Neal A. Bringe

β-Conglycinins among Sources of Bioactives in Hydrolysates of Different Soybean Varieties That Inhibit Leukemia Cells in Vitro

Soybean is a complex matrix containing several potentially bioactive components. The objective was to develop a statistical model to predict the in vitro anticancer potential of soybean varieties based on the correlation between protein composition and bioactive components after simulated gastrointestinal enzyme digestion with their effect on leukemia mouse cells. The IC 50 values of the hydrolysates of soy genotypes (NB1-NB7) on L1210 leukemia cells ranged from 3.5 to 6.2 mg/mL. Depending on genotype, each gram of soy hydrolysates contained 2.7-6.6 micromol of total daidzein, 3.0-4.7 micromol of total genistein, 0.5-1.3 micromol of glycitein, 2.1-2.8 micromol of total saponins, 0.1-0.2 micromol of lunasin, and 0.1-0.6 micromol of Bowman-Birk inhibitor (BBI). The IC 50 values calculated from a partial least-squares (PLS) analysis model correlated well with experimental data ( R (2) = 0.99). Isoflavones and beta-conglycinin positively contributed to the cytotoxicity of soy on L1210 leukemia cells. Lunasin and BBI were potent L1210 cell inhibitors (IC 50 = 13.9 and 22.5 microM, respectively), but made modest contributions to the activity of defatted soy flour hydrolysates due to their relatively low concentrations. In conclusion, the data demonstrated that beta-conglycinins are among the major protein components that inhibit leukemia cell growth in vitro. Furthermore, it was feasible to differentiate soybean varieties on the basis of the biological effect of their components using a statistical model and a cell-based assay.

Beta-conglycinin embeds active peptides that inhibit lipid accumulation in 3T3-L1 adipocytes in vitro.

Obesity is a worldwide health concern because it is a well-recognized predictor of premature mortality. The objective was to identify soybean varieties that have improved potential to inhibit fat accumulation in adipocytes by testing the effects of soy hydrolysates having a range of protein subunit compositions on lipid accumulation and adiponectin expression in 3T3-L1 adipocytes. The results showed that differences in the protein distribution of 15 soy genotypes led to different potentials for the reduction of fat accumulation. The inhibition of lipid accumulation of soy alcalase hydrolysates in 3T3-L1 adipocytes ranged from 29 to 46%. Soy hydrolysates made from genotypes with 45.3 +/- 3.3% of total protein as beta-conglycinin, on average, showed significantly higher inhibition of lipid accumulation compared to those with 24.7 +/- 1.5% of extracted total protein as beta-conglycinin. Moreover, after in vitro simulated digestion with pepsin-pancreatin of the soy alcalase hydrolysates, 86% of the original activity remained. Adiponectin expression was induced in 3T3-L1 adipocytes treated with 15 soy hydrolysates up to 2.49- and 2.63-fold for high and low molecular weight adiponectin, respectively. The inhibition of lipid accumulation calculated from a partial least squares (PLS) analysis model correlated well with experimental data (R(2) = 0.91). In conclusion, it was feasible to differentiate soy varieties on the basis of the potential of their proteins to reduce fat accumulation using a statistical model and a cell-based assay in vitro. Furthermore, beta-conglycinin embeds more peptides than glycinin subunits that inhibit lipid accumulation and induce adiponectin in 3T3-L1 adipocytes. Therefore, soy ingredients containing beta-conglycinin may be important food components for the control of lipid accumulation in adipose tissue.

Protein hydrolysates from β-conglycinin enriched soybean genotypes inhibit lipid accumulation and inflammation in vitro.

Obesity is a worldwide health concern and a well recognized predictor of premature mortality associated with a state of chronic inflammation. The objective was to evaluate the effect of soy protein hydrolysates (SPH) produced from different soybean genotypes by alcalase (SAH) or simulated gastrointestinal digestion (SGIH) on lipid accumulation in 3T3-L1 adipocytes. The anti-inflammatory effect of SPH produced by alcalase on LPS-induced macrophage RAW 264.7 cell line was also investigated. SAH (100 microM) derived from soybean enriched in beta-conglycinin (BC) (up to 47% total protein) decreased lipid accumulation (33-37% inhibition) through downregulation of gene expression of lipoprotein lipase (LPL) and fatty acid synthase (FAS). SGIH (100 microM) inhibited lipid accumulation to a lesser extent (8-14% inhibition) through inhibition of LPL gene expression. SAH (5 microM) decreased the production of nitric oxide (NO) (18-35%) and prostaglandin E(2) (PGE(2)) (47-71%) and the expression of inducible nitric oxide synthase (iNOS) (31-53%) and cycloxygenase-2 (COX-2) (30-52%). This is the first investigation showing that soy hydrolysates inhibit LPS-induced iNOS/NO and COX-2/PGE(2 )pathways in macrophages. Soybeans enriched in BCs can provide hydrolysates that limit fat accumulation in fat cells and inflammatory pathways in vitro and therefore warrant further studies as a healthful food.

Peptides in pepsin-pancreatin hydrolysates from commercially available soy products that inhibit lipopolysaccharide-induced inflammation in macrophages

The potential of pepsin-pancreatin hydrolysates, from different foods, to inhibit inflammation using lipopolysaccharide (LPS)-induced RAW 264.7 macrophages as an in vitro model was evaluated. Eight different products were digested sequentially with pepsin and pancreatin and were evaluated for their anti-inflammatory properties. Hydrolysates from strawberry-banana soymilk (SBH), mixed berry soymilk (MXH) and vanilla soymilk (SVMH) inhibited the production of nitric oxide (27.9%, 16.4% and 28.6%, respectively), interleukin-1β (26.3%, 39.5% and 21.6%, respectively) and tumour necrosis factor-α (50.2%, 47.5% and 33.3%, respectively). In addition, SBH, MXH and SVMH inhibited the expression of pro-inflammatory enzymes: inducible nitric oxide synthase (66.7%, 65.1% and 88.0%, respectively) and cyclooxygenase-2 (62.0%, 69.9% and 40.6%, respectively). Bioactive peptides (RQRK and VIK) were generated. In conclusion, soymilk products can potentially be used to maintain health under inflammatory stress.

Consumption of different soymilk formulations differentially affects the gut microbiomes of overweight and obese men

The effects of consuming foods on the intestinal microbiome of obese individuals remain unclear. The objective of this study was to compare the effects of consuming low glycinin soymilk (LGS, 49.5% β-conglycinin/6% glycinin), conventional soymilk (S, 26.5% β-conglycinin/38.7% glycinin) or bovine milk (M, 0% β-conglycinin/0% glycinin) on the intestinal microbiome in overweight and obese men. In a randomized double-blind study, participants (64 men, BMI > 25, 20–45 y old), organized in three groups, consumed 500 mL of LGS, S or M daily for 3 mo. Three fecal samples were collected before (baseline) and after 3 mo of consumption. Dietary energy and macronutrient intake were monitored monthly and remained constant throughout the study (p > 0.05). Microbial composition was analyzed with qPCR and bTEFAP. Within groups, qPCR analysis showed that the total bacteria increased in all treatments over time (p < 0.001). Bacteroides-Prevotella (p = 0.001) and Lactobacillus (p < 0.001) increased in LGS and M, respectively. Bifidobacterium was significantly reduced in LGS (p = 0.003) and S (p < 0.001). Bacterial diversity decreased for LGS, S and M (p = 0.004, 0.005, 0.001; respectively). Unweighted UniFrac analysis revealed that the microbial communities were more similar within than between individuals. The Firmicutes to Bacteroidetes ratio decreased in both LGS and S groups and remained relatively unchanged in the M group (Time p = 0.012; Interaction p = 0.059). Indicator analysis revealed several genera that were indicative of each treatment including Lactobacillus and Prevotella. Consumption of the three beverages differentially altered the microbiota in overweight and obese men including a potentially beneficial alteration of the Firmicutes to Bacteroidetes ratio in both soymilk groups.

Properties of Low-Fat, Low-Cholesterol Egg Yolk Prepared by Supercritical CO2 Extraction

A dry egg yolk ingredient called Eggcellent has 74% less fat and 90% less cholesterol than liquid egg yolks, when reconstituted on an equal protein basis. The phospholipids and proteins are retained, enabling the ingredient to have the taste and texturizing properties of fresh egg yolk. Using the new yolk, it is possible to significantly improve the acceptability of low-fat, low-cholesterol bakery products, scrambled eggs and mayonnaise dressings without losing nutritional claims. The structures and functional properties of egg yolk components and the conditions required to optimize their benefits in foods are reviewed. The lipoproteins of low-fat, low-cholesterol yolk have valuable properties as flavorants, texturizers, foaming agents, emulsifiers, antioxidants, colorants, and nutraceuticals.