DRYING PROCESS AND MANGOSTEEN RIND POWDER PRODUCT

Mangosteen is one of the most delicious and best flavored tropical fruits, known as the queen of fruits. Its edible portion is only one third of the whole fruit and the rest is rind. The mangosteen rind contains polyphenolic compounds known as xanthones, which provide a powerful antioxidant activity. Therefore, the manufacture of mangosteen rind powder (MRP) might lead to a healthy product and help reduce waste in the food industry. The objectives of this study were to determine the effect of the drying process, including different temperatures, on MRP quality and the effect of the addition of different polymers to MRP on xanthone content. The sensory evaluation of MRP dried in a hot air oven at 60 and 80°C were not significantly different, but they were different when dried at 100°C (p≤0.05). Whereas, sensory quality of MRP dried with drum at 130°C and 0.52 rpm speed showed no differences from MRP dried in hot air oven at 100°C. Overall, the best sensory quality was for MRP dried in hot air oven at 60°C. For this reason, MRP dried at 60°C was selected to study the effect of polymer addition on xanthone content. Incorporation of whey protein isolate into MRP increased the xanthone content (15.20 mg/kg) compared with maltodextrin addition. MRP-whey protein had a brownish appearance with fine texture. MRP stored in a plastic bag with vacuum seal at room temperature after 8 weeks presented 0.56 aW and 7.71% moisture content. When MRP-whey protein was dissolved in hot water to obtain mangosteen rind tea, the solution had a pH of 5.36, the solubility in water was 0.83 g water/g DM total soluble solid and the solubility time at 90°C in hot water was 23 s. Therefore, whey protein isolate incorporated into MRP helped maintain the xanthone content and improved the solubility of MRP to obtain mangosteen rind tea. This work represents a new development for the use of MRP.