Effect of pre-treatments on qualitative characteristics of osmotically dehydrated apple

The present study aimed to evaluate the effect of various pre-treatments viz., potassium sorbate (T2), steam process (T3) and rose-flavored syrup (T4) compared to control (T1) on the final quality of osmo-dried apple cubes. Osmo-dried apple cubes developed from each treatment had moisture content in the range of 7.3-8.6% with 0.55-0.66 water activity. Pre-treatments proved to be effective on the product as bioactive components and antioxidant activity (%) were maximally retained in rose flavored apple cubes except ascorbic acid. Higher reducing sugars were observed in steam-treated apple cubes and lowest in rose-flavored apple cubes. In terms of colour attributes, potassium sorbate-treated apple cubes retained the most brightness, but texturally, these samples had the most hardness and the least cohesiveness. In contrast, steam-treated apple cubes had the lowest hardness and highest cohesiveness. The highest overall acceptability was noted for rose-flavored apple cubes in sensory properties. Red coloration of these apple cubes resulted in reduced L and highest a values with optimum textural properties. Overall, rose-flavored syrup as an osmotic agent produced flavoured dried apple cubes of improved quality.