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To comprehend the decline in post-production of pre-cooked flour products, this study examined the impact of curdlan on structural properties and aggregation behavior of pre-cooked wheat gluten (PCWG) during freeze-thaw (FT) cycling. The results revealed that as the number of FT cycles increased, the gel fracture strength and distance of PCWG decreased, while the extractable protein increased. The extent of PCWG deterioration increased with more FT cycles. However, the addition of curdlan mitigated these changes, with a notable effect seen at 0.5% (w/w) addition. Microstructural analysis indicated curdlan's role in enhancing PCWG homogeneity. Secondary structure analysis demonstrated a transition in PCWG's secondary structure from β-sheets to random coils and β-turns as the FT cycle increased. Notably, 0.5% curdlan significantly inhibited this transition. The chemical interaction results suggested that curdlan's impact on changing PCWG's structure was linked to shifts in free sulfhydryl groups, disulfide bonds, and hydrophobic interactions. As the FT cycle increased, the free sulfhydryl content in PCWG rose, while the disulfide bond content decreased. Hydrogen bonding decreased, and hydrophobic interactions increased. These trends were effectively countered by low doses of curdlan (especially 0.5%). However, excess curdlan (0.9%) exacerbated the disruption of PCWG's protein network structure during FT cycling, potentially through steric hindrance effects or hydrogen bonding. In conclusion, this study provides theoretical support for enhancing the quality of PCWG and employing curdlan in frozen flour products. [Display omitted] • The degradation of WG gel properties increased with successive freeze-thaw cycles. • Hydrophobic interactions were strengthened through freeze-thaw cycles. • Phase transitions in the thaw phase rearranged the WG structure. • Excess curdlan could affect gluten aggregation behavior through hydrogen bonding. [ABSTRACT FROM AUTHOR]

Oral textural perception is a complex process that involves tooth fragmentation and salivary lubrication. To reveal the associated in-mouth mechanisms, three stages of testing were conducted in this study, including the initial cooked rice stage (0%), the deformation stage (50%), and the swallowing stage (100%). The total chewing time of high/low heating rate rice (HHRR/LHRR) was 25.46 ± 6.22 s and 22.11 ± 5.02 s, respectively. However, no significant difference in the chewing frequency. The salivary flow rate in LHRR (28.18 mg/s) was higher than in HHRR (22.57 mg/s). At the 0% stage, LHRR had a higher moisture content and expansion rate. At the 50% stage, rice boluses exhibited a significant difference in texture properties measured by instrumental analysis. At the 100% stage, two rice boluses reached similar hardness and chewiness, with smaller particles for swallowing. These results indicated that the deformation stage (50%) played a critical role in differentiating the textural perception. The initial properties of cooked rice influenced chewing manner and salivary secretion, contributing to differences in the reduction of particle size, water migration, and the inner microstructure evolution of corresponding rice boluses. These differences will feed back as different texture perceptions during oral processing. [ABSTRACT FROM AUTHOR]

Changes in the physicochemical properties of wheat gluten (WG) during cooking are mainly dependent on its intramolecular and intermolecular interactions when subjected to high-temperature treatment. In this study, the effects and mechanisms of cooking on the aggregation behavior of WG were investigated. Results showed that an increase in cooking time led to an initial increase and subsequent decrease in WG viscoelasticity, with optimal viscoelastic properties observed at 5 min. As cooking proceeded, covalent cross-linking of WG deepened and the contribution of hydrogen bonds to maintaining WG structure weakened, while the contribution of hydrophobic interactions strengthened. Cooking increased the proportion of gauche-gauche-gauche in the disulfide (SS) bridge conformation and decreased the homogeneity of the WG network. The unfolding of gluten molecules caused by hydrogen bonds breaking and intermolecular cross-linking through hydrophobic interactions and SS formation jointly contributing to the rheological properties of WG. Notably, glutenin (Glu) exhibited more similar physicochemical changes to WG during cooking than gliadin (Gli). Glu was more sensitive to cooking than Gli and formed dense, continuous aggregates prior to Gli. Cross-links formed by Glu occupied the majority of three-dimensional network of WG, while Gli was involved only in the form of branched chains. This may explain why Glu dominates the physicochemical changes of WG during cooking. This study contributes to a deeper understanding of the thermal denaturation mechanism of WG and provides new insights into the processing of flour-based foods. [Display omitted] • Cooking had a dual effect on the viscoelasticity of wheat gluten. • Gliadin underwent different physicochemical changes than glutenin during cooking. • Glutenin was more sensitive to cooking than gliadin. • Gliadin limited the physicochemical changes of glutenin during cooking. [ABSTRACT FROM AUTHOR]

Graphene-based materials are subject to photochemical process when releasing into the environment. In this study, three kinds of graphene-based materials, graphene oxide (GO), soot and graphene (G), were selected to investigate their photoinduced changes of properties and the corresponding reasons. GO underwent reduction-dominant disproportionation, resulting in less oxygen-containing function groups (OFGs) and higher percentage of carbon-centered persistent free radicals (PFRs). Different kinds of soot particles all experienced self-oxidation, expressed as more OFGs, defects and carbon-centered PFRs adjacent to oxygen atom. Oxidative potential (OP) tested by DTT activity showed a decrease in GO but an increase in soot, agreeing with their changes of physicochemical properties. G remained almost unchanged in terms of both physicochemical properties and OP. Photoactivity measured by the productivity of photogenerated electron-hole pair and reactive oxygen species was responsible for above changes and correlated with the inner carbonaceous core. Carbonaceous core can behave as a photocatalyst to initiate photocatalytic reaction, and its oxidation degree (O/C ratio and OFGs content) determines the photoactivity. The relationship among the physicochemical properties, OP, photoactivity and inner microstructure found in this paper will help for better understanding of the environmental behavior and health effects of graphene-based materials. [Display omitted] • Visible light irradiation induces reduction on GO but oxidation on soot. • O/C ratio and OFGs of carbonaceous core are key factors influencing photoactivity. • Photoactivity is responsible for the physicochemical properties and OP changes. [ABSTRACT FROM AUTHOR]

Extensive studies have been conducted on the environmental degradation of multiwall carbon nanotubes (MWCNTs), but primarily focused on the extent and rate of MWCNTs mineralization. Few studies have explored possible structural changes that may occur to MWCNTs during natural or engineered processes. We systematically examined MWCNTs in oxidative coupling reactions in the presence of a common contaminant tetrabromobisphenol A (TBBPA). MWCNTs was modified by the radicals of TBBPA resulting from peroxidase-mediated coupling reaction. Interactions between TBBPA radicals and MWCNTs were definitely confirmed by analyzing the characteristic mass spectrometry response of bromine in TBBPA and the structures of MWCNTs. After reaction with TBBPA radicals for 60 min, the content of bromine contained in MWCNTs was 6.84(±0.12)%, a quantity equivalent to a 501.65(±2.19) mg loading of TBBPA per gram MWCNTs. Modified MWCNTs had better stability and smaller sizes than that of MWCNTs and TBBPA-adsorbed MWCNTs. Assessment using zebrafish embryos revealed that the modified MWCNTs passed through the chorion and entered the embryo inducing acute toxicity, while the MWCNTs/TBBPA-adsorbed MWCNTs was trapped by chorion. These findings indicated that MWCNTs was modified in peroxidase-mediated coupling reactions, and suggested that such modifications may have an influence on the ecological risks of MWCNTs. [ABSTRACT FROM AUTHOR]

We investigated the alterations on bioactive compounds after treatments with ozonated water during the storage of organically and conventionally cultivated mangoes, cv. Palmer. Mangoes were stored in a cold chamber (14 ± 2 °C) for 15 d and evaluated after the harvest and sanitization treatments (chlorine and ozonated water—10 and 20 min) at 7 and 15 d. To simulate the market, after 7 d, mangoes were removed from cold storage and kept at room temperature (27 ± 2 °C) to be analyzed following 4 (7 + 4) and 8 (7 + 8) d at room temperature. The conventionally mango showed higher firmness, regardless of the sanitization system used. Ozonated water did not alter the levels of β-carotene, ascorbic acid, dehydroascorbic acid and phenol in organically or conventionally cultivated mangoes during storage, but when the mangoes, cv. Palmer were transferred to room temperature, the β-carotene level increased. Organically cultivated mangoes showed higher levels of antioxidant activity. Ozonated water can be used as an alternative to chlorine sanitizer without causing damage to mango, cv. Palmer fruit or inducing a decrease in the various compounds and the treatment using ozonated water was efficient for maintaining fruit without microorganisms, preventing the reduction of quality and avoiding the generation of organic waste. [ABSTRACT FROM AUTHOR]

This study investigates the effects of lime-saturated water and water–CO 2 cyclic recuring on strength recovery of thermally damaged high-performance concretes (HPC). The HPC samples were subjected to elevated temperatures up to 1000 °C in 200 °C increments and underwent recuring. Phase assemblage and distribution, microstructure evolution, and pore structure of the HPC samples were identified. According to the results, recovered compressive strength of the HPC samples with low silica content can surpass their original strength after 600 and 800 °C exposure and recuring. In contrast, HPC with high silica content is unfavorable for strength recovery at temperatures above 800 °C because the low-calcium phases formed have low reactivity. After 1000 °C exposure, only water–CO 2 cyclic recuring coalesces the disintegrated microstructure and recovers the compressive strength. Strength recovery primarily depends on healing the microcracks and large pores rather than the coarsened cement paste. [ABSTRACT FROM AUTHOR]

Oxidation is an important factor for denaturing of whey protein isolate (WPI) during food processing. We studied the effects of chemical oxidation on physicochemical and structural changes along with in vitro digestibility of WPI in this work. Evaluation of physicochemical changes showed that carbonyl level and dityrosine content increased, whereas total and free thiol group levels decreased for oxidized WPI samples. For the structural changes, protein aggregation was measured by surface hydrophobicity, turbidity, and particle diameter, which was increased for oxidized WPI samples. The increase of the secondary structure β-sheets and antiparallel β-sheet also supported the aggregation of oxidized WPI. A direct quantitative relationship between physicochemical and structural changes and protein digestibility indicated that oxidation-related damage restricts the susceptibility of WPI to proteases. In conclusion, WPI had high susceptibility to oxidative stress, and both physicochemical and structural changes caused by severe oxidative stress could decrease the rate of in vitro digestibility of WPI. [ABSTRACT FROM AUTHOR]

Nutraceutical quality of fruits can be influenced by the stage of ripening. The present project objective was to evaluate physicochemical changes of mango cv. Keitt that included total soluble solids (TSS), titratable acidity (TA), firmness and color, concentration of total phenolics (TPC), ascorbic acid (AA), antioxidant capacity (ORAC value), carotenoids, and total dietary fiber (TDF) at 6 postharvest ripening-stages (RS1–6). Results indicated a decrease in firmness from 62 to 0.69 N, while TSS increased from 9 to 17% and TA decreased. Mango TPC increased by 54% at RS2 and at RS3 returned to the original levels. It was found that AA increased by 133% at RS2 and at RS6 showed the lowest value. A correlation between TPC and ORAC value ( R 2 = 0.88) was found. Regarding carotenoids content, there were no significant differences from RS1 to RS4, but at RS6 carotenoids increased 49% in contrast with RS1. Furthermore, TDF increased at RS2 and remained with slightly differences from RS2 to RS5. At RS6, TDF diminished 13% as compared to RS1. Results permitted the visualization of optimum ripening-stages (RS2 and RS6) that contained the highest concentration of specific bio-active compounds in order to produce high-quality products and improve health-benefits. [ABSTRACT FROM AUTHOR]

This study aimed to characterize goji berry (Lycium barbarum L.) fruit across different stages of maturity and ripening in terms of color, firmness, phytochemicals, and metabolic behavior. According to the producer's indication, the goji berry fruit was divided into six classes: early immature (green) to fully ripe (full red). Several maturity indexes were monitored for all classes, including dimension, weight, color (hue angle), firmness, soluble solid content (SSC), pH, and titratable acidity (TA). Fruit dimensions on the plant increased from class 1–6 starting from 8.08 mm in length, 3.95 mm in width, and 0.07 g of weight, to 16.26 mm, 13.15 mm, and 1.29 g, respectively. Soluble solids increased from 2.68% to 23.5%; the highest value observed even after storage. Goji berries showed a rise in respiration rate and ethylene production in the early stages of development. Goji berry stored for 8 d at 25 °C showed significant changes in color, soluble solids, TA, respiration, and ethylene production. Soluble solids from class 5 stabilized around the maximum value of 23% after eight days of storage at room temperature. Their high nutritional value was confirmed by the content of vitamin C, which is comparable to that of citrus fruit. It reached the maximum value of 0.52 g/kg at full ripening, whereas the phenolic content decreased during ripening to values of 2.15 g/kg. The latest contributed considerably to the high antioxidant content of the berries. Results obtained in this study contribute to better understand the postharvest behavior of goji fruits enabling a clearer definition of quality attributes during ripening and, in turn, improving postharvest handling and distribution of goji berries as fresh fruit. • Goji berries are classified into six developmental stages. • Goji berry fruit showed climacteric behavior in the early stages of development. • Vitamin C content increased over ripening, while phenolic content decreased. • We recommend harvesting at stage 5 and not earlier than stage 4. • This information is crucial for postharvest handling and consumption of goji fruit. [ABSTRACT FROM AUTHOR]

Abstract: Impact of zinc sulphate (ZnSO4) and zinc chloride (ZnCl2) on heat-induced aggregation of natural actomyosin (NAM) extracted from yellow stripe trevally (Selaroides leptolepis) was investigated. In the presence of ZnSO4 or ZnCl2, the transition temperature (T max) of myosin shifted from 47.83±0.30°C to 46.05±0.36 and 46.49±0.49°C, with the coincidental decreases in ΔH from 1.07±0.03J/g to 0.63±0.02 and 0.67±0.04J/g, respectively (P <0.05). Additionally, Ca2+–ATPase activity of NAM decreased with increasing the concentrations of ZnSO4 or ZnCl2 during heating up to 40°C. During heating from 20 to 75°C, higher turbidity, surface hydrophobicity and disulphide bond formation were obtained in NAM added with ZnSO4 or ZnCl2 at temperatures ranging from 40 to 75°C, compared with the control. Nevertheless, a higher aggregation was found in NAM added with ZnSO4, compared with ZnCl2. Zeta potential (ζ) analysis suggested that the surface of NAM added with ZnSO4 became less negatively charged, compared with that of ZnCl2 counterpart. Transmission electron microscopy showed that the structure of NAM was highly interconnected, finer and denser when zinc salts, especially ZnSO4 were incorporated. Therefore, ZnSO4 could be used to induce aggregation of fish muscle proteins, thereby improving gelling property of fish mince or surimi. [Copyright &y& Elsevier]

Abstract: Changes in natural actomyosin (NAM) from Pacific white shrimp (Litopenaeus vannamei) treated with sodium bicarbonate (NaHCO3) at different concentrations (0–1M) in the absence or the presence of 2.5% NaCl were studied. Turbidity of NAM solutions decreased with coincidental increase in solubility as the concentration of NaHCO3 increased. Surface hydrophobicity (SoANS) and total sulfhydryl content of NAM also increased when NaHCO3 concentration increased. Greater decreases in Ca2+- and Mg2+-ATPase activity were found in all NAM as NaHCO3 concentration increased, suggesting the denaturation of myosin head and the dissociation of actomyosin complex. The zeta potential (ζ) analysis suggested that the surface of NAM became more negatively charged (−12.12 to −26.98) as NaHCO3 concentration increased. Those changes were more intense in the presence of 2.5% NaCl. Transmission electron microscopy showed that the structure of actomyosin was more dissociated and lost the filamental structure when NaHCO3 at higher levels was used. [Copyright &y& Elsevier]

Abstract: The effect of wet and dry saltings on the physicochemical changes of tilapia (Oreochromis niloticus) muscle was investigated. Dry salting resulted in the higher rate of salt uptake into tilapia muscle facilitating the faster decrease in A w (p <0.05). The pH of both dry and wet salted fish muscles tended to decrease throughout the salting time and the lower pH was found in dry salted fish (p <0.05). The increase in the protein content in the salting medium was found during wet salted tilapia production (p <0.05). The TCA-soluble peptide content tended to decrease with increasing the salting time in both salting methods (p <0.05), suggesting a leaching effect of the salting medium or the exudative loss occurred in salted tilapia. Wet salting caused the greater formation of metmyoglobin in tilapia muscle when compared to dry salting at all time points (p <0.05) and the content of metmyoglobin increased as salting time increased in both salting methods (p <0.05). A lowered metmyoglobin with a lowered redness index of dry salted tilapia muscle was found, indicating the continuous oxidation of metmyoglobin to other hypervalent derivatives and hence the discolouration of salted tilapia. Lipid hydrolysis and oxidation of tilapia meat occurred with varying degrees in both salting methods and these changes depended on salting time. Dry salting resulted in a higher oxidation of tilapia muscle lipid as indicated by the higher PV and TBARS throughout the salting period when compared with that of wet salting (p <0.05). In conclusion, the physicochemical changes of tilapia muscle during salting are governed by the salting method and the salting time applied. [Copyright &y& Elsevier]

Abstract: Physicochemical changes, such as peel and flesh colours, total anthocyanin content, browning index, firmness, total soluble solid (TSS), titratable acidity (TA), sugar acid ratio (TSS/TA), antioxidant capacity, total phenolic content and ascorbic acid content, in fresh-cut Taaptimjan wax apple fruit stored at 4±2°C and 12±2°C for 7days were investigated. The skin of fresh-cut fruit stored at 4±2°C showed higher a ∗ value, chroma and total anthocyanin content and lower hue angle than those stored at 12±2°C. Lightness (L ∗ value) and whiteness index of the fresh-cut fruit flesh stored at 12±2°C showed significantly lower than those stored at 4±2°C which related to an significant increase in browning index. Firmness, total soluble solid, titratable acidity and sugar acid ratio did not significant changes during storage. Antioxidant capacity and total phenolic content increased throughout storage. Ascorbic acid content of the fresh-cut fruit stored at 4±2°C remained constant throughout storage whilst ascorbic content at 12±2°C decreased and was lower than that at 4±2°C. At 4±2°C antioxidant capacity and ascorbic acid content were higher than that stored at 12±2°C whilst there was no significant difference in total phenolic content. In conclusion, the reduction of whiteness index and the increase in browning index of fresh-cut wax apple flesh were the key factors affecting its quality and storage at 4±2°C could reduce the change in the flesh colour and maintained the peel colour and nutritional values of fresh-cut wax apple fruit during storage. [Copyright &y& Elsevier]

Abstract: Mechanochemical-assisted extraction (MCAE) technique was developed for the efficient extraction of rutin from Hibiscus mutabilis L. This process was carried out via mechanochemical pretreatment in AGO-2 high intensity planetary mill. Highest yield of rutin was obtained by grinding H. mutabilis with Na2CO3 (15.0wt.%) and Na2B4O7·10H2O (1.5wt.%) for 4min, extraction temperature at 25°C, total extraction time of 15min (two cycles of 10min and 5min), acidification pH 5.0 and solvent/material ratio of 25mL/g. Scanning electron microscopy, X-ray powder diffraction and diffuse-reflectance UV–Vis spectrum were applied to identify the physicochemical property changes. These changes mainly included the enhanced diffusivity and water solubility of rutin resulting from the breakage of cell walls and its transformation into a water-soluble salt form by the mechanochemical pretreatment. Compared with heat reflux and superfine grinding extraction, MCAE showed the advantages of efficiency, no organic solvent consumption and much lower extraction temperature. Industrial relevance: In this study, mechanochemical-assisted extraction of rutin from H. mutabilis was developed and the physicochemical changes in this process were supervised. Owing to its great potential to transform the target compounds into water-soluble forms, MCAE provided a good alternative for efficient aqueous extraction of bioactive compounds, especially some poorly water-soluble natural products. [Copyright &y& Elsevier]

Abstract: The mechanisms of interactions in whey protein concentrate (WPC) texturized by reactive supercritical fluid extrusion and pH modifications were evaluated in terms of protein solubility in different extraction buffers, electrophoresis, free sulfhydryl (SH) groups, and apparent viscosity. The soluble protein content and free SH groups of the texturized WPC (tWPC) produced at pH 2.89 decreased by ∼20% and 16% relative to the unextruded control. It was completely soluble in the presence of urea and SDS, indicating the importance of non-covalent interactions in maintaining the structure of this product. Its dispersion (20% w/w) yielded a creamy texture with a particle size in the micron-range (mean diameter ∼5μm) and contributed ∼258 times higher viscosity compared to the unextruded control. The tWPC produced at pH 8.16 was soluble only in the presence of a reducing agent. It yielded a grainy texture with a high proportion of large particles due to an extensive aggregation via intermolecular disulfide formations. [Copyright &y& Elsevier]

• Induction physicochemical changes in particles prepared by prolonged high-energy wet ball milling. • Conversion the applied oleic acid surfactant into a thin amorphous carbon layer on magnetic nanoparticles. • Mechanochemically activation Fe atoms in the NdFeB powder in the environment of ball milling. • The decomposition and transformation of OA molecules by Fe atoms with active surfaces. • Using more fatty acids rich in carbon atoms in wet ball milling, increasing permittivity, and shielding absorption efficiency. Fabrication and improvement of electromagnetic interference (EMI) shielding products have recently been the subject of intense research. In the present study, the NdFeB magnetic powder was used in prolonged high-energy wet ball milling to synthesize and enhance properties of the magnetic filler of EMI shielding composites. The physicochemical changes induced in particles prepared by the process confirmed that the applied oleic acid surfactant was simply converted into a thin amorphous carbon layer on NdFeB nanoparticles. Increasing the amount of surfactant in the ball milling procedure caused a thicker layer of the carbonaceous blend to be formed on magnetic nanoparticles. We found that the thicker layer of the amorphous carbon covering the synthesized magnetic particles increased the real and imaginary dielectric permittivity of the resulting product about 15% and 95%, respectively. This also increased the shielding absorption efficiency (SE A) about 40% and the total shielding efficiency (SE T) about 30% at some frequencies. Furthermore, more carbonaceous surfactant in composite (II) improved impedance matching, leading to a decrease in reflection loss and an increase in microwave absorption of the composite. [ABSTRACT FROM AUTHOR]