Influence of processing conditions of atmospheric freeze-drying/low-temperature drying on the drying kinetics of sliced fruits and their vitamin C retention

Sliced fruits (apple and kiwi) were dried under atmospheric freeze-drying (AFD) and/or low-temperature drying (LTD) conditions, the kinetics, resultant degree of shrinkage, vitamin C retention evaluated. The air temperature programs set in range −20 to 10 °C, impact sub-zero setting was investigated. As expected, shortening time increasing led a shorter total time. Notably, application freezing had an effect reduce LTD condition without significantly increased compared with that freezing. When stepwise from effectively reduced when maintained for relatively long This most practical program maintaining product quality. It found at temperatures has advantages reducing shrinkage; however, not remarkable. conditions advantageous both apple kiwi drying. However, if negative on quality is significant, simple may be good compromise balancing • conditions. Drying retention. In some