Cavendish banana and red dragon fruit instant powdered with the addition of okara protein hydrolysate using foam mat drying

Cavendish banana and red dragon fruit contain vitamins, fiber, and antioxidants. However, the fruits are quickly spoiled, and requires processing into instant powder with the foam mat drying for extend the storage time. Okara protein hydrolysate through enzymatic hydrolysis process and soy protein isolate will be used as foaming agent. This study evaluated the effect of adding okara protein hydrolysate and soy protein isolate on the physicochemical properties such as water absorption index (WAI), water solubility index (WSI), hygroscopicity, bulk density, color, viscosity, antioxidant activity, vitamin C, total soluble solid, titratable acidity, proximate composition, acceptance test, and shelf life of instant powder. The results showed that the instant powder with okara protein hydrolysate produced a moisture content of 2.81%, WAI 0.69 g/g, and bulk density 0.39 g/cm3, lower than the addition of soy protein isolate. The acceptance test of instant powder with okara protein hydrolysate had an average score of 4.40 (neutral) to 5.06 (slightly like). The addition of okara hydrolysate can significantly (p < 0.05) increased the WSI value to 81.42%, antioxidant activity 49.86%, and longer shelf life of 144 days. Therefore, okara protein hydrolysate can be used as foaming agents with natural antioxidants and produced the stable instant powder.