Open AccessMicrowave and Blanching Pretreatments for Hot Air Drying of Orange-Fleshed Sweet Potato Slices (Ipomoea batatas)
Author(s) -
Ernest Ekow Abano
Publication year - 2020
Publication title -
international journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.479
H-Index - 18
eISSN - 2356-7015
pISSN - 2314-5765
DOI - 10.1155/2020/8872429
Subject(s) - blanching , ipomoea , microwave , orange (colour) , airflow , chemistry , ascorbic acid , thermal diffusivity , food science , moisture , water content , dehydration , materials science , horticulture , biochemistry , biology , mechanical engineering , physics , geotechnical engineering , organic chemistry , quantum mechanics , engineering
Microwave and steam blanching as pretreatments to hot air drying of orange-fleshed sweet potato (OFSP) were studied. The air-drying experiment was performed at constant temperature of 70°C and airflow of 1.0 m/s. The effective moisture diffusivity varied from 1.5 × 10 −9 to 4.4 × 10 −9 m 2 /s, and 1.1 × 10 −10 to 7.9×10 −10 m 2 /s, for the microwave and blanched assisted hot air drying, respectively. The activation energy obtained for the various microwave-assisted hot air drying was 29.1 W/mm for 4 min, 68.1 W/mm for 3 min, and 79.7 W/mm for 2 min. Ascorbic acid degradation and formation of brown pigments in the OFSP slices were lower in microwave than in steam blanch-assisted drying. Microwave-assisted drying of OFSP is best governed by Page model, MR = exp(−k t n ), while the blanch-assisted followed the logarithmic model, MR = a exp(−k t ) + c. To produce better quality OFSP flour, it is recommended to cut the tubers into 3 mm slices, microwave at a power of 630 W for 2 min or blanch for 1 min, 43 seconds prior to hot air drying.