In this study, the following two experiments were conducted to examine the effect of the mulberry leaves administration on carbohydrate and lipid metabolism in the type I and type II diabetes mellitus model rats. Exp. I : The effect of mulberry leaves diet was evaluated in GK rats, one of the animal models of non-insulin dependent diabetic mellitus (Type II). The postprandial blood glucose level of the 1% mulberry leaves (MS) diet group became lower than those of the DM group. Blood glucose level of the MS-diet group was lower than that of the DM group after the dissection, whereas no significant difference was observed in the both groups. Total cholesterol and TBARS levels in the serum of the MS-diet group were significantly reduced than those of the DM group (p<0.05). Exp. II : The effect of mulberry leaves diet was evaluated in the STZ-induced diabetic rats, one of the models of insulin dependent diabetic mellitus (Type I). Blood glucose and total cholesterol levels in the serum of the 5% mulberry leaves (ML) diet group were lower than those of the STZ group. TBARS levels in the serum, the liver, the pancreas and the kidneys of the ML-diet group were also lower than those of the STZ group. In the ML-diet group, expression ratio of the pancreatic CD 4-T cells was higher than that of CD 8-T cells in the proportion of 3 to1. On the other hand, expression ratio of pancreatic CD 4-T cells and CD 8-T cells in the STZ group had no change in the proportion. These results suggest that the mulberry leaves diet improves glucose tolerance ability and lipid metabolism in the both diabetic model rats, and that it contributes to enhancement of the cellmediated immune function by suppressing the lipid peroxidation.

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Microbial counts in different tissues of carrots (Daucus carota L. var sativ DC.) were determined by varying their cultivation method (conventional, reduced-agrochemicals or organic), variety (European or Asian) and transportation period (distributed in the market or evaluated immediately after harvest). The microbial counts in all carrots were found to be in the order of epidermis>phloem>cambium≥xylem. In the epidermis, cambium and xylem, the organic products cultivated without agricultural chemicals resulted in the highest microbial population, and the conventional products in the lowest counts. The two variety did not show significant difference in the microbial counts of the four tissues. Carrots evaluated just after harvest at field showed lower microbial counts than those in the market.

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Electrolysis of dilute salt water generates electrolyzed alkaline water at the cathode, which contains a large amount of Na. Use of this water as the basis of hydroponic nutrient solution may result in accumulation of chemical components contributing to the plant quality. In this study, a 10-fold, 3-fold or 1-fold diluted electrolyzed alkaline water was used as the basis of nutrient solution for hydroponics to evaluate its effect on the yield and chemical content of the cultured plants. As a result, the lot using a 10-fold solution as the basis of hydroponic nutrient solution had a higher yield (leaf blade weight, stalk weight and root weight) and dry weight than the control lot, with almost equal chemical content (inorganic components, chlorophyll, phenols and free amino acid). The above result showed that a nutrient solution with a 10-fold electrolyzed alkaline water was effective for growth promotion and yield increase. On the other hand, the nutrient solution based on a 3-fold or 1-fold electrolyzed alkaline water caused growth inhibition to have a lower yield and reduced the chlorophyll and free amino acid content. The 3-fold or 10-fold dilution decreased the P and K content but increased the Ca and Mg content.

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Chemical and physical properties of five cultivar potatoes were measured in order to explain the varietal differences in blackspot susceptibility. Bruise-resistant potatoes had lower polyphenol content and polyphenol oxidase activity, and higher failure stresses of both skin and underlying tissues than susceptible ones. In addition, there was a significant (p<0.05) relationship between bruise scores and skin failure stresses and it directly implied that the measurement of skin failure stress using a plunger is a useful method for screening potato varieties for blackspot susceptibility because of the ease of measurement.

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Invertase activities and sugar contents of four Japanese processing varieties (Norin-1, Toyoshiro, Hokkai-76 and Hokkai-82) were measured at intervals during storage at 5 and 12°C in order to invetigate the role of invertase activity in sugar accumulation during cold storage. The experimental data revealed that the invertase activity of potatoes stored at 5°C correlated significantly (r=0.81, p <0.01) with the reducing sugar content, whereas potatoes stored at 12°C showed no significant relationship (r=0.01, p>0.05) between the invertase activity and reducing sugar content. The invertase activity of cold-stored processing potatoes accounts for 66% of the variability in reducing sugar content, implying that invertase is one of the key enzymes for reducing sugar accumulation in cold-stored processing potatoes.

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