Eight yeast strains were isolated from samples collected in Hokkaido after enrichment culture with a high concentration of sucrose. Among them, strain AK 46, which was derived from dough containing fermented cherry fruits was identified as Saccharomyces cerevisiae. The nucleotide sequence of the rDNA spacer region from this strain was identical to those from yeasts used for the production of whisky, wine, and bread. Strain S. cerevisiae AK 46 carried only only SUC2, which is one of multiple genes that encodes invertase, in contrast to the other baking strains, and its sequences were diverged from those of the corresponding gene found in the other strains. In a comparison of six baking strains, strain AK 46 showed lower leavening ability in dough with and without the addition of 5% sucrose by weight of flour but showed high leavening ability in sweet dough containing 30% sucrose. The activities of enzymes α-glucosidase and invertase, which are related to dough fermentation, were lower than those in the other strains. A baking test showed that strain AK 46 was suitable for breadmaking by various methods. Cells of strain AK 46 were propagated industrially and used for the commercial production of dry yeast called “Tokachino”, which is named for the region from which it was isolated.

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In the present study, we evaluated the astringencies of infusions of Kamairi-cha and Sen-cha using a taste sensor system. The results obtained using the taste sensor system showed that the astringency of Kamairi-cha was lower than that of Sen-cha and that the astringency of Sen-cha decreased with increasing steaming duration. Both catechin and water-soluble pectin contents were lower in the Kamairi-cha infusion than in the Sen-cha infusion. Moreover, the elution ratio of water-soluble pectin in Kamairi-cha was lower than in Sen-cha. This difference is attributed to the shorter duration of the pressing process for the tea leaves used in the production of Kamairi-cha than for the production of Sen-cha. In contrast, as steaming duration is increased, the water-soluble pectin content in the tea leaves increases. However, water-soluble pectin content did not demonstrate an upward trend during post-steaming drying at a constant rate. Based on these results, we surmised that the water-soluble pectin content in tea leaves increases when leaves are heated to approximately 90-100°C. The results of multiple linear regression analysis of the obtained data showed that astringency was related to the catechin and water-soluble pectin content in the tea infusion and astringency increased as content of catechins increased and content of water-soluble pectin decreased.

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The aim of this study is to investigate the use of bentonite to control histamine (Hm) in commercial fish sauce and model fish sauce. Addition of bentonite at 0.1 to 30% (w/v) to commercial fish sauce resulted in an increase in Hm adherence and adsorption followed by increasing amount of additive bentonite. In the commercial fish sauce, the adhered and absorbed Hm content began to increase immediately after the addition of bentonite, and equilibrium was not attained for Hm adherence and adsorption for about 3 h. The effect of temperature (10-100°C), pH (2.0-8.0) and NaCl concentration (5-25%) on Hm adherence and adsorption in model fish sauce with bentonite was investigated. The lower the temperature and pH, the higher the Hm adherence and adsorption. However, there was no significant difference (p>0.05) in the adhered and adsorbed Hm content in the range of 5 to 25% NaCl. These results suggest that Hm level in fish sauce can be effectively reduced with bentonite.

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The effects of the concentration and molecular weight (M_w) of collagen-peptide (CP) from tilapia scales on the rheological and thermal properties of agar gel (AG) were examined by gel permeation chromatography, dynamic viscoelasticity, rupture properties, syneresis and differential scanning calorimetry. Three kinds of CP from tilapia scales (CP1000, CP5000 and CP10000) with M_w=7.4×10², 4.5×10³ and 1.0×10⁴, respectively, were investigated. The results showed that CP1000 had the highest rupture stress, Young’s modulus and syneresis of the AGs tested. For CP5000 and CP10000, rupture stress and Young’s modulus were lower, syneresis was repressed and enthalpy was decreased. Therefore, it was suggested that higher molecular weight CP hindered cross-linking formation in AGs. Also, a comparison of CP from porcine skin and tilapia scales suggested that viscosity and enthalpy of CP solutions and gel strength were influenced by molecular weight and amino acids composition.

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Plant glucosylceramides (GlcCer) are currently used as functional materials in supplements, general foods, and drinks for skin care. However, the routine analytical method for quantification of the functional lipid has not yet been established because it is difficult to obtain analytical standard material. In this study, we carried out single-laboratory validation of the high-performance liquid chromatography/evaporative light-scattering detection (HPLC-ELSD) method for expansion of the matrix which has already been established. Performance characteristics such as selectivity, linearity, trueness (recovery), repeatability, and intermediate precision were examined. The reported analytical protocol, which was developed for the quantification of wheat GlcCer, was shown to be also applicable for different matrices such as rice and corn. Moreover, judging from these results together with published data, it was assumed that the method could be extended to other matrices by using the standard curves of individual GlcCer prepared from the same source material as the target matrices.

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Fresh-cut cabbage processors prefer white cabbage, which tends to bolt from April to May and is therefore in short supply. We compared the characteristics of cabbages harvested in February and stored for 2 months and the cabbages grown in the field until April. Cabbages harvested in February had high total soluble solids and vitamin C. A portion of these cabbages were wrapped in plastic film packaging and stored for 2 months at 5°C. While the quality was almost the same after storage, the usable proportion decreased to about 65% due to yellowing and diseases of the leaves. In contrast, cabbages kept in the field until April had weights that were about 1.5 times greater and total soluble solids and vitamin C contents that were half of those harvested in February. The degree of browning of the fresh-cut cabbage prepared from cabbages that had been stored for 2 months was about half that for cabbages harvested in April.

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Constituents of five commercial teas (Kippukucha, Saryusoso, Yamabukinadeshiko, Suraribijin and Kuroyamecha) fermented with Aspergillus were analyzed with HPLC. All analyzed tea products contained catechins and teadenols but in varying concentrations. Isolation of teadenols A and B from Kippukucha tea using column chromatography was also performed.

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