Effect of Relative Humidity on Shrinkage and Color Changes in Dehydrated Strawberry

摘要

The final color of freeze-dried strawberries during storage was the result of loss of redness and browning development. Redness loss and browning could be related to the decrease of CIELAB coordinates a~* and L~*, respectively. During storage at 45 ℃ for 22.5 h, a~* constantly decreased with increasing RH, but L~* decrease was not significant below 43 % RH. Sample shrinkage and redness loss were significantly affected by RH. Both shrinkage and color changes seem to be affected by RH and (T-T_g) values at which water mobility is characterized by T_2 relaxation times in the order of ms, and water is able to crystallize. The segmented image analysis revealed that humidification level and storage time, besides influencing the kinetics of changes, were determinant factors in defining the degree of color heterogeneity in dehydrated strawberries.