Drying Characteristics of Loquat Slices Using Different Dehydration Methods by Comparative Evaluation
The objective of this research was to evaluate the impact of four drying methods namely, hot air (HA), solar drying (SD), halogen oven drying (HO) (at 80 and 90°C) and Refractance window drying (RWD) (at 80 and 90°C) on chemical components, physicochemical, physical properties, color parameters, sensory evaluation of loquat (Eriobotrya japonica) slices after drying. In order to evaluate color quality of loquat slices the reflected color parameters (L*, a*, b*, chrome and hue value) were measured immediately after drying and during six month storage at 25°C. The results indicated that ascorbic acid content, phenolic compounds, total flavonoid, total sulphur dioxide content decreased after drying by different methods. The highest amounts of total phenolics for loquat slices were obtained at RW drying followed by halogen oven drying. Refractance window dried loquat exhibited a good retention of total carotenoid content similar to that halogen dried samples and color value higher than that of the hot air and solar dried slices. The RW dried loquat slices had the highest value for appearance, color, taste, odor, texture and overall acceptability. After 6 months storage at room temperature all color parameters decreased and the color of dried loquat slices became darker. The results of these trials showed the loquat slices samples that dried by RW drying method have higher quality and their color, an appearance are closer to fresh loquat fruit.