Contents variation analysis of free amino acids, nucleosides and nucleobases in semen sojae praeparatum fermentation using UFLC-QTRAP MS

UFLC-QTRAP MS was used to develop a sensitive and rapid method of evaluating content variation during Semen sojae praeparatum (SSP) fermentation. It did this through the simultaneous quantification of 22 free amino acids and 16 nucleosides and nucleobases in the raw materials and processed products of SSP. The method was shown to be reproducible and accurate. The limits of detection and quantity values were 0.09-168.75 and 0.31-562.50 ng/mL for the 38 analytes, respectively. The data were examined through principal components analysis to compare the content variations. The quantitative results showed that the ingredients were properly determined in most of the samples and were converted regularly throughout the SSP fermentation process. These results correspond to the morphologic changes and principal components analysis results.

[Determination of 3-monochloropropane-1,2-diol in grease food by solid phase extraction-derivatization-gas chromatography-mass spectrometry]

OBJECTIVE

To establish the method of determination of 3-monochloropropane-1,2-diol( 3-MCPD) in grease food by gas chromatography-mass spectrometry( GC-MS).

METHODS

3-MCPD in grease food represented by bean paste was extracted by ultrasound,purified by alkaline earth solid phase extraction column,derivatived using phenylboronic acid( PBA) and detected by GC-MS.

RESULTS

The linearity of 3-MCPD ranged from 1-100 ng/mL,with correlation coefficient at 0. 9993.The limits of quantitation( LOQ) in soy sauce,bean paste,pepper oil were 0. 6,0. 5 and7. 0 μg/kg and limits of detection( LOD) were 1. 9,1. 6 and 18. 8 μg/kg,respectively.Average recovery rate and relative standard deviation was 78. 3%-106. 7% and 1. 9%-11. 6%( n = 6), when 3-MCPD was added in grease food at 2. 5-1000 μg/kg.

CONCLUSION

The method has good purification effect and the detection sensitivity and accuracy,and can be used for the determination of 3-MCPD in grease food.

Formation of heterocyclic amines in Chinese marinated meat: effects of animal species and ingredients (rock candy, soy sauce and rice wine)

BACKGROUND

Heterocyclic aromatic amines (HAAs) are one type of neo-formed contaminants in protein-rich foods during heat processing. Recently, accumulative studies have focused on the formation of HAs in Western foods. However, there is little knowledge about the occurrence of HAAs in traditional Chinese foods. The objective of this study was to determinate the contents of main HAs in traditional marinated meat products by UPLC-MS/MS, and to investigate the effects of animal species and the ingredients (soy sauce, rock candy, and rice wine) on the formation of HAAs in marinated meats.

RESULTS

Five HAs - 2-amino-3-methylimidazo[4,5-f]-quinolone (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4-dimethylimidazo[4,5-f]quinoxaline (MeIQ), 9H-pyrido[3,4-b]indole (Norharman) and l-methyl-9H-pyrido[3,4-b]indole (Harman) - were detected in 12 marinated meats, but 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was only found in three chicken marinates. The animal species and ingredients (soy sauce, rock candy and rice wine) have significant influence on the formation of HAAs in meat marinates. Beef had the highest content of total HAAs compared with pork, mutton and chicken. Meanwhile, soy sauce contributed to the formation of HAAs more greatly than rock candy, soy sauce, and rice wine.

CONCLUSION

Choice of raw materials and optimisation of ingredients recipe should be become a critical point to control the HAAs formation in marinated meats. © 2017 Society of Chemical Industry.

Degradation and removal of soybean allergen in Japanese soy sauce

Soy sauce is a traditional fermented seasoning of Japan and is available throughout the world. The two main raw ingredients of soy sauce are soybean and wheat, both of which are established food allergens. The present study examined the degradation and removal of soybean allergens in soy sauce by immunoblotting with anti‑soybean protein antibody from rabbit and sera from two children with soybean allergy. It was demonstrated that soybean allergens were gradually degraded during the fermentation process, but were not completely degraded in raw soy sauce. During the processes of heat‑treatment and filtration, the soluble soybean allergens in raw soy sauce were denatured to insoluble allergens by heat‑treatment and subsequently completely removed from soy sauce by filtration. Therefore, to reduce the allergenicity of soy sauce, heat‑treatment and filtration are very important processes in addition to the enzymatic degradation during the fermentation of soy sauce.

Dynamics of microbial community during the extremely long-term fermentation process of a traditional soy sauce

BACKGROUND

Soy sauce produced by long-term natural fermentation is a traditional specialty in Asia, with a reputation for superior quality and rich flavour. In this study, both culture-dependent and culture-independent approaches were used to investigate the microbial diversity and community dynamics during an extremely long-term (up to 4 years) natural fermentation of Xianshi Soy Sauce, a national intangible cultural heritage.

RESULTS

Genera of Bacillus, Aspergillus and Cladosporium were detected by both methods above. The relative abundance of the genera Bacillus and Weissella was significantly higher in the late stage than in the early one, while the genera Klebsiella and Shimwellia were opposite (P < 0.05). For microbial community structure, subsequent analyses showed that obvious changes occurred with fermentation time, while there was a fair homogeneousness among samples of the same year, especially during the late fermentation stage.

CONCLUSIONS

The clustering analysis tended to separate the fermented mashes of the 4th year from the earlier stages, suggesting the necessity of the long fermentation period for developing distinctive microbiota and characteristic quality-related compounds. This is the first report to explore the temporal changes in microbial dynamics over a period of 4 years in traditional fermentation of soy sauce, and this work illustrated the importance of isolation of appropriate strains to be used as starter cultures in brewing processes. © 2016 Society of Chemical Industry.

HPMC (hydroxypropyl methylcellulose) as a fat replacer improves the physical properties of low-fat tofu

BACKGROUND

The effect of the addition of hydroxypropyl methylcellulose (HPMC) on the textural properties of low-fat tofu was investigated. Three fat levels (240, 100 and 30 g kg^-1 ) were used to make tofu, which were identified as C (full-fat tofu), L1 and L2. HPMC (5 g kg^-1 ) was added to soymilk to prepare control and low-fat tofu, designated as CH, L1H and L2H.

RESULTS

Soymilk with a lower fat level had a lower viscosity: 143 (C), 100 (L1) and 42 (L2) cP. The addition of HPMC increased the viscosity of all types of soymilk, particularly in L2H (107 cP). With fat reduction, tofu syneresis increased from 19% (C) to 29% (L2), although syneresis of L2H recovered to 19%, which is similar to high-fat control tofu. Decreased fat resulted in a lower firmness in L2 (0.67 N) compared to control (0.78 N). Firmness increased to 1.08 N in L2H tofu, whereas the firmness of CH tofu was 0.63 N. All types of tofu showed a denser, well-connected and cross-linking structure when HPMC was added, especially in L2H tofu.

CONCLUSION

HPMC improved the texture of the low-fat tofu by creating a harder texture and reducing syneresis. HPMC is an effective fat replacer for lower fat soymilk. © 2017 Society of Chemical Industry.

An LC/MS/MS method for quantitation of chemopreventive sphingadienes in food products and biological samples

Colorectal cancer (CRC) is a leading cause of cancer mortality. Diet has a significant influence on colon cancer risk. Identifying chemopreventive agents, dietary constituents, practices and/or diet supplements that promote gut health and reduce the incidence of intestinal neoplasias and CRC could significantly impact public health. Sphingadienes (SDs) are dietary sphingolipids found in plant-based food products. SDs are cytotoxic to colon cancer cells and exhibit chemopreventive properties. The aim of the present study was to develop a sensitive and robust ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for quantifying SDs in food products and biological samples. The assay was linear over a concentration range of 80nM to 50μM and was sensitive to a detection limit of 3.3nM. Post-extraction stability was 100% at 24h. SD content in soy oils was approximately 10nM. SDs were detected transiently in the plasma of adult mice 10min after gavage delivery of a 25mg/kg bolus and declined to baseline by 1h. SD uptake in the gut was maximal in the duodenum and peaked 1h after gavage delivery. Disappearance of SDs in the lower gastrointestinal tract suggests either rapid metabolism to yet unidentified products or potentially luminal export.

Health impact of childhood and adolescent soy consumption

Soyfoods have been intensely researched, primarily because they provide such abundant amounts of isoflavones. Isoflavones are classified as both plant estrogens and selective estrogen receptor modulators. Evidence suggests that these soybean constituents are protective against a number of chronic diseases, but they are not without controversy. In fact, because soyfoods contain such large amounts of isoflavones, concerns have arisen that these foods may cause untoward effects in some individuals. There is particular interest in understanding the effects of isoflavones in young people. Relatively few studies involving children have been conducted, and many of those that have are small in size. While the data are limited, evidence suggests that soy does not exert adverse hormonal effects in children or affect pubertal development. On the other hand, there is intriguing evidence indicating that when soy is consumed during childhood and/or adolescence, risk of developing breast cancer is markedly reduced. Relatively few children are allergic to soy protein, and most of those who initially are outgrow their soy allergy by 10 years of age. The totality of the available evidence indicates that soyfoods can be healthful additions to the diets of children, but more research is required to allow definitive conclusions to be made.

Wide target analysis of acylglycerols in miso (Japanese fermented soybean paste) by supercritical fluid chromatography coupled with triple quadrupole mass spectrometry and the analysis of the correlation between taste and both acylglycerols and free fatty acids

RATIONALE

The acylglycerols in miso have not been studied although it is known that they are important to the taste. In order to determine the fatty acid constituents in the acylglycerols and analyze them individually, multiple reaction monitoring (MRM) was performed utilizing a single platform, typically using both gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry.

METHODS

Acylglycerols and fatty acids (FAs) in miso were extracted using the Bligh-Dyer method. Supercritical fluid chromatography (SFC) with a C30 column was conducted for separation, and mass spectrometric (MS) analysis was performed with electrospray ionization using a triple quadrupole mass spectrometer (QqQMS) in the MRM mode.

RESULTS

The detection of FAs from the hydrolysis of acylglycerols and individual acylglycerols was achieved using only an SFC/MS platform. From the quality control (QC) sample of miso, we determined the main FA constituents, and then performed wide target analysis using MRM. In total, 23 triacylglycerols, 10 diacylglycerols, two monoacylglycerols, and five FAs were annotated effectively. Furthermore, the important compounds related to taste were determined through the analysis using both the relative quantitative data of acylglycerols and FAs and the quantitative descriptive analysis data of miso.

CONCLUSIONS

A method for the determination of the FA constituents in acylglycerols after hydrolysis and the comprehensive analysis of acylglycerols and FAs using MRM with SFC/QqQMS was developed. Using the data from the comprehensive analysis of acylglycerols and quantitative descriptive data, the key compounds related to taste were investigated. This type of research on lipids and the taste of food is expected to progress hereafter. Copyright © 2017 John Wiley & Sons, Ltd.

PPARγ2 C1431T Polymorphism Interacts with the Antiobesogenic Effects of Kochujang, a Korean Fermented, Soybean-Based Red Pepper Paste, in Overweight/Obese Subjects: A 12-Week, Double-Blind Randomized Clinical Trial

Kochujang, a Korean fermented soybean-based red pepper paste, has been reported to have beneficial health effects. The aim of this study was to examine the antiobesity effects of Kochujang as a supplement in overweight/obese subjects according polymorphisms in the obesity-linked gene, peroxisome proliferator activator receptor γ (PPARγ2). Sixty overweight/obese subjects, who had body mass indexes (BMI, kg/m2) ≥23 or waist/hip ratios (WHR) ≥0.90 for males or ≥0.85 for females, were randomly assigned to either taking 32 g/day of placebo or Kochujang for 12 weeks. Before and after the intervention, anthropometric and metabolic parameters and body fat distribution (by computed tomography) were measured. After PPARγ2 C1431T polymorphism was analyzed by PCR-restriction fragment length polymorphism, the differences among the four groups (wild and mutant alleles in Kochujang and placebo groups) were determined. Between the Kochujang (n = 26) and placebo (n = 27) groups, there were no differences in body composition, insulin resistance, or antioxidant biomarkers before and after intervention. Compared to placebo, Kochujang significantly decreased plasma triglyceride (TG), TG/high-density lipoprotein (HDL), and dietary intakes of protein, sodium, and potassium after age, sex, and BMI were adjusted. The beneficial effects of Kochujang on lowering of TG and TG/HDL were weakened in subjects with the PPARγ2 mutant T allele with increasing subcutaneous fat area. However, the interaction between Kochujang and the PPARγ2 T allele improved insulin sensitivity. The obesogenic variables affected by the T mutant allele of PPARγ2 C1431T SNP were different in overweight/obese subjects in response to Kochujang.

Utilization of fermented soybeans paste as flavoring lamination for Turkish dry-cured meat

The effects of utilizing fermented soybeans paste (miso) as an alternative flavor-coating material for eliminating unpleasant odor of sulphuric and sotolone compounds from cemen in commercial pastirma were investigated. Results showed that miso-pastirma (MP) and commercial pastirma (CP) had higher L* values in comparison with the fresh meat. While no pathogen was detected in all the meat samples, statistically significant stearic acid was increased (P<0.05) and also oleic and arachidic acids were observed in MP. SDS-PAGE patterns indicated that miso had higher impacts on muscle proteins than cemen suggesting that miso can generate proteins and peptides with better technological or nutritional properties. None of the sulphur containing compounds responsible for unpleasant odor was detected in MP. Limonene, 5 esters, beta-pinene and saponins in MP contributed to citrus fruit aroma with smoother, roasty flavor and delicious taste. These findings suggest that miso contain good flavoring molecules for enhancing fruity smell and quality of pastirma. Thus, laminating cured meat with miso can be used as an alternative to cemen for producing healthier pastirma with extended shelf life and better flavor.

Changes in microbial composition and the prevalence of foodborne pathogens in crab marinated in soy sauce produced by six manufacturing plants

BACKGROUND

The present study examined the changes in microbiological composition during the production process of crab marinated in soy sauce, potential microbial hazards, potential contamination routes and effective critical control points. Crab and soy sauce samples were obtained from six different manufacturing plants at different stages, and their microbiological content was comprehensively assessed by quantitative and qualitative analyses.

RESULTS

The results revealed the following: (1) the final products contained 4.0 log colony-forming units (CFU) g^-1 aerobic plate counts (APCs) and 1.1 log CFU g^-1 coliforms, which may have been introduced from the raw materials (the level of APCs in raw crab and soy sauce mixed with other ingredients was 3.8 log CFU g^-1 and 4.0 log CFU mL^-1 respectively); (2) marination of crab in soy sauce may allow cross-contamination by coliforms; (3) only Bacillus cereus and Staphylococcus aureus were qualitatively detected in samples at different stages of manufacture (detection rate of 28 and 5.6% respectively), and these bacteria may impact the microbiological quality and safety of crab marinated in soy sauce; and (4) bacterial counts were either maintained or increased during the manufacturing process (suggesting that no particular step can be targeted to reduce bacterial counts).

CONCLUSION

Proper management of raw materials and the marination process are effective critical control points, and alternative interventions may be needed to control bacterial quantity. The results provide important basic information about the production of crab marinated in soy sauce and may facilitate effective implementation of sanitary management practices in related industries and research fields. © 2016 Society of Chemical Industry.

Comparison of soybean cultivars for enhancement of the polyamine contents in the fermented soybean natto using Bacillus subtilis (natto)

Polyamines have beneficial properties to prevent aging-associated diseases. Raw soybean has relatively high polyamine contents; and the fermented soybean natto is a good source of polyamines. However, detailed information of diversity of polyamine content in raw soybean is lacking. The objectives of this study were to evaluate differences of polyamines among raw soybeans and select the high polyamine-containing cultivar for natto production. Polyamine contents were measured chromatographically in 16 samples of soybean, which showed high variation among soybeans as follows: 93-861 nmol/g putrescine, 1055-2306 nmol/g spermidine, and 177-578 nmol/g spermine. We then confirmed the high correlations of polyamine contents between raw soybean and natto (r = 0.96, 0.95, and 0.94 for putrescine, spermidine, and spermine, respectively). Furthermore, comparison of the polyamine contents among 9 Japanese cultivars showed that 'Nakasen-nari' has the highest polyamine contents, suggesting its suitability for enhancement of polyamine contents of natto.

Identification of a Key Gene Involved in Branched-Chain Short Fatty Acids Formation in Natto by Transcriptional Analysis and Enzymatic Characterization in Bacillus subtilis

Natto as a fermented soybean product has many health benefits for human due to its rich nutritional and functional components. However, the unpleasant odor of natto, caused by the formation of branched-chain short fatty acids (BCFAs), prohibits the wide acceptance of natto products. This work is to identify the key gene of BCFAs formation and develop the guidance to reduce natto odor. Transcriptional analysis of BCFAs synthesis pathway genes was conducted in two Bacillus subtilis strains with obvious different BCFAs synthesis abilities. The transcriptional levels of bcd, bkdAA, and ptb in B. subtilis H-9 were 2.7-fold, 0.7-fold, and 8.9-fold higher than that of B. subtilis H-4, respectively. Therefore, the ptb gene with the highest transcriptional change was considered as the key gene in BCFAs synthesis. The ptb encoded enzyme Ptb was further characterized by inducible expression in Escherichia coli. The recombinant Ptb protein (about 32 kDa) was verified by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis analysis. The catalysis functions of Ptb were confirmed on substrates of isovaleryl-CoA and isobutyryl-CoA, and the higher catalysis efficiency of Ptb on isovaleryl-CoA explained the higher level of isovaleric acid in natto. The optimal activities of Ptb were observed at 50 °C and pH 8.0, and the enzymatic activity was inhibited by Ca2+, Zn2+, Ba2+, Mn2+, Cu2+, SDS, and EDTA. Collectively, this study reports a key gene responsible for BCFAs formation in natto fermentation and provides potential strategies to solve the odor problem.

Dietary predictors and plasma concentrations of perfluorinated alkyl acids in a Singapore population

Perfluorinated alkyl acids (PFAAs), a family of man-made organofluorinated compounds, have drawn much attention due to their ubiquitous existence in the environment and their bioaccumulation potential. Here, we examined the plasma concentrations of thirteen PFAAs in a healthy population (N = 270) in Singapore, and investigated the association between major food groups and plasma PFAA concentrations. We detected eight types of PFAAs in more than 75% of all samples (N = 270), and their median concentrations ranged from 0.05 to 8.34 ng mL^-1. Age- and gender-related differences were observed for the three dominant PFAAs, i.e., perfluorooctanesulfonic acid (PFOS), perfluorohexane sulfonate (PFHxS) and perfluorooctanoate acid (PFOA), with concentrations being higher in men and older adults. Multiple linear regression analyses showed that fish, shellfish, red meat and poultry were associated with increased PFAAs concentrations in plasma, whereas grains and soy products showed inverse associations with PFAAs. Further, significant correlations were observed between various long-chain PFAAs and plasma concentrations of omega-3 fatty acids, suggesting seafood was a significant source of these PFAAs, within this population. Future studies on diet exposure to PFAAs are encouraged to focus more on the effects on diet pattern.

Simultaneous quantification of twenty Amadori products in soy sauce using liquid chromatography-tandem mass spectrometry

A liquid chromatography-tandem mass spectrometry method using a pentafluorophenylpropyl-bonded silica column was developed to simultaneously quantify twenty Amadori products (APs), including N-(1-Deoxy-d-fructosyl-1-yl)-l-isoleucine (Fru-Ile) and N-(1-Deoxy-d-fructosyl-1-yl)-l-leucine (Fru-Leu), in soy sauce, without the need for an ion-pairing reagent or sample derivatization. The method was applied to six types of soy sauce, to determine the total AP levels and the levels of individual APs. The level of total APs widely varied between the eight samples, from 358mg/L to 24347mg/L. The concentrations of N-ε-(1-deoxy-d-fructosyl-1-yl)-l-lysine (Fru-Lys) and N-(1-deoxy-d-fructosyl-1-yl)-l-pyroglutamic acid (Fru-pGlu) were the highest among the APs and the level of Fru-pGlu was similar to that of Fru-Lys. Furthermore, fermentation periods of up to six months greatly influenced AP levels in soy sauce but the levels remained constant thereafter. Thermal treatment of soy sauce had little effect on AP levels.

Development of soybeans with low P34 allergen protein concentration for reduced allergenicity of soy foods

BACKGROUND

In soybean, at least 16 seed proteins have been identified as causing allergenic reactions in sensitive individuals. As a soybean genebank accession low in the immunodominant protein P34 (Gly m Bd 30K) has recently been found, introgression of the low-P34 trait into adapted soybean germplasm has been attempted in order to improve the safety of food products containing soybean protein. Therefore, marker-assisted selection and proteomics were applied to identify and characterize low-P34 soybeans.

RESULTS

In low-P34 lines selected from a cross-population, concentrations of the P34 protein as identified with a polyclonal antibody were reduced by 50-70% as compared to P34-containing controls. Using 2D electrophoresis and immunoblotting, the reduction of P34 protein was verified in low-P34 lines. This result was confirmed by liquid chromatographic-tandem mass spectrometric analysis, which revealed either a reduction or complete absence of the authentic P34 protein as suggested from presence or absence of a unique peptide useful for discriminating between conventional and low-P34 lines.

CONCLUSION

Marker-assisted selection proved useful for identifying low-P34 soybean lines for the development of hypoallergenic soy foods. The status of the P34 protein in low-P34 lines needs further characterization. In addition, the food safety relevance of low-P34 soybeans should be tested in clinical studies. © 2016 Society of Chemical Industry.

Changes in volatile profile of soybean residue (okara) upon solid-state fermentation by yeasts

BACKGROUND

Soybean residue (okara), a by-product of soymilk, is produced in large volumes by the soy food industry and is often discarded due to its undesirable flavour. As it contains a considerable amount of protein and fats, biotransformation of okara to improve its flavour presents an opportunity for alternative utilisation. This paper evaluated 10 yeasts in the solid-state fermentation of okara based on their volatile profiles as analysed with HS-SPME GC-MS/FID. Four 'dairy yeasts' (Geotrichum candidum, Yarrowia lipolytica, Debaryomyces hansenii and Kluyveromyces lactis) and six 'wine yeasts' (Saccharomyces cerevisiae, Lachancea thermotolerans, Metschnikowia pulcherrima, Pichia kluyveri, Torulaspora delbrueckii, and Williopsis saturnus) were studied.

RESULTS

The main off-odourants in okara, hexanal and trans-2-hexenal, significantly decreased after fermentation due to their bioconversion into methyl ketones and/or esters. The okara fermented by dairy yeasts contained greater proportions of methyl ketones, while that by wine yeasts contained more ethyl and acetyl esters. Notably, the okara fermented by W. saturnus contained 13 esters and the total GC-FID peak area of esters was about 380 times that in fresh okara, leading to a perceptible fruity note.

CONCLUSION

Okara can be exploited as an inexpensive substrate for bioflavour extraction and/or a more pleasant food ingredient via yeast fermentation. © 2016 Society of Chemical Industry.

Protein and quality analyses of accessions from the USDA soybean germplasm collection for tofu production

Food-grade soybeans with large seed size, uniformity, clear hilum and a high 11S/7S ratio are favoured by the food industry for making tofu. In order to search for soybean lines with desirable characteristics for making foods, 22 soybean lines were selected from the USDA-Soybean Germplasm Collection, were grown in Stoneville, MS for biochemical analysis and tofu texture and sensory quality tests. Eight lines were identified, from 22 lines harvested in 2014, to be suitable for tofu making, as judged by chemical composition and sensory quality of pressed tofu. In the filled tofu making and texture analysis study, the correlation between A3 subunit content and filled tofu firmness was significant (N=22, r=0.77, P<0.001). The results indicated that the A3 subunit could be an indicator for predicting the firmness of tofu. The results provided important food quality information for the selection of soybean genotypes for improving food quality.

Analysis of the cooked aroma and odorants that contribute to umami aftertaste of soy miso (Japanese soybean paste)

Soy miso, the traditional Japanese fermented soybean paste prepared using soybean koji, is used for imparting umami aftertaste to cooked dishes. The objective of this study was to identify the key odorants of cooked soy miso and their influence on umami aftertaste perception. Volatile compounds of soy miso and two rice misos were prepared using simultaneous distillation-extraction, and the key odorants were identified by using the gas chromatography-olfactometry/aroma extract dilution assay approach, and soy miso was compared with rice misos. Forty-one aroma-active compounds were detected in cooked soy miso, and malty, green, roasty and sulfury aromas were identified as the characteristic aromas. Finally, sensory evaluation was conducted to assess the contribution to the umami aftertaste of six key compounds with the highest flavour dilution factor. Results revealed that dimethyl trisulfide, which was newly identified in cooked miso, contributes to the umami aftertaste and palatability of cooked soy miso.

Anti-neuroinflammatory activities of indole alkaloids from kanjang (Korean fermented soy source) in lipopolysaccharide-induced BV2 microglial cells

Kanjang (Korean soy sauce) is a byproduct of the production of the Korean fermented soybean. In the present study, seven indole alkaloid derivatives were isolated from methanol extract of kanjang. Their structures were identified as 1-propyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (1), 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (2), 1-methyl-1,2,3,4-tetrahydro-β-carboline-1-carboxylic acid (3), 3-indoleacetic acid (4), Nb-acetyltryptamine (5), 1-methyl-3,4-dihydro-β-carboline (6), and flazine (7) by NMR and MS analyses. Preliminary screening for anti-neuroinflammatory effects of isolated indole alkaloids in lipopolysaccharide (LPS)-stimulated BV2 cells revealed that these compounds inhibited the production of nitric oxide and prostaglandin E2. For the subsequent investigation of anti-neuroinflammatory action of these metabolites, compounds 4 and 7 were selected, and the results revealed that these inhibitory effects correlated with the suppressive effect of 4 and 7 on inducible nitric oxide synthase and cyclooxygenase-2 expression in LPS-stimulated BV2 cells. In regards to the mechanism of the anti-inflammatory effect, 4 and 7 significantly inhibited the nuclear factor-kappa B pathway.

Soy and Gut Microbiota: Interaction and Implication for Human Health

Soy (Glycine max) is a major commodity in the United States, and soy foods are gaining popularity due to their reported health-promoting effects. In the past two decades, soy and soy bioactive components have been studied for their health-promoting/disease-preventing activities and potential mechanisms of action. Recent studies have identified gut microbiota as an important component in the human body ecosystem and possibly a critical modulator of human health. Soy foods' interaction with the gut microbiota may critically influence many aspects of human development, physiology, immunity, and nutrition at different stages of life. This review summarizes current knowledge on the effects of soy foods and soy components on gut microbiota population and composition. It was found, although results vary in different studies, in general, both animal and human studies have shown that consumption of soy foods can increase the levels of bifidobacteria and lactobacilli and alter the ratio between Firmicutes and Bacteroidetes. These changes in microbiota are consistent with reported reductions in pathogenic bacteria populations in the gut, thereby lowering the risk of diseases and leading to beneficial effects on human health.

Simultaneous Quantitation of Advanced Glycation End Products in Soy Sauce and Beer by Liquid Chromatography-Tandem Mass Spectrometry without Ion-Pair Reagents and Derivatization

The aim of this study was to develop a simple and sensitive method to analyze several advanced glycation end products (AGEs) simultaneously using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and to apply this method to the quantitation of AGEs in brown-colored foods. The developed method enabled to separate and quantitate simultaneously seven AGEs, and was applied to the determination of free AGEs contained in various kinds of soy sauce and beer. The major AGEs in soy sauce and beer were N^ε-carboxymethyllysine (CML), N^ε-carboxyethyllysine (CEL), and N^δ-(5-hydro-5-methyl-4-imidazolon-2-yl)ornithine (MG-H1). Using the developed LC-MS/MS method, recovery test on soy sauce and beer samples showed the recovery values of 85.3-103.9% for CML, 95.9-107.4% for CEL, and 69.5-123.2% for MG-H1. In particular, it is the first report that free CML, CEL, and MG-H1 were present in beer. Furthermore, long-term storage and heating process of soy sauce increased CML and MG-H1.

Rebalance between 7S and 11S globulins in soybean seeds of differing protein content and 11SA4

Protein content and globulin subunit composition of soybean seeds affect the quality of soy foods. In this proteomic study, the protein profile of soybean seeds with high (∼45.5%) or low (∼38.6%) protein content and with or without the glycinin (11S) subunit 11SA4 was examined. 44 unique proteins and their homologues were identified and showed that both protein content and 11SA4 influenced the abundance of a number of proteins. The absence of 11SA4 exerted a greater impact than the protein content, and led to a decreased abundance of glycinin G2/A2B1 and G5/A5A4B3 subunits, which resulted in lower total 11S with a concomitant higher total β-conglycinin (7S). Low protein content was associated with higher glycinin G3/A1aB1b and lower glycinin G4/A5A4B3. Using the proteomic approach, it was demonstrated that 11SA4 deficiency induced compensatory accumulation of 7S globulins and led to a similar total abundance for 7S+11S irrespective of protein content or 11SA4.

Risks and benefits of phytoestrogens: where are we now?

PURPOSE OF REVIEW

The estrogenic effects of genistein, as reconfirmed by the American National Toxicology Program (USA-NTP), have led to several new clinical studies being undertaken. Here, we highlight the most relevant recent data, reporting either beneficial or adverse effects.

RECENT FINDINGS

Phytoestrogens are natural molecules from edible plants exhibiting estrogenic activities. Post-USA-NTP studies investigated both human and animal reproductive and other physiological issues. These studies showed that estrogens can be either deleterious for reproduction and estrogen-dependent diseases, or beneficial for those with steroid deficiencies, that is more than 50. The specific outcome depends on exposure level and on the estrogenic status of the patients exposed. Recently, it was reported that, with the industrialization of soybean process, phytoestrogen exposure dramatically increased in both humans and cattle, whereas traditional Asian soy-food-processing empirically removed isoflavones. Phytoestrogen exposure has also become more widespread with the progressive internationalization of soybean use in human and cattle food.

SUMMARY

Phytoestrogens should be considered as modern endocrine disruptors and studied as such.