Osmotic dehydration and combined osmotic dehydration-hot air drying of banana and apple slices. Mass transfer and quality issues.

N. WAIS; M. V. SANTOS; C. M. MARANI; M. AGNELLI; R. MASCHERONI

San Pablo, Brasil

Simposio; Proceedings of the 14th International Drying Symposium (IDS); 2004

Mass transfer evolution in banana and apple slices treated by osmotic dehydration (OD) in sugar solutions was followed through weight loss and solids gain. Different concentrations of sucrose were used in the osmotic solutions. After OD, fruits were dried to their final condition in a batch hot air drier (HAD) using air at 70°C and 1.5 m/s . Fruit quality was evaluated after each step, testing for color and texture changes. Fresh fruit and only-HAD fruits were used to compare the possible advantages of OD and ODHAD and the influence of OD conditions (soluble sugars and contact time). The results show that different treatments must be chosen according to the intended use of the final product (i.e.: in candies, yogurts, ice creams).