Study on microcut and vacuum drying technology in onion powder

Jinchang local excellent onion as the raw material, the effect of microcut and vacuum low-temperature on nutritional components (especially rutin, quercetin and vitamins) and comprehensive evaluation value were studied by contrast analysis of single factors and Box-Behnken Design. The results showed that the best technological parameters were:microcut speed 9000r/min (microcut grain size 0.00127mm) , concentrated hydrolysates 45%～50% before drying, drying vacuum 23mbar and with the five drying temperature of 38, 35, 30, 25, 5℃. Under this condition, the sensory indexes of onion power products were the best. With the rutin and quercetin content of 0.57mg/g and 4.033mg/g, which was twenty-six times and fouty-two times higher than the onion power product for sale in market produced by spray drying, separately. The content of vitamin A and vitamin E in onion powder increased more than one time compared with spray drying products.