In order to elucidate the staling characteristics of low-amylose rice (apparent amylose content ; 3.7-11.0%), low-compression test (25% deformation), high-compression test (90% deformation) and continuous progressive compression test using a Tensipresser were carried out. Among these textural analyses, the degree of hardness and stickiness changes obtained by low compression test could express the staling characteristics of cooked rice, and three low-amylose lines of Ouu 343, Ouu 344 and Ouu 354 were showed to be varieties with lower degrees of staling. Physicochemical properties of low-amylose rice were also investigated to determine the factors responsible for its staling characteristics. Apparent amylose contents of Ouu 343, Ouu 344 and Ouu 354 ranged from 3.7% to 9.3%, and were not simply related to the degree of staling of cooked low-amylose rice. It was considered that the Rapid-Visco-Analyser values, especially at the final temperature of 5°C, were useful for the selection of staling-resistant-lines, as three varieties of Ouu showed lower final viscosities and set back values on RVA analysis. The principal-component analysis of the values by Tensipresser (degree of hardness and stickiness changes), RVA (final viscosity and set back) and gel strength of rice flour revealed that 8 lines of low-amylose rice were classified into 4 groups. We assumed that the principal-component analysis of these indices could clarify the staling characteristics of low-amylose rices.

View full abstract

We examined effects of various surfactants on physical and sensory properties of roasted beef. Succinylated glycerol monostearate (SGMS), a safety anionic surfactant, was the most effective tenderizer among various surfactants tested. When both sides of sliced beef were coated with 2% (w/w) SGMS powder, then roasted at 200°C, about 11% of the total amount of SGMS penetrated into the beef. SGMS did not affect the shrinkage rate of myofibrils, but reduced that of the epimysium, and reduced the shear-force value of the intramuscular connective tissue. After heating the SGMS-coated epimysium for 30 min at 65°C, collagen fibrils were decorated with granular and sheet-like materials. The latter may be a complex of SGMS and heat-denatured collagen. These results indicate that SGMS tenderizes beef through inhibiting the heat-shrinkage of the intramuscular connective tissue. We conclude, therefore, that SGMS is a novel and effective meat tenderizer.

View full abstract

Grain quality evaluations, such as chemical component analyses, cooking quality test (CT), pasting behavior (PB) and physical properties measurement of cooked rice (PP), of the New-Characteristic-Rices developed in Hokuriku District were carried out and the results were compared with those of various domestic and foreign rices. Hokuriku No 147 and Habataki showed similar cooking qualities with ordinary rices, and revealed high peak viscosities and breakdown on PB. And their cooked rice grains were soft and sticky. Hokuriku No 149 showed low whiteness of polished rice grains, low peak viscosities and hard cooked grains in case of high protein grains. It showed lower Iodine Blue Value (IBV) on CT and cooked rice grains had similar dynamic viscoelasticity with that of Honenwase in case of low protein grains. Ochikara is high-yielding applied with high nitrogen. It generated many broken or brewers' grains on polishing because of white-belly kernels. And its cooking quality was low because of high soluble substance and IBV. Its peak viscosity was lowest second to sugary rice and tan σ was also low on PP. In case of sugary rice, great amount of soluble substance on CT and low viscosity on PB were promising factors as the material for fermentation. The foreign typical indica rices showed high expanded volume, IBV/SS and high final viscosity, and high G' and low tan σ. Some foreign rices showed low IBV, high expanded volume and low G' It became possible to classify these various kind of rice grains into several groups by the principal component analysis and cluster analysis based on the physicochemical data.

View full abstract

Production of elastase by Bacillus subtilis (natto) KFP 419 was investigated to obtain enough enzyme for studying on physiological functionality of itohiki-natto. Batch type shaking culture was performed with 100 ml of NBP medium in a 500 ml shaking flask. When glucose was added in NBP medium as a sugar source, the elastase activity increased, and one percentage addition of phytone was optimum as a nitrogen source. Optimum pH was 6.5-7.0. Optimum concentrations of beef extract, phytone and NaCI in the medium was 1.0, 1.0 and 0.5%, respectively. The maximum elastase activity was obtained at pH 7.0 after 24 hour fermentation. Elastase activity obtained by a jar fermentor was higher than that by a column type bioreactor, and a jar fermentor was considered more suitable for elastase production than a column type bioreactor.

View full abstract

Ferulic acid is known to exist as esters (with arabinoxylan) in a cell wall and to have antioxidative activities. In this study, ferulic acid contents of daily foods, especially in the products from Gramineae, were measured by HPLC. In the same materials, unpurified foods contained more ferulic acid than highly purified one. For example, brown rice contained more ferulic acid than well-milled rice. Minor cereals, such as rye flour, oatmeal, foxtail millet, barley and bamboo shoots contained more ferulic acid than cereals such as rice, flour and their processed foods. It was confirmed that ferulic acid contents were related to total and insoluble dietary fiber contents. This may be caused by ferulic acid esterified with arabinoxylan, which is matrix polysaccharide in a cell wall.

View full abstract

Physical properties correlated to eating qualities of rice kernels cooked in different conditions were measured and analysed using a continuous minute deformation method of the multi-biting test. Rice kernels which were fairly small size compared to normal testing samples could be measured by this method using a improved Tensipresser Boy. This method could be effectively analysed the physical properties of exterior and inner layer of cooked rice kernels. Cooked rice kernels of Asahi were hard especially in the inner layer compared to that of Koshihikari. Cooked rice kernels of Thai rice were much hard and much less stickiness compared to that of Koshihikari and Asahi and also especially hard in the inner layer of cooked rice kernels. Cooked rice kernels of Indica type rice cultured in Japan also hard in the inner layer but fairly soft and sticky compared to the cooked rice kernels of Thai. Cooked rice kernels of glutinous rice Koganemochi were most soft, and the measured parameters of the eating qualities of softness were most declined according to increased added water level. The total amounts of parameters of hardness and stickiness of cooked rice kernels due to increased biting ratio and the balance values using these parameters were more appropriately indicated the eating qualities of cooked rice of different qualities, compared to the routine balance values of one point mensuration.

View full abstract

When tubers of potatoes (Solanum tuberosum L. cv. Irish Cobbler and cv. Kitaakari, a variety of high Vitamin C content) were stored at 4°C within 10 days after the harvest at about 23°C, both Vitamin C (ascorbic acid, AsA) content and the activity of L-galactono-r-lactone dehydrogenase (EC 1.3.2.3, GLDHase) increased after 2 days, and decreased thereafter. When tubers of 6 caltiver varieties including cv. Irish Cobbler, cv. May Queen, cv. Kitaakari, cv. Tsunika, cv. Touya and cv. Hokkai 79 were stored at 4°C, a marked decrease in the AsA content and an increase in GLDHase activity were observed in comparison with storage at 15°C. These results suggested that AsA was supplied by the increased GLDHase activity, while a large amount of AsA was exhausted by a strong low temperature stress.

View full abstract