Binary blends of normal corn starch and cow cockle starch for the slow-thickening behavior upon pasting.

Corn starch with slow thickening property may facilitate more efficient heat transfer and safety of corn starch-thickened foods. Partial substitution of normal corn starch (NCS) with slow-pasting behavior of cow cockle starch (CCS) was hypothesized to impart binary starch blend with slow-thickening effect during hydrothermal heating. To test hypothesis, a series of starch blend dispersions (with weight ratios of CCS to NCS = 75:25, 50:50, 25:75) were prepared at various starch concentrations (6 %, 8 %, 10 %, and 12 %) and subjected to the Rapid Viscosity Analysis (RVA). RVA viscographs of starch blends were compared with that of NCS, suggesting that nearly all starch blends at various concentrations showed longer time span of pasting and lower pasting rate. Although CCS and NCS blend gels exhibited lower Young's modulus and hardness based on textural profile analysis, the sensory panels revealed that 6 % and 8 % starch blend gels (with weight ratio of CCS to NCS = 25:75) showed the mouthfeel analogous to NCS gel. These findings highlight a viable non-chemical modification strategy that enables binary blends of CCS and NCS as a novel gelling agent with slow-pasting property and may aid in safety and high-quality processing of hydrogel foods.

The attenuating effect of fermented soymilk on DSS-induced colitis in mice by suppressing immune response and modulating gut microbiota.

Fermented soymilk (FSM) as a new plant-based yoghurt has attracted attention for its nutritional and health benefits. The aim of this research is to explore the effect of consuming FSM before and during inflammatory bowel disease (IBD) on intestinal immune response, and to assess whether fermentation and sucrose can improve the anti-inflammatory activity of soymilk (SM) and FSM, and finally clarify their effect on the gut microbiota and levels of short-chain fatty acids (SCFAs). Consuming FSM in advance can effectively alleviate weight loss and bloody stools in mice with colitis and is associated with a 27% colon length repair rate. It can also prevent spleen and liver enlargement, inhibit immune response and oxidative stress, and increase the expression of the tight junction protein occludin gene (60%). Meanwhile, intaking FSM during IBD reduced weight loss, prevented liver damage, and repaired colon injury. In addition, fermentation enhance the inhibitory effects of FSM on colitis, whereas adding 3% sucrose to FSM had no effect on its intervention in colitis. Analysis of the composition of the gut microbiota in mice showed that the intake of FSM reduced the relative abundance of the pathogenic bacteria Parasutterella, Turicibater, and Bacteroide by 75%, 62%, and 50%, respectively, and increased the relative abundance of the beneficial bacteria Akkermansiaceae, Lachnospiraceae, Alloprevotella, and Dubosella by 28%, 50%, 80%, and 63%, respectively. It further restored the levels of SCFAs in the mouse intestine. The results provide a scientific basis for FSM as a natural anti-inflammatory food that can improve inflammatory intestinal microbiota imbalance and promote gut health.

Differences in fat digestion from milk of different Species: In vitro gastrointestinal digestion model for infants.

The differences in the milk fat digestion from goat milk (GM), camel milk (CM), bovine milk (BM), sheep milk (SM), mare milk (MM) and human milk (HM) using an in vitro gastrointestinal digestion model for simulated infants were investigated. The particle size distributions in goat and mare milk were similar to that of HM after digestion in the small intestine. During in vitro digestion, the zeta-potential change of MM was more consistent with that of HM. After 60 min of gastric digestion, the lipolysis degree (LD) of different milks were<2%, of which the highest LD was MM (1.84%), followed by HM (1.45%). At the end of intestinal digestion, the LD of HM was the highest, reaching 88.47%, and the LD of SM was similar to that of HM, reaching 83.92%, followed by GM (57.00%), BM (40.98%) and MM (39.37%), respectively, the LD of CM was only 29.99%, which was much lower than HM. The results of the glyceride composition hierarchical clustering analysis revealed that MM and HM were clustered into one category at the end of gastric and intestinal digestion. This study provides a scientific basis for the development of lipid ingredients in infant formula.

In vitro protein digestibility of different soy-based products: effects of microstructure, physico-chemical properties and protein aggregation.

This study investigates the effects of protein structure and food microstructure on the in vitro protein gastrointestinal digestibility of different soy-based products, such as soy drink, reconstituted soy drink powder, firm tofu, and yuba. The results of the chemical cross-linking analysis showed that hydrogen bonds and hydrophobic interactions were the main forces driving protein aggregation in (reconstituted) soy drink powder and firm tofu, whereas disulphide bonds were significantly more important for soy drink and yuba. The ß-sheet content of soy drink (36.5%) was lower than that of yuba (43.3%), but significantly higher than those of soy drink powder (23.2%) and firm tofu (29.8%). The in vitro protein digestibility decreased in the order of firm tofu > reconstituted soy drink powder > yuba > soy drink. Principal component analysis showed that protein gastrointestinal digestibility was positively correlated with the surface SH content and soluble protein content released by SDS + urea (SB-SA) but negatively correlated with the disulphide bonds and ß-sheet content for the four soybean products.

Mechanism of the glucono-δ-lactone induced soymilk gelation: Enthalpy and entropy transformation in the cross-linking of protein molecules.

This study aimed to explore new techniques to regulate the quality of soy products. The glucono-δ-lactone (GDL) induced soymilk gelation process and the gel network structure characteristic were compared as a matter of temperature, and the role of reaction kinetics was discussed. Results showed that there were similarities in the development of G' curves under different temperatures, whereas the gel network structures and the energy requirements of cross-linking reactions were different. In the high-temperature region (70 °C-95 °C), the exposure and binding of reactive groups were promoted. The activation enthalpy (ΔH*) required by protein aggregates decreased and the effect of entropy reduction (-TΔS*) was enhanced, which led to shorten the preaggregation time (tg) and increase the gelation rate (k), resulting in the formation of rough, porous gel network with high stiffness. By contrast, in the low-temperature region (40 °C-70 °C), high enthalpy contributions and low entropy changes were required, then a fine, soft, and tender gel network formed. Besides, a funnel-shaped model of the enthalpy-entropy energy transformation mechanism of soymilk gelation was proposed. The results of this study revealed that adjusting the enthalpy-entropy energy requirements of the protein cross-linking reaction could be utilized to the regulation of the network structure and quality of soymilk gels, which could enrich the reaction kinetics theory and provide innovative ideas for food quality control technology from the perspective of energy requirement and energy input.

Identification of the key off-flavor odorants for undesirable spoiled odor in thermally sterilized fermented soymilk.

Spoiled odors are a problem in thermally sterilized fermented soymilk. This study aims to clarify production conditions and key odorants of spoiled odors. The sensory evaluation showed that thermal sterilization caused a decrease in the sensory intensity of yogurt and fruity odors while significantly increasing undesirable aromas including beany, acidic, cooked-beans and spoiled odors. The spoiled odors increased with increasing acidity and heating temperatures. The strongest spoiled odor was observed in fermented soymilk at titratable acidity of 5.4 g/kg, sterilized at 90 °C. Apart from common volatiles that were inherent in soymilk and generated from lactic fermentation, 2-methyltetrahydrothiophen-3-one was found for the first time in soybean foods and was found to cause the spoiled odor. 44 volatiles found in thermally sterilized fermented soymilk were jointly formed its flavor wheel. This study provides important theoretical support for solving the problem of spoiled odor restricting the popularization of plant-based fermented soymilk.

Succession and Diversity of Microbial Flora during the Fermentation of Douchi and Their Effects on the Formation of Characteristic Aroma.

This study aims to understand the development and succession of the microbial community during the production of traditional Aspergillus-type Douchi as well as their effects on the formation and variation of characteristic aroma compounds. High-throughput sequencing technology, solid-phase microextraction, gas chromatography-mass spectrometry, and Spearman correlation analysis were conducted to study the changes in the microbial community and characteristic flavor during the fermentation process. Aspergillus spp. was dominant in the early stage of fermentation, whereas Staphylococcus spp., Bacillus spp., and Millerozyma spp. became dominant later. At the early stage, the main flavor compounds were characteristic soy-derived alcohols and aldehydes, mainly 1-hexanol, 1-octen-3-ol, and nonanal. In the later stage, phenol, 2-methoxy-, and 3-octanone were formed. Correlation analysis showed that six bacterial genera and nine fungal genera were significantly correlated with the main volatile components, with higher correlation coefficients, occurring on fungi rather than bacteria. Alcohols and aldehydes were highly correlated with the relative abundance of bacteria, while that of yeast species such as Millerozyma spp., Kodamaea spp., and Candida spp. was positively correlated with decanal, 3-octanol, 2-methoxy-phenol, 4-ethyl-phenol, 3-octanone, and phenol. The novelty of this work lies in the molds that were dominant in the pre-fermentation stage, whereas the yeasts increased rapidly in the post-fermentation stage. This change was also an important reason for the formation of the special flavor of Douchi. Correlation analysis of fungi and flavor substances was more relevant than that of bacteria. As a foundation of our future focus, this work will potentially lead to improved quality of Douchi and shortening the production cycle by enriching the abundance of key microbes.

Effects of heat treatment on protein molecular structure and in vitro digestion in whole soybeans with different moisture content.

The effects of heat treatment on protein structure and in vitro digestibility in whole soybeans with different moisture content (10.68%, 29.70%, 46.29%, and 62.05% wet basis) were investigated. Scanning electronic microscopy presented that thermal treatment destroyed the subcellular structure of soybean seeds and resulted in formation of protein aggregates. When ß-conglycinin (7S) was heat-denatured, the protein aggregates were maintained mainly by hydrogen bonds and hydrophobic interactions (non-covalent) for each moisture content. Also, the decrease of the protein solubility and increase of in vitro digestibility were observed. However, when glycinin (11S) was denatured in soybeans with 10.68% and 29.70% moisture content, the insoluble and indigestible protein aggregates with protein oxidation-induced crosslinking and high content of ß-sheet were presented; in contrast, for 46.29% and 62.05% moisture content, mild protein oxidation, low content of ß-sheet, non-covalent interactions and increased protein digestibility were shown. Non-covalent interactions were shown a positive correlation with gastrointestinal digestibility (r = 0.59, p < 0.05). Meanwhile, protein oxidation or ß-sheet content was significantly negatively correlated with in vitro protein digestibility (r = -0.69 and -0.61, respectively, p < 0.05). Protein structure rather than solubility contributed to difference of in vitro digestibility. The optimum thermal conditions to obtain high-quality digestible protein in whole soybeans are 160 °C for 10.68%, 145 °C for 29.70%, 160 °C for 46.29% and 115 °C/140 °C for 62.05% moisture content.

Antioxidant properties of fermented soymilk and its anti-inflammatory effect on DSS-induced colitis in mice.

Lactic acid-fermented soymilk as a new plant-based food has aroused extensive attention because of its effects on nutrition and health. This study was conducted to delve into the antioxidative and anti-inflammatory activities of lactic acid-fermented soymilk. To elucidate the key factors that affect the antioxidant properties of fermented soymilk, the strains and preparation process were investigated. Findings show that the fermented soymilk prepared using hot-water blanching method (BT-80) demonstrated a better antioxidant activity than that using conventional method (CN-20). Besides, a huge difference was observed among the soymilks fermented with different strains. Among them, the YF-L903 fermented soymilk demonstrated the highest ABTS radical scavenging ability, which is about twofold of that of unfermented soymilk and 1.8-fold of that of L571 fermented soy milk. In vitro antioxidant experiments and the analysis of H2O2-induced oxidative damage model in Caco-2 cells showed that lactic acid-fermentation could improve the DPPH radical scavenging ability, ABTS radical scavenging ability, while reducing the content of reactive oxygen species (ROS) and malondialdehyde (MDA) in Caco-2 cells induced by H2O2, and increasing the content of superoxide dismutase (SOD). Consequently, cells are protected from the damage caused by active oxidation, and the repair ability of cells is enhanced. To identify the role of fermented soymilk in intestinal health, we investigate its preventive effect on dextran sodium sulfate-induced colitis mouse models. Results revealed that the fermented soymilk can significantly improve the health conditions of the mice, including alleviated of weight loss, relieved colonic injury, balanced the spleen-to-body weight ratio, reduced the disease index, and suppressed the inflammatory cytokines and oxidant indexes release. These results suggest that YF-L903 fermented soymilk is a promising natural antioxidant sources and anti-inflammatory agents for the food industry. We believe this work paves the way for elucidating the effect of lactic acid-fermented soymilk on intestinal health, and provides a reference for the preparation of fermented soymilk with higher nutritional and health value.

Effects of high-temperature pressure cooking on cold-grind and blanched soymilk: Physico-chemical properties, in vitro digestibility and sensory quality.

The present work investigated effects of high-temperature pressure cooking (HP) on physico-chemical properties and in vitro protein digestibility of cold-grind soymilk (CS) and blanched soymilk (BS). Confocal laser scanning microscopy presented that proteins and lipids in BS were obviously coalesced compared with CS, while HP treatment contributed to homogeneous dispersion of protein and lipid. Particle size of the BS and BSHP were larger than that of CS and CSHP. Tertiary structure of protein suggested that hydrophobic interactions and disulfide bonds in CS and CSHP were main force among protein molecules. Meanwhile hydrophobic interactions were account for 70% of the total bonds in BS and BSHP. The maximum fluorescence excitation wavelength (λmax) of BSHP (349.0 nm) was shown a red shift compared with CS (346.5 nm). For secondary structure of protein, ß-sheet was 30.61% in CS, while CSHP, BS and BSHP decreased by 2.65%, 5.73% and 7.77%, respectively. Thus, the protein in BS and BSHP were evidently aggregated, loose and disorder; while the CS and CSHP protein were dense and orderly. Also, HP treatment led to loose and unordered protein structure. Moreover, the in vitro digestibility was BSHP > BS > CSHP > CS. The difference in digestibility of four soymilk was determined by the protein structure. Sensory evaluation showed that blanching treatment effectively reduced beany flavor and HP decreased the diameter of oil bodies of BS, which led to smooth mouth feel and thus the highest global impression of BSHP.

Phytic acid and its interactions: Contributions to protein functionality, food processing, and safety.

Is phytic acid (IP6) an undesirable constituent for vegetables and foods? This question is getting harder to answer. Phytic acid contributes to mineral/protein deficiency, but also brings about potential physiological benefits. Both the positive and negative effects boil down to the interactions among IP6, metal ions, and biopolymers. In the wake of the booming market of plant-based foods, an unbiased understanding of these interactions and their impacts on the foods themselves is a necessity to the smart control and utilization of plant-sourced phytates. This overview presents updated knowledge of IP6-related interactions, with a strong focus on their contributions to food functionality, processability, and safety.

Analysis on physicochemical and sensory qualities of soymilk prepared by various cultivars: Application of fuzzy logic technique.

Soymilk has a complicated system, and its sensory and physicochemical characteristics are influenced by the components of the soybean seeds. Thirty-five soybean cultivars were selected, and correlation analysis and clustering analysis were applied to determine the significant correlations between soybean seed traits and soymilk physiochemical properties. Four sensory quality attributes of soymilk, including taste, odor, appearance, and mouthfeel, were quantified in numerical values and scored based on a weighting criterion which was constructed via the fuzzy logic technique. Soymilk prepared from the soybean seeds with the lower crude protein and the higher crude fat content displayed better sensory qualities. A multivariate linear regression analysis was used to establish a predictive model for overall sensory scores of soymilk, which could be the reference for soybean cultivars selection in soymilk processing. To comprehensively optimize the processing costs, nutritional values, and sensory qualities, a set of detailed attributes of soybean seeds were recommended based on this study: 100-seed weight is higher than 20 g; ash content is less than 5.5 g/100 g; crude fat content is 20 to 24 g/100 g; and crude protein content is as high as possible, while the maximum limit is 40 g/100 g. PRACTICAL APPLICATION: The established predictive model can be a reference for soybean cultivars selection in soymilk processing. Moreover, the soybean composition range that is revealed by this study also provides a recommendation for the soybean breeding.

Colostral and mature breast milk protein compositional determinants in Qingdao, Wuhan and Hohhot: maternal food culture, vaginal delivery and neonatal gender.

BACKGROUND AND OBJECTIVES: Breast milk proteins are essential to infants as they provide nutrition and protection. This study evaluated multiple factors that might influence breast milk proteins to identify the determinants that lead to inter-individual and longitudinal differences. METHODS AND STUDY DESIGN: Five major breast milk proteins (ß-casein, α-lactalbumin, lactoferrin, serum albumin and κ-casein) from breast milk samples collected from 55 mothers in three cities (Hohhot, Wuhan and Qingdao) in China were analyzed using a validated ultraperformance liquid chromatography-mass spectrometry method. Various factors were statistically evaluated for their associations with breast milk proteins: mother's age, parity, delivery mode, infant gender and infant birthweight. RESULTS: Although decreased in concentrations, the proportions of ß-casein and α-lactalbumin increased from colostrum (33.8% and 26.8%) to mature milk (40.3% and 31.6%), respectively. Mothers of older age were found to produce a lower concentration of total protein. Compared with vaginal delivery, caesarean section was associated with lower concentrations of κ-casein, lactoferrin and ß-casein in mature milk. Infant gender influenced breast milk proteins in colostrum: mothers who delivered a girl tended to produce more κ-casein, lactoferrin and total protein. Furthermore, regional differences were found, and mothers from Hohhot produced significantly higher concentrations of α-lactalbumin and lactoferrin than those from Qingdao and Wuhan. This regional difference might be linked to the different dietary patterns of these mothers among cities. CONCLUSIONS: Our study deepens the understanding of breast milk protein dynamics in Chinese population and provides evidence on potential determinants, which can serve as guidance for infant nutrition optimization.

Effects of succinylation on the structure and thermal aggregation of soy protein isolate.

The structures of soy protein isolate, beta-conglycinin, and glycinin at increasing succinylation levels (0-94.88%) were determined to control the formation of soy protein thermal aggregates. In addition, the thermal aggregation was investigated under various temperatures (70-100 °C) and ionic strengths (0-1.0 mol/L NaCl) at pH 7.0. Results showed that soy protein isolate, beta-conglycinin, and glycinin underwent obvious structural changes when their succinylation degrees reached around 60%, 30%, and 65%, respectively. After which, the acylation rates markedly declined. During succinylation, soy proteins, particularly glycinin, endured gradual damages in its secondary and tertiary structures. Consequently, the thermal stability of glycinin was reduced, whereas that of beta-conglycinin was hardly affected. However, as the colloid stability of succinylated soy protein isolate was enhanced significantly, its thermal aggregation was markedly suppressed. Thus, succinylation could be used to improve the stability of soy proteins after heating.

Interaction mode of calcium-binding peptides and Caco-2 cell membrane.

In our previous studies, soluble soybean protein hydrolysate (SPH)-calcium complexes were shown to promote the calcium uptake of Caco-2 cells. However, the calcium transport mode involved remains unknown. In this article, several experiments were carried out via cytological analysis to investigate the calcium transport mode of peptides with low calcium binding capacities (F1), peptides with high calcium-binding capacities (F2), and their separate calcium complexes (F1-Ca and F2-Ca) when interacting with cell membranes. The interaction between one of them and a cell membrane is the first step in intracellular transport, as indicated by fluorescence blue shift experiments and acrylamide quenching experiments. The results of zeta potential experiments showed that only the "charge neutralization" phenomenon occurs when the F1 peptide or F1-Ca complex interacts with cell membranes and thus cannot be transported into cells. On the contrary, in an F2 at high concentrations or F2-Ca complex, a "charge recovery" phenomenon occurs apart from "charge neutralization" and can thus be transported into cells through endocytosis.

Compressed food with added functional oligopeptides improves performance during military endurance training.

BACKGROUND AND OBJECTIVES: Oligosaccharide or oligopeptide supplementation may have a significant impact on endurance performance. This study evaluated the effects of adding maltooligosaccharides (MO) or soy oligopeptides (SO) to compressed food (CF) on the physical response of soldiers to daily military training. METHODS AND STUDY DESIGN: Twelve soldiers were randomized to four diet groups: regular meals, CF, CFMO, and CFSO (crossover design). They participated in exercise tests including 90 minutes running at 55-65% VO2max and exhaustive running. Heart rates, rating of perceived exertion (RPE), and blood and urine samples were collected during exercise and recovery. RESULTS: The recovery heart rates were significantly lower with the CFMO diet compared with the other diets. Compared with all other diets, blood glucose levels were higher, post-exercise blood lactate levels were lower, and lactate clearance during recovery was higher with the CFMO diet, followed by the CFSO diet. Post-exercise levels of erythrocytes and hematocrit were significantly higher with the CFSO diet. Post-exercise urine specific gravity was lower with the CFMO diet and urine pH was decreased with the CFSO diet. Blood urea nitrogen (BUN) and uric acid (UA) were significantly higher with the CFSO diet than with the other diets. There was no significant difference in skeletal and cardiac muscle injury indices and RPE among diets. CONCLUSIONS: CFMO led to better heart rate recovery, improved and maintained blood glucose and increased removal of blood lactate. CFSO accelerated removal of blood lactate during recovery, maintained oxygen supply, and increased fluid retention.

The analysis of the causes of protein precipitate formation in the blanched soymilk.

This paper explored the causes of protein precipitate formation in blanched soymilk prepared by blanching soybeans through studying the changes in composition and amount of protein particles during its thermal processing. Compared with the traditional method of preparing soymilk, blanching changed the thermal aggregation behavior of protein particles. Results showed that when blanching was applied to soybeans, ß-conglycinin (7S) was denatured in the blanched soybeans, which resulted in the fixation and aggregation of 7S prior to the grinding processing. Therefore, 7S lost its inhibitory ability on the growth of other protein aggregation, explaining the increased insoluble precipitates in the blanched soymilk.

Yield and textural properties of tofu as affected by soymilk coagulation prepared by a high-temperature pressure cooking process.

The cooking of raw soymilk is a necessary procedure prior to the production of tofu. The effects of the high-temperature pressure cooking (HTPC) and traditional cooking methods on the yield and textural properties of tofu products were investigated. Results showed that when HTPC was applied, the content of protein particles increased, thereby contributing to the formation of a dense network of tofu gel. Thus, significant improvement of textural properties, including hardness, chewiness and springiness, was observed. Moreover, HTPC contributes to the change in the composition of the particulate protein, whereas the proportion of ß-conglycinin in the non-particulate protein increased. The start and end points of the protein coagulation induced by Ca(2+) moved backward, and slowed the coagulation process, which was conducive to the incorporation of water or dry matter into the gel.

Effects of endogenous small molecular compounds on the rheological properties, texture and microstructure of soymilk coagulum: Removal of phytate using ultrafiltration.

This study aims to clarify the roles played by endogenous small molecular components in soymilk coagulation process and the properties of gels. Soymilk samples with decreasing levels of small molecules were prepared by ultrafiltration, to reduce the amount of phytate and salts. CaSO4-induced coagulation process was analyzed using rheological methods. Results showed that removal of free small molecules decreased the activation energy of protein coagulation, resulting in accelerated reaction and increased gel strength. However, too fast a reaction led to the drop in storage modulus (G'). Microscopic observation suggested that accelerated coagulation generated a coarse and non-uniform gel network with large pores. This network could not hold much water, leading to serious syneresis. Endogenous small molecules in soymilk were vital in the fine gel structure. Coagulation rate could be controlled by adjusting the amount of small molecules to obtain tofu products with the optimal texture.

Effects of high-temperature pressure cooking and traditional cooking on soymilk: Protein particles formation and sensory quality.

This study focused on the effect of high-temperature pressure cooking on the sensory quality of soymilk. Soymilk was prepared by high-temperature pressure cooking (105-125°C and 0.12-0.235MPa) and traditional cooking (97°C and 0.1MPa). The size distribution and composition of protein particles and the rheological properties of soymilk were compared. Results showed that the content of protein particles and the average size of soymilk particles were higher in high-temperature pressure cooking than in traditional cooking (p<0.05). High-temperature pressure cooking affected soymilk protein denaturation and favored protein aggregation. Similar to traditional soymilk, soymilk cooked at 115°C was categorized as a Newtonian fluid but was found with increased viscosity in the rheological test. Soymilk cooked at 115°C for 10min exhibited a homogeneous, smooth, and creamy texture with a high acceptability in the sensory test.