Studies On Technology And Antioxidant Activities Of Black Rice Beverage

Black rice, which has anti-aging and prophylactic function, not only has abundant nutrional components but also riches in bioactive components such as flavonoids and anthocyanins. In order to make full use of this resource in our country and make further progress on the utilization ratio and added-value of black rice, a novel cereal-based beverage, black rice beverage was developed.The roasted black rice was soaked to extract more functional components. And the extracting condition was optimized by factorial and orthogonal experiments: temperature 75°C, time 75min, ratio of material to liquid 10:1. Then the materials were liquefied and saccharified by thermostableα-amylase and glucoamylase. The enzymatic hydrolysis condition of glucoamylase was optimized from factorial and orthogonal experiments: temperature 60℃, enzyme quantity 100u/g raw material, and pH 4.5. The DE value can achieved 96.71 under this condition.The volatile flavor components of black rice beverage were analyzed by solid phase microextraction-gaschromatography-mass spectroscopy (SPME-GC-MS). Aldehydes and alcohols are the main flavor. 10 kinds of new flavors, most of which were pyrazines added full-bodied flavor to the beverage, were produced after the material was roasted. The stability of black rice beverage was studied by the factor of store temperature, and the light. Cold and dark storage were good for the preservation of anthocyanin in the beverage.The antioxidant activities of water extraction, enzymolysis liquid and beverage of black rice were evaluated by some different vitro antioxidant methods. During all of the antioxidant systems studied in this paper include antioxidant ability during linoleic acid system, reducing power, DPPH·and superoxide anion free radical scavenging ability, chelating metal ion ability , the inhibition ability of H₂O₂ induced rats' RBC hemolysis, and H₂O₂ induced MDA production in liver homogenate, water extraction had the best antioxidant activities, the beverage take the second place, while the enzymolysis liquid has the poorest.