Fresh kiwifruit slices were pre-treated (brief hot water soaking) before drying, and the effects of pre-treatment on the hot air drying characteristics were evaluated. Change in color, volume, surface area, mass, temperature and surface hardness of kiwifruit samples during hot air drying were measured at 40, 50, 60 and 80°C. The pre-treatment inhibited color change by inactivating enzymes, and the color difference (ΔE) during the drying process was expressed according to an equation describing the reaction kinetics. The volume ratio and surface area ratio were best described as a linear function of moisture content. The pre-treated samples had shorter drying times and higher drying rate than control samples. In addition, a constant-rate drying period was found in the pre-treated samples in the initial period of the drying process. Brief hot water pre-treatment increased the drying rate because it inhibited the surface hardness of the sample.

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The potential application of DNA and stable isotope analyses as tools for verifying the geographical origin of raw and processed (suboshi and kamaage) Sakuraebi from Suruga Bay in Shizuoka, Japan, and Taiwan was examined. No clear genetic differences were observed in partial mitochondrial DNA 16SrRNA sequences (404bp) extracted from raw Sakuraebi from Suruga Bay and Taiwan. However, both raw and processed Sakuraebi from Suruga Bay had higher carbon and nitrogen isotope ratios than specimens from Taiwan. The results suggested that analyses of stable carbon and nitrogen isotopes were useful for determining the geographical origin of Sakuraebi. We also examined the effects of acidification and processing (i.e. sun-drying and boiling) on the stable carbon and nitrogen isotope ratios of raw Sakuraebi. Acidification caused a significant decrease in δ¹³C values and an increase in δ¹⁵N values of the raw Sakuraebi samples. Sun-drying had no significant effect on either δ¹³C or δ¹⁵N values, but boiling caused a decrease in δ¹⁵N values of several individuals of raw Sakuraebi.

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We investigated the relationship between phase separation and fracture properties of egg white protein (EWP)/agar co-gels. We focused on the formation of the bicontinuous micro-phase, which enables enhanced gel mechanical strength. We also discussed differences in the fracture properties of EWP/agar co-gels with different solid concentrations and different blend ratios of EWP and agar, from the viewpoint of co-gel structure with micro- and macro-phase separation. In this study, fracture properties of co-gels were measured using a large deformation test. The gel structure was observed by confocal laser scanning microscopy and scanning electron microscopy. Co-gels with bicontinuous macro-phase showed an additive average effect on each fracture property. On the other hand, co-gels with bicontinuous micro-phase showed synergistic effects on fracture properties. In particular, the formation of a novel bicontinuous micro-phase enhanced the mechanical strength of the co-gels. The structure of bicontinuous micro-phase separation was an interpenetrating network at the nanometer scale. These results demonstrate that the formation of an interpenetrating network at the nanometer scale enhances the mechanical strength of phase-separated gels.

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For the purpose of promoting the utilization of venison as a functional food, we investigated the carnitine content in cooked venison. The present work aimed to quantitate free carnitine and acylcarnitine in cooked venison using liquid chromatography-tandem mass spectrometry [LC-MS/MS]. As a result of heat treatment, hydrophilic L-carnitine showed a tendency to decrease, and hydrophobic acylcarnitine showed a tendency to increase, except under frying. However, only the acetylcarnitine showed a tendency to decrease because it is a low molecular weight compound that is connected to a two-carbon fatty acid. We propose that steaming is the most effective of the heat treatment methods tested in the present work for promoting the utilization of venison as a functional food.

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