EFFECT OF SSB (SUPERHEATED STEAM BLANCHING) TIME AND DRYING TEMPERATURE ON HOT AIR IMPINGEMENT DRYING KINETICS AND QUALITY ATTRIBUTES OF YAM SLICES

摘要

The effects of SSB (superheated steam blanching) time (0, 3, 6, 9 andn12 min) and drying temperature (50, 60, 70 and 80C) on drying kinetics andnquality of yam slices under air impingement drying were investigated in thisnpaper. Results indicated that the positive effect of SSB on drying rate might benovershowed by the negative effect of starch gelatinization and appropriate SSBncould accelerate drying rate, whereas the effect of excessive SSB is reversed.nThe moisture effective diffusivity ranged from 1.1540 ￥ 10-9 to 2.8431 ￥n10-9 m2/s, calculated using Fick’s second law of diffusion. The activationnenergy determined from the slope of the Arrhenius plot, ln(Deff) versusn1/(T + 273.15), was 20.925 kJ/mol. Moderate increase in SSB time orndecrease in drying temperature can improve the whiteness index of dried yamnslices, whereas increase in SSB time and drying temperature can decrease thenrehydration ratio of dried yam slices