High-pressure and heat pretreatment effects on rehydration and quality of sweet potato.

摘要

Effects of high-pressure and heat pre-treatments, used prior to drying, were investigated on the rehydration rate and quality of sweet potato. Sweet potato was pressurized at 200 Mpa for 5 min and heat treatment was performed at 100 degrees C for 5 min. 3 different pretreatment sequences were performed: heat treatment; heat treatment after high-pressure treatment; and high-pressure treatment after heat treatment. There were no differences in the colour parameters (L*, C* and h) or gelatinization rates of rehydrated sweet potato exposed to the 3 different pretreatments. However, heat treatment after high-pressure treatment resulted in pronounced texture improvements compared to the other pretreatments. The relative hardness of the rehydrated sweet potato exposed to heat treatment after high-pressure treatment was higher than after the other pretreatments. Furthermore, the rehydration rate of sweet potato exposed to heat treatment after high-pressure treatment was lower than after either heat treatment alone or high-pressure treatment after heat treatment. Heat treatment after high-pressure treatment prior to drying prevented cubes of sweet potato from collapsing during rehydration. Results suggest that in sweet potato, the use of heat treatment after high-pressure treatment prior to drying could serve as an effective method for texture improvement.