Experimental and modeling investigation of mass transfer during combined infrared-vacuum drying of Hayward kiwifruits.

In this work, we tried to evaluate mass transfer during a combined infrared-vacuum drying of kiwifruits. Infrared radiation power (200-300 W) and system pressure (5-15 kPa), as drying parameters, are evaluated on drying characteristics of kiwifruits. Both the infrared lamp power and vacuum pressure affected the drying time of kiwifruit slices. Nine different mathematical models were evaluated for moisture ratios using nonlinear regression analysis. The results of regression analysis indicated that the quadratic model is the best to describe the drying behavior with the lowest SE values and highest R value. Also, an increase in the power led to increase in the effective moisture diffusivity between 1.04 and 2.29 × 10-9  m2 /s. A negative effect was observed on the Δ E with increasing in infrared power and with rising in infrared radiation power it was increased. Chroma values decreased during drying.