root‐mean‐square deviation of prediction in an external validation set could reach 0.9532 and 0.628 log (CFU/g) by the viable B. subtilis model. These findings suggest that rapid detection of B. subtilis in SSF is achieved by the combination of synergy interval partial least squares and NIR spectroscopy. [ABSTRACT FROM AUTHOR]

Antioxidant activity, total phenolic content (TPC), total flavonoids, carotenoids, pH, and total titratable acidity of red and black date's vinegar were analyzed. The extraction method was designed and optimized for this purpose with respect to the variety and solvent concentrations along with the time of ultrasonication. The results showed that red dates' vinegar has significantly (p < 0.05) higher total phenols (3.38 ± 0.13 mg GAE/ml) and antioxidant activity as compared to black dates' vinegar, which had a higher amount of carotenoids (3.43 ± 0.11 mg/100 ml). Similarly, red dates' vinegar has more flavonoids as compared to commercially available Zhenjiang vinegar. In terms of physiochemical properties, both red and black date's vinegar were not significantly different (p > 0.05). Use of 50% and 80% methanol with 25 min of ultrasonication for extraction seemed more effective. The total phenols, flavonoids, antioxidant activity, carotenoids, and physiochemical analysis of the red and black date's vinegar indicated that vinegar from dates (red or black dates) is a competitive product in the marketplace. [ABSTRACT FROM AUTHOR]

Summary: In order to enhance the application scope and usage effect of ε‐polylysine, it was modified by Maillard reaction through endowing antioxidant activity. Characterisations of different type of reaction systems were investigated. Results showed that with increased heating treatment time at constant 90 °C and UV‐Vis absorbance at 294 and 420 nm, fluorescence intensity of modified products were increased. DPPH radical scavenging activity of modified products from D‐glucose (D‐Glc), D‐fructose (D‐Fru) and D‐xylose (D‐Xyl) was increased to 40.5%, 44.0% and 69.4%, and the reducing power was increased to 0.9, 1.0 and 1.3 respectively (P < 0.05). Moreover, compared with ε‐polylysin, three types of modified products have similar antibacterial property. In addition, three types of modified products showed low cytotoxicity against the cultured human HepG2 cells in vitro. Therefore, the modified products derived from ε‐polylysine model could be used as potential food preservatives. [ABSTRACT FROM AUTHOR]

BACKGROUND The salt tolerance of proteases secreted by Aspergillus oryzae 3.042 closely relates to the utilization of raw materials and the quality of soy sauce. However, little is known about the salt‐tolerant proteases and their salt‐tolerant mechanisms. RESULTS: In this study, we isolated and identified a salt‐tolerant alkaline protease (AP, approximately 29 kDa) produced by A. oryzae 3.042. It was considered as a metal‐ion‐independent serine protease. The optimum and stable pH values were both pH 9.0 and the optimum temperature was 40 °C. Over 20% relative activity of AP remained in the presence of 3.0 mol L−1 NaCl after 7 days, but its Km and Vmax were only mildly influenced by the presence of 3.0 mol L−1 NaCl, indicating its outstanding salt tolerance. Furthermore, AP was more stable than non‐salt‐tolerant protease at high salinity. The salt‐tolerant mechanisms of AP could be due to more salt bridges, higher proportion of ordered secondary structures and stronger hydrophobic amino acid residues in the interior. CONCLUSIONS: The above results are vital for maintaining, activating and/or modulating the activity of AP in high‐salt environments. They would also provide theoretical guidance for the modification of AP and the engineering of A. oryzae 3.042 so as to secrete more AP. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: To evaluate the feasibility of high‐temperature solid‐state fermentation (SSF) using soybean meal (SBM) during the non‐sterile process, Bacillus stearothermophilus was employed to assess the nutritional quality and bioactivity of SBM after fermentation. RESULTS: The fermented SBM (FSBM) without autoclaving showed significant improvements in nutritional quality and bioactivity. The contents of peptides and crude and soluble proteins increased by 131.21%, 5.3% and 15.52%, respectively. Meanwhile, DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) scavenging ability, reducing ability and hydroxyl free radical‐scavenging activity rose by 57.07%, 238.92% and 368.26%, respectively. The inhibitory activity of angiotensin I‐converting enzyme increased from 1.43 ± 0.83% to 26.89 ± 1.03%, while the trypsin inhibitor activity decreased by 74.05%. The contents of neutral and alkaline proteases and the growth of microorganisms in FSBM without autoclaving were higher and better than in steam‐treated FSBM. After steam treatment, the water‐holding capacity of SBM decreased, and a high crosslink density was observed on the surface of SBM particles. CONCLUSIONS: It is feasible to ferment SBM by high‐temperature SSF using B. stearothermophilus under non‐sterile conditions. Adverse effects of SSF using sterile SBM might be owing to the low water‐holding capacity caused by autoclaving. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Pulsed light (PL) is a new potential technology to degrade aflatoxin. The objective of this study was to investigate the degradation characters of aflatoxin B1 (AFB1) and B2 (AFB2) treated under PL irradiation. A kinetic degradation study of AFB1 and AFB2 in solid medium was performed under PL irradiation at different initial concentrations of AFB1 (229.9, 30.7 and 17.8 μg kg−1) and AFB2 (248.2, 32.2 and 19.5 μg kg−1) and irradiation intensities (2.86, 1.60 and 0.93 W cm−2) of PL. A second‐order reaction model was applied to describe degradation of AFB1 and AFB2. RESULTS: The results showed that the degradation of AFB1 and AFB2 followed the second‐order reaction kinetic model well (R2 > 0.97). The degradation rate was proportional to the intensities of PL irradiation and the initial concentrations of aflatoxins. CONCLUSION: It is concluded that the degradation of AFB1 and AFB2 with the use of PL could be accurately described using the second‐order reaction kinetic model. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Background and objectives: Bioactive peptides are expected to be ingested orally; it is important to study the effect of simulated gastrointestinal (GI) digestion on the stability and antioxidant activity of these peptides. Findings: After simulated GI digestion, degree of hydrolysis of corn protein hydrolysates (CPH) significantly increased from 22.7% to 39.4% while 77.5% peptides were still retained. Compared to the undigested CPH, the final CPH digests exhibited excellent antioxidant activity, including 1,1‐diphenyl‐2‐picrylhydrazyl radical 2,2‐diphenyl‐1‐(2,4,6‐trinitrophenyl) hydrazyl radical scavenging activity (12.9% increase), hydroxyl radical scavenging activity (4.1% increase), and reducing power (50.9% increase), but lower inhibition rate of linoleic acid peroxidation (41.5% decrease). The free amino acids including Pro, Asp, and Glu maintained at a low proportion during the entire course of digestion. Two GI‐resistant antioxidant peptides (Tyr‐Pro‐Gln, 406.45 Da; Ala‐Tyr‐Leu, 365.43 Da) were purified with multistep chromatography and identified by UPLC‐ESI‐MS. Conclusions: The CPH digests exhibited excellent antioxidant activity after simulated GI digestion. The results suggested that CPH obtained by alcalase digestion are potential functional foods or nutraceuticals due to their content of bioactive peptides. Significance and novelty: Some peptides containing Pro, Asp, and Glu had a strong ability to resist digestion. Two novel antioxidant peptides have been purified and identified from the CPH digests. [ABSTRACT FROM AUTHOR]

Abstract: This research aimed at improving the protein extraction process from sunflower meal using the Box‐Behnken design to get the optimal ultrasonic extraction conditions, based on yield of protein and consumed energy. The optimal extraction points were observed at power density (220 W/L), temperature (45 °C) and extraction time (15 min). Under optimum UAE conditions, the measured yield of protein and energy consumed values were 54.26% and 0.13 kW hr, respectively. The observed values for these responses were found to be comparable to the predicted values created by the mathematical models. Functional and physicochemical characteristics of protein isolate were estimated at the optimal points. The protein content, particle size, bulk density and water and oil holding capacities were 934.92 g/kgd.b, 627.6 nm, 0.372 g/mL, 0.985 gwater/gprotein and 2.06 goil/gprotein, respectively. The highest solubility, emulsifying activity (EA) and emulsion stability (ES) were 74.59, 52.45, and 50.45% respectively and were obtained at pH 9.0. Practical applications: This study provides significant information on ultrasound energy consumption, yield of protein, physicochemical characteristics and functional properties of the sunflower meal protein isolate to the food systems. Additionally, sunflower protein isolate yielded by dual‐frequency ultrasound is recommended for use in food formulations including salad dressing and meat products. [ABSTRACT FROM AUTHOR]

Abstract: Low‐cost bagasse and microcrystalline cellulose were used as the raw materials to prepare solid acid catalysts via incomplete carbonization and sulphonation. The solid acid synthesized from microcrystalline cellulose (C‐SO3H) exhibited better catalytic performance than that synthesized from bagasse. C‐SO3H was characterized by various techniques to study the reaction conditions of the catalytic transformation from glucose and fructose to 5‐hydroxymethylfurfural (5‐HMF). The conversion of glucose was 73.29 ± 0.74 %, and the conversion of fructose reached a maximum of 98.85 ± 0.01 %. The selectivity and yield of 5‐HMF reached maxima of 65.04 ± 0.28 % and 64.29 ± 0.27 %, respectively. Using C‐SO3H as the catalyst, the conversion of glucose followed second‐order kinetics at various temperatures, while the conversion of fructose followed first‐order kinetics. The activation energies of the glucose and fructose transformations were 73.75 and 51.87 kJ · mol−1, respectively. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Ultrasound pretreatment could improve the angiotensin‐I converting enzyme (ACE) inhibitory activity of hydrolysates of wheat gluten (WG). The working mode of ultrasound has an important effect on the enzymatic hydrolysis of protein. RESULTS: The results showed that the optimum working mode of ultrasound was alternate dual‐frequency mode (20/35 kHz), substrate concentration was 30 g L−1, initial temperature of the suspension was 30 °C, ultrasound pretreatment time was 10 min and power density was 150 W L−1. Under optimised conditions, ACE inhibitory activity of WG hydrolysates reached to its maximum value in advance. The surface hydrophobicity (H0) of WG and the content of small peptides at the beginning of the enzymolysis were improved by the ultrasound pretreatment. The structure of WG was destroyed by the ultrasound pretreatment. The enzymatic residue of ultrasound pretreated WG were damaged greater than control. CONCLUSION: It was concluded that alternate dual‐frequency ultrasound pretreatment improved the ACE inhibitory activity. Ultrasonic pretreatment may loosen the tissue of WG aggregate, and help the enzyme alcalase to attack the interior of WG aggregate easily, which resulted in the release of low molecular weight peptides from WG aggregate. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Frying is one of the methods of processing foods, which imparts flavour, taste, colour and crispness in the fried foods. In spite of an increase in the demand for fried foods by consumers all over the world, the danger posed by consuming too much fat is still a challenge. Many researchers have put forward many ideas on how to reduce the oil uptake and improve the nutritional and organoleptic qualities of foods during frying. Several pretreatment techniques applied to food materials prior to frying have been investigated by researchers in a bid to reduce the oil uptake and improve the quality parameters of fried foods. Therefore, this review focuses on the various pretreatment methods and the recent novel methods like ultrasound, infrared, superheated steam drying, microwave technique and pulsed electric field applied to foods prior to frying and its effects on the qualities of fried foods. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

We evaluated the effect of sequential dual-frequency ultrasound ( SDFU) pretreatments on rapeseed protein enzymolysis, using alcalase as a model enzyme. Hydrolysed protein concentrations, enzymolysis kinetics and thermodynamic parameters were investigated. The results showed that the hydrolysed rapeseed protein concentration following SDFU pretreatments was higher compared to that of the control for up to 75 min of enzymolysis at various substrate concentrations of 5-25 g L−1; both control and SDFU pretreatment groups showed first-order reaction kinetics. Compared to the control, the Michaelis-Menten constant ( KM) value decreased remarkably by 17.61%, while an increase in the binding frequency between enzyme and substrate ( KA) by 10.47% was observed. The thermodynamic parameters, enthalpy, entropy and activation energy were reduced in the SDFU pretreatment group compared to the control by 31.78%, 18.0% and 29.56%, respectively. SDFU pretreatment showed little effect on Gibbs free energy at the various temperatures studied. [ABSTRACT FROM AUTHOR]

The inactivation mechanism of PMF on Listeria grayi ( L. grayi) was investigated through the analysis of biological effects as well as the monitoring of morphology, membrane permeability and intracellular proteins of cells. Under the optimal inactivation conditions of PMF (2.5 T and 25 pulses), the analysis of transmission electron microscopy ( TEM) and laser scanning confocal microscopy ( LSCM) showed that PMF-treated cells membranes were damaged, resulting in the increase in intracellular Ca2+ fluorescence intensities. A significant ( P < 0.01) negative correlation between intracellular Ca2+ fluorescence intensities and the amount of colonies was found. Proteomic analysis showed that the mode-of-action of cells outer membrane, the stability of intracellular proteins and the metabolism-related proteins might be affected by PMF. Kyoto Encyclopedia of Genes and Genomes ( KEGG) pathway analysis revealed that PMF treatment could affect the nitrogen, organic and energy metabolisms of L. grayi, inducing the death of cells finally. [ABSTRACT FROM AUTHOR]

BACKGROUND Collagen hydrolysates ( CHs) have been demonstrated to have positive effects on skin photoaging by topical application or oral ingestion. However, there has been little research on their influence on skin chronological aging. In this study, 9-month-old female ICR mice were given normal AIN-93M diets containing CHs (2.5, 5 and 10% w/w) from Nile tilapia scale. RESULTS After 6 months, the collagen content and antioxidant enzyme (superoxide dismutase and glutathione peroxidase) activities increased significantly ( P < 0.05), while the survival rate, viscera indices and contents of moisture, fat and non-collagenous protein in skin did not change ( P > 0.05). The color, luster and quantity of hair were obviously ameliorated. Moreover, the structure of epidermis and dermis, the density and distribution of collagen fibers and the ratio of type I to type III collagen were improved in a dose-dependent manner as shown by histochemical staining. CONCLUSION Oral ingestion of CHs increased the collagen content and antioxidant enzyme activities and improved the appearance and structure of skin. These results suggest the potential of CHs as an anti-skin-aging ingredient in nutraceuticals or functional foods. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The moisture and solute diffusivities, texture and colour of sweet potato pretreated in distilled water with ultrasound ( UD), osmotic dehydration without ultrasound ( OD) and osmotic dehydration with ultrasound ( UOD) were investigated to determine the effects of ultrasound on osmodehydrated sweet potato. The moisture and solute diffusivities of all the pretreatments ranged from 2.89 to 4.95 × 10−10 and 1.17 to 1.67 × 10−10 m2 s−1, respectively. The moisture diffusivity of samples treated in UOD was significantly ( P < 0.05) higher than that of OD and UD by 30.82% and 41.62%, respectively. Compared to the fresh sample, the firmness of samples treated in OD and UOD was reduced by 83.53% and 92.47%, respectively. UD increased the brightness (L*) and reduced the redness (a*) of sweet potato, while UOD enhanced the yellowness (b*) and chroma (C*) of sweet potato. The sweet potato samples treated in UOD had the highest total colour difference (Δ E). [ABSTRACT FROM AUTHOR]

In this study, Counter-current ultrasound-assisted alkali was employed to extract rice dreg protein (RDP) from rice dreg flour (RDF). The results indicated that extraction yield of RDP reached a maximum value at 0.08 mol/L alkali concentrate. It was only 43.20% in absence of ultrasound, whereas it reached up to 88.44% under ultrasonic condition. Amino acid composition, scanning electron microscopy, atomic force microscopy and fourier transform infrared spectra were used to determine amino acid composition, morphology, aggregates and microstructure of RDP. Ultrasound treatment could result in improving of hydrophobic amino acids content and changing of RDF and RDP microstructure, showing enhancement in the porosity of RDF particle, variation of RDP particle size. Thus, the acceleration of protein extraction was related to the changes of RDF and RDP microstructure caused by ultrasound. Counter-current ultrasound-assisted alkali extraction, as a modified method, was proved to be helpful in industrial manufacture of RDP from RDF. Practical Applications Low-frequency high-intensity ultrasound has been used in many aspects in laboratory, such as extraction of components, pretreatment. Counter-current ultrasound-assisted extraction was proved to be helpful in industrial manufacture of protein because it can dramatically improve extraction rate of rice dreg protein, and Counter-current ultrasound method can achieve continuous production of industrialization. [ABSTRACT FROM AUTHOR]

To decrease NaOH consumption in the process of removal of free gossypol ( FG) in cottonseed meal ( CSM), ultrasound was applied in the detoxification experiments. The effects of various factors on the removal efficiency were studied by single-factor experiments, and detoxification conditions were optimized by response surface methodology. The result indicated that removal ratio of FG increased with increasing NaOH concentration (0.5-1.5 g/L), ultrasonic power (0-1,000 W), treatment time (0-20 min) and pulse duration (1-5 s); however, further increase of pulse duration (6-7 s) resulted in a decrease. The removal ratio even reached 95.82 ± 2.75% ( n = 3) under optimal conditions of NaOH concentration (1.5 g/L), sonication time (16 min) and pulse duration (5 s). The Box-Behnken design generated satisfactory mathematical models that accurately explained the behavior of the system, allowing one to predict the removal efficiency of FG in CSM. Practical Applications Cottonseed meal ( CSM) has long been considered as a good source of protein for animals. However, a polyphenolic compound, particularly free gossypol ( FG), that existed in CSM limits its application as feeding stuffs. The findings in the present study demonstrated the beneficial effects of ultrasound on the removal efficiency of FG in the detoxification experiments. The application of ultrasound can not only significantly decrease the NaOH consumption but also improve the detoxification effect compared with conventional detoxification method using only NaOH solution. Therefore, this study exhibits a new detoxification technique and is of practical significance. [ABSTRACT FROM AUTHOR]

BACKGROUND Due to the disadvantages of traditional enzymolysis, pretreatments are crucial to enhance protein enzymolysis. Enzymolysis kinetics and thermodynamics, amino acids composition, molecular weight distribution, fluorescence spectroscopy and antioxidant activity of thermal ( HT) and single frequency counter-current ultrasound ( SCFU) pretreated sodium caseinate ( NaCas) were studied. RESULTS Enzymolysis of untreated NaCas (control) improved significantly ( P < 0.05) by SFCU and followed by HT. Values of the Michaelis-Menten constant ( KM) of SFCU and HT were 0.0212 and 0.0250, respectively. HT and SFCU increased ( P < 0.05) the reaction rate constant ( k) by 38.64 and 90.91%, respectively at 298 K. k values decreased with increasing temperature. The initial activation energy (46.39 kJ mol−1) reduced ( P < 0.05) by HT (39.66 kJ mol−1) and further by SFCU (33.42 kJ mol−1). SFCU-pretreated NaCas hydrolysates had the highest contents of hydrophobic, aromatic, positively and negatively charged amino acids. Medium-sized peptides (5000-1000 Da) are higher in SFCU (78.11%) than HT and the control. SFCU induced molecular unfolding of NaCas proteins. Accordingly, SFCU-pretreated NaCas hydrolysate exhibited the highest scavenging activity on DPPH and hydroxyl radicals, reducing power, and iron chelating ability. CONCLUSION SFCU pretreatment would be a useful tool for production of bioactive peptides from NaCas hydrolysate. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]