Acerola is a fruit known to have high ascorbic acid content. We examined the effects on the skin of intake of an acerola beverage for 12 weeks in healthy, premenopausal women, aged 40-49 by double-blind, parallel comparison with an ascorbic acid beverage and an ascorbic acid-free beverage as controls. The effects were evaluated by three methods : instrumental evaluation, self-evaluation of skin conditions by the subjects using a 12-question survey, and evaluation of skin condition by a professional dermatologist. In the instrumental evaluation, the acerola beverage produced no significant ameliorating effects on skin condition. However, evaluations by both the subjects and the dermatologist produced significantly higher scores in several aspects of skin conditions for the acerola beverage than the ascorbic acid and the ascorbic acid-free beverages. The ameliorating effects of skin conditions by acerola beverage are probably related to other functional constituents in acerola fruit, in addition to ascorbic acid.

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Encapsulation of flax seed oil in crystalline maltose and trehalose with porous and non-porous structures was investigated to improve the stability of fatty acid during storage in the encapsulated oil. Anhydrous crystalline maltose and trehalose with fine porous structure were obtained by dehydration using ethanol. The oil powders encapsulated with anhydrous crystalline maltose and trehalose with porous structure had good fluidity. The stability of fatty acids in the encapsulated oil powders was investigated for storage at 40°C. By using crystalline trehalose to encapsulate the fatty acids, degradation was markedly inhibited, irrespective of structure porosity. Formation of volatile aldehydes in porous crystalline trehalose or maltose was reduced to about half the amount of that for the non-porous crystalline encapsulates. This indicates that volatile aldehyde was adsorbed into the fine pores.

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The resistant starch (RS) content in polished rice and processed rice products (boiled rice and rice crackers) was measured by the Prosky method, the RS-kit method, and the artificial digestion method (ADM). The RS content of rice crackers and cooked rice measured by the Prosky method was 1% or less. There are some differences in the conditions of the Prosky method and in the human digestive tract. Therefore, it is difficult to compare the effects of different processing methods and of different varieties of rice on RS content. For measurement by the RS-kit method, RS content of milled rice was about 20%, while the largest value was about 2% in boiled rice or rice crackers, and measurement by RS-kit method corresponded to RS content in a narrow sense. For measurement by the ADM, RS content of the milled rice was about 80%, while the largest value for boiled rice and rice crackers was about 20%. Thus, ADM seems to also be suitable for making comparisons among processed rice products which undergo cooking processes and also reflects the actual digestibility in the human body. Based on the results of comparison testing among various rice cultivars, RS content was shown to decrease after cooking processes, although it did not differ among milled rice samples of different cultivars as measured by the RS-kit method and ADM. The RS of processed rice products prepared from high amylose rice remained higher compared with that from low amylose rice. These findings indicate that RS content can be adjusted through conditions of heating and cooking, because RS differs with different processing methods.

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To utilize whole bodies of small Horse mackerel, we attempted to dissolve the fish bone by citrate treatment and prepared fish-miso. The fish were minced, treated by 2.3% (W/W) citrate for 72hr at 4°C, and fermented with 9% (W/W) NaCl and 21% (W/W) Koji at 30°C for 100 days. When compared with the fish-miso without citrate-treatment (MNC), the product with citrate (MWC) contained almost no hard bones (less than approximately 1/8 pretreatment levels). Additionally, the soluble calcium content of MWC was 300mg/100g, whereas that of MNC was 129mg/100g. MWC contained substantial levels of free amino acids (reaching 91% of MNC), suggesting that proteins were efficiently hydrolyzed in the presence of citrate. During the fermentation, proliferation of bacteria in MWC was greatly suppressed, resulting in minute de novo production of major organic acids, such as lactate (except pyroglutamate). Sensory evaluation suggested that the addition of MWC to the miso-soup enhanced umami. This study suggested that citrate-dependent production might be useful for dissolving fish bone, and improving the quality of fish-miso prepared from whole bodies of small fish.

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γ-Aminobutyric acid (GABA) is consumed by yeast during fermentation. To prevent the loss of GABA in fermented food, mutants defective in the assimilation of GABA were isolated from a baker's yeast stain. Each mutant harbored a mutation in the DAL81 gene which encodes a transcription activator that promotes nitrogen source catabolism. Fermentation ability of the mutants was comparable to that of the wild-type strain. Consumption of GABA in fermentation medium by the mutants was significantly suppressed. These mutants could be applied to bread making fermentation in order to maintain GABA at a high level in dough.

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[in Japanese]

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