The importance of texture control in food and health in Japan was discussed on the occasion of the celebration of the 100th anniversary of Japanese immigration to Brazil. Dietary patterns in both countries, recent research activities, and governmental recommendation of food intake are also described, including some historical changes. Recent advances in study on texture terms, functional foods, food gels, and gelling process in the food science and technology in Japan are also reviewed.
Magnetic resonance imaging (MRI) was employed to observe water diffusion within two kinds of buckwheat noodles (marunuki, sarashina) and one kind of wheat noodle during boiling and holding. The apparent diffusion coefficients for water were statistically estimated with Fick's second law using a rectangular cylinder model, and the changes in moisture distribution in buckwheat and wheat noodles were compared quantitatively. Apparent diffusion coefficients of water in noodles during boiling were 4 to 7 × 10–6 cm2/sec. The diffusion coefficients of water in buckwheat noodles during boiling were higher than those in wheat noodles. For each noodle, the diffusion coefficient during holding after boiling was 2 to 3 × 10–7 cm2/sec and constant through the holding time, from 30 to 120 min. The diffusion coefficients in buckwheat noodles during holding were lower than those in wheat noodles. These results show that, as compared with wheat noodles, buckwheat noodles cooked more rapidly and lost favorable texture during holding.
Flavor compounds in white bread have been analyzed by a static-headspace-type GC/MS and sensory evaluation for clarifying the effects of mixing stage and fermentation time on the intensity of flavor compounds as assessed in the crumb and sensory scores of flavor in white bread. Principal component analysis (PCA) and analysis of variance (ANOVA) were applied to the peak area of total ion chromatogram as well as sensory scores of 8 sensory descriptors for flavor intensity. Although the results of instrumental analyses showed the superiority of fermentation time over mixing energy as the governing factor of white bread flavor, the results of statistical analyses for the scores of sensory evaluation showed the superiority of mixing energy over fermentation time. The difference in the governing factor was probably due to overestimation for the effect of alcohols on the flavor quality of white bread, especially ethanol derived from the fermentation process.
Recently we developed a method that estimates the temperatures of a cylindrical sausage exposed at various temperature patterns (FSTR 14:111-116, 2008); the method was based on the heat conduction law and temperature difference between a standard point and points on the surface of the food as the boundary conditions. In this study, we confirmed that the method also successfully estimates the temperature of a hamburger patty at various patterns of temperature. Then, we simulated bacterial growth in the food at a dynamic temperature using a combination of our temperature estimation method and our growth model. This combined simulation can be used as an alert system for microbial growth in foods for the purpose of food safety.
The transit velocity through the human throat and rheological properties of nonglutinous rice starch (NGRS) and glutinous rice starch (GRS) were investigated. The maximum transit velocity decreased with increasing concentrations of starch, with marked changes from 0 to 6% and gradual changes from 6 to 12% for NGRS and GRS, respectively, with no further changes at concentrations higher than 18%. The hardness, adhesiveness and cohesiveness of the two rice starches increased with increasing concentrations of starch. In the sensory evaluation, the rice starches became more difficult to masticate and swallow, and the masticated pellet formed a more compact bolus with increasing starch concentrations.
Much attention has focused on the health benefits of isoflavone. Investigating the absorption and metabolism of isoflavonoids is essential for understanding their biological activity. We explored the effect of a high fiber diet containing rice bran hemicellulose on the plasma and cecal isoflavonoids in mice. Mice were fed a 5% rice bran hemicellulose and 5% cellulose-0.1% daidzein diet (RBI diet) or a 5% cellulose-0.1% daidzein diet (CI diet) for 30 days. After the 30-day feeding period, the mice were sacrificed and blood and cecal contents were collected. The plasma isoflavonoids and plasma total cholesterol concentrations were measured. The plasma daidzein concentrations were significantly lower in the RBI group compared to the CI group. In contrast, there were no significant differences in the plasma equol concentrations or plasma total cholesterol concentrations between the RBI and CI groups. Binding affinity against isoflavonoids and/or the bulking effect in the gut might be related with the reduction in plasma daidzein concentration in the RBI group.
Coffee bean extract (CBE) was prepared from raw green coffee beans and contained 10.0% caffeine and 27.0% chlorogenic acid. Male Sprague-Dawley rats were fed a diet containing 1% CBE for 4 weeks. Although there was no difference in food intake between rats fed the control diet without CBE and those fed the CBE-containing diet, body weight gain and white adipose tissue weight were significantly decreased in CBE-fed rats than in control rats. The CBE-fed group exerted a significant and extreme reduction in serum and liver triglyceride concentrations compared to the control group. Also, in the CBE-fed group, activities of fatty acid synthetic enzymes in the hepatic cytosol were significantly decreased, while that of fatty acid oxidative enzymes in the hepatic mitochondria was significantly increased. Our results suggest that CBE has potent anti-obesity and hypotriglyceridemic properties, and there is a possibility that these effects are exerted at least in part by the suppression of lipogenesis and the acceleration of lipolysis.
Effects of several nonthermal disinfection processes, including high pressure carbon dioxide treatment (HCT), gaseous chlorine dioxide treatment (GCT) and pulsed xenon treatment (PXT), on the inactivation of microorganisms and antioxidants in ten cut vegetables (red paprika, green pepper, cucumber, cabbage, lettuce, mizuna, celery, onion, carrot, and bean sprout) were investigated. HCT (6 or 10 MPa, 10 min, 35°C) showed similar inactivation effects on microorganisms using conventional NaOCl treatment (100 ppm, 10 min) by controlling pressure. However, HCT caused a loss of more antioxidants such as vitamin C and phenolic compounds in cut vegetables under severe conditions. In addition, HCT softened the leaf vegetables, cabbage, lettuce, and mizuna. All samples after PXT (500 J, 10 times) had the same antioxidant contents and DPPH radical scavenging activities as the untreated intact samples, suggesting PXT could be a disinfection method that does not influence the antioxidants in cut vegetables. For inactivation of microorganism, PXT decreased the viable cell count by about 10-fold, but not significantly. On the other hand, GCT (10 ppm, 30 min) showed almost the same microorganism inactivation as NaOCl treatment. The loss of vitamin C and phenolic compounds due to GCT were negligible. These results suggest that GCT might be a promising nonthermal disinfection treatment for cut vegetables.
We previously reported that soybean phospholipids improved the storage stability of fish fillets. The object of this study was to identify the active component of soybean phospholipids and its mechanism. Rainbow trout were fed purified diets supplemented with no phospholipids (Control), 1% soybean phosphatidylcholine (S-PC), and 1% soybean phosphatidylethanolamine (S-PE) for 4 weeks. After the feeding period, fish fillets were subjected to an oxidation test. The storage stability of fish fillets was improved in the S-PC and S-PE groups compared to the Control group. The rate of phospholipid-bound docosahexaenoic acid (DHA) in the S-PC and S-PE groups was higher than that in the Control group. These results indicate that phosphatidylcholine and phosphatidylethanolamine in soybean phospholipids contributed to the improved storage stability of fish fillets. It was speculated that high phosphatidylcholine- and phosphatidylethanolamine-bound DHA levels were involved in the improved storage stability of fish fillets.
The reproducibility and reliability of the micro-β-carotene-linoleic acid bleaching (BCB) assay have been improved, enabling comparison to the antioxidant activity (AOA) of extracts from eleven kinds of crops evaluated by the oxygen radical absorbance capacity (ORAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. All assays were conducted using 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) as a calibrator, and AOAs were expressed as micromoles of Trolox equivalent per gram of weight. The coefficient variation (CV) of the BCB assay using a microplate was 14.40%, which was comparable to that of the ORAC assay (H-ORAC (14.10%), L-ORAC (18.76 %)).
Oral administration of carnosine (β-alanyl-L-histidine) in mice treated with restraint stress moderately alleviated a stress-induced decrease in plasma oxygen radical absorbance capacity (ORAC) activity (P = 0.075). Carnosine treatment also increased the level of plasma glutathione (GSH) and ascorbic acid compared with those in the restraint stress mice. Carnosine and related compounds anserine, histidine and histamine exhibited ORAC activity in vitro, while β-alanine was not effective. These results suggest that carnosine exerts a protective effect against the stress-induced elevation of the oxidative level in plasma.
This study examined the effects of food additives on gram-negative bacteria. The food additives used included synthetic antioxidants (butylated hydroxyanisole, BHA, and butylated hydroxytoluene, BHT), a curing agent and lactic acid with or without a cell-free supernatant (CFS) containing antimicrobial compounds of Lactobacillus sakei D-1001. The gram-negative bacteria were selected from dry-fermented sausages and cultured with different food additives for 18 h in nutrient broth, and then another 24 h with or without CFS adjusted (at pH 6.0) to inactivate lactic acid or not adjusted (at pH 4.0). BHA (0.1%) resulted in total viable cell inhibition following 18 h culture. A reduction in cell growth was observed in culture broths with 0.1% lactic acid and synthetic antioxidants at different concentrations. Furthermore, greater susceptibility of gram-negative bacteria could be obtained in 18+24-h cultures with combinations of selected food additives and antimicrobial compounds of Lactobacillus sakei D-1001, in a low pH environment depending on the lactic acid concentration.
In the present study, degradation of a bitter peptide derived from β-casein by lactic acid bacterial peptidase was examined. Nine species of lactococci (L. lactis ssp. lactis 303, L. lactis ssp. lactis 527, L. lactis ssp. lactis IAM 1198, L. lactis ssp. cremoris SK11, L. lactis ssp. cremoris AM2, L. lactis ssp. cremoris HP, L. lactis ssp. cremoris 317, L. lactis ssp. cremoris H61 and L. lactis ssp. cremoris IAM1150), which are extensively used as starter cultures for cheese manufacturing, were examined. The heptapeptide Gly-Pro-Phe-Pro-Ile-Ile-Val, derived from β-casein, was used as the bitter peptide. All the cell-free extracts prepared from lactic acid bacteria (LAB) could degrade the bitter peptide, but the degree of degradative activity varied depending on the type of LAB. In particular, L. lactis ssp. lactis 527 showed a higher level of degradative activity than L. lactis ssp. cremoris SK11 and L. lactis ssp. cremoris AM2; all have been reported as debittering LAB. From these results, it was concluded that L. lactis ssp. lactis 527 may be used for debittering dairy products including cheese.
Many athletes experience a change in taste sensitivity due to physical fatigue. Nutrition is an important factor during training and recovery. Previous reports have described the ideal alimentation for athletes, however, the alimentation appropriate for physical fatigue has not been investigated. As a part of gustation research aimed at formulating an ideal alimentation for fatigue, we investigated the relationship between fatigue and taste sensitivity to sweet substances. Athletes were asked to perform a half marathon to induce physical fatigue. We used a triangle test to determine the detection threshold for sucrose solutions before and after running. The results revealed that the threshold decreased after the half marathon. Thus, we confirmed that taste sensitivity to sweetness increased as a consequence of physical fatigue. To avoid either a lack or excess in nutrient intake during post-exercise physical fatigue, an alimentation regime that takes into consideration this change in taste sense is necessary.
Natto is a popular traditional Japanese food made by fermenting steamed soybeans with Bacillus subtilis natto. It has long been thought that natto is effective in preventing hypertension. But there have not been any reports demonstrating in vivo antihypertensive effects of natto. In this study, we demonstrate for the first time the antihypertensive activity of natto in vivo. We determined optimal conditions for producing natto with the highest angiotensin I converting enzyme (ACE) inhibitory activity. An ACE inhibitor partially purified from natto was orally administered as a single dose (1 mg, 10 mg, and 100 mg/kg body weight) in spontaneously hypertensive rats, and then their blood pressure was measured five times every hour after administration. The administration of the inhibitor, even at the lowest dose, resulted in a significant decrease in blood pressure 4 h after administration. Thus, the ACE inhibitor from natto appears to moderately reduce blood pressure relative to increases in dosage.