Fermented Soy Product Research Articles

Impact of inulin and okara on Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 viability in a fermented soy product and probiotic survival under in vitro simulated gastrointestinal conditions

The effect of inulin and/or okara flour on Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 viability in a fermented soy product (FSP) and on probiotic survival under in vitro simulated gastrointestinal conditions were investigated throughout 28 days of storage at 4 °C. Employing a 22 design, four FSP trials were produced from soymilk fermented with ABT-4 culture (La-5, Bb-12, and Streptococcus thermophilus): FSP (control); FSP-I (with inulin, 3 g/100 mL of soymilk); FSP-O (with okara, 5 g/100 mL); FSP-IO (with inulin + okara, ratio 3:5 g/100 mL). Probiotic viabilities ranged from 8 to 9 log cfu/g during the 28 days of storage, and inulin and/or okara flour did not affect the viability of La-5 and Bb-12. Bb-12 resistance to the artificial gastrointestinal juices was higher than for La-5, since the Bb-12 and La-5 populations decreased approximately 0.6 log cfu/g and 3.8 log cfu/g, respectively, throughout storage period. Even though the protective effect of inulin and/or okara flour on probiotic microorganisms was not significant, when compared to a fresh culture, the FSP matrix improved Bb-12 survival on day 1 of storage and may be considered a good vehicle for Bb-12 and could play an important role in probiotic protection against gastrointestinal juices.

Propriedades funcionais tecnológicas das fibras de soja, aveia e trigo e produtos de soja com adição de fibras e fermentados com cultura de kefir

The objective of this study was to characterize the technological functional properties of soy, oats and wheat fibers and evaluate soy products with added fiber and fermented with kefir. The fibers were characterized with regard to pH, water adsorption capacity, water and oil absorption capacity and swelling volume. Soy products were developed with the addition of 3% soy fiber, oat and wheat and fermented with kefir. The fermented products were characterized for pH, acidity, syneresis, viscosity and firmness, Lactococcus lactis counts and analysis of sanitary conditions. The soy fiber showed a higher content of protein and lipids, pH, water adsorption and adsorption capacity. The wheat fiber showed a higher oil absorption capacity. The addition of soy, oat and wheat fibers influence pH, acidity, syneresis, viscosity and firmness of fermented soy products with kefir. The lowest syneresis and highest viscosity and firmness were obtained with the soy fermented products with soy fiber. The addition of soy fiber stimulated Lactococcus lactis growth. The fermented soy products had enough Lactococcus lactis counts to be considered probiotics. The products presented satisfactory hygienic sanitary conditions.

Propriedades funcionais tecnológicas das fibras de soja, aveia e trigo e produtos de soja com adição de fibras e fermentados com cultura de kefir

The objective of this study was to characterize the technological functional properties of soy, oats and wheat fibers and evaluate soy products with added fiber and fermented with kefir. The fibers were characterized with regard to pH, water adsorption capacity, water and oil absorption capacity and swelling volume. Soy products were developed with the addition of 3% soy fiber, oat and wheat and fermented with kefir. The fermented products were characterized for pH, acidity, syneresis, viscosity and firmness, Lactococcus lactis counts and analysis of sanitary conditions. The soy fiber showed a higher content of protein and lipids, pH, water adsorption and adsorption capacity. The wheat fiber showed a higher oil absorption capacity. The addition of soy, oat and wheat fibers influence pH, acidity, syneresis, viscosity and firmness of fermented soy products with kefir. The lowest syneresis and highest viscosity and firmness were obtained with the soy fermented products with soy fiber. The addition of soy fiber stimulated Lactococcus lactis growth. The fermented soy products had enough Lactococcus lactis counts to be considered probiotics. The products presented satisfactory hygienic sanitary conditions.

A soy-based product fermented by Enterococcus faecium and Lactobacillus helveticus inhibits the development of murine breast adenocarcinoma

PurposeSoy and its fermented products are considered functional foods. The study objective was to assess three functional food – a non-fermented soy product (NFP), fermented soy product (FSP), fermented soy product enriched with isoflavones (FI) – in terms of their ability to reduce the development of adenocarcinoma in mice, as well their ability on modulating immune system. MethodsIt was observed tumor volume and to verify correlations with the immune system it was measured levels of the cytokines IL-1β and TNF-α produced by macrophages as well as IFN-γ produced by lymphocytes using ELISA test, and nitric oxide production by macrophages using Griess reagent. ResultsAll products showed immunological activity, but FSP showed the most effective tumor containment, resulting in smallest tumor volumes. FI animals expressed larger amounts of nitric oxide and IL-1β and exhibited larger tumor sizes than FSP and NFP animals. ConclusionsThe results suggested that the ingestion of FSP was most efficient in tumor containment, possibly due to a positive modulation of the immune system by when Enterococcus faecium and Lactobacillus helveticus are added to the soy product.

Supplementation of the fermented soy product ImmuBalance™ effectively reduces itching behavior of atopic NC/Tnd mice

Effects of probiotics on the prevention of atopic diseases have been proposed recently. Although we have already reported the suppressive effects of the probiotic, ImmuBalance™, on a mouse model for peanuts allergy, its influence on atopic diseases remains unclear. Potential efficacy of ImmuBalance™, which is the fermented soy product, on treatment of atopic dermatitis (AD) was investigated using a mouse model for human AD, NC/Tnd mice. For in vivo study, ImmuBalance containing chow or a control diet were fed to NC/Tnd mice with moderate dermatitis for 2 weeks. Topical application of FK506 ointment was used as a positive control. Clinical skin severity scores, scratching behaviors, trans-epidermal water loss (TEWL), and histological features were analyzed. For in vitro study, suppressive effect of ImmuBalance™ on nerve growth factor (NGF)-activated neurite outgrowth of PC12 cells was examined. Clinical skin severity scores of the mice fed with ImmuBalance containing chow were gradually reduced as well as the mice treated with FK506. Feeding with ImmuBalance completely inhibited the increase in scratching behavior of NC/Tnd mice. The value of TEWL of NC/Tnd mice fed with ImmuBalance was significantly decreased. In addition, histological examination revealed that application of ImmuBalance decreased the number of PGP9.5-positive neuronal fibers in the lesional skin. When ImmuBalance extract was added to the culture, NGF-activated neurite outgrowth of PC12 cells was diminished through the inhibition of the phosphatidylinositol 3-kinase phosphorylation. ImmuBalance could exhibit favorable alterations on AD symptoms, particularly through down regulation of the itch sensation.

Balancing steroidal hormone cascade in treatment-resistant veteran soldiers with PTSD using a fermented soy product (FSWW08): a pilot study.

Abstract Introduction: A clinical study was conducted to determine steroidal hormone cascade in the blood to relate them to mental performance with the Clinician-Administered PTSD scale (CAPS), serum lipid concentrations, and steroidal hormones, particularly cortisol, testosterone, estradiol, dehydroepiandrosterone (DHEA), and pregnenolone, in treatment-resistant male veterans with combat-related chronic posttraumatic stress disorder (PTSD) before and after consumption of a special fermented soy formulation (FSWW08). Admitted veterans in the study were resistant to conventional psychological and pharmacological therapies. Ten treatment-resistant soldiers with combat-related PTSD (according to the International Classification of Diseases, 10th Revision code) for ≤1.5 years were enrolled in this study. A specially formulated fermented soy product, FSWW08, was given to the veterans for 3 months and then extended to 6 months. CAPS was used to assess the severity of PTSD. Immunologic cytokines, triglycerides, and 16 steroidal hormones were also determined from the blood of the PTSD patients before, during, and after consumption of the FSWW08. FSWW08 increased blood levels of steroids, such as testosterone, estradiol, and particularly the adrenal hormones cortisol and androstenediol. Decreased steroidal hormones from the upper part of the hormone cascade, such as cholesterol, DHEA, and pregnenolone were experienced. The arteriosclerotic risk was reduced (cholesterol, 280±35 to 205±22 mmol/L, p<0.001; triglycerides, 645±267 to 161±22 mg/dL, p<0.001; very-low-density lipoprotein cholesterol, 312±112 to 151±20 mg/dL, p<0.001; homocysteine in serum (i.s.), 26±4 to 11.8±2.1 μmol/L, p<0.001). High-density lipoprotein cholesterol concentration was significantly lower after consumption of FSWW08 (51±15 to 89±7.8 mg/dL, p<0.001). FSWW08 significantly reduced mental symptoms according to CAPS after 7 days throughout the 6-month study. Insomnia (estradiol increased from 53±24 to 88±41 pg/L), breathing disorders (may be related to increased aldosterone) are hormone dependent and were corrected in those with insomnia. The increase in testosterone and decrease in prolactin was corroborated by an increase in sex drive and improved partner relationships. Common immunity disorders of the veterans, such as increased herpes labialis, flu-like syndromes, and stomach pain were resolved in all veterans and was corroborated by significant improvements in immunologic cytokines: tumor necrosis factor α was reduced (from 13.5±0.4 to 9.0±1.4 pg/mL, p<0.001) and interleukin β (from 7.0±0.5 to 4.5±1.8 pg/mL) and interferon γ (from 10.4±2.4 to 6.3±1.5 pg/mL, p=0.001) were also detected. PTSD is associated with clinically elevated leukocytes and lymphocytes, which are reduced by FSWW08 as well. It is the first time that the normalization of the whole steroidal hormone cascade in the blood could be correlated with improvements in mental and physical parameters (especially metabolic and immunologic disorders) in veterans with combat-related and treatment-resistant PTSD. Studies of FSWW08 in larger cohorts and over longer periods of time, as well as dosing effects, have to be conducted to validate these results.

Discovery of an S-equol rich food stinky tofu, a traditional fermented soy product in Taiwan

A recent epidemiological study showed that daily intake of mg quantities of S-equol is required for health-promoting effects in menopausal women. However, the maximum equol content in food was reported to be approximately 130 μg/100 g in egg yolk. The objective of this study was to find a high equol-containing food. We measured the equol content of 33 egg yolks and 21 fermented soybean foods. Equol was detected in 28 egg yolks at the maximum content of 43 μg/100 g. In the fermented soybean foods, equol was detected only in stinky tofu. We examined 16 stinky tofu samples purchased during different seasons and the average equol content was 1.39 mg/100 g, ranging from 0.34 to 2.68 mg/100 g. Equol was present in stinky tofu as the S-enantiomeric form and as an aglycon type. This is the first report demonstrating that stinky tofu contains high levels of S-equol, which may exert beneficial effects in menopausal women.

Determination of 15 Isoflavone Isomers in Soy Foods and Supplements by High-Performance Liquid Chromatography

Soy isoflavone is the generic name for the isoflavones found in soy. We determined the concentrations of 15 soy isoflavone species, including 3 succinyl glucosides, in 22 soy foods and isoflavone supplements by high-performance liquid chromatography (HPLC). The total isoflavone contents in 14 soy foods and 8 supplements ranged from 45 to 735 μg/g and from 1,304 to 90,224 μg/g, respectively. Higher amounts of succinyl glucosides were detected in natto, a typical fermented soy product in Japan; these ranged from 30 to 80 μg/g and comprised 4.1-10.9% of the total isoflavone content. In soy powder, 59 μg/g of succinyl glucosides were detected, equivalent to 4.6% of the total isoflavone content. These data suggest that the total isoflavone contents may be underestimated in the previous studies that have not included succinyl glucosides, especially for Bacillus subtilis -fermented soy food products.

Purification and Characterization of a Major Fibrinolytic Enzyme from Bacillus amyloliquefaciens MJ5-41 Isolated from Meju

Meju is a traditional Korean fermented soy product used as a key element for soy sauce and doenjang. Bacilli with antimicrobial activity were isolated from meju prepared by traditional methods at Sunchang county, Jeollabukdo, Korea. Six isolates were identified as Bacillus amyloliquefaciens by recA gene sequencing and RAPD-PCR. One isolate, B. amyloliquefaciens MJ5-41, showed the strongest fibrinolytic activity. A 27 kDa active fibrinolytic enzyme, AprE5-41, was purified from the culture supernatant of MJ5-41 grown on LB by chromatographic methods. The optimum pH and temperature for purified AprE5-41 were 7.0 and 45°C, respectively. AprE5-41 quickly degraded Aα and Bβ chains but not the gamma-chain of fibrinogen. AprE5-41 exhibited the highest specificity for N-succinyl-Ala-Ala-Pro-Phe pnitroanilide, a known substrate for α-chymotrypsin, cathepsin G, and subtilisin BPN'. The structural gene, aprE5-41, was cloned by PCR and successfully expressed in B. subtilis.

Formation of Volatile Sulfur-Containing Compounds by Saccharomyces cerevisiae in Soymilk Supplemented with L-methionine

The formation of volatile sulfur-containing flavor compounds from L-methionine catabolism by Saccharomyces cerevisiae EC-1118 was investigated in soymilk supplemented with this sulfur-containing amino acid with a focus on methionol (3-methylthio-1-propanol). Methionol produced from L-methionine metabolism of yeast in soymilk was extracted by solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). The effects of time (0 – 72 h), L-methionine concentration (0.05–0.20%), yeast extract concentration (0.00–0.30%), initial medium pH (4.5–6.9), and temperature (25–34°C) on the production of methionol were investigated. One-liter scale-up fermentation of soymilk by Saccharomyces cerevisiae EC-1118 was conducted for 48 h under static conditions with 0.15% of L-methionine, 0.10% of yeast extract, initial medium pH of 5.5, and temperature of 25°C, yielding 190 ppm of methionol. GC-olfactometry dilution analysis was conducted on extracts of the fermented soymilk, and no single compound was found to account for the overall odor perception. Methional (3-methylthio-1-propanal) and methionol were determined to be most potent odor-active compounds in the fermented soymilk. The fermented soy milk may serve as a complex sulfur flavor concentrate for applications in foods such as fermented soy products, enzyme-modified, and imitation cheeses.

Simultaneous Enhancement of Free Isoflavone Content and Antioxidant Potential of Soybean by Fermentation with Aspergillus oryzae

In order to determine the fungal strain and fermentation period which produce the highest antioxidant activity of fermented soy product, soybean was fermented with Aspergillus oryzae NL 5 isolated from Korean traditional meju produced in Sunchang Yeastopia Land in Korea, and was subjected to analyzing isoflavone profiles and assaying antioxidant activity. Antioxidant potential of the samples was evaluated by ferric reducing antioxidant power assay, 2,2'-azinobis (2-ethylbenzthiazoline-6-sulfonic acid) radical scavenging activity and total phenolic contents. In addition, antioxidant assay using fluorescent probes, 2',7'-dichlorofluorescin diacetate and dihydroethidium, in HepG2 cells was conducted for the samples. The results showed that both high isoflavone variety Aga 3 and medium isoflavone variety Daewon of soybean fermented with Asp oryzae NL5 for 4 to 5 d showed the highest increase in free isoflavone contents, together with the highest antioxidant activity. In conclusion, the antioxidant activity of fermented soy was proportional to the concentration of free isoflavones, and was significantly influenced by total isoflavone content of soybean variety and fermentation period. Practical Application: Isoflavone profile and antioxidant capacity of soybean were widely variable during fermentation with Asp oryzae, and thereby it is recommended that meju (or koji) preparation condition, in particular, fermentation time is carefully optimized to maximize the antioxidant capacity of soy products fermented by Asp oryzae.

Effect of ingestion of soy yogurt on intestinal parameters of rats fed on a beef-based animal diet

The aim of this study was to investigate whether the ingestion of soy yogurt fermented with Enterococcus faecium CRL 183 would modify the intestinal count of enterococci, fecal pH and ammonia content in rats fed on a diet containing red meat. The rats were placed in 4 groups: for 60 days, group I was given a standard casein-based rodent feed and groups II-IV, the beef-based feed. From day 30, groups III-IV also received the following products: III) soy yogurt; IV) suspension of E. faecium CRL 183. At the start and on days 30 and 60, feces were collected for the determination of pH, ammonia content, count of enterococci and identification of their species. On day 60, rats were sacrificed and their colons also removed for count of enterococci and identification of their species. Rats that ingested soy yogurt showed no significant change (P<0.05) in fecal counts of Enterococcus spp., but, this rat group showed a higher count of E. faecium than rats that ingested suspension of E. faecium CRL 183. The ingestion of soy yogurt and E. faecium culture caused a significant rise (P < 0.05) in fecal pH and ammonia content. Our results suggest that consumption of soy yogurt fermented with E. faecium CRL 183 and L. helveticus subsp. jugurti could change the species of Enterococcus spp. present in the feces and colon of rats fed on a beef-based diet. However, the fermented soy product and the pure culture of E. faecium CRL 183 also induced undesirable effects such as the increase of fecal pH and ammonia content in the feces of rats fed on a beef-based diet.

S-equol and the fermented soy product SE5-OH containing S-equol similarly decrease ovariectomy-induced increase in rat tail skin temperature in an animal model of hot flushes

The aim of this study was to compare the effect of SE5-OH, a fermented soy product containing S-equol, with purified S-equol on hot flushes in an ovariectomized rat model. Eleven-week-old female Sprague-Dawley rats were assigned to either the sham group (vehicle; n = 30) or one of four ovariectomized groups: control (vehicle; n = 30), conjugated equine estrogens (CEE; 6.0 mg kg(-1) d(-1) CEE; n = 10), SE5-OH (2,000 mg kg(-1) d(-1) SE5-OH containing 11.7 mg kg(-1) d(-1) as S-equol; n = 30), and S-equol (11.7 mg kg(-1) d(_1) S-equol; n = 30). Three days after sham operation or ovariectomy, animals were treated once daily for 38 days. Tail skin temperature (TST) was assessed on days 21, 28, and 35 after surgery. Plasma estradiol and follicle-stimulating hormone levels and uterine weight and uteri histology were evaluated at the end of treatment. The rise in TST resulting from ovariectomy was inhibited by CEE, SE5-OH, and S-equol. Compared with the control, TST was decreased by 68.9% and 86.2% in SE5-OH group on days 21 and 28, respectively (P = 0.014, 0.020), and by 60.1% and 89.1% in S-equol group, respectively (P = 0.038, 0.016). Unlike in the CEE group, plasma estradiol and follicle-stimulating hormone levels, uterine weight, epithelial height, stromal expansion, and myometrial thickness were not affected in SE5-OH and S-equol groups. The results of this animal model of hot flushes suggest that S-equol is one of the primary components of SE5-OH and that both SE5-OH and S-equol represent promising alternatives for the treatment of menopausal symptoms. Clinical research is needed to confirm these findings.

Conjoint Analysis on the Purchase Intent for Traditional Fermented Soy Product (Natto) among Japanese Housewives

The effect of sensory and extrinsic attributes on consumer intentions to purchase the Japanese traditional fermented soybean product natto was evaluated using conjoint analysis. Six attributes with 2 levels each were chosen and manipulated: price (high compared with low), the country of origin of the soybeans (domestic compared with imported), stickiness (strong compared with moderate), smell (rich compared with moderate), attached seasonings (attached compared with no attached seasonings), and the environmental friendliness of the packaging (high compared with low). A fractional factorial design was applied and 8 hypothetical product labels were produced. A sample of 479 Japanese housewives ranked these product labels based on their purchase intentions. Overall purchase intention was affected by country of origin, attached seasonings, and price; those attributes accounted for 81.0%, while the sensory attributes of the product accounted for 19.0% of purchase intents. In order to estimate market segments for the natto products based on consumer preference, a cluster analysis was performed. It identified 4 segments of consumers: 1 oriented to attached seasonings, another conscious of the price, and the other 2 oriented to origins. The behavioral and demographic characteristics of the respondents had a limited influence on segment membership. This research was conducted to understand how consumers valuate various sensory and nonsensory product attributes based on their assessment of the overall product in the case of Japanese fermented soy product (natto). The data of this research would be of great importance both in understanding consumer behavior and in designing strategies for product development.

Influence of a probiotic soy product on fecal microbiota and its association with cardiovascular risk factors in an animal model

BackgroundPrevious work showed that daily ingestion of an aqueous soy extract fermented with Enterococcus faecium CRL 183 and Lactobacillus helveticus 416, supplemented or not with isoflavones, reduced the total cholesterol and non-HDL-cholesterol levels, increased the high-density lipoprotein (HDL) concentration and inhibited the raising of autoantibody against oxidized low-density lipoprotein (ox-LDL Ab) and the development of atherosclerotic lesions.ObjectiveThe aim of this study was to characterize the fecal microbiota in order to investigate the possible correlation between fecal microbiota, serum lipid parameters and atherosclerotic lesion development in rabbits with induced hypercholesterolemia, that ingested the aqueous soy extract fermented with Enterococcus faecium CRL 183 and Lactobacillus helveticus 416.MethodsThe rabbits were randomly allocated to five experimental groups (n = 6): control (C), hypercholesterolemic (H), hypercholesterolemic plus unfermented soy product (HUF), hypercholesterolemic plus fermented soy product (HF) and hypercholesterolemic plus isoflavone-supplemented fermented soy product (HIF). Lipid parameters and microbiota composition were analyzed on days 0 and 60 of the treatment and the atherosclerotic lesions were quantified at the end of the experiment. The fecal microbiota was characterized by enumerating the Lactobacillus spp., Bifidobacterium spp., Enterococcus spp., Enterobacteria and Clostridium spp. populations.ResultsAfter 60 days of the experiment, intake of the probiotic soy product was correlated with significant increases (P < 0.05) on Lactobacillus spp., Bifidobacterium spp. and Enterococcus spp. and a decrease in the Enterobacteria population. A strong correlation was observed between microbiota composition and lipid profile. Populations of Enterococcus spp., Lactobacillus spp. and Bifidobacterium spp. were negatively correlated with total cholesterol, non-HDL-cholesterol, autoantibodies against oxidized LDL (oxLDL Ab) and lesion size. HDL-C levels were positively correlated with Lactobacillus spp., Bifidobacterium spp., and Enterococcus spp. populations.ConclusionIn conclusion, daily ingestion of the probiotic soy product, supplemented or not with isoflavones, may contribute to a beneficial balance of the fecal microbiota and this modulation is associated with an improved cholesterol profile and inhibition of atherosclerotic lesion development.

Effect of ingestion of soy yogurt on intestinal parameters of rats fed on a beef-based animal diet

The aim of this study was to investigate whether the ingestion of soy yogurt fermented with Enterococcus faecium CRL 183 would modify the intestinal count of enterococci, fecal pH and ammonia content in rats fed on a diet containing red meat. The rats were placed in 4 groups: for 60 days, group I was given a standard casein-based rodent feed and groups II-IV, the beef-based feed. From day 30, groups III-IV also received the following products: III) soy yogurt; IV) suspension of E. faecium CRL 183. At the start and on days 30 and 60, feces were collected for the determination of pH, ammonia content, count of enterococci and identification of their species. On day 60, rats were sacrificed and their colons also removed for count of enterococci and identification of their species. Rats that ingested soy yogurt showed no significant change (P<0.05) in fecal counts of Enterococcus spp., but, this rat group showed a higher count of E. faecium than rats that ingested suspension of E. faecium CRL 183. The ingestion of soy yogurt and E. faecium culture caused a significant rise (P < 0.05) in fecal pH and ammonia content. Our results suggest that consumption of soy yogurt fermented with E. faecium CRL 183 and L. helveticus subsp. jugurti could change the species of Enterococcus spp. present in the feces and colon of rats fed on a beef-based diet. However, the fermented soy product and the pure culture of E. faecium CRL 183 also induced undesirable effects such as the increase of fecal pH and ammonia content in the feces of rats fed on a beef-based diet.

Cancer protection of soy resembles cancer protection during pregnancy.

It has been established that carrying a pregnancy to full-term at an early age can protect against contracting cancer by up to 50% in later life. The trophoblast theory of cancer states that trophoblast and cancer tissue are very similar. New findings suggest that the loss of fetal cells during pregnancy resemble those cells responsible for causing metastasis in cancer. Fetal cells and spreading cancer cells are highly proliferative. They are similar to stem cells, exhibiting no or low hormone receptor expression, and require a hormone receptor independent mechanism for control. Control of membrane stability during pregnancy is of vital importance for a successful pregnancy and is mediated by androstenediol and 2-methoxyestradiol. 2-Methoxyestradiol has no hormone receptor affinity and elicits strong anticancer effects particularly against cancer stem cells and fetal cells, for which currently no treatment has yet been established. There is a discussion whether pregnancy reduces cancer stem cells in the breast. Soy isoflavones are structurally similar to both hormones, and elicit strong anticancer effects and antiangiogenesis via inhibition of NF-κB, even in hormone receptor independent breast cancers seen in epidemiologic studies. The trophoblast theory of cancer could help to explain why soy baby nutrition formulas have no effect on baby physiology, other than the nutritional aspect, although soy elicits many effects on the adult immune system. To survive the immune system of the mother, the immune system of the fetus has to be separated; otherwise, the reduction of the immune system in the mother, a necessary feature for the blastocyst to grow, would immediately reduce the immunity for the fetus and endanger its survival. Similar to a fetus, newly born babies show immune insensitive to Th1 and Th2 cytokines, which are necessary and crucial for regulating the immune system of the mother, thus raising the risk of the baby of developing allergies and neurodermatitis. Gene expression studies in vitro as well as in circulating tumor cells from patients consuming a fermented soy product support the antiangiogenic as well as antiproliferative effects of soy.

Volatile profiles of thua nao, a Thai fermented soy product

Thua nao, a Thai traditional fermented soybean has a unique odour due to the presence of several volatile components. In this investigation, the cooked non-fermented soybeans and soybean ( thua nao) fermented by pure Bacillus subtilis TN51 (TNB51) and naturally fermented soybean (TNMX) were analysed for odour components by GC–MS, using the PDMS-SPME head space technique. The quantities of total volatiles in both TNB51 and TNMX were analogous, but the major volatile classes present in TNB51 and TNMX were pyrazines and ketones, respectively. The predominant volatiles in pure Bacillus-fermented thua nao included 2,5-dimethylpyrazine, 2-methylbutanoic acid, 2,3,5-trimethylpyrazine, 2-methylpropanoic acid and acetic acid, whereas the major volatiles in the naturally fermented soybean included 2,5-dimethylpyrazine, benzaldehyde, 5-methyl-3-hexanone, 2-butanone and 3-methyl-2-pentanone. In total, 85 volatile compounds were detected.

Sodium content of fermented soy foods in the USA

The sodium content of fermented soy foods is quite high on a weight basis. However, fermented soy foods are typically used as seasonings and soup bases, and are not consumed alone. It is possible that if fermented soy foods are the sole source of added salt, that fermented soy foods may not be excessively high in sodium content. A survey of commonly consumed soy foods found that there is a wide variation in the salt content common foods made with fermented soy products and that the foods may indeed be high in sodium, but they may also have a lower sodium content that their Western counterparts. Therefore, fermented soy foods are not necessarily high in sodium and can be used to prepare healthful foods.

Antidiabetic effects of fermented soybean products on type 2 diabetes

Historically, the incidence of type 2 diabetes has been lower in Asian populations compared with those in Western countries. One possible reason for the lower incidence among Asians is that they consume fermented soybean products, which are unique to the traditional Asian diet. Some have hypothesized that dietary phytoestrogens and soy peptides in fermented soybean foods consumed in traditional Asian diets may help prevent and slow the progression of type 2 diabetes. This review evaluates the existing evidence from animal studies and clinical and epidemiologic investigations on fermented soybeans in the prevention and treatment of type 2 diabetes. Nutritional studies performed in animals and intervention studies with humans suggest that the ingestion of soy protein with isoflavones improves glucose control and reduces insulin resistance. Korean fermented soybean products such as doenjang, kochujang, and chungkookjang contain alterations in the structures and content of isoflavonoids and small bioactive peptides, which are produced during fermentation. Several studies revealed improvements in insulin resistance and insulin secretion with the consumption of these fermented products. Therefore, fermented soybean products may help prevent or attenuate the progression of type 2 diabetes. Although the lack of human intervention trials does not permit definitive conclusions, the evidence does suggest that fermented soy products may be better for preventing or delaying the progression of type 2 diabetes compared with nonfermented soybeans.