Drying characteristics and quality evaluation of kiwi slices under hot air natural convective drying method

Dried kiwis are highly needed in food industries such as cereals, ice-cream, beverages and supplemental products. In this paper, drying characteristics and product quality of hot air dried kiwi slices were studied. Hot air drying of kiwi slices was investigated at drying temperature ranged from 40 degrees C to 60 degrees C and slice thickness of 0.3 cm and 0.6 cm. Results showed that drying of kiwi slices at higher drying temperature stimulates the drying rate, which leads to shorter total drying time required. The drying kinetics of kiwi slices was best fitted by approximation diffusion model. Increased in drying temperatures and slice thickness of kiwi enhanced the effective moisture diffusivity (D-eff). The highest D-eff of the kiwi slices was recorded as 1.5681 x 10(-8) m(2)/min at slice thickness of 0.6 cm. In terms of quality analysis, kiwi slices dried at temperature of 60 degrees C with fastest drying rate retained most of the Total Phenolic Content (TPC) in the dried sample. However, drying of kiwi slices at high drying temperature deteriorated the vitamin C content of kiwi slices due to thermal degradation. Thinner kiwi slices could preserve higher amount of TPC and vitamin C during the drying process, yet the best hot air drying temperature for drying of kiwi slices could be relied on the consumers' preference based on the dried product quality as reported in the current work. (C) All Rights Reserved