Abstract:

Microwave treatment and hot-air treatment were separately applied to the drying of orange skin. The drying rate, temperature distribution, water-holding capacity, fat-absorption capacity, and appearance of orange skin dried by both drying methods were investigated. Meanwhile, effects of both drying methods on quality of treated samples were also compared. Results indicated that less time consumption was required to achieve the same water content in treated samples using microwave drying. In addition, microwave drying provided higher temperature in the center and lower temperature in the edge of the samples; in contrast, hot-air drying provided the even temperature distribution in the samples. Significant effects on waterholding capacity, fat-absorption capacity and appearance of treated samples using both drying methods were also observed. Better water-holding capacity and fat-absorption capacity were revealed in the samples treated by lower hot-air temperature or lower microwave power. The uneven texture and quality of the treated samples could be resulted from higher hot-air temperature and stronger microwave power.

Key words: orange skin, hot-air drying, microwave drying, drying characteristics, quality