Microwave pretreatment and optimization of osmotic dehydration of wild blueberries using response surface methodology

This study investigated the effects of pretreatments and optimized osmotic dehydration (OD) of lowbush blueberries using response surface methodology (RSM) to produce dehydrated blueberries with high antioxidants content and shelf life. Fresh wild blueberries (WB) were initially pretreated and then subjected to osmotic dehydration. Microwave pretreated WB had shown better water loss during osmotic dehydration as compared to other pretreatment methods investigated. The highest levels of phenolics, flavonoids, and anthocyanin content of the dehydrated WB were found to be 742.61 mg/100 g, 263.12 mg/100 g, and 428.11 mg/100 g d.m respectively, at optimized temperature of 40 °C, for 5 h OD, with 65% (w/w) Brix and 1:5 ratio of sample to Brix%. These results revealed that with rigorous optimization of the critical osmotic dehydration parameters high level of antioxidants could be obtained in the dehydrated product.