Contribution of the retronasal odor of soy sauce to salt reduction.

The characteristic odor of soy sauce has been reported to enhance saltiness. However, soy sauce is used not only as a sauce that is added directly to food, but also as a seasoning. In addition, some of the aromatic compounds that contribute to the soy sauce odor change during cooking or heating. In the present study, the effects of the retronasal odor of uncooked and cooked soy sauce on the enhancement of saltiness and palatability of a low-salt solution were sensory evaluated. A probit analysis indicated that the saltiness-enhancing effect of the odor of 15% uncooked soy sauce was lost by heating. The odors of soy sauce boiled for 10 min (cooked SS) and the residue of soy sauce heated at 200 °C for 1 min improved the palatability of the low-salt solution. Gas chromatography (GC) analyses, namely, GC-olfactometry and GC-mass spectrometry, showed that one active candidate aromatic component of soy sauce contributing to saltiness enhancement was 3-methyl-1-butanol (3-Me-BuOH). The saltiness-enhancing effects of cooked SS could be restored by adding 3-Me-BuOH, as assessed by the sensory evaluation. These data demonstrated that 3-Me-BuOH contributes to saltiness enhancement. PRACTICAL APPLICATION: We found that the odor of cooked soy sauce could improve the palatability of low-salt food. Although the saltiness-enhancing effect provided by the odor of uncooked soy sauce was lost, the saltiness-enhancing effect of the odor of cooked soy sauce can be partially restored by adding 3-methyl butanol. Thus, not only the odor of unheated soy sauce but also the odor of heated soy sauce following addition of 3-methyl butanol may be useful for developing palatable salt-reduced food.

Inhibition of Glucose Transport by Tomatoside A, a Tomato Seed Steroidal Saponin, through the Suppression of GLUT2 Expression in Caco-2 Cells.

We investigated whether tomatoside A (5α-furostane-3ß,22,26-triol-3-[O-ß-d-glucopyranosyl (1→2)-ß-d-glucopyranosyl (1→4)-ß-d-galactopyranoside] 26-O-ß-d-glucopyranoside), a tomato seed saponin, may play a role in the regulation of intestinal glucose transport in human intestinal Caco-2 cells. Tomatoside A could not penetrate through Caco-2 cell monolayers, as observed in the transport experiments using liquid chromatography-mass spectrometry. The treatment of cells with 10 µM tomatoside A for 3 h resulted in a 46.0% reduction in glucose transport as compared to untreated cells. Western blotting analyses revealed that tomatoside A significantly (p < 0.05) suppressed the expression of glucose transporter 2 (GLUT2) in Caco-2 cells, while no change in the expression of sodium-dependent glucose transporter 1 was observed. In glucose transport experiments, the reduced glucose transport by tomatoside A was ameliorated by a protein kinase C (PKC) inhibitor and a multidrug resistance-associated protein 2 (MRP2) inhibitor. The tomatoside A-induced reduction in glucose transport was restored in cells treated with apical sodium-dependent bile acid transporter (ASBT) siRNA or an ASBT antagonist. These findings demonstrated for the first time that the nontransportable tomato seed steroidal saponin, tomatoside A, suppressed GLUT2 expression via PKC signaling pathway during the ASBT-influx/MRP2-efflux process in Caco-2 cells.

Key compounds contributing to the fruity aroma characterization in Japanese raw soy sauce.

In order to clarify the aroma characteristics of raw soy sauce (RS), the application of gas chromatography-olfactometry analysis to the aroma concentrate from a RS revealed 76 aroma peaks, of which 25 peaks showed fruit-like aromas. Furthermore, the head space aromatic compounds of RS were analyzed with 32 peaks detected. Ethyl 2-methylpropanoate, ethyl butanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, and ethyl 4-methylpentanoate were detected with higher flavor dilution factor (FD factor) than other aroma compounds by aroma extract dilution analysis. Quantitative analysis suggested that these compounds were common in all RS samples tested in this study, and were present at higher concentrations than their perception thresholds. The concentrations and the FD factors of these compounds were significantly decreased during the heating of the RS. Fruitiness is one of the key aroma characteristics of RS and the ethyl esters identified in this study are the key components contributing to this distinct aroma.

Contribution of 2-methyl-3-furanthiol to the cooked meat-like aroma of fermented soy sauce.

The cooked meat-like aroma compound, 2-methyl-3-furanthiol (2M3F), was detected in fermented soy sauce (FSS) by GC-olfactometry and GC-MS. 2M3F was present in FSS at a concentration considerably greater than the perception threshold, and the 2M3F concentration increased with heating temperature. Sensory analysis indicated that with the addition of only 0.2 µg/L of 2M3F to the soy sauce sample, the cooked meat-like aroma is significantly stronger than that of sample without the addition of 2M3F. Hence, 2M3F contributes to the cooked meat-like aroma of FSS, which constitutes the key aroma component of FSS. In addition, 2M3F was generated from the addition of ribose and cysteine in FSS by heating at 120 °C, but it was not detected in a phosphate buffer under the same condition. Furthermore, 2M3F was not detected in acid-hydrolyzed vegetable-protein-mixed soy sauce (ASS) and heated ASS. These results indicated that fermentation by micro-organisms facilitates the generation of 2M3F in FSS.

Flavor characteristics of the juices from fresh market tomatoes differentiated from those from processing tomatoes by combined analysis of volatile profiles with sensory evaluation.

Various commercial tomato juices with different flavors are available at markets worldwide. To clarify the marker compounds related to the flavor characteristics of tomato juice, we analyzed 15 pure commercial tomato juices by a combination of volatile profiling and sensory evaluation. The correlations among volatiles and the relationship between volatiles and sensory descriptors were elucidated by multivariate analyses. Consequently, the tomato juices made from fresh market tomatoes (including the popular Japanese tomato variety "Momotaro") were clearly separated from other juices made from processing tomatoes, by both the volatile composition and sensory profiles. cis-3-Hexenol, hexanal, and apocarotenoids negatively contributed to the juices from fresh market tomatoes, whereas Strecker aldehydes and furfural showed positive contributions to the juices. Accordingly, the sensory characteristics of juices from fresh market tomatoes were related to cooked and fruity flavors but not to green or fresh notes.

Fluorescence fingerprint as an instrumental assessment of the sensory quality of tomato juices.

BACKGROUND: Sensory analysis is an important standard for evaluating food products. However, as trained panelists and time are required for the process, the potential of using fluorescence fingerprint as a rapid instrumental method to approximate sensory characteristics was explored in this study. RESULTS: Thirty-five out of 44 descriptive sensory attributes were found to show a significant difference between samples (analysis of variance test). Principal component analysis revealed that principal component 1 could capture 73.84 and 75.28% variance for aroma category and combined flavor and taste category respectively. Fluorescence fingerprints of tomato juices consisted of two visible peaks at excitation/emission wavelengths of 290/350 and 315/425 nm and a long narrow emission peak at 680 nm. The 680 nm peak was only clearly observed in juices obtained from tomatoes cultivated to be eaten raw. The ability to predict overall sensory profiles was investigated by using principal component 1 as a regression target. Fluorescence fingerprint could predict principal component 1 of both aroma and combined flavor and taste with a coefficient of determination above 0.8. CONCLUSION: The results obtained in this study indicate the potential of using fluorescence fingerprint as an instrumental method for assessing sensory characteristics of tomato juices.

Metabolic profiling approach to explore compounds related to the umami intensity of soy sauce.

A metabolic profiling approach was employed to explore the compounds that affect the intensity of umami taste in soy sauce. Twenty-five kinds of soy sauces were analyzed using GC-MS and LC-MS, wherein measurement data for 427 compounds were obtained. The umami taste intensity of each soy sauce sample was also quantitated by sensory evaluation and a projection to latent structure (PLS) regression analysis was conducted using the compounds' measurements and umami taste intensity data. Variable importance for the projection (VIP) value obtained via PLS was used for the estimation of the relevance for umami taste intensity. N-(1-Deoxyfructos-1-yl)glutamic acid (Fru-Glu) had the highest VIP value, and addition of Fru-Glu to soy sauce increased umami taste intensity better than glutamic acid at the same concentration as confirmed by sensory evaluation. This study showed that the combination of metabolic profiling approach and sensory evaluation can be used effectively to determine compounds related to taste.

Analysis of the correlation between dipeptides and taste differences among soy sauces by using metabolomics-based component profiling.

Characterizing the relationships between the components and taste differences among soy sauces can help evaluate and improve the quality of soy sauces. Although previous studies have reported that certain taste-active dipeptides, the relationships between taste differences and dipeptides of soy sauces are unknown. Therefore, our objective in this study was to investigate the correlations between the dipeptides and the taste differences among soy sauces. To analyze the dipeptides, we constructed an analytical method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) in multiple reaction monitoring mode. Based on this method, we detected 237 dipeptides, the largest number ever detected in soy sauce research. Next, orthogonal projections to latent structures regressions were performed. The data matrix of components, including dipeptides and other low-molecular-weight hydrophilic components obtained from gas chromatography/mass spectrometry (GC/MS), served as explanatory variables (366 in total), whereas a sensory data matrix obtained using quantitative descriptive analysis served as the response variable. The accuracy of models for the sweetness and saltiness differences constructed using the LC/MS/MS and GC/MS data matrix were higher than did models constructed using only the GC/MS data matrix. As a result of investigation of the correlation between the dipeptides and taste differences among soy sauces by using variable importance in the projection (VIP) score, many dipeptides showed the high correlation with taste differences. Specifically, Ile-Gln, Pro-Lys, Ile-Glu, Thr-Phe, and Leu-Gln showed the high VIP score on sweet differences. This study is the first report that reveals the correlations between the dipeptides and taste differences among soy sauces.

Anti-influenza virus effects of elderberry juice and its fractions.

Elderberry (Sambucus nigra L.) has traditionally been used for treating influenza and colds. We evaluated the antiviral effect of concentrated juice of elderberry (CJ-E) on the human influenza A virus (IFV). CJ-E had a relatively strong effect on IFV-infected mice, although its anti-IFV activity was weak in a cell culture system. The in vivo anti-IFV activities of the fractions were determined after separating CJ-E by ultrafiltration and anion-exchange chromatography. Oral administration of the high-molecular-weight fractions of CJ-E to IFV-infected mice suppressed viral replication in the bronchoalveolar lavage fluids (BALFs), and increased the level of the IFV-specific neutralizing antibody in the serum, as well as the level of secretory IgA in BALFs and feces. Fr. II from high-molecular-weight fraction HM, which contained acidic polysaccharides, showed relatively strong defense against IFV infection. We conclude that CJ-E had a beneficial effect by the stimulating immune response and preventing viral infection.

Metabolite profiling of soy sauce using gas chromatography with time-of-flight mass spectrometry and analysis of correlation with quantitative descriptive analysis.

Soy sauces, produced from different ingredients and brewing processes, have variations in components and quality. Therefore, it is extremely important to comprehend the relationship between components and the sensory attributes of soy sauces. The current study sought to perform metabolite profiling in order to devise a method of assessing the attributes of soy sauces. Quantitative descriptive analysis (QDA) data for 24 soy sauce samples were obtained from well selected sensory panelists. Metabolite profiles primarily concerning low-molecular-weight hydrophilic components were based on gas chromatography with time-of-flightmass spectrometry (GC/TOFMS). QDA data for soy sauces were accurately predicted by projection to latent structure (PLS), with metabolite profiles serving as explanatory variables and QDA data set serving as a response variable. Moreover, analysis of correlation between matrices of metabolite profiles and QDA data indicated contributing compounds that were highly correlated with QDA data. Especially, it was indicated that sugars are important components of the tastes of soy sauces. This new approach which combines metabolite profiling with QDA is applicable to analysis of sensory attributes of food as a result of the complex interaction between its components. This approach is effective to search important compounds that contribute to the attributes.

A sulfated polysaccharide, fucoidan, enhances the immunomodulatory effects of lactic acid bacteria.

Fucoidan, a sulfated polysaccharide contained in brown algae, has a variety of immunomodulatory effects, including antitumor and antiviral effects. On the other hand, lactic acid bacteria (LAB) also have immunomodulatory effects such as anti-allergic effects. In this study, we demonstrated that fucoidan enhances the probiotic effects of LAB on immune functions. By using Peyer's patch cells and spleen cells in vitro, fucoidan amplified interferon (IFN)-γ production in response to a strain of LAB, Tetragenococcus halophilus KK221, and this activity was abolished by desulfation of fucoidan. Moreover, this IFN-γ response was abolished by interleukin (IL)-12 neutralization. These results indicate that fucoidan enhanced IL-12 production in response to KK221, resulting in promoting IFN-γ production. In an in vivo study, Th1/Th2 immunobalance was most improved by oral administration of both fucoidan and KK221 to ovalbumin-immunized mice. These findings suggest that fucoidan can enhance a variety of beneficial effects of LAB on immune functions.

Lactobacillus plantarum strain YU from fermented foods activates Th1 and protective immune responses.

Lactic acid bacteria (LAB) are known to have effects on immune function. From 203 strains of LAB isolated from fermented foods, we selected a beneficial strain, Lactobacillus plantarum strain YU (LpYU), which has high interleukin (IL)-12-inducing activity in mouse peritoneal macrophages. This activity of LpYU was partially mediated by Toll-like receptor (TLR) 2, but not TLR4 or TLR9. Oral administration of LpYU to ovalbumin (OVA)-immunized mice caused suppression of serum OVA-specific immunoglobulin E (IgE) levels, enhancing interferon (IFN)-γ production from spleen cells in response to OVA. Furthermore, LpYU enhanced natural killer cell activity in spleen cells and the production of IgA from Peyer's patch cells. Because activation of Th1 immune responses and IgA production induce antiviral effects, we evaluated the inhibitory effects of LpYU against the influenza A virus (A/NWS/33, H1N1) (IFV). Oral administration of LpYU suppressed viral proliferation in the lungs and in bronchoalveolar lavage fluids (BALFs). Both levels of IFV-specific secretory IgA in BALF and feces and titers of IFV-specific neutralizing antibody in BALFs and sera were increased. These results indicate that LpYU has a protective effect against IFV replication. We conclude that this strain has a beneficial effect in activating Th1 immune responses and preventing viral infection.

Identification, characterization, and molecular cloning of a novel hyaluronidase, a member of glycosyl hydrolase family 16, from Penicillium spp.

Hyaluronidase (HAase) activity was detected in the culture supernatants of Penicillium purpurogenum and Penicillium funiculosum. The HAase from Penicillium spp. (HAase-P) was a hyaluronate 4-glycanohydrolase, which catalyzed the endolytic hydrolysis of the ß-1,4 glycosidic linkage, as do vertebrate HAases. The gene encoding HAase-P was cloned and expressed in Escherichia coli. According to homology analyses of the deduced amino acid sequences, HAase-P is not classified into any of the known HAase groups, but belongs to glycoside hydrolase family 16, which includes endo-ß-1,3(4)-glucanase. Regarding the substrate specificities, no chondroitinase and glucanase activities were detected. Judging from homology analyses and enzymatic properties, HAase-P seems to be a new type of HAase.

Antihypertensive effect of a gamma-aminobutyric acid rich tomato cultivar 'DG03-9' in spontaneously hypertensive rats.

This study aimed to investigate the effects of a gamma-aminobutyric acid (GABA) rich tomato (Solanum lycopersicum L.) cultivar 'DG03-9' in comparison with 'Momotaro', a commonly consumed tomato cultivar in Japan, on systolic blood pressure (SBP) in spontaneously hypertensive rats (SHR). In a single administration study, treatment with the GABA-rich cultivar elicited a significant decrease in SBP compared to the control group. In a chronic administration study, SHR were fed diets containing one of the tomato cultivars for 4 weeks. Both cultivars significantly reduced the increase in SBP compared to the control. The antihypertensive effect of the GABA-rich cultivar was higher than that of the commonly consumed cultivar in both the single- and chronic-administration studies. Treatment with a comparable amount of GABA elicited a similar response to treatment with the GABA-rich cultivar. These results suggest that the GABA-rich cultivar 'DG03-9' is a potent antihypertensive food and may be useful for treating hypertension effectively.

Naringenin chalcone suppresses allergic asthma by inhibiting the type-2 function of CD4 T cells.

BACKGROUND: Some polyphenols possess anti-allergic activities. Naringenin chalcone is one of the polyphenols that is present in the skin of red tomatoes. In this study, we investigated the effect of naringenin chalcone in allergic responses in vivo using an experimental mouse model system of allergic asthma. METHODS: Allergic airway inflammation was induced in mice by sensitization and challenge with ovalbumin. Naringenin chalcone was orally administrated every day during the course of the experiment. Airway hyperreactivity, the eosinophilic infiltration in the bronchioalveolar lavage fluid and Th2 cytokine production from splenic CD4 T cells were assessed. RESULTS: Eosinophilic airway inflammation, airway hyperreactivity and Th2 cytokine production from CD4 T cells were significantly suppressed in mice that were treated with naringenin chalcone. Hyperproduction of mucus was slightly reduced. CONCLUSIONS: The results of this study suggest that naringenin chalcone suppresses asthmatic symptoms by inhibiting Th2 cytokine production from CD4 T cells. Thus, naringenin chalcone may be a useful supplement for the suppression of allergic symptoms in humans.

Identification and quantification of metabolites of orally administered naringenin chalcone in rats.

Naringenin chalcone is the main active component of tomato skin extract, which has an antiallergic activity. In this study, naringenin chalcone was orally administered to rats, and the chemical structures and levels of the major metabolites in the plasma and urine of rats were determined. HPLC analysis indicated the presence of three major metabolites in the urine. LC-MS and NMR analyses tentatively identified these as naringenin chalcone-2'-O-beta-D-glucuronide, naringenin-7-O-beta-D-glucuronide, and naringenin-4'-O-beta-D-glucuronide. Naringenin chalcone-2'-O-beta-D-glucuronide was the only metabolite detected in the plasma, and its peak plasma level was observed 1 h after naringenin chalcone administration. Naringenin chalcone-2'-O-beta-D-glucuronide also inhibited histamine release from rat peritoneal mast cells stimulated with compound 48/80. This activity might contribute to the antiallergic activity of naringenin chalcone in vivo. To the best of the authors' knowledge, this study is the first to report determination of naringenin chalcone metabolites in rat plasma and urine.

Clinical efficacy of halophilic lactic acid bacterium Tetragenococcus halophilus Th221 from soy sauce moromi for perennial allergic rhinitis.

BACKGROUND: Recently, some common foods in daily life, especially lactic acid bacteria, have been found to have anti-allergic effects. We previously isolated a halophilic lactic acid bacterium, Tetragenococcus halophilus Th221, from soy sauce moromi, a mixture of koji and salt solution, and showed that it possesses an immunomodulatory activity that promotes T helper type 1 immunity. METHODS: To evaluate the anti-allergic effects of Th221, we performed a randomized, double-blind, placebo-controlled study in 45 subjects with perennial allergic rhinitis (PAR) treated by oral administration of Th221 (high dose, 60 mg/day, 15 subjects; low dose, 20.4 mg/day, 15 subjects) or a placebo (15 subjects) for 8 weeks. RESULTS: There were no significant differences among the groups that ingested Th221 and the placebo group regarding the disease severities, total nasal symptom scores and total nasal sign scores examined by physicians. However, the disease severity examined by physicians significantly improved in the high-dose group at the end of the trial compared with the beginning (p < 0.05). The total score for nasal symptoms of subjects who received a high dose of Th221 also showed a significant improvement at the end of the trial compared with the beginning (p < 0.01). According to the subjects' diaries, significant improvements in sneezing and rhinorrhea were observed during some periods in the high-dose group. The change in serum total immunoglobulin E improved significantly at the end of the trial compared with the beginning in this group (p < 0.05). The safety of Th221 treatment was confirmed by laboratory tests and inspection of the general condition of each subject. CONCLUSIONS: Th221 can be expected to safely improve the symptoms of PAR.

Dietary soy isoflavone-aglycone lowers food intake in female rats with and without ovariectomy.

OBJECTIVE: Estrogens downregulate eating behavior, and soy isoflavones are known to be estrogenic agents. We aimed to examine whether the estrogenic property of soy isoflavones can affect food intake and body weight. METHODS AND PROCEDURES: Seven-week-old male, female, and ovariectomized (OVX) Sprague-Dawley rats were given free access to a diet containing 100-300 mg total isoflavone/kg diet, or to a control diet, either with or without concurrent administration of estradiol by subcutaneous implantation. RESULTS: Dietary soy isoflavone was shown to lower food intake in female rats, whether or not the animals had undergone ovariectomy. Administration of estradiol lowered the food intake in male rats and in OVX female rats. The decrease in weekly food intake in female rats led to a reduction in their weekly gain in body weight. Dietary soy isoflavone significantly increased the concentration of serum isoflavones, especially equol (a metabolite of daidzein), regardless of gender or ovariectomy. Dietary soy isoflavone did not affect either serum estradiol concentration or uterine and didymus weights, but estradiol administration improved the uterine atrophy in OVX rats, and decreased the didymus weight in male rats. DISCUSSION: Soy isoflavone lowers the food intake in female rats, but not in the male animals. Contrary to the hypothesis currently in vogue, the reduction in food intake caused by soy isoflavone may not be a purely estrogenic effect. This follows from the finding that the effects of soy isoflavones on food intake and on the reproductive organs differ from the corresponding effects produced by estrogen.

Application of an Aspergillus saitoi protease preparation to soybean curd to modify its functional and rheological properties.

An Aspergillus saitoi protease preparation, Molsin, was found to contain beta-glucosidase as well as protease activities. Application of Molsin to soybean curd improved its functionality by converting the contained isoflavone glycosides to their aglycones through beta-glucosidase, and also modified the rheological property into a creamy consistency through protease. The enzymatically modified soybean curd was characterized by a ductility flow having no particular rupture point.

Inhibitory effect of naringenin chalcone on inflammatory changes in the interaction between adipocytes and macrophages.

Obese adipose tissue is characterized by an enhanced infiltration of macrophages. It is considered that the paracrine loop involving monocyte chemoattractant protein (MCP)-1 and tumor necrosis factor (TNF)-alpha between adipocytes and macrophages establishes a vicious cycle that augments the inflammatory changes and insulin resistance in obese adipose tissue. Polyphenols, which are widely distributed in fruit and vegetables, can act as antioxidants and some of them are also reported to have anti-inflammatory properties. Tomato is one of the most popular and extensively consumed vegetable crops worldwide, which also contains many flavonoids, mainly naringenin chalcone. We investigated the effect of flavonoids, including naringenin chalcone, on the production of proinflammatory mediators in lipopolysaccharide (LPS)-stimulated macrophages and in the interaction between adipocytes and macrophages. Naringenin chalcone inhibited the production of TNF-alpha, MCP-1, and nitric oxide (NO) by LPS-stimulated RAW 264 macrophages in a dose-dependent manner. Coculture of 3T3-L1 adipocytes and RAW 264 macrophages markedly enhanced the production of TNF-alpha, MCP-1, and NO compared with the control cultures; however, treatment with naringenin chalcone dose-dependently inhibited the production of these proinflammatory mediators. These results indicate that naringenin chalcone exhibits anti-inflammatory properties by inhibiting the production of proinflammatory cytokines in the interaction between adipocytes and macrophages. Naringenin chalcone may be useful for ameliorating the inflammatory changes in obese adipose tissue.