Method for preparing purple sweet potato powder by enzymolysis technology

The invention discloses a method for preparing purple sweet potato spray-dried powder, belonging to the technical field of intensive processing and production of agricultural products. The method comprises the following steps: selecting fresh purple sweet potatoes with no serious damage caused by plant diseases and insect pests; cleaning the purple sweet potatoes with water; peeling off and slicing the purple sweet potatoes with thickness of 2-4mm; carrying out hot iron with steam for 2-3min; beating the purple sweet potato slices with water by mass ratio of 12:88 and transmitting the mixture to a colloid mill for colloid milling twice; regulating the pH value of the purple sweet potato serosity to be 6.0-6.5; adding intermediate temperature alpha-amylase or heat-resistant alpha-amylase which accounts for 0.05-0.5% of the weight of the fresh sweet potatoes; stirring, preserving the temperature for 60-80min and carrying out enzyme denaturalixation; regulating the pH value of the purple sweet potato serosity after enzymolysis to be the initial value; and carrying out spray-drying with air inlet temperature of 120-180 DEG C and air outlet temperature of 50-90 DEG C. In the invention, starch in the purple sweet potatoes is decomposed into glucose maltose and other reducing sugars, thereby helping spray-drying competition, improving product mouthfeel and widening product application range.