Mathematical Modeling and Optimization of Lactobacillus Species Single and Co-Culture Fermentation Processes in Wheat and Soy Dough Mixtures

To improve food production via fermentation with co-cultures of microorganisms (e.g., multiple lactic acid bacteria-LAB strains), one must fully understand their metabolism and interaction patterns in various conditions. For example, LAB can bring added quality to bread by releasing several bioactive compounds when adding soy flour to wheat flour, thus revealing the great potential for functional food development. In the present work, the fermentation of three soy and wheat flour mixtures is studied using single cultures and co-cultures of Lactobacillus plantarum and Lactobacillus casei. Bio-chemical processes often require a significant amount of time to obtain the optimal amount of final product; creating a mathematical model can gain important information and aids in the optimization of the process. Consequently, mathematical modeling is used to optimize the fermentation process by following these LAB’s growth kinetics and viability. The present work uses both multiple regression and artificial neural networks (ANN) to obtain the necessary mathematical model, useful in both prediction and process optimization. The main objective is to find a model with optimal performances, evaluated using an ANOVA test. To validate each obtained model, the simulation results are compared with the experimental data.

Effects of soy intake on circulating levels of TNF-α and interleukin-6: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Pro-inflammatory mediators, including serum tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), can be used as biomarkers to indicate or monitor disease. This study was designed to ascertain the effects of soy products on TNF-α and IL-6 levels.

METHODS

PubMed, EMBASE, Science Direct, Web of Science, Google Scholar and the Cochrane Central Register of Controlled Trials were searched to November 2019 for RCTs around the effects of soy-based products on TNF-α and IL-6. A random effects model was used to calculate overall effect size.

RESULTS

In total, 29 eligible publications were considered in the present systematic review, of which 25 were included in this meta-analysis. The overall effect of soy products on TNF-α and IL-6 levels failed to reach statistical significance (MD = - 0.07; 95% CI - 0.22-0.09; I² 50.9; MD = 0.03; 95% CI - 0.07-0.14; I² 42.1, respectively). According to a subgroup analysis, natural soy products led to a reduction in TNF-α concentration compared with processed soy products (MD = - 0.32; 95% CI - 0.45 to - 0.19; I² 0.0). Moreover, IL-6 reduction was stronger in participants who were affected by different diseases (MD = - 0.04; 95% CI - 0.07 to - 0.02; I² 0.0).

CONCLUSIONS

A review of RCTs published to November 2019 found that natural soy products are effective in lowering TNF-α levels. While the beneficial effects on reduction of IL-6 appeared stronger in individuals affected by different diseases, this finding cannot be generalized to all individuals affected by different diseases.

Exploitation of Lactic Acid Bacteria and Baker's Yeast as Single or Multiple Starter Cultures of Wheat Flour Dough Enriched with Soy Flour

Sourdough fermentation presents several advantageous effects in bread making, like improved nutritional quality and increased shelf life. Three types of experiments aimed to evaluate comparatively the efficiency of two Lactobacillus (Lb.) strains, Lb. plantarum ATCC 8014 and Lb. casei ATCC 393, to metabolize different white wheat flour and soybeans flour combinations to compare their efficiency, together with/without Saccharomyces cerevisiae on sourdough fermentation. For this purpose, the viability, pH, organic acids, and secondary metabolites production were investigated, together with the dynamic rheological properties of the sourdough. During sourdough fermentation, LAB presented higher growth, and the pH decreased significantly from above pH 6 at 0 h to values under 4 at 24 h for each experiment. Co-cultures of LAB and yeast produced a higher quantity of lactic acid than single cultures, especially in sourdough enriched with soy-flour. In general, sourdoughs displayed a stable, elastic-like behavior, and the incorporation of soy-flour conferred higher elasticity in comparison with sourdoughs without soy-flour. The higher elasticity of sourdoughs enriched with soy-flour can be attributed to the fact that through frozen storage, soy proteins have better water holding capacity. In conclusion, sourdough supplemented with 10% soy-flour had better rheological properties, increased lactic, acetic, and citric acid production.

Fractional-Order Models for Biochemical Processes

Biochemical processes present complex mechanisms and can be described by various computational models. Complex systems present a variety of problems, especially the loss of intuitive understanding. The present work uses fractional-order calculus to obtain mathematical models for erythritol and mannitol synthesis. The obtained models are useful for both prediction and process optimization. The models present the complex behavior of the process due to the fractional order, without losing the physical meaning of gain and time constants. To validate each obtained model, the simulation results were compared with experimental data. In order to highlight the advantages of fractional-order models, comparisons with the corresponding integer-order models are presented.

Isoflavones enhance the plasma cholesterol-lowering activity of 7S protein in hypercholesterolemic hamsters

Previous studies have shown that 7S protein is the active ingredient responsible for the plasma cholesterol-lowering activity of soybean. It is hypothesized that isoflavones in soybean could enhance the blood cholesterol-lowering activity of 7S protein. Forty-eight hamsters were divided into six groups and fed a non-cholesterol diet or one of the five high-cholesterol diets containing 12.1% 7S protein with 0-15.62 mg g-1 isoflavones. The results showed that addition of isoflavones in diets dose-dependently enhanced the plasma total cholesterol-lowering activity of 7S protein. Addition of isoflavones in 7S protein-based diets significantly reduced hepatic cholesterol accumulation by 12.6-26.1%, compared with the high cholesterol control diet. Isoflavones could also facilitate excretion of neutral sterols in a dose-dependent manner. Supplementation of isoflavones in diets favourably modulated mRNA expression and the protein mass of HMG-CoA reductase. It was concluded that the enhancing effect of isoflavones on the blood cholesterol-lowering activity of 7S protein was mediated by inhibiting the cholesterol absorption and de novo cholesterol synthesis in hypercholesterolemic hamsters.

Analysis of γ-Tocopherol methyl transferase3 promoter activity and study of methylation patterns of the promoter and its gene body

Soybeans are known for its good source of protein (40%), oil (20%) and also serve as a source of nutraceutical compounds including tocopherols (toc). To know the molecular basis of differential α-toc accumulation in two contrasting soybean genotypes: DS74 (low α-toc - 1.36 μg/g and total-toc -29.72 μg/g) and Bragg (high α-toc - 10.48 μg/g and total-toc 178.91 μg/g), the analysis of γ-TMT3 promoter activity and its methylation patterns were carried out. The sequencing results revealed nucleotide variation between Bragg:γ-TMT3-P and DS74:γ-TMT3-P, however none of the variations were found in core-promoter region or in cis-elements. The histochemical GUS assay revealed higher promoter activity of Bragg:γ-TMT3-P than that of DS74:γ-TMT3-P and correlated with significantly higher and lower (P < 0.05) expression of γ-TMT3 gene respectively. To know the molecular basis of differential accumulation of α-toc in these contrasting soybean genotypes, the DNA methylation pattern of γ-TMT3 gene body and its promoter was studied in both varieties. The results showed higher percentage (62.5%) of methylation in DS74:γ-TMT3-P than in Bragg:γ-TMT3-P (50%). Out of all the methylation sites in the promoter region, one of methylation site was found at CAAT box (-190 bp) of DS74:γ-TMT3-P. Further gene body methylation patterns revealed lowest % (40%) of CG methylation in DS74:γ-TMT3 gene as compared to Bragg:γ-TMT3 (64.2%). Thus our study revealed that, expression of γ-TMT3 gene was influenced by its promoter activity and methylation patterns in cis-elements of γ-TMT3 promoter and gene body. This study will help us to understand the possible role of methylation and promoter activity in determining the α-toc content in soybean seeds.

The soybean rhizosphere: Metabolites, microbes, and beyond-A review

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Rhizosphere microbial communities are important for plant health.

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Specialized metabolites in the rhizosphere influence the microbial communities.

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Isoflavones and saponins are major specialized metabolites secreted by soybean.

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Secretion is regulated developmentally and nutritionally.

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Possible links between specialized metabolites and microbial communities are highlighted.

The rhizosphere is the region close to a plant’s roots, where various interactions occur. Recent evidence indicates that plants influence rhizosphere microbial communities by secreting various metabolites and, in turn, the microbes influence the growth and health of the plants. Despite the importance of plant-derived metabolites in the rhizosphere, relatively little is known about their spatiotemporal distribution and dynamics. In addition to being an important crop, soybean (Glycine max) is a good model plant with which to study these rhizosphere interactions, because soybean plants have symbiotic relationships with rhizobia and arbuscular mycorrhizal fungi and secrete various specialized metabolites, such as isoflavones and saponins, into the soil. This review summarizes the characteristics of the soybean rhizosphere from the viewpoint of specialized metabolites and microbes and discusses future research perspectives. In sum, secretion of these metabolites is developmentally and nutritionally regulated and potentially alters the rhizosphere microbial communities.

Comparative study of the quality characteristics of defatted soy flour treated by supercritical carbon dioxide and organic solvent

Defatted soy flour is a potential source of food protein, amino acids, ash and isoflavones. The supercritical carbon dioxide (SC-CO₂) and a traditional organic solvent extraction methods were used to remove fat from soy flour, and the quality characteristics of a control soy flour (CSF), defatted soy flour by SC-CO₂ (DSFSC-CO₂) and defatted soy flour by an organic solvent (DSF-OS) were compared. The SC-CO₂ process was carried out at a constant temperature of 45 °C, and a pressure of 40 MPa for 3 h with a CO₂ flow rate of 30 g/min. The DSFSC-CO₂ had significantly higher protein, ash, and amino acids content than CSF and DSF-OS. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis demonstrated that CSF and DSFSC-CO₂ had protein bands of similar intensity and area that indicated no denaturation of protein, whereas DSF-OS showed diffuse bands or no bands due to protein denaturation. In addition to higher nutritional value and protein contents, DSFSC-CO₂ showed superior functional properties in terms of total soluble solids content, water and oil absorption, emulsifying and foaming capacity. The SC-CO₂ method offers a nutritionally and environmentally friendly alternative extraction processing approach for the removal of oil from high-protein food sources. It has a great potential for producing high-protein fat-free, and low-calorie content diet than the traditional organic solvent extraction method.

Developmental and nutritional regulation of isoflavone secretion from soybean roots

Isoflavones play important roles in plant-microbe interactions in rhizospheres. Soybean roots secrete daidzein and genistein to attract rhizobia. Despite the importance of isoflavones in plant-microbe interactions, little is known about the developmental and nutritional regulation of isoflavone secretion from soybean roots. In this study, soybeans were grown in hydroponic culture, and isoflavone contents in tissues, isoflavone secretion from the roots, and the expression of isoflavone conjugates hydrolyzing beta-glucosidase (ICHG) were investigated. Isoflavone contents did not show strong growth-dependent changes, while secretion of daidzein from the roots dramatically changed, with higher secretion during vegetative stages. Coordinately, the expression of ICHG also peaked at vegetative stages. Nitrogen deficiency resulted in 8- and 15-fold increases in secretion of daidzein and genistein, respectively, with no induction of ICHG. Taken together, these results suggest that large amounts of isoflavones were secreted during vegetative stages via the hydrolysis of (malonyl)glucosides with ICHG.

Dietary soy intake is not associated with risk of cardiovascular disease mortality in Singapore Chinese adults

Although soy food has been recommended because of its presumed cardiovascular benefits, the long-term prospective association between habitual soy food intake and cardiovascular disease mortality remains unclear. This study aimed to evaluate the relation of soy protein and isoflavone intake with the risk of cardiovascular disease mortality in middle-aged and older Chinese adults residing in Singapore. The Singapore Chinese Health Study is a population-based study that recruited 63,257 Chinese adults aged 45-74 y from 1993 to 1998. Usual diet was measured at recruitment by using a validated semiquantitative food-frequency questionnaire, and mortality information was identified via registry linkage until 31 December 2011. Cox proportional hazards models were used to calculate HRs, with adjustment for potential confounders. The median intake was 5.2 g/d for soy protein, 15.8 mg/d for soy isoflavones, and 87.4 g/d for soy expressed as tofu equivalents. We documented 4780 cardiovascular deaths during 890,473 person-years of follow-up. After adjustment for sociodemographic, lifestyle, and other dietary factors, soy protein intake was not significantly associated with cardiovascular disease mortality: HRs (95% CIs) were 1.00 (reference), 1.02 (0.94, 1.11), 1.02 (0.93, 1.11), and 1.06 (0.97, 1.17) for increasing quartiles of soy protein (P-trend = 0.24). Similarly, no significant association was observed for soy isoflavones and total tofu equivalents and when deaths from coronary heart disease (n = 2697) and stroke (n = 1298) were considered separately. When stratified by sex, HRs for cardiovascular disease mortality across quartiles of soy protein were 1.00, 1.00, 1.05, and 1.16 (95% CI: 1.03, 1.31) in men (P-trend = 0.02) and 1.00, 1.01, 0.96, and 0.95 (95% CI: 0.81, 1.10) in women (P-trend = 0.31), although the interaction was not significant (P-interaction = 0.12). In conclusion, soy intake was not significantly associated with risk of cardiovascular disease mortality in the Chinese population. However, a slightly increased risk associated with high soy protein intake in men cannot be excluded and requires further investigation.

Analysis of daidzein in nanoparticles after oral co-administration with sodium caprate to rats by ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry

An ultra-performance-liquid-chromatography-quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS) method was developed and validated for the quantitation of daidzein (DZ) in rat plasma. Ethylparaben was chosen as internal standards (IS). DZ was linear over the range of 0.001-5 μg/mL. The lower limit of quantification (LLOQ) was 0.001 μg/mL and the limit of detection (LOD) was 0.0005 μg/mL. The intra-day and inter-day relative standard deviations (RSDs) were ranged from 3.59% to 6.43% and 5.35% to 7.25%, respectively. This UPLC/Q-TOF-MS method provided good specifity, highly sensitivity, accurate and high-speed detection (6 min), applicable to the pharmacokinetics study in rats in vivo after oral administration of free daidzein solution, daidzein-loaded poly (lactide-co-glycolide) (PLGA) nanoparticles (D-NPs) suspension and D-NPs co-administered with sodium caprate (C(10)) which as the oral absorption promoter. It was shown that the pharmacokinetics behavior was significantly improved after the oral administration of D-NPs suspension co-administered with absorption promoter C(10) by the fact that the relative bioavailability were enhanced about 4.24-fold, compared to that of DZ suspension.

Physicochemical and sensory characteristics of a medicinal soy yogurt containing health-benefit ingredients

Medicinal soy yogurt (sogurt) containing high levels of gamma-aminobutyric acid (GABA), free amino acids (FAAs), statins, and isoflavone aglycones was developed using lactic acid bacteria (1:1 mixture of Lactobacillus delbrueckii subsp. latis KFRI 01181 and Lactobacillus plantarum KFRI 00144) and Monascus-fermented soybean extract (MFSE, 1.5%, w/v). Changes in the content of some functional components (GABA, FAAs, statins, isoflavones) and physical (pH, titratable acidity, water-holding capacity), biological (viable cell counts), and sensory characteristics of sogurts during fermentation and cold storage were examined. The medicinal sogurt contained significantly (p < 0.05) high levels of FAAs (2011.2 +/- 8.1 mg/100 g of dry weight of sogurt), GABA (45.5 +/- 1.9 mg), statins (100.1 +/- 7.5 microg), and isoflavone aglycones (56.4 +/- 4.6 mg) compared with the control sogurt (1167.1 +/- 8.1 mg, 32.1 +/- 2.5 mg, not detected, and 19.2 +/- 1.9 mg, respectively) after fermentation for 24 h at 35 degrees C. During cold storage for 30 days at 4 degrees C, medicinal sogurt displayed higher water-holding capacity and titratable acidity and total bacterial cells and lower pH than the control sogurt (p < 0.05). Overall sensory acceptability of medicinal sogurt supplemented with MFSE was higher than that of the control sogurt prepared without MFSE. The results indicate that the addition of the appropriate MFSE concentrations (1.5%, w/v) improved the physicochemical properties as well as sensory characteristics of soy yogurt, resulting in enhanced health-benefit ingredients and consumers' preferences.

Extraction and characterization of oil bodies from soy beans: a natural source of pre-emulsified soybean oil

Soybeans contain oil bodies that are coated by a layer of oleosin proteins. In nature, this protein coating protects the oil bodies from environmental stresses and may be utilized by food manufacturers for the same purpose. In this study, oil bodies were extracted from soybean using an aqueous extraction method that involved blending, dispersion (pH 8.6), filtration, and centrifugation steps. The influence of NaCl (0-250 mM), thermal processing (30-90 degrees C, 20 min) and pH (2-8) on the properties and stability of the oil bodies was analyzed using zeta-potential, particle size, and creaming stability measurements. The extracted oil bodies were relatively small ( d 32 approximately 250 nm), and their zeta-potential went from around +12 mV to -20 mV as the pH was increased from 2 to 8, with an isoelectric point around pH 4. The oil bodies were stable to aggregation and creaming at low (pH = 2) and high (pH >/= 6) pH values but were unstable at intermediate values (3 Collapse

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MESH Headings

• Emulsions/chemistry
• Food Handling/methods
• Hot Temperature
• Hydrogen-Ion Concentration
• Particle Size
• Plant Extracts
• Seeds/chemistry
• Soybean Oil/chemistry
• Soybean Oil/isolation & purification
• Soybean Proteins/chemistry
• Glycine max/chemistry

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Affiliation(s)

Daigo Iwanaga Biopolymers and Colloids Research Laboratory, Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, USA
David A Gray
Ian D Fisk
Eric Andrew Decker
Jochen Weiss
David Julian McClements

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Commercial soy protein ingredients as isoflavone sources for functional foods

The knowledge of the contents and profile of isoflavones present in soy protein ingredients, as well as the effect of industrial processing, is important for the development of functional foods rich in these compounds. The results obtained here showed that the total isoflavone content varied significantly among products. For defatted and whole soy flours the total isoflavone content ranged from 120 to 340 mg/100 g, for soy protein isolates from 88 to 164 mg/100 g, and for commercial textured soy proteins, from 66 to 183 mg/100 g (wet basis, expressed as aglycones). The highest isoflavone content was found for soy hypocotyl flours, from 542 to 851 mg/100 g. Compared to hypocotyl and whole and defatted flours, soy ingredients presented a decrease of malonylglycosides and deesterified beta-glycosides with a significant increase in the percentage of aglycones, mainly for soy fibers (65-76%). While defatting was shown to cause isoflavone concentration without altering conjugation, extrusion process caused destruction of isoflavones and a significant increase in the amount of acetylglycosides, but this effect was less intense for the concentrates. From the results obtained it can be concluded that differences in isoflavone concentration and profile may be related to oscillations in the isoflavone content present in the raw material and to the type of processing.

Analysis of isoflavone daidzein in Puerariae radix with micelle-mediated extraction and preconcentration

Nonionic surfactant oligo(ethylene glycol) monoalkyl ether (Genapol X-080) was employed as an alternative and effective solvent for the extraction of daidzein from Puerariae radix for the first time. Optimum experimental conditions were established. With 5% Genapol X-080 (w/v), liquid/solid ratio of 25:1 (mL/g), and ultrasonic-assisted extraction for 45 min, the extraction percentage of daidzein reached the highest value. For the preconcentration of daidzein by cloud-point extraction (CPE), sodium chloride was added to the solution to facilitate the phase separation and increase the preconcentration factor by reducing the volume of the surfactant-rich phase. The preconcentration factor for daidzein was about 13. Satisfactory results were obtained for the analysis of daidzein from P. radix with this established method.