Soy Intake Since the Prepubertal Age May Contribute to the Pathogenesis of Endometriosis in Adulthood.

High prevalence of endometriosis was reported in Asian women as a result of their traditionally high intake of soy foods during infancy. Soy is widely used in infant feeding after weaning from breast milk or cow milk. This study thus aimed to determine to what extent soy intake before puberty may contribute to the development of endometriosis. For this purpose, immature (6-week old) female rats were fed with various soy formulas (0%, 10%, 20%, 30%, 40%, 50%, and 60%). Normal control animals were fed with a soy-free diet. At 13 weeks of age, animals (except the normal control) underwent a transplantation surgery to establish endometriosis. Estradiol valerate and oxytocin were used to induce pelvic pain. Endometrial implant levels of glutathione (GSH) and malondialdehyde (MDA) allowed estimating tissue oxidative status. Physiological ovarian function was assessed by histological analysis of ovaries. Results showed that soy-fed animals grew faster than animals receiving a soy-free diet (P < .001). In animals supplemented with more than 10% of soy, the intensity of pelvic pain increased (P < .001) as well as the volume of ectopic foci. In addition, tissue levels of MDA and GSH increased (P < .001). The ovarian function was altered and the number of luteinized unruptured follicles increased. In conclusion, although animals supplemented with soy at the prepubertal stage displayed a good growth performance, regular soy consumption may promote the development and progress of endometriosis in adulthood, especially when soy content in food is more than 10%.

The Effects of Soy Milk Enriched with Lactobacillus casei and Omega-3 on the Tibia and L5 Vertebra in Diabetic Rats: a Stereological Study.

Bone fragility, despite relatively high BMD values, is an important complication related to insulin resistance and oxidative stress in diabetes mellitus type 1. The present study aimed to compare the effects of soy milk (SM), soy milk containing Lactobacillus casei (PSM), and soy milk enriched with Lactobacillus casei and omega-3 (OPSM) on the stereology of the tibia and vertebra, and antioxidant activity in type 1 diabetic rats. Sixty-five male Sprague Dawley rats were randomly assigned into 5 groups of 13 animals each. Diabetes was induced by a single injection of STZ (60 mg/kg); two control groups (non-diabetic: CN and diabetic: CD) were selected and then fed with 1 mL of distilled water. Three treatment groups were fed 1 ml of SM, PSM, and OPSM via intragastric gavage for 60 days. Treatment with SM, PSM, and OPSM significantly decreased (P < 0.05) the number of the osteoclasts in both tibia and L5 vertebra, and plasma alkaline phosphatase level. Also, the osteoblast number, calcium level, catalase activity, and total antioxidant capacity were increased in the SM, PSM, and OPSM groups compared to the STZ group. OPSM had the greatest effects on the stereological and biochemical parameters compared to the SM and PSM groups. Soy milk combination with Lactobacillus casei and omega-3 can ameliorate the stereological changes in the tibia and vertebra. In addition, this combination increased the antioxidant activity and improved the redox homeostasis in diabetic rats. These results suggest the potential role of soy milk containing Lactobacillus casei enriched with omega-3 in preventing and delaying osteoporosis in diabetic patients.

Fermented Soymilk Alleviates Lipid Accumulation by Inhibition of SREBP-1 and Activation of NRF-2 in the Hepatocellular Steatosis Model.

Ingredients of soy and fermented soy products have been widely utilized as food supplements for health-enhancing properties. The aim of this study was to evaluate the effects of fermented soymilk (FSM) and soymilk (SM) on free fatty acid-induced lipogenesis in the hepatocellular steatosis model. HepG2 cells were incubated with palmitic acid (PA) for 24 h to induce lipogenesis and accumulation of intracellular lipid contents. The PA-treated cells were co-incubated with FSM, SM, genistein, and estrogen, respectively. Lipid accumulation in the PA-treated HpG2 cells was significantly decreased by co-incubation with FSM. Treatment of HepG2 cells with PA combined with genistein or estrogen significantly increased the expression of SREBP-1. However, FSM co-incubation significantly attenuated SREBP-1 expression in the PA-treated HepG2 cells; in addition, expression of NRF-2 and phosphorylation of ERK were significantly increased in the PA and FSM co-incubated cells. PA-induced ROS production was significantly reduced by FSM and SM. Our results suggested that the bioactive components of FSM could protect hepatocytes against the lipid accumulation and ROS production induced by free fatty acids. These effects may be mediated by the inhibition of SREBP-1 and the activation of NRF-2 via the ERK pathway in HepG2 cells.

Effect of Fermentation pH on Protein Bioaccessibility of Soymilk Curd with Added Tea Polyphenols As Assessed by in Vitro Gastrointestinal Digestion.

The aim of this study was to compare the effect of fermentation pH on protein bioaccessibility of four soymilk curds enriched with tea polyphenols (TP). The curds were generated by fermentation with Weissella hellenica D1501 and the fermentation terminated at different pH values, namely at pH 5.7, 5.4, 5.1, and 4.8 (SMTP-5.7, SMTP-5.4, SMTP-5.1, SMTP-4.8). Particle-size distribution, soluble protein content, gel electrophoresis, and peptides content were monitored at oral, gastric, and intestinal levels. Results showed that SMTP-4.8 was the matrix most resistant to protein digestion in the gastric phase according to the soluble protein content. Similar particle size distribution and protein degradation patterns were observed for these curds in gastric and intestinal phase. However, there was a significant difference (P < 0.05) in the content of small peptides (<10 kDa) at the end of intestinal digestion among the four curds. Overall, terminating fermentation at pH 5.4-5.7 of soymilk curds enriched with TP is recommended.

Passion fruit by-product and fructooligosaccharides stimulate the growth and folate production by starter and probiotic cultures in fermented soymilk.

Two starter cultures (Streptococcus (St.) thermophilus ST-M6 and TA-40) and five probiotic strains (St. thermophilus TH-4, Lactobacillus (Lb.) acidophilus LA-5, Lb. rhamnosus LGG, Lb. fermentum PCC, and Lb. reuteri RC-14) were used to ferment different soymilk formulations supplemented with passion fruit by-product and/or fructo-oligosaccharides (FOS) with the aim of increasing folate concentrations. Growth and folate production of individual strains were evaluated and the results used to select co-cultures. Both St. thermophilus ST-M6 and TH-4 were the best folate producers and were able to increase the folate content of all soymilk formulations when used alone or in co-culture with lactobacilli strains, especially in the presence of both passion fruit by-product and FOS. Thus, passion fruit by-product and FOS could be used as dietary ingredients to stimulate the folate production by selected bacterial strains during the fermentation of soymilk. It was also shown that vitamin production by microorganisms is strain-dependent and may also be influenced by nutritional and environmental conditions.

Soymilk enriched with green coffee phenolics - Antioxidant and nutritional properties in the light of phenolics-food matrix interactions.

This study investigated the effect of soymilk fortification with green coffee extract (GCE) on phenolic contents, antioxidant capacity, relative in vitro digestibility of proteins and starch, and consumer acceptance. Special attention was paid to the effect of phenolics-food matrix interactions on fortification efficiency. Soymilk was enriched with GCE extracts containing 0.025-1mg of phenolics per 1mL-samples M1-M6. Compared to control, an increase in phenolic contents of up to 70% (M6) was observed for potentially bioaccessible fractions (AD). The antiradical activity and reducing power were also about 1.9 and 10.1 times higher, respectively. However, the determined phenolic and antioxidant activities differed from those predicted. Fortification improved the digestibility of nutrients when higher doses of GCE was introduced (M4-M6). The addition of GCE at an adequate dose allowed the production of a beverage with elevated hedonic properties. In conclusion, fortification was a successful in improving the pro-health status of soymilk.

Soyamilk fermented with riboflavin-producing Lactobacillus plantarum CRL 2130 reverts and prevents ariboflavinosis in murine models.

It has been previously shown that Lactobacillus plantarum CRL 2130 is able to produce riboflavin in soyamilk. The aim of the present study was to evaluate the efficiency of this riboflavin-bio-enriched soyamilk to revert and/or prevent the nutritional deficiency of riboflavin using different animal models. When used to supplement the diets of previously depleted animals, it was shown that the growth, riboflavin status and morphology of the small intestines reverted to normal parameters and were similar to animals supplemented with commercial riboflavin. In the prevention model, the same tendency was observed, where animals that received soyamilk fermented with L. plantarum CRL 2130 did not show signs of riboflavin deficiency. This new bio-fortified soya-based product could be used as part of normal diets to provide a more natural alternative to mandatory fortification with riboflavin for the prevention of its deficiency.

Fermentation of soy milk via Lactobacillus plantarum improves dysregulated lipid metabolism in rats on a high cholesterol diet.

We aimed to investigate whether in vitro fermentation of soy with L. plantarum could promote its beneficial effects on lipids at the molecular and physiological levels. Rats were fed an AIN76A diet containing 50% sucrose (w/w) (CTRL), a modified AIN76A diet supplemented with 1% (w/w) cholesterol (CHOL), or a CHOL diet where 20% casein was replaced with soy milk (SOY) or fermented soy milk (FSOY). Dietary isoflavone profiles, serum lipids, hepatic and fecal cholesterol, and tissue gene expression were examined. The FSOY diet had more aglycones than did the SOY diet. Both the SOY and FSOY groups had lower hepatic cholesterol and serum triglyceride (TG) than did the CHOL group. Only FSOY reduced hepatic TG and serum free fatty acids and increased serum HDL-CHOL and fecal cholesterol. Compared to CHOL, FSOY lowered levels of the nuclear forms of SREBP-1c and SREBP-2 and expression of their target genes, including FAS, SCD1, LDLR, and HMGCR. On the other hand, FSOY elevated adipose expression levels of genes involved in TG-rich lipoprotein uptake (ApoE, VLDLR, and Lrp1), fatty acid oxidation (PPARα, CPT1α, LCAD, CYP4A1, UCP2, and UCP3), HDL-biogenesis (ABCA1, ApoA1, and LXRα), and adiponectin signaling (AdipoQ, AdipoR1, and AdipoR2), as well as levels of phosphorylated AMPK and ACC. SOY conferred a similar expression profile in both liver and adipose tissues but failed to reach statistical significance in many of the genes tested, unlike FSOY. Our data indicate that fermentation may be a way to enhance the beneficial effects of soy on lipid metabolism, in part via promoting a reduction of SREBP-dependent cholesterol and TG synthesis in the liver, and enhancing adiponectin signaling and PPARα-induced expression of genes involved in TG-rich lipoprotein clearance, fatty acid oxidation, and reverse cholesterol transport in adipose tissues.

Bioconversion of isoflavones and the probiotic properties of the electroporated parent and subsequent three subcultures of Lactobacillus fermentum BT 8219 in biotin-soymilk.

This study was aimed at an evaluation of the potential inheritance of electroporation effects on Lactobacillus fermentum BT 8219 through to three subsequent subcultures, based on their growth, isoflavone bioconversion activities, and probiotic properties, in biotin-supplemented soymilk. Electroporation was seen to cause cell death immediately after treatment, followed by higher growth than the control during fermentation in biotin-soymilk (P<0.05). This was associated with enhanced intracellular and extracellular beta-glucosidase specific activity, leading to increased bioconversion of isoflavone glucosides to aglycones (P<0.05). The growing characteristics, enzyme, and isoflavone bioconversion activities of the first, second, and third subcultures of treated cells in biotin-soymilk were similar to the control (P>0.05). Electroporation affected the probiotic properties of parent L. fermentum BT 8219, by reducing its tolerance towards acid (pH 2) and bile, lowering its inhibitory activities against selected pathogens, and reducing its ability for adhesion, when compared with the control (P<0.05). The first, second, and third subcultures of the treated cells showed comparable traits with that of the control (P>0.05), with the exception of their bile tolerance ability, which was inherited to the treated cells of the first and second subcultures (P<0.05). Our results suggest that electroporation could be used to increase the bioactivity of biotin-soymilk via fermentation with probiotic L. fermentum BT 8219, with a view towards the development of functional foods.

Effects of ultrasound on growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of Lactobacillus fermentum BT 8633 in biotin-supplemented soymilk.

This study aimed to evaluate the effects of ultrasound on Lactobacillus fermentum BT 8633 in parent and subsequent passages based on their growth and isoflavone bioconversion activities in biotin-supplemented soymilk. The treated cells were also assessed for impact of ultrasound on probiotic properties. The growth of ultrasonicated parent cells increased (P<0.05) by 3.23-9.14% compared to that of the control during fermentation in biotin-soymilk. This was also associated with enhanced intracellular and extracellular (8.4-17.0% and 16.7-49.2%, respectively; P<0.05) ß-glucosidase specific activity, leading to increased bioconversion of isoflavones glucosides to aglycones during fermentation in biotin-soymilk compared to that of the control (P<0.05). Such traits may be credited to the reversible permeabilized membrane of ultrasonicated parent cells that have facilitated the transport of molecules across the membrane. The growing characteristics of first, second and third passage of treated cells in biotin-soymilk were similar (P>0.05) to that of the control, where their growth, enzyme and isoflavone bioconversion activities (P>0.05) were comparable. This may be attributed to the temporary permeabilization in the membrane of treated cells. Ultrasound affected probiotic properties of parent L. fermentum, by reducing tolerance ability towards acid (pH 2) and bile; lowering inhibitory activities against selected pathogens and reducing adhesion ability compared to that of the control (P<0.05). The first, second and third passage of treated cells did not exhibit such traits, with the exception of their bile tolerance ability which was inherited to the first passage (P<0.05). Our results suggested that ultrasound could be used to increase bioactivity of biotin-soymilk via fermentation by probiotic L. fermentum FTDC 8633 for the development of functional food.

Urinary (1)H-NMR metabonomics study on intervention effects of soya milk in Africans.

Metabonomics is an important tool in understanding the toxicological or therapeutic effects of interventions by analysing metabolic profiles and interpreting complex multi-dimensional spectroscopic/spectrometric data using multivariate data analysis. The objectives of this study were to evaluate the metabolic changes following a short-term 5 day soya milk intervention, and to investigate factors that influence soy-phytoestrogen metabolism focused on Africans based in either UK or Nigeria. (1)H-NMR metabonomics was applied to analyse urine samples collected at four phases I-IV (pre, days 3 and 5, and post) of the soy-intervention from African volunteers (n = 40 in total). Individual proton NMR spectra were visually and statistically assessed using multivariate analyses (MVA): principal component analysis (PCA) and (orthogonal-) partial-least square-discriminant analysis ((O-) PLS-DA). In addition, 22 endogenous metabolites were quantified using a Chenomx NMR suite. The results showed the levels of analysed endogenous metabolites (creatinine adjusted) present ranged from 4 µM to 12 mM with large inter-subject variances in acetate, acetone, lactate and trimethylamine. The MVA results showed high inter-individuality and sampling variances based on PCA score plots, and demonstrated soy metabolism to be significantly influenced by location and gender by both PLS-DA and O-PLS-DA.

Effect of bioactive compounds in lactobacilli-fermented soy skim milk on femoral bone microstructure of aging mice.

BACKGROUND: Soy skim milks fermented with lactobacilli contain various phytochemicals such as isoflavones and peptides. We used lactobacilli-fermented soy skim milk as a nutritional supplement for 6 weeks to investigate its anti-osteoporosis effect in 13-month-old female BALB/c aging mice. Freeze-dried powder of soy skim milk fermented by Lactobacillus paracasei subsp. paracasei NTU 101 (NTU 101F) and L. plantarum NTU 102 (NTU 102F) were used in this study. RESULTS: The trabecular bone volumes in mice fed NTU 101F and NTU 102F increased by a factor of 3.48 and 2.16 compared with control values, respectively. The network density and thickness of distal metaphyseal trabecular bone in mice fed with NTU 101F and NTU 102F milks were significantly denser than that of control mice; moreover, the NTU 101F group had the largest resting area ratio and smallest resorbing area compared with other groups. The beneficial effect may due to isoflavones as well as higher amounts of polysaccharide and peptide in NTU 101F milk. CONCLUSION: The results suggest that dietary supplement with fermented soy skim milk can attenuate aging-induced bone loss in BALB/c mice and possibly lower the risk of osteopenia or osteoporosis in aging.

Enhanced growth of lactobacilli and bioconversion of isoflavones in biotin-supplemented soymilk upon ultrasound-treatment.

This study aimed at utilizing ultrasound treatment to further enhance the growth of lactobacilli and their isoflavone bioconversion activities in biotin-supplemented soymilk. Strains of lactobacilli (Lactobacillus acidophilus BT 1088, L. fermentum BT 8219, L. acidophilus FTDC 8633, L. gasseri FTDC 8131) were treated with ultrasound (30 kHz, 100 W) at different amplitudes (20%, 60% and 100%) for 60, 120 and 180 s prior to inoculation and fermentation in biotin-soymilk. The treatment affected the fatty acids chain of the cellular membrane lipid bilayer, as shown by an increased lipid peroxidation (P<0.05). This led to increased membrane fluidity and subsequently, membrane permeability (P<0.05). The permeabilized cellular membranes had facilitated nutrient internalization and subsequent growth enhancement (P<0.05). Higher amplitudes and longer durations of the treatment promoted growth of lactobacilli in soymilk, with viable counts exceeding 9 log CFU/mL. The intracellular and extracellular ß-glucosidase specific activities of lactobacilli were also enhanced (P<0.05) upon ultrasound treatment, leading to increased bioconversion of isoflavones in soymilk, particularly genistin and malonyl genistin to genistein. Results from this study show that ultrasound treatment on lactobacilli cells promotes (P<0.05) the ß-glucosidase activity of cells for the benefit of enhanced (P<0.05) isoflavone glucosides bioconversion to bioactive aglycones in soymilk.

Enhanced growth of lactobacilli and bioconversion of isoflavones in biotin-supplemented soymilk by electroporation.

This study aimed at utilizing electroporation to further enhance the growth of lactobacilli and their isoflavone bioconversion activities in biotin-supplemented soymilk. Strains of lactobacilli were treated with different pulsed electric field strength (2.5, 5.0 and 7.5 kV/cm) for 3, 3.5 and 4 ms prior to inoculation and fermentation in biotin-soymilk at 37°C for 24 h. Electroporation triggered structural changes within the cellular membrane of lactobacilli that caused lipid peroxidation (p < 0.05) and alteration of membrane fluidity (p < 0.05). This was due to the application of electric potential difference across membrane that induced pores formation and subsequently increased membrane permeability. Reversible permeabilized cells resumed growth to >9 log CFU/ml after fermentation in biotin-soymilk (p < 0.05). Lactobacilli cells treated at electric field strength of 7.5 kV/cm for 3.5 ms also showed enhanced ß-glucosidase activity (p < 0.05) compared to lower doses and control, leading to increased bioconversion of isoflavones glucosides to aglycones in biotin-soymilk (p < 0.05). Results from this study show that electroporation could be used to produce biotin-soymilk with increased bioactive aglycones.

Calcium absorption in Australian osteopenic post-menopausal women: an acute comparative study of fortified soymilk to cows' milk.

Calcium loss after menopause increases the risk of osteoporosis in aging women. Soymilk is often consumed to reduce menopausal symptoms, although in its native form, it contains significantly less calcium than cow's milk. Moreover, when calcium is added as a fortificant, it may not be absorbed efficiently. This study compares calcium absorption from soymilk fortified with a proprietary phosphate of calcium versus absorption from cow's milk. Preliminary studies compared methods for labelling the calcium fortificant either before or after its addition to soymilk. It was established that fortificant labelled after it was added to soymilk had a tracer distribution pattern very similar to that shown by fortificant labelled before adding to soymilk, provided a heat treatment (90?C for 30 min) was applied. This method was therefore used for further bioavailability studies. Calcium absorption from fortified soy milk compared to cow's milk was examined using a randomised single-blind acute cross-over design study in 12 osteopenic post-menopausal women aged (mean +/- SD) 56.7+/-5.3 years, with a body mass index of 26.5+/-5.6 kg/m2. Participants consumed 20 mL of test milk labelled after addition of fortificant with 185 kBq of 45Ca in 44 mg of calcium carrier, allowing the determination of the hourly fractional calcium absorption rate (alpha) using a single isotope radiocalcium test. The mean hourly fractional calcium absorption from fortified soymilk was found to be comparable to that of cows' milk: alpha = 0.65+/-0.19 and alpha =0.66+/-0.22, p>0.05, respectively.

Viability and growth characteristics of Lactobacillus in soymilk supplemented with B-vitamins.

Ten strains of Lactobacillus were evaluated for their viability in soymilk. Lactobacillus acidophilus ATCC 314, L. acidophilus FTDC 8833, L. acidophilus FTDC 8633 and L. gasseri FTDC 8131 displayed higher viability in soymilk and were thus selected to be evaluated for viability and growth characteristics in soymilk supplemented with B-vitamins. Pour plate analyses showed that the supplementation of all B-vitamins studied promoted the growth of lactobacilli to a viable count exceeding 7 log CFU/ml. alpha-Galactosidase specific activity of lactobacilli as determined spectrophotometrically showed an increase upon supplementation of B-vitamins. High-performance liquid chromatography analyses revealed that this led to increased hydrolysis of soy oligosaccharides and subsequently higher utilization of simple sugars. Production of organic acids as determined via high-performance liquid chromatography also showed an increase, accompanied by a decrease in pH of soymilk. Additionally, the supplementation of B-vitamins also promoted the synthesis of riboflavin and folic acid by lactobacilli in soymilk. Our results indicated that B-vitamin-supplemented soymilk is a good proliferation medium for strains of lactobacilli.

Production of beta-glucosidase and hydrolysis of isoflavone phytoestrogens by Lactobacillus acidophilus, Bifidobacterium lactis, and Lactobacillus casei in soymilk.

The study determined beta-glucosidase activity of commercial probiotic organisms for hydrolysis of isoflavone to aglycones in fermenting soymilk. Soymilk made with soy protein isolate (SPI) was fermented with Lactobacillus acidophilus LAFTI L10, Bifidobacterium lactis LAFTI B94, and Lactobacillus casei LAFTI L26 at 37 degrees C for 48 h and the fermented soymilk was stored for 28 d at 4 degrees C. beta-Glucosidase activity of organisms was determined using rho-nitrophenyl beta-D-glucopyranoside as a substrate and the hydrolysis of isoflavone glycosides to aglycones by these organisms was carried out. The highest level of growth occurred at 12 h for L. casei L26, 24 h for B. lactis B94, and 36 h for L. acidophilus L10 during fermentation in soymilk. Survival after storage at 4 degrees C for 28 d was 20%, 15%, and 11% greater (P < 0.05) than initial cell counts, respectively. All the bacteria produced beta-glucosidase, which hydrolyzed isoflavone beta-glycosides to isoflavone aglycones. The decrease in the concentration of beta-glycosides and the increase in the concentration of aglycones were significant (P < 0.05) in the fermented soymilk. Increased isoflavone aglycone content in fermented soymilk is likely to improve the biological functionality of soymilk.

Fermentation of calcium-fortified soymilk with Lactobacillus: effects on calcium solubility, isoflavone conversion, and production of organic acids.

The objective of this study was to enhance calcium solubility and bioavailability from calcium-fortified soymilk by fermentation with 7 strains of Lactobacillus, namely, L. acidophilus ATCC 4962, ATCC33200, ATCC 4356, ATCC 4461, L. casei ASCC 290, L. plantarum ASCC 276, and L. fermentum VRI-003. The parameters that were used are viability, pH, calcium solubility, organic acid, and biologically active isoflavone aglycone content. Calcium-fortified soymilk made from soy protein isolate was inoculated with these probiotic strains, incubated for 24 h at 37 degrees C, then stored for 14 d at 4 degrees C. Soluble calcium was measured using atomic absorption spectrophotometry (AA). Organic acids and bioactive isoflavone aglycones, including diadzein, genistein, and glycetein, were measured using HPLC. Viability of the strains in the fermented calcium-fortified soymilk was > 8.5 log(10) CFU/g after 24 h fermentation and this was maintained for 14-d storage at 4 degrees C. After 24 h, there was a significant increase (P < 0.05) in soluble calcium. L. acidophilus ATCC 4962 and L. casei ASCC 290 demonstrated the highest increase with 89.3% and 87.0% soluble calcium after 24 h, respectively. The increase in calcium solubility observed was related to lowered pH associated with production of lactic and acetic acids. Fermentation significantly increased (P < 0.05) the level of conversion of isoflavones into biologically active aglycones, including diadzein, genistein, and glycetein. Our results show that fermenting calcium-fortified soymilk with the selected probiotics can potentially enhance the calcium bioavailability of calcium-fortified soymilk due to increased calcium solubility and bioactive isoflavone aglycone enrichment.

Microbial and dietary factors are associated with the equol producer phenotype in healthy postmenopausal women.

Equol, a microbial metabolite of daidzein, has been hypothesized as a clue to the effectiveness of soy and its isoflavones but is excreted by only 33% of Caucasians. Microbial and dietary factors associated with the ability to harbor equol-producing bacteria were studied in a randomized dietary intervention trial with 100 healthy postmenopausal women. After a 4-d baseline period, subjects delivered first-void urine, fecal, and breath samples. During the 5-d treatment period, 3 portions of either soymilk or soy germ containing 28.51 and 37.99 mg isoflavone aglycone equivalents/portion, respectively, were administered daily, and on the last day, 24-h urine samples were collected. The urinary recoveries of genistein and daidzein from soymilk were significantly higher than those from soy germ tablets. Because the proportion of equol:(daidzein + metabolites) in the urine did not differ between the treatment groups, subjects were pooled and classified into poor, moderate, and strong equol producers based on this criterion. The strong equol producer phenotype correlated negatively [in vivo, r = -0.478 (-0.256 to -0.893), P = 0.021; in vitro, r = -0.576 (-0.350 to -0.949), P = 0.030] with Clostridium coccoides-Eubacterium rectale counts and positively [in vivo, r = 1.158 (0.971-1.380), P = 0.048; in vitro, r = 1.156 (1.007-1.327), P = 0.039] with the abundance of sulfate-reducing bacteria. Furthermore, persons with a higher PUFA [in vivo, r = 2.150 (1.058-4.371), P = 0.034; in vitro, r = 2.131 (1.144-3.967), P = 0.017] and alcohol [in vivo, r = 1.166 (0.721-1.887), P = 0.050; in vitro, r = 1.850 (1.215-2.817), P = 0.004] intake were more likely to be strong equol producers. Finally, we validated the daidzein metabolism by fecal cultures as screening assay to identify equol producers without dietary intervention.

A comparison of changes in the transformation of isoflavones in soymilk using varying concentrations of exogenous and probiotic-derived endogenous beta-glucosidases.

AIMS: To compare endogenous and exogenous beta-glucosidases for the hydrolysis of the predominant isoflavone glucosides in soymilk in order to improve the biological activity. METHODS AND RESULTS: beta-glucosidase activity of probiotic organisms, including Bifidobacterium animalis ssp. lactis Bb12, Lactobacillus acidophilus ATCC 4461 and Lactobacillus casei 2607 in soymilk, was evaluated and was related to the increase in the concentration of isoflavone aglycones during fermentation. The concentrations of isoflavone compounds in soymilk were monitored using a Varian model HPLC with an Amperometric electrochemical detector. The aglycone composition, also known as aglycone equivalent ratio, has been considered to be important for the delivery of health benefits of isoflavones, and was monitored during the fermentation of soymilk. Comparison of the hydrolytic effectiveness of both exogenous and endogenous enzyme during 4-h incubation in soymilk was conducted using the Otieno-Shah (O-S) index. Results showed that exogenous enzyme exhibited faster rate of isoflavone glucoside hydrolysis than that by endogenous enzyme. Highest O-S indices were obtained after 4, 3 and 2 h of incubation with enzyme solution having beta-glucosidase activity of 0.288 U ml(-1), 0.359 U ml(-1) and 0.575 U ml(-1), resulting into aglycone concentration increments of 5.87-, 6.07- and 5.94-fold, respectively. Conversely, aglycone concentration in the soymilk with B. animalis ssp. lactis Bb12, L. casei 2607 and L. acidophilus 4461 increased by 3.43-, 2.72- and 3.03-fold, respectively, after 4 h of fermentation at 37 degrees C. In addition, the O-S index of endogenous enzyme was much lower than that of the exogenous enzyme over the same 4-h incubation period. Optimum aglycone equivalent ratios coincided with highest O-S indices and highest aglycone concentrations in soymilk hydrolysed with exogenous enzyme. The same correlation of O-S indices and highest aglycone concentrations occurred for endogenous enzyme during the 24 h of fermentation. CONCLUSIONS: Obtaining highest aglycone concentration and optimum aglycone equivalent ratio could provide a critical beginning point in clinical trials for the realization of unique health benefits of soy isoflavones. SIGNIFICANCE AND IMPACT OF THE STUDY: Screening for beta-glucosidase activities of probiotics in soymilk and comparing their hydrolytic potentials with that of exogenous beta-glucosidase could find wide applications in the development of different aglycone-rich functional soy beverages.