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The five different microwave power levels (800, 640, 480, 320, and 160 W) assisted with the vacuum of 40 kPa were investigated for the drying kinetics, effective moisture diffusivity and rehydration ratio of the dried pomelo albedo. The comparison of some product quality indicators after production and 6 months of storage was also taken place in this study. The higher microwave power levels provided the shorter drying times, the higher moisture diffusion and the drying rates. Drying time at 160 W needed more than 120 min while the rest needed less than 25 min to reach the moisture content below 8% (dry basis). By basing on χ 2 and root mean square error and R 2 , experimental drying data were best performed for the Page equations compared to other eight models (Diffusion approach, Two term exp, Henderson and Pabis, Lewis, Logarithmic, Vermar, Two modified compartment, Wang and Singh).The effective moisture diffusivity coefficient determined by Fick's second law was varied from 1.0 Â 10 À5 to 6.52 Â 10 À7 m 2 /s. The developed models describing the relationship between different drying parameters in this study can be used for optimizing the parameters in the drying process at a larger scale. The microwave power level of 480 or 640 W and the sample weight of 50 g were recommended for the drying of the pomelo albedo. Under these conditions, the dried albedo product possesses high quality. Most of the characteristic quality indicators changed insignificantly as compared after production and stored for 6 months at room temperature (25-28 C).

The research aimed to understand the soil structure for pepper agriculture, the relationship between nematodes distribution and some soil quality parameters. Secondary data collection, field survey, and soil sampling and analysis were conducted in field and in laboratory. The results showed that the soil had pH values ranging from acid to neutral, average N and P levels, and high organic matter content. The isolation of nematodes showed that there were 26 genera of nematodes belonging to 17 families and 7 orders in soil. The lower the soil organic matter content and pH value were, the higher the density of nematodes was, indicating the possibility of survival and development of nematodes in extreme soil environment. This is one of significant factors that may impact the pepper productivity. Therefore, increasing nutrient contents of soil would prevent nematode activities and at the same time enhance the resistance of pepper to nematodes.

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