Abstract:

The optimal sugar osmosis of low-sugar preserved apples under microwave assistance for achieving both high sugar content and sensory quality was investigated by analyzing the effects of pretreatment methods, slice thickness and sugar permeation time on sugar content and sensory quality using single factor and orthogonal array design methods. Results indicated that sugar osmosis was obvious under the conditions of freezing pretreatment and slice thickness of 6 mm. Preserved apples obtained after 40 min sugar permeation under 30% microwave power (240 W) exhibited the highest sugar content, good appearance with glossy and glittering transparency and excellent mouthfeel. Therefore, apple slice thickness of 6 mm, soaking time in 2% saline of 2 h and sugar permeation time under 30% microwave power of 40 min were found optimum for achieving both high sugar content and sensory quality.

Key words: apple, low-sugar preserved fruits, sugar content, microwave-assisted sugar osmosis