Search

Summary: The in vitro effects of six hydrophilic colloids on bread flour properties, rheological properties, water distribution, microstructure, baking quality and starch digestibility were examined. The incorporation of xanthan gum (XG), hydroxypropyl methylcellulose (HPMC), apple pectin powder (APCT) and Curdlan gum (CDL) into rye dough was observed to enhance the gluten network and reduce the gelatinisation and ageing. The addition of APCT and CDL improved softness and ductility and resulted in more complete and orderly protein network of the rye dough than when XG, trehalose (THL) and CDL were added. The addition of THL and XG increased the specific volume, softened the texture of the rye bread and decreased the blood glucose index by approximately 5%. In conclusion, the addition of six common hydrophilic colloids may enhance the quality of bread, albeit with a reduction in the in vitro starch digestibility of rye bread. [ABSTRACT FROM AUTHOR]

Summary: Whole wheat bread is rich in nutrition, but its starch digestibility is unsatisfactory. Thus, how to reduce its digestibility has attracted much attention. This study investigated the effects of highland barley protein and β‐glucan on the pasting properties, and thermal properties of whole wheat flour to reveal the mechanism of highland barley protein and β‐glucan regulating the in vitro digestibility. The digestibility results showed that β‐glucan and protein could slow down starch digestion to some degree. The cross‐section structure determination results indicated that β‐glucan and protein decreased the porosity. The differential scanning calorimetry and thermogravimetric analysis results showed that β‐glucan and protein increased the onset of pasting, decreased the peak temperature and enthalpy of pasting and decreased the thermal stability. The Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy results revealed a blue‐shift in the ‐OH position of the bread added with protein and β‐glucan (from 995.59 to 996.07 cm−1), indicating that the hydrogen bonding might form intramolecularly. In this study, the addition of highland barley protein and β‐glucan was proved to be helpful in decreasing the in vitro digestibility and showed modification in the texture quality of bread, which might be suitable for diabetic patients. [ABSTRACT FROM AUTHOR]

Summary: Oat milk has received increasing attention because of its health benefits, however, the problems of easy sedimentation and deterioration of taste during storage are common problems faced by the industry. Enzymatic extrusion is a technology that combines high‐temperature, high‐pressure and high‐shear extrusion with enzymatic hydrolysis for rapid biological transformation of materials. To evaluate the feasibility of enzymatic extrusion to overcome these disadvantages, the effects of this technology on the physicochemical properties of oat flour and on the stability and sensory score of oat milk have been studied. The results showed that the water solubility index of the enzymatic extrusion sample (2‰ α‐amylase) increased by 37.64% (from 5.99% to 43.63%) and the reducing sugar content increased about 11 times (from 11.61 to 128.31 mg g−1) compared with original oat flour. The enzymatic extrusion samples were almost completely gelatinised and their viscosity and degree of order were significantly reduced. The rheological results indicated that the enzymatic extrusion samples exhibited greater viscous fluid characteristics. After enzymatic extrusion treatment, the stability of oat milk was significantly enhanced, sensory evaluation indicated a highest score of 7.29 on the 9‐point hedonic scale (2‰ α‐amylase). This study provides a new way to produce high‐quality oat milk. [ABSTRACT FROM AUTHOR]

Background: Whole wheat bread is high in nutritional value but poor in technological quality; therefore, research on how to improve its technological quality has attracted extensive attention. The effects of fermentation methods, including straight dough(STD), sourdough (SOD), sponge dough (SPD), and refrigerated SPD (RSD) methods, on the dough and bread quality of whole wheat bread were investigated, focusing on pasting properties, rheological properties, thermal properties, microstructure, basic quality, and starch digestibility. Results: The rapid viscosity analysis and rheological results demonstrated that SOD had the highest pasting temperature and the lowest viscosity, indicating an inhibition of starch pasting and partial protein hydrolysis, whereas the opposite trend presented by SPD and RSD indicated a greater starch hydration and a stronger gluten network. Thermal gravimetric analysis and differential scanning calorimetry results indicated reduced starch thermal degradation and increased starch pasting enthalpy in SOD and RSD. Scanning electron microscopy images revealed that the starch granules of SOD and RSD were tightly wrapped by a gluten network. SOD and RSD breads had the largest specific volume, the softest texture, and the lowest glycemic index. Conclusion: The effects of different fermentation methods on dough and bread structure can provide instructive information for future studies on their applications in whole wheat bread production. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Summary: Whole wheat bread is poor in quality, and it is necessary to use certain methods to improve bread texture and glycaemic index, such as adding exogenous protein. This study evaluated the effects of adding different proportions of gluten (focus on exogenous protein enrichment) on dough structure, bread quality, and starch digestibility, focusing on mixing properties, rheological properties, pasting properties, microstructure, basic quality, and starch digestibility. Dough microstructure results showed that gluten addition helped to form a more complete gluten network. The bread quality results showed that gluten‐enriched bread had larger specific volume, lower baking loss, and better textural quality. Starch digestibility results showed that gluten addition slowed down starch digestion to some extent. The experimental results indicated that 40% added gluten could produce bread samples with optimal quality. The subject systematically studied the effect of gluten enrichment on the quality of whole wheat bread, which is a guide to the application. [ABSTRACT FROM AUTHOR]

BACKGROUND: The poor gelling and emulsification properties of pea protein (PeaP) limit its application in gel‐based products. In this study, a strong hydrogel and a high internal phase emulsion (HPLE) gel of PeaP were constructed by covalent cross‐linking of transglutaminase (TGase) assisted by high‐intensity ultrasound. RESULTS: Ultrasound promoted the catalytic efficiency of TGase, with the gel‐point temperature dropping from 44 °C to 28 °C after 10 min of ultrasound. As the ultrasound time increased from 1 min to 10 min, the microstructure of the hydrogel also changed from an irregular macropore structure to a relatively homogeneous honeycomb structure. This was accompanied by an improvement in gel strength, water holding capacity, and ultimate stress. Ultrasound enhanced the binding of water to PeaP, but had little effect on the water‐locking ability of the network structure. Ultrasonication improved the self‐supporting ability of the HPIE gels. The oil droplets within the HPIE gels were closely aligned to form a hexagonal structure. The PeaP layer was further cross‐linked by TGase, strengthening the network structure. High internal phase emulsion gel displayed a higher gel strength, viscosity, and good self‐healing ability under 1 min ultrasound. Meanwhile, HPIE gel at 1 min of ultrasound could be printed with the highest clarity. CONCLUSION: This work provided some insights into improving the functional properties of PeaP, which is helpful for the design and development of PeaP‐based gel products. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

SUMMARY: In view that enzymatic extrusion can change the degradation degree of raw materials, this paper studied the regulation rules of four indexes of degradation degree of enzymatically extruded glutinous rice flour and the correlation between these indexes and the quality indexes of brewed Chinese rice wine. The results showed that at appropriate water content, dextrose equivalent (DE) and water solubility index (WSI) were linearly related to the enzyme content in extrusion with thermostable α‐amylase (TS‐αA) and mesophilic α‐amylase (MS‐αA), respectively. But water absorption index (WAI) was not significantly affected by enzyme content. The percentages of each degree of polymerisation (DP) (1–7) and that of the sum of the rest DPs called other DP were the fundamental reasons for different DE values, WSI, WAI and quality indexes of Chinese rice wine. DP1 was significantly positively correlated with alcohol degree, and negatively correlated with total acid. DP2–DP7 (except DP4) was significantly positively correlated with amino acid nitrogen. Besides, other DP was significantly positively correlated with total sugar and total acid. The percentages of DP1, DP2–DP7 and other DP could be respectively adjusted by changing enzyme content in extrusion with MS‐αA, MS‐αA/TS‐αA and TS‐αA to control the related quality indexes of Chinese rice wine. [ABSTRACT FROM AUTHOR]

Summary: To promote the industrial production of Chinese rice wine made by enzymatic extrudates, the first is to ensure the consistency of the raw material. That is, an evaluation standard of enzymatic extrudate should be set up. It was studied for the first time. By studying the changes of seven indexes of samples at different sites of extruder barrel and the die along the extrusion direction and making the correlation analysis to select the representative indexes. The results showed that the change trends of dextrose equivalent (DE), molecular weight distribution (MWD) and oligosaccharide composition (OC) were the same, and these indexes were more affected by mechanical force than by temperature. The ability of degradation of different zones was: conveying area < kneading area << exit of the die. There was little difference in extent of gelatinisation (GE) at the temperature where the enzyme activity was relatively high. Different from DE value, water solubility index (WSI) rose gradually. Surprisingly, DE was negatively correlated with GE, and positively correlated with oligosaccharides except DP1 and DP6, and had no significant correlation with water absorption index (WAI) and WSI. In conclusion, DE, WSI, DPD (especially DP6) could be used as a comprehensive evaluation index of enzymatic extrudates. [ABSTRACT FROM AUTHOR]

BACKGROUND: In order to supply adequate dietary protein for chronic kidney disease (CKD) patients while simultaneously controlling phosphorus intake, a novel method was developed for the preparation of low‐phosphorus egg yolk protein (LPYP) using alkaline protease auxiliary dephosphorization. In addition, the physicochemical properties of LPYP were studied. RESULTS: In comparison with raw egg yolk protein (RYP) and defatted egg yolk protein (DFYP), LPYP was found to exhibit differences in amino acid (AA) composition, protein secondary structure, surface hydrophobicity, solubility and emulsion stability. It was observed that dephosphorization improved the AA composition, soluble protein content and dissolution stability of egg yolk protein. In addition, phosphate groups were found to impose a critical influence on the emulsion stability and particle size distribution. The final phosphorus to protein mass ratio (P/Pro) of LPYP was 5.64, which met the requirements of a protein diet for CKD patients. The FAO/WHO mode closeness and stability coefficient were 0.958 and 98.62% respectively. CONCLUSION: LPYP can be effectively obtained by alkaline protease hydrolysis and subsequent alkali dephosphorization. The prepared LPYP can be considered to be a type of safe and suitable protein resource for CKD patients. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Summary: To enhance the rehydration and palatability characteristics of extruded noodles, a new type of instant noodles with a well‐developed porous structure was successfully created by cooperating medium temperature α‐amylase (MTA) with extrusion technique. To explain the formation reason of the porous structure, a detailed mechanism analysis was firstly carried out. It turned out that a portion of starch was degraded into water‐soluble dextrin during the enzymatic extrusion treatment. Besides, a slight restriction of the excessive MTA on the starch gelatinisation was demonstrated. The appearance of the well‐developed porous structure was attributed to the leaching of dextrin and loosely bound starch fragments. Therefore, the extruded noodles with 0.40‰ MTA concentration were recommended based on the results of cooking quality, textural characteristics and sensory evaluation. [ABSTRACT FROM AUTHOR]

RATIONALE 2,2'-Ditellurobis(2-deoxy-β-cyclodextrin) (2-TeCD) is one of the most well-known glutathione peroxidase (GPx) mimics. However, because the critical reaction intermediates had not previously been isolated or directly detected due to its short lifetime, the catalytic mechanism of 2-TeCD is not very clear and further experiments are needed to characterize each of the intermediates in the catalytic cycle. METHODS Using electrospray ionization mass (and tandem) spectrometry (ESI-MS and ESI-MS/MS) experiments, the decomposition of hydrogen peroxide at the expense of glutathione (GSH) catalyzed by 2-TeCD was monitored on-line. RESULTS The key intermediates were successfully intercepted and structurally characterized for the first time by coupling a microreactor on-line to the ESI ion source, which permitted the fast screening of intermediates directly from solution. CONCLUSIONS The catalytic mechanism of 2-TeCD catalysis has been elaborated based on mass spectrometric data and exerted its peroxidase activity via tellurol, tellurenic acid, and tellurosulfide, in analogy with natural GPX. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]