Effect of Soy Protein Supplementation on Muscle Adaptations, Metabolic and Antioxidant Status, Hormonal Response, and Exercise Performance of Active Individuals and Athletes: A Systematic Review of Randomised Controlled Trials.

BACKGROUND: Protein supplements are important to maintain optimum health and physical performance, particularly in athletes and active individuals to repair and rebuild their skeletal muscles and connective tissues. Soy protein (SP) has gained popularity in recent years as an alternative to animal proteins. OBJECTIVES: This systematic review evaluates the evidence from randomised controlled clinical trials of the effects of SP supplementation in active individuals and athletes in terms of muscle adaptations, metabolic and antioxidant status, hormonal response and exercise performance. It also explores the differences in SP supplementation effects in comparison to whey protein. METHODS: A systematic search was conducted in PubMed, Embase and Web of Science, as well as a manual search in Google Scholar and EBSCO, on 27 June 2023. Randomised controlled trials that evaluated the applications of SPs supplementation on sports and athletic-related outcomes that are linked with exercise performance, adaptations and biomarkers in athletes and physically active adolescents and young adults (14 to 39 years old) were included, otherwise, studies were excluded. The risk of bias was assessed according to Cochrane's revised risk of bias tool. RESULTS: A total of 19 eligible original research articles were included that investigated the effect of SP supplementation on muscle adaptations (n = 9), metabolic and antioxidant status (n = 6), hormonal response (n = 6) and exercise performance (n = 6). Some studies investigated more than one effect. SP was found to provide identical increases in lean mass compared to whey in some studies. SP consumption promoted the reduction of exercise-induced metabolic/blood circulating biomarkers such as triglycerides, uric acid and lactate. Better antioxidant capacity against oxidative stress has been seen with respect to whey protein in long-term studies. Some studies reported testosterone and cortisol fluctuations related to SP; however, more research is required. All studies on SP and endurance performance suggested the potential beneficial effects of SP supplementation (10-53.3 g) on exercise performance by improving high-intensity and high-speed running performance, enhancing maximal cardiac output, delaying fatigue and improving isometric muscle strength, improving endurance in recreational cyclists, increasing running velocity and decreasing accumulated lactate levels; however, studies determining the efficacy of soy protein on VO2max provided conflicted results. CONCLUSION: It is possible to recommend SP to athletes and active individuals in place of conventional protein supplements by assessing their dosage and effectiveness in relation to different types of training. SP may enhance lean mass compared with other protein sources, enhance the antioxidant status, and reduce oxidative stress. SP supplementation had an inconsistent effect on testosterone and cortisol levels. SP supplementation may be beneficial, especially after muscle damage, high-intensity/high-speed or repeated bouts of strenuous exercise.

Effect of heat treatment on protein quality of rapeseed protein isolate compared with non-heated rapeseed isolate, soy and whey protein isolates, and rice and pea protein concentrates.

BACKGROUND: Rapeseed protein isolate is used in the food industry, and heating is often used during rapeseed processing. However, the digestible indispensable amino acid score (DIAAS) for heat-treated rapeseed protein isolate is unknown. The present study aimed to test the hypothesis that heating rapeseed protein isolate improves protein quality resulting in DIAAS that is greater than for pea and rice protein concentrates, and comparable to that of soy and whey protein isolates. RESULTS: Standardized ileal digestibility (SID) of amino acids (AA), except leucine and methionine, was not different between heat-treated rapeseed protein isolate and soy protein isolate, but SID of most AA was greater (P < 0.001) for heat-treated rapeseed protein isolate than for brown rice protein concentrate, pea protein concentrate, rapeseed protein isolate and soy protein isolate, but not whey protein isolate. Non-heated rapeseed protein isolate had a reduced (P < 0.001) DIAAS for 6-month-old to 3-year-old children compared with soy protein isolate, but this was greater (P < 0.001) than for pea and brown rice protein concentrates. The DIAAS for heat-treated rapeseed protein isolate was greater (P < 0.001) than for non-heated rapeseed protein isolate for all age groups. Heat-treated rapeseed protein isolate and whey protein isolate had a DIAAS > 100 for individuals older than 3 years. CONCLUSION: Rapeseed protein isolate had a DIAAS comparable to soy protein isolate, but heat-treated rapeseed protein isolate and whey protein isolate had DIAAS ≥ 100, qualifying these proteins as 'excellent'. Rice and pea protein concentrates had DIAAS < 75. © 2023 Society of Chemical Industry.

Identification of quantitative trait loci controlling soybean seed protein and oil content.

Soybean is a major source of seed protein and oil globally with an average composition of 40% protein and 20% oil in the seed. The goal of this study was to identify quantitative trait loci (QTL) conferring seed protein and oil content utilizing a population constructed by crossing an above average protein content line, PI 399084 to another line that had a low protein content value, PI 507429, both from the USDA soybean germplasm collection. The recombinant inbred line (RIL) population, PI 507429 x PI 399084, was evaluated in two replications over four years (2018-2021); the seeds were analyzed for seed protein and oil content using near-infrared reflectance spectroscopy. The recombinant inbred lines and the two parents were re-sequenced using genotyping by sequencing. A total of 12,761 molecular markers, which came from genotyping by sequencing, the SoySNP6k BeadChip and selected simple sequence repeat (SSR) markers from known protein QTL chromosomal regions were used for mapping. One QTL was identified on chromosome 2 explaining up to 56.8% of the variation for seed protein content and up to 43% for seed oil content. Another QTL identified on chromosome 15 explained up to 27.2% of the variation for seed protein and up to 41% of the variation for seed oil content. The protein and oil QTLs of this study and their associated molecular markers will be useful in breeding to improve nutritional quality in soybean.

In Silico Approach of Glycinin and Conglycinin Chains of Soybean By-Product (Okara) Using Papain and Bromelain.

This study explores utilization of a sustainable soybean by-product (okara) based on in silico approach. In silico approaches, as well as the BIOPEP database, PeptideRanker database, Peptide Calculator database (Pepcalc), ToxinPred database, and AllerTop database, were employed to evaluate the potential of glycinin and conglycinin derived peptides as a potential source of bioactive peptides. These major protein precursors have been found as protein in okara as a soybean by-product. Furthermore, primary structure, biological potential, and physicochemical, sensory, and allergenic characteristics of the theoretically released antioxidant peptides were predicted in this research. Glycinin and α subunits of ß-conglycinin were selected as potential precursors of bioactive peptides based on in silico analysis. The most notable among these are antioxidant peptides. First, the potential of protein precursors for releasing bioactive peptides was evaluated by determining the frequency of occurrence of fragments with a given activity. Through the BIOPEP database analysis, there are several antioxidant bioactive peptides in glycinin and ß and α subunits of ß-conglycinin sequences. Then, an in silico proteolysis using selected enzymes (papain, bromelain) to obtain antioxidant peptides was investigated and then analyzed using PeptideRanker and Pepcalc. Allergenic analysis using the AllerTop revealed that all in silico proteolysis-derived antioxidant peptides are probably nonallergenic peptides. We also performed molecular docking against MPO (myeloperoxidases) for this peptide. Overall, the present study highlights that glycinin and ß and α subunits of ß-conglycinin could be promising precursors of bioactive peptides that have an antioxidant peptide for developing several applications.

Effects of Branched-Chain Amino Acids on Skeletal Muscle, Glycemic Control, and Neuropsychological Performance in Elderly Persons with Type 2 Diabetes Mellitus: An Exploratory Randomized Controlled Trial.

Although branched-chain amino acids (BCAA) are known to stimulate myofibrillar protein synthesis and affect insulin signaling and kynurenine metabolism (the latter being a metabolite of tryptophan associated with depression and dementia), the effects of BCAA supplementation on type 2 diabetes (T2D) are not clear. Therefore, a 24-week, prospective randomized open blinded-endpoint trial was conducted to evaluate the effects of supplementation of 8 g of BCAA or 7.5 g of soy protein on skeletal muscle and glycemic control as well as adverse events in elderly individuals with T2D. Thirty-six participants were randomly assigned to the BCAA group (n = 21) and the soy protein group (n = 15). Skeletal muscle mass and HbA1c, which were primary endpoints, did not change over time or differ between groups. However, knee extension muscle strength was significantly increased in the soy protein group and showed a tendency to increase in the BCAA group. Homeostasis model assessment for insulin resistance did not significantly change during the trial. Depressive symptoms were significantly improved in the BCAA group but the difference between groups was not significant. Results suggested that BCAA supplementation may not affect skeletal muscle mass and glycemic control and may improve depressive symptoms in elderly individuals with T2D.

Selenium-Enriched Black Soybean Protein Prevents Benzo(a)pyrene-Induced Pyroptotic Colon Damage and Gut Dysbacteriosis.

Selenium-enriched black soybean protein (SeBSP) is a kind of high-quality selenium resource with many physiological functions. Benzo(a)pyrene (BaP) is a well-known injurant that widely exists in high-temperature processed food and has been previously found to cause colon injury. In this study, the effects of SeBSP on colonic damage induced by BaP in BALB/C mice were investigated by comparing it with normal black soybean protein (BSP). SeBSP inhibited the BaP-induced reductions on body weight, food intake, and water intake. Moreover, metabolic enzymes, including AhR, CYP1A1, CYP1B1, and GST-P1, that were promoted by BaP were downregulated by SeBSP, reducing oxidative damage caused by BaP in the metabolic process. The classical pyroptosis indexes (i.e., NLRP3, ASC, Caspase-1, GSDMD) and inflammatory factors (i.e., TNF-α, IL-1ß, IL-18, iNOS, COX-2) were downregulated by SeBSP in BaP-treated mice, suggesting the benefits of SeBSP in reducing colonic toxicity. Notably, SeBSP enhanced microbial diversity of gut microbiota and increased relative abundances of prebiotic bacteria, for example, Lactobacillus reuteri, Bacteroides thetaiotaomicron, and genera Bifidobacterium, and Blautia, along with the promotion of short-chain fatty acids. Integrative analysis showed strong links between the antioxidant and anti-inflammatory effects of SeBSP and its altered gut microbiota. Collectively, our study demonstrates the pronounced benefits of Se-enriched black soybean in preventing the colonic toxicity of BaP, and such effects could be mediated by gut microbiota.

Preparation and Properties of Salecan-Soy Protein Isolate Composite Hydrogel Induced by Thermal Treatment and Transglutaminase.

Salecan (Sal) is a novel marine microbial polysaccharide. In the present research, Sal and soy protein isolate (SPI) were adopted to fabricate Sal-SPI composite hydrogel based on a stepwise process (thermal treatment and transglutaminase induction). The effect of Sal concentration on morphology, texture properties, and the microstructure of the hydrogel was evaluated. As Sal concentration varied from 0.4 to 0.6 wt%, hydrogel elasticity increased from 0.49 to 0.85 mm. Furthermore, the internal network structure of Sal-SPI composite hydrogel also became denser and more uniform as Sal concentration increased. Rheological studies showed that Sal-SPI elastic hydrogel formed under the gelation process. Additionally, FTIR and XRD results demonstrated that hydrogen bonds formed between Sal and SPI molecules, inferring the formation of the interpenetrating network structure. This research supplied a green and simple method to fabricate Sal-SPI double network hydrogels.

Selenium-enriched soybean peptides pretreatment attenuates lung injury in mice induced by fine particulate matters (PM2.5) through inhibition of TLR4/NF-κB/IκBα signaling pathway and inflammasome generation.

This study aimed to identify and prepare peptides from selenium (Se)-enriched soybeans and determine whether dietary Se-enriched soybean peptides (Se-SPep) could inhibit lung injury in mice induced by fine particulate matter 2.5 (PM2.5). BALB/c mice were randomly divided into six groups. The mice in the prevention groups were pretreated with 378 mg kg-1 of Se-SPep, soybean peptides (SPep), and Se-enriched soybean protein (Se-SPro), respectively, for four weeks. The mice in the PM2.5 exposure group received concentrated PM2.5 (15 µg per day mice) for 1 h daily from the third week for two weeks. The results showed that the leukocyte and cytokine (IL-1ß, IL-6, TNF-α) levels in the bronchoalveolar lavage fluid (BALF) of the PM2.5 exposure group were higher than those in the control group. Se-SPep pretreatment decreased the IL-1ß, IL-6, and TNF-α levels compared with the PM2.5 exposure group. Additionally, Se-SPep pretreatment inhibited TLR4/NF-κB/IκBα and NLRP3/ASC/caspase-1 protein expression in the lungs. In conclusion, Se-SPep pretreatment may protect the lungs of the mice against PM2.5-induced inflammation, suggesting that Se-SPep represents a potential preventative agent to inhibit PM2.5-induced lung injury.

Soy protein concentrate replacing animal protein supplements and its impacts on intestinal immune status, intestinal oxidative stress status, nutrient digestibility, mucosa-associated microbiota, and growth performance of nursery pigs.

This study was to evaluate the effects of soy protein concentrate (SPC) supplementation replacing animal protein supplements on intestinal immune status, intestinal oxidative stress status, nutrient digestibility, mucosa-associated microbiota, and growth performance of nursery pigs. Thirty-two newly weaned pigs at 21 d of age with 6.4 ± 0.4 kg body weight (BW) were allotted to four treatments in a randomized complete block design with initial BW and sex as blocks. Pigs were fed for 35 d in three phases. Dietary treatments were SPC 0% (diets with fish meal 4/2/1%, poultry meal 10/8/4%, blood plasma 4/2/1%, and crude protein 24.6/22.6/20.9% for phase 1/2/3, respectively), SPC 33%, SPC 66%, and SPC 100% (SPC 0% diets with SPC replacing 33/66/100% of animal protein supplements, respectively). Pigs were euthanized on day 35 to collect jejunal mucosa and tissues to evaluate intestinal immune status, intestinal oxidative stress status, intestinal morphology, and mucosa-associated microbiota in the jejunum. Titanium dioxide was added in phase three diets as an indigestible marker. Ileal digesta was collected to measure apparent ileal digestibility (AID) of nutrients. Data were analyzed using MIXED and NLMIXED procedures of SAS. Increasing SPC supplementation by replacing animal protein supplements linearly decreased (P < 0.05) the BW, ADG, and ADFI of pigs during the overall period, and linearly increased (P < 0.05) peptide tyrosine tyrosine (PYY) in jejunum. Increasing SPC supplementation linearly decreased (P < 0.05) feed cost per weight gain. In the exponential model, SPC can replace animal protein supplements up to 10.5% and 16.5% without reducing the ADG and ADFI of pigs, respectively. The SPC 100% decreased (P < 0.05) Helicobacteraceae, Campylobacteraceae, alpha diversity, and changed beta diversity of microbiota in the jejunal mucosa. In conclusion, SPC supplementation replacing animal protein supplements reduced growth performance by reducing feed intake, which might be related to increased PYY. However, 10.5% and 16.8% of animal protein supplements can be replaced by SPC without affecting BW gain and feed intake of nursery pigs, respectively. Complete removal of animal protein supplements by SPC supplementation modulated the composition of jejunal mucosa-associated microbiota by reducing Helicobacteraceae and Campylobacteraceae, whereas without affecting the intestinal immune status, intestinal oxidative stress status, intestinal morphology, and AID of nutrients in nursery pigs.

Due to the high-quality nutrients and functional compounds, animal protein supplements are generally included in nursery pig diets to relieve the negative impacts caused by weaning stress. However, the high cost, short supply, and potential safety issues of animal protein supplements limit their use. Soybean meal is commonly used in swine diets due to the high nutritional values and competitive cost, however, antinutritional factors in soybean meal have been shown to impair the health and growth of nursery pigs. Soy protein concentrate is processed from soybean meal by ethanol extraction and efficiently removes the anti-nutritional factors. The aim of this study was to investigate the effects of soy protein concentrate replacing animal protein supplements at various levels on intestinal immune status, intestinal oxidative stress status, nutrient digestibility, and growth performance of nursery pigs. The use of soy protein concentrate completely replacing animal protein supplements showed benefits on modulating the bacterial ecosystem on the mucosal lining of the small intestine by decreasing potentially harmful bacteria, whereas without affecting intestinal immune status, intestinal oxidative stress status, intestinal morphology, and nutrient digestibility. However, excessive use of soy protein concentrate replacing animal protein supplements decreased the weight gain of nursery pigs due to reduced feed intake.

Emulsions co-stabilized by soy protein nanoparticles and tea saponin: Physical stability, rheological properties, oxidative stability, and lipid digestion.

Herein, the effects of the concentration (0.1%-1.0%, w/v) and addition sequence of tea saponin (TS) on the physical stability, oxidative stability, rheological properties, and in vitro digestion of the emulsions stabilized by heat-induced soy protein isolate nanoparticles (SPs) were investigated. The results revealed that the concentration and addition sequence of TS have significant impact on the microstructure, stability, rheological properties, and in vitro digestion of the emulsions. TS was shown to not only fill the interfacial gaps but also adsorb on the particle surfaces, contributing to interfacial wettability. With increasing TS concentration, interfacial tension decay is clearly observed. Further, TS endows the droplets with electrostatic repulsion and steric resistance, preventing their flocculation, coalescence, and oxidation. Finally, in vitro digestion experiments demonstrated that the presence of TS delayed the lipid digestion of the emulsions.

Fabrication and biomedical applications of Arabinoxylan, Pectin, Chitosan, soy protein, and silk fibroin hydrogels via laccase - Ferulic acid redox chemistry.

The unique physiochemical properties and the porous network architecture of hydrogel seek the attention to be explored in broad range of fields. In the last decade, numerous studies on the development of enzymatically cross-linked hydrogels have been elucidated. Implementing enzyme based cross-linking for fabrication of biomaterials over other cross-linking methods harbor various advantages, especially hydrogels designed using laccase exhibits mild reaction environment, high cross-linking efficiency and less toxicity. To our knowledge this is the first report reviewing the formulation of laccase mediated cross-linking for hydrogel preparation. Here, laccase catalyzed synthesis of hydrogel using polysaccharide viz. arabinoxylan, sugar beet pectin, galactomannan, chitosan etc. and proteins namely soy protein, gelatin, silk fibroin were discussed on highlighting their mechanical properties and its possible field of application. We have summarized the role of phenolic acids in laccase mediated cross-linking particularly ferulic acid which is a component of lignocellulose, serving cell rigidity via cross-linkage. The review also discusses on various biomedical applications such as controlled protein release, tissue engineering, and wound healing. It is anticipated that this review will give a detailed information on different laccase mediated reaction strategies that can be applied for the synthesis of various new biomaterials with tailor made properties.

Krill Protein Hydrolysate Provides High Absorption Rate for All Essential Amino Acids-A Randomized Control Cross-Over Trial.

BACKGROUND: adequate protein intake is essential to humans and, since the global demand for protein-containing foods is increasing, identifying new high-quality protein sources is needed. In this study, we investigated the acute postprandial bioavailability of amino acids (AAs) from a krill protein hydrolysate compared to a soy and a whey protein isolate. METHODS: the study was a randomized, placebo-controlled crossover trial including ten healthy young males. On four non-consecutive days, volunteers consumed water or one of three protein-matched supplements: whey protein isolate, soy protein isolate or krill protein hydrolysate. Blood samples were collected prior to and until 180 min after consumption. Serum postprandial AA concentrations were determined using 1H NMR spectroscopy. Hunger and satiety were assessed using visual analogue scales (VAS). RESULTS: whey and krill resulted in significantly higher AA concentrations compared to soy between 20-60 min and 20-40 min after consumption, respectively. Area under the curve (AUC) analyses revealed that whey resulted in the highest postprandial serum concentrations of essential AAs (EAAs) and branched chain AAs (BCAAs), followed by krill and soy, respectively. CONCLUSIONS: krill protein hydrolysate increases postprandial serum EAA and BCAA concentrations in a superior manner to soy protein isolate and thus might represent a promising future protein source in human nutrition.

Quantitative proteomic and lipidomics analyses of high oil content GmDGAT1-2 transgenic soybean illustrate the regulatory mechanism of lipoxygenase and oleosin.

KEY MESSAGE: Proteomic and lipidomics analyses of WT and GmDGAT1-2 transgenic soybeans showed that GmDGAT1-2 over-expression induced lipoxygenase down-regulatation and oleoin up-regulatation, which significantly changed the compositions and total fatty acid. The main goal of soybean breeding is to increase the oil content. Diacylglycerol acyltransferase (DGAT) is a key rate-limiting enzyme in fatty acid metabolism and may regulate oil content. Herein, 10 GmDGAT genes were isolated from soybean and transferred into wild-type (WT) Arabidopsis. The total fatty acid was 1.2 times higher in T3 GmDGAT1-2 transgenic Arabidopsis seeds than in WT. Therefore, GmDGAT1-2 was transferred into WT soybean (JACK), and four T3 transgenic soybean lines were obtained. The results of high-performance gas chromatography and Soxhlet extractor showed that, compared with those of JACK, oleic acid (18:1), and total fatty acid levels in transgenic soybean plants were much higher, but linoleic acid (18:2) was lower than WT. Palmitic acid (16:0), stearic acid (18:0), and linolenic acid (18:3) were not significantly different. For mechanistic studies, 436 differentially expressed proteins (DEPs) and 180 differentially expressed metabolites (DEMs) were identified between WT (JACK) and transgenic soybean pods using proteomic and lipidomics analyses. Four lipoxygenase proteins were down-regulated in linoleic acid metabolism while four oleosin proteins were up-regulated in the final oil formation. The results showed an increase in the total fatty acid and 18:1 composition, and a decrease in the 18:2 composition of fatty acid. Our study brings new insights into soybean genetic transformation and the deep study of molecular mechanism that changes the total fatty acid, 18:1, and 18:2 compositions in GmDGAT1-2 transgenic soybean.

Dietary supplementation of ß-conglycinin, with or without sodium butyrate on the growth, immune response and intestinal health of hybrid grouper.

We investigated the effects of low and high doses of ß-conglycinin and the ameliorative effects of sodium butyrate (based on high-dose ß-conglycinin) on the growth performance, serum immunity, distal intestinal histopathology, and gene, protein expression related to intestinal health in hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). The results revealed that the instantaneous growth rate (IGR) of grouper significantly increased, decreased, and increased in the low-dose ß-conglycinin (bL), high-level ß-conglycinin (bH) and high-level ß-conglycinin plus sodium butyrate (bH-NaB), respectively. The feed coefficient ratio (FCR) was significantly increased in the bH and bH-NaB, serum levels of IFN-γ, IL-1ß, and TNF-α were upregulated in the bH. The intestinal diameter/fold height ratio was significantly increased in the bH. Furthermore, there were increases in nitric oxide (NO), total nitric oxide synthase (total NOS), and peroxynitrite anion (ONOO-) in the bH, and decreases in total NOS and ONOO- in the bH-NaB. In the distal intestine, IL-1ß and TGF-ß1 mRNA levels were downregulated and upregulated, respective in the bL. The mRNA levels of TNF-α and IL-6 were upregulated in the bH, and downregulated in the bH-NaB, respectively. Occludin, claudin3 and ZO-3 mRNA levels were upregulated in the bL, downregulated in the bH and then upregulated in the bH-NaB. No significant differences were observed in the mRNA levels of IFN-γ and jam4. And the p-PI3K p85Tyr458/total PI3K p85 value was significantly increased in the bH and then decreased in the bH-NaB, and the total Akt value was significantly increased in the bH. These indicate ß-conglycinin has a regulatory effect on serum immunity and affect distal intestinal development by modulating distal intestinal injury-related parameters. Within the distal intestinal tract, low- and high-dose ß-conglycinin differentially affect immune responses and tight junctions in the distal intestine, which eventually manifests as a reduction in growth performance. Supplementing feed with sodium butyrate might represent an effective approach for enhancing serum immunity, and protects the intestines from damage caused by high-dose ß-conglycinin.

Effects of heat treatment on the antigenicity, antigen epitopes, and structural properties of ß-conglycinin.

In this study, the effects of heat treatment on antigenicity, antigen epitopes, and structural changes in ß-conglycinin were investigated. Results showed that the IgG (Immunoglobulin G) binding capacity of heated protein was inhibited with increased temperature, although IgE (Immunoglobulin E) binding capacity increased. Linear antigen epitopes generally remained intact during heat treatment. After heat treatment, ß-conglycinin was more easily hydrolyzed by digestive enzymes, and a large number of linear epitopes was destroyed. In addition, heat denaturation of ß-conglycinin led to the formation of protein aggregates and reduction of disulfide bonds. The contents of random coils and ß-sheet of heated ß-conglycinin decreased, but the contents of ß-turn and α-helix increased. Moreover, the protein structure of heated ß-conglycinin unfolded, more hydrophobic regions were exposed, and the tertiary structure of ß-conglycinin was destroyed. Heat treatment affected the antigenicity and potential sensitization of ß-conglycinin by changing its structure.

Physical properties of zein networks treated with microbial transglutaminase.

Potential improvements to the physical properties of brittle, self-assembled zein networks through microbial transglutaminase crosslinking were investigated. The formation of crosslinked heteropolymers was also explored with networks containing zein and either soy or pea protein isolates as supplemented lysine sources. The observed SDS-PAGE bands did not show any evidence of zein crosslinking. Soy and pea isolates underwent extensive crosslinking on their own, but heteropolymers were not observed in multiprotein networks with zein. Despite the lack of crosslinking observed, rheological and textural analysis revealed that the enzymatic treatment of zein produced a weaker, more brittle structure. With no significant changes in secondary structure, determined through FTIR, the observed behaviour was primarily attributed to glutamine deamidation by microbial transglutaminase in the absence of sufficient lysine through changes to the hydrophobicity of the protein such that non-covalent bonding within network was modified.

Effect of feed form, soybean meal protein content, and Rovabio Advance on poult live performance to 3 wk of age.

Based on research reports, feed characteristics can increase poult growth via several factors. Two rearing experiments (EXP) were conducted to test the effects of feed form and ingredient quality in turkey poults. Bird performance and the duodenum, jejunum, ileum, and cecum morphology were observed in both EXP. Poults were reared in battery cages (48 cages in EXP 1 and 72 cages in EXP 2). Four dietary treatments with differing feed form and function factors were evaluated in EXP 1. A completely randomized block design with a 2 × 2 × 2 factorial arrangement of treatments consisting of 2 levels of fines, 2 soybean meal (SBM) sources, and 2 levels of an enzyme cocktail (Rovabio Advance) was tested in EXP 2. Poult BW, BW gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were determined in both EXP. Apparent metabolizable energy corrected for nitrogen (AMEn) was determined in EXP 2. Differences were considered to be statistically significant at P ≤ 0.05. Feeding increased feed crumble particle size with fewer fines in the starter feed resulted in an increased BWG accompanied by an increased FI. Reduced feed fines reduced AMEn when the dietary enzyme cocktail was not present. The feed formulation with 60% CP SBM resulted in a lower FI and an improved FCR. The enzyme cocktail interacted synergistically with screening and fed SBM source factors on the AMEn and FCR. It was concluded that both the feed form and quality, as used in this study, affect poult performance.

Soybean meal allergenic protein degradation and gut health of piglets fed protease-supplemented diets.

Two experiments were conducted to determine the effects of protease supplementation on degradation of soybean meal (SBM) allergenic proteins (glycinin and ß-conglycinin) and gut health of weaned pigs fed soybean meal-based diets. In experiment 1, 2 SBM samples from 2 different sources were subjected to porcine in vitro gastric degradation to determine the effects of protease (at 15,000 U/kg of feedstuff) on degradation of the soybean allergenic proteins. In experiment 2, 48 weaned pigs (body weight = 6.66 kg) were obtained in 2 batches of 24 pigs each. Pigs were individually housed in metabolic crates and fed 4 diets (12 pigs/diet). The diets were corn-based diet with SBM 1 or SBM 2 without or with protease at 15,000 U/kg of diet in 2 × 2 factorial arrangement. Diets were fed for 10 d and pigs were sacrificed on day 10 for measurement of small intestinal histomorphology, permeability of small intestine mounted in Ussing chambers, and serum concentration of pro-inflammatory cytokines. Two SBM sources (SBM 1 and SBM 2) contained 46.9% or 47.7% CP, 14.0% or 14.6% glycinin, and 9.90% or 10.3% ß-conglycinin, respectively. Protease and SBM source did not interact on any of the response criteria measured in the current study. Protease supplementation tended to increase (P = 0.069) the in vitro gastric degradation of glycinin. Protease supplementation tended to reduce (P = 0.099) fluorescein isothiocyanate dextran 4,000 Da (which is a marker probe for intestinal permeability) flow in jejunum, and reduced (P = 0.037) serum TNF-α concentration. Protease did not affect small intestinal histomorphology. In conclusion, protease tended to increase gastric degradation of glycinin and reduce gut permeability, and serum concentration of pro-inflammatory cytokines, indicating that the protease used in the current study can be added to SBM-based diets for weanling pigs to improve gut health.

Enzyme-treated soy protein supplementation in low protein diet enhanced immune function of immune organs in on-growing grass carp.

A 56 days feeding trial was conducted to investigate the effects of enzyme-treated soy protein (ETSP) supplementation in low protein diets on immune function of immune organs (head kidney, spleen and skin) in on-growing grass carp. A total of 540 on-growing grass carp (initial average weight: 325.72 ± 0.60 g) were fed six diets, which included a normal protein diet (28% crude protein) and five low protein diets (26% crude protein) supplemented with graded levels of ETSP (0.0, 0.8, 1.2, 1.6 and 2.0%). At the end of feeding period, a challenge test was performed by infection with Aeromonas hydrophila for two weeks. The results indicated that (1) reducing dietary protein content from 28 to 26% decreased antibacterial substances and aggravated inflammatory responses of above three immune organs; (2) under the condition of reducing protein level in diet, 0.8-1.2% ETSP supplementation reversed these above adverse effects on immune function of above three immune organs; (3) suitable ETSP supplementation-decreased inflammatory responses were partly associated with [IκB kinase ß (IKKß)/inhibitor of κBα (IκBα)/nuclear factor kappa B (NF-κB) p65 and p52 or NF-κB p65] signaling and [target of rapamycin (TOR)/(S6K1, 4E-BP)] signaling in above three immune organs. (4) On the basis of C3 content (head kidney), C4 content (spleen) and skin hemorrhage and lesion, the optimal ETSP supplementation levels in low protein diets were estimated to be 1.48%, 1.61% and 1.03%, respectively. In summary, ETSP supplementation in low protein diets improved immune function of head kidney, spleen and skin in on-growing grass carp.

Molecular mechanisms of selenium-biofortified soybean protein and polyphenol conjugates in protecting mouse skin damaged by UV-B.

Selenium-biofortified crops are a quality functional food resource because of their anti-tumor and anti-cancer properties. In the present study, the conjugates of selenium-biofortified soybean protein and polyphenols were prepared and evaluated by alkali-induced synthesis and in vitro antioxidant tests. Moreover, the antioxidant mechanisms of protecting mice skin damaged by UV-B were studied. The results showed that the antioxidant activity of the conjugate between 7S globulin from selenium-enriched soybean (Se-7S) and EGCG (Se-7S-EGCG) was significantly higher (P < 0.05) than that of Se-7S-GA. Structural characterizations implied that the polymerization of polyphenols with amino acid residues occurred. Se-7S-EGCG inhibited the apoptosis of epidermal cells induced by UV-B. The overexpression of phosphorylated proteins in the MAPK signaling pathway, the activation of related inflammatory factors, and the boost in the MMPs were reversed by Se-7S-EGCG. Overall, this research provides a theoretical and experimental basis for the application of protein and polyphenol conjugates in food and medicine fields.