Effects of dried tofu supplementation during interval walking training on the methylation of the NFKB2 gene in the whole blood of older women.

Muscle atrophy with aging is closely associated with chronic systemic inflammation and lifestyle-related diseases. Here, we assessed whether dried tofu intake during 5-month interval walking training (IWT) enhanced increases in thigh muscle mass and strength and ameliorated susceptibility to inflammation in older women. Subjects (n = 32, ~ 65 years) who performed IWT for > 6 months participated in this study. They were randomly divided into 2 groups: IWT + placebo intake (PLG, n = 16; 108 kcal, 0.2 g protein, 5.5 g fat, and 14.4 g carbohydrate) and IWT + dried tofu intake (DTG, n = 16; 111 kcal, 9.6 g protein, 6.0 g fat, and 4.6 g carbohydrate). They were instructed to repeat ≥ 5 sets of fast and slow walking for 3 min each at ≥ 70 and 40% peak aerobic capacity for walking, respectively, per day for ≥ 4 days/week. Immediately after daily exercise, subjects were instructed to consume the supplements assigned to each group. In the DTG, after IWT, the methylation increased at 4/6 sites in the promoter region of the NFKB2 gene in the whole blood (all, P < 0.04), with an 18% increase in the average methylation of the 6 sites (P = 0.035). On the other hand, in the PLG, the increase occurred at only 2/6 sites, with no significant increase in the average methylation of the 6 sites. No significant differences were observed in increases in thigh muscle strength or cross-sectional area between the groups (all, P > 0.2). Altogether, dried tofu supplementation during IWT likely enhanced the methylation of the NFKB2 gene more than IWT alone, without detectably enhanced increases in thigh muscle strength or cross-sectional area.

Improving surface functional properties of tofu whey-derived peptides by chemical modification with fatty acids.

Effect of acylation with saturated fatty acids on surface functional properties of tofu whey-derived peptides was investigated. Tofu whey (TW) and soy proteins (7S, 11S, and acid-precipitated soy protein [APP]) were hydrolyzed by Protease M 'Amano' G, and resulting peptide mixtures were acylated with esterified fatty acids of different chain length (6C to 18C) to form a covalent linkage between the carboxyl group of fatty acid and the free amino groups of peptide. Acylation significantly (P < 0.05) increased emulsifying properties of 7S, 11S, and APP peptides independent of fatty acid chain length. Acylation decreased water binding capacity although oil binding capacity of acylated tofu whey ultra filtered fraction (UFTW < 3 kDa), 7S- and 11S-peptides were improved compared to native peptides. 7S peptides acylated with long chain fatty acids had shown significant higher surface hydrophobicity as in contrast with acylated UFTW < 3 kDa and APP peptides. Fluorescence spectra studies revealed structural conformation of acylated soy peptides as compared to native peptides. This study shows that chemical modification with fatty acids can further affect functional properties of soy proteins.

Disruption of the cell wall lytic enzyme CwlO affects the amount and molecular size of poly-γ-glutamic acid produced by Bacillus subtilis (natto).

Poly-γ-glutamic acid (γPGA), a polymer of glutamic acid, is a component of the viscosity substance of natto, a traditional Japanese food made from soybeans fermented with Bacillus subtilis (natto). Here we investigate the effects of the cell wall lytic enzymes belonging to the D,L-endopeptidases (LytE, LytF, CwlO and CwlS) on γPGA production by B. subtilis (natto). γPGA levels in a cwlO disruptant were about twofold higher than that of the wild-type strain, whereas disruption of the lytE, lytF and cwlS genes had little effect on γPGA production. The molecular size of γPGA in the cwlO disruptant was larger than that of the wild-type strain. A complementary strain was constructed by insertion of the entire cwlO gene into the amyE locus of the CwlO mutant genome, and γPGA production was restored to wild-type levels in this complementary strain. These results indicated that the peptidoglycan degradation enzyme, CwlO, plays an important role in γPGA production and affects the molecular size of γPGA.

Cholesterol-lowering effect of kori-tofu protein and its high-molecular-weight fraction content.

The serum total cholesterol concentration was significantly lower in the kori-tofu feeding group than in the soy protein isolate (SPI) group, except on the 28th day of the experiment. The high-molecular-weight fraction (HMF) content of the kori-tofu protein was significantly higher than that of SPI. This difference in the HMF content may have influenced the cholesterol-lowering effect of the protein.

Enhanced antiviral activity of soybean ß-conglycinin-derived peptides by acylation with saturated fatty acids.

Peptide mixtures prepared from soybean ß-conglycinin (7S-peptides) were acylated with saturated fatty acids of different chain length (6C-18C) in order to improve their antiviral activity against Feline calicivirus (FCV) strain F9 which is a typical norovirus surrogate. Among the fatty acids varieties, it was revealed that 7S-peptides acylated with myristic and palmitic acids potently inhibited FCV replication. Myristorylation and palmitoylation of 7S-peptides kept host cells viability at 91.51% and 98.90%, respectively. The infectivity of FCV on Crandell-Reese feline kidney cells was further determined after exposure of initial titer of 10(6.47) TCID50/mL. Myristoylated and palmitoylated 7S-peptides significantly (P < 0.006) reduced FCV infectivity as compared to native 7S-peptides. Native 7S-peptides showed 25% FCV inhibitory activity while myristoylated and palmitoylated 7S-peptides exhibited 98.59% and 99.98% reduction in FCV infectivity, respectively. Myristoylated and palmitoylated 7S-peptides demonstrated higher anti-FCV activity in a wide range of concentration with complete reduction at 25 µg/mL. Surface hydrophobicity was significantly (P < 0.05) increased after attachment of long hydrocarbon fatty acids to 7S-peptides as supported by changes in fluorescence intensity. Enzymatic hydrolysis together with acylation will give an insight into surface and physiological functional lipopeptides derived from soy ß-conglycinin.

Development of natto with germination-defective mutants of Bacillus subtilis (natto).

The effects of cortex-lysis related genes with the pdaA, sleB, and cwlD mutations of Bacillus subtilis (natto) NAFM5 on sporulation and germination were investigated. Single or double mutations did not prevent normal sporulation, but did affect germination. Germination was severely inhibited by the double mutation of sleB and cwlD. The quality of natto made with the sleB cwlD double mutant was tested, and the amounts of glutamic acid and ammonia were very similar to those in the wild type. The possibility of industrial development of natto containing a reduced number of viable spores is presented.