Effects of radiation temperature on dehydration and moisture migration in banana slices during far-infrared radiation drying

摘要

The changes in the various water states of bananas dried at different far-infraredradiation (FIR) temperatures were investigated via low-field nuclear magnetic resonance(LF-NMR). Results revealed that increasing FIR temperatures could significantlyenhance drying rates. Scanning electron microscopy results demonstratedthat FIR heating could produce additional porous structures in dried bananas andthat porosity increased with the elevation of FIR temperatures. LF-NMR results revealedthat high FIR temperatures were associated with significant changes in thepeak areas of different water states, indicating that increasing FIR temperature wasbeneficial to hastening water migration. Free water was removed first during drying.At the end of drying, residual moisture in banana samples was dominated by boundwater. The images of moisture distribution in banana slices at various FIR temperaturesrevealed the regulatory mechanism of moisture transfer. Water was graduallylost from the outside to the inside of samples, and high FIR temperatures accelerateddehydration rates.