Kinetics of moisture transfer during air drying of blanched and/or osmotically dehydrated mango

• Published in: Journal of food engineering 2001-11, Vol.50 (3), p.175-185
• Main Authors: Nieto, A, Castro, M.A, Alzamora, S.M
• Format: Article
• Language: English
• Subjects: Air drying; Biological and medical sciences; Blanching; Food engineering; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; General aspects; Glucose osmotic dehydration; Kinetics; Mango; Structure changes
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/S0260-8774(01)00026-7

The effect of previous blanching and/or osmotic dehydration (at atmospheric pressure or in vacuum) with glucose syrups on the kinetics of water transport during the first falling rate period of air drying of mango at 60°C was investigated. Both pre-drying treatments decreased strongly the effective moisture diffusivity ( D eff) calculated with Fick's second law. For osmotically concentrated fruit at atmospheric pressure, the increase in glucose concentration of the immersion solution decreased the drying rate. D eff values were similar for mangoes predehydrated to a w 0.97 by vacuum or atmospheric osmosis, but previous blanching slightly decreased the D eff value for vacuum treated slices compared with those osmotically dehydrated to the same a w at atmospheric pressure. The air drying behaviour of blanched and/or osmotically dehydrated mangoes was ascribed to glucose uptake during the impregnation step, volume shrinking, low modification of cell wall resistance to water flux by the pretreatments and/or gelatinization of starch and denaturation of protein – carbohydrate mucilage.