Understanding the mechanism of moisture migration impact on the texture and color characters of dried apple cubes

Abstract

This work investigated the effects of water migration velocity on water status, microstructure, texture, and color of three varieties apple cubes (Fuji FJ, Granny Smith GS, and Golden Delicious GD) after hot air drying. Different moisture migration velocity induced the specific water status, microstructure, and chromatic substances distribution, and therefore formed different appearance color in dried apple cubes. Higher moisture migration velocity induced high bound intensity of bound water, which correlated with the hardness and crispness of dried samples. As moisture migration velocity descending, the pore size of sample microstructure corresponded to crispness decreasing. As moisture migration velocity increase, total color change was gradually increased in FJ, but decreased in GS and GD. Therefore, the distribution of the fluorescent substances was notably different as water migration varied, which contributes to the higher scattering effect of chromatic substances. Overall, moisture migration velocity was positively correlated with frangibility, brightness, while negatively correlated with redness in significance (0.772, 0.731, −0.873; **p < 0.01). This research confirmed that the water migration velocity could be the important way for modulating and controlling the texture and color properties of apple products in hot air drying. Novelty impact statement The results of this study show that difference of moisture migration velocity caused by air velocity during drying can significantly affect the hardness, frangibility, apparent color of the product. It would provide reference for modulating texture and color quality in dried apple product processing by adjusting water migration velocity.