The Full Use Of Early Indica Rice

The alkaline and enzyme were used to extract the protein and starch from Early Indica Rice. The extracted rice protein was hydrolyzed using Alcalase and Neutrase to prod-uce bioactive pepetides and the extracted starch was digested by a-amylase to produce the maltodextrin with low DE value. The bioactivity of the obtained hydrolyzates we-re also studied in the paper to acheive the full use of indica rice and improve the econ-omic value.Combined with the single factor and orthogonal tests, the optimum conditions of the alkaline extraction for rice protein were obtained, which were that:the solid to liquid ratio was 1:5, the alkali concentration was 0.06mol/L, the time was 2h and the tempe-rature was 40℃. Protein concentration and extraction rate on the above conditions w-ere 15.44mg/mL and 80.61% respetively. Then the optimum conditions to purify the rice starch were obtained by the combination of single factor experiments and respon-se surface analysis, which were:temperature 43℃, solid to liquid ratio of 1:7.5, the time of 6h. At these conditions, the protein content of the obtained starch was 0.38% and the extracted protein concentration was 2.52mg/mL.Neutrase and Alcalase with Na2SO3 were used to hydrolyze rice ptotein for 4h. The seperated fractions of peptide with different molecular weight were obtained by. Ultr-afiltration technology. The Alcalase and Neutrase hydrolyzates contained 79.79% and 70.22% of peptides with molecular weight below 5kDa respectively. Furthermore the antioxidant activity of peptides with different molecular weights were studied. Anti-oxidant activity of Neutrase hydrolysates generally higher than that of Alcalase hyd-ro lysates, and peptides with molecular weight less than 1kDa from the Neutrase hyd-rolysates had the highest antioxidant activity, compared with Vc. Meanwhile, ACE inhibitory activity of the two kinds of peptide obtained by different enzymatic hydr-olysis with molecular weight less than 1kDa were studied. The results showed that the alkaline was more suitable to develop ACE inhibitory peptides with antioxidant acti-vity; and Neutrase was more suitable to develop antioxidant peptides with ACE inhib- itory activity.After that, the conditions of a-amylase hydrolysis of starch to develop maltodextrin with DE 2.5 were determined according to the relevant reports:The dose of enzyme is 8U/g, hydrolyzing time is 12.5 minutes, hydrolyzing temperature is 92℃.At these conditions, the solubility and water separating proportion of the obtained maltodextrin were 95% and 16.14% respectively. At the concentration of 25%, the gel strength is 20g/cm2. The result showed the maltodextrin can be used as fat substitutes and the concentration in the practical application should be higher than 25%.Finally, the main components of the residue after the exttaction of protein and starch of the rice were analyzed, which contained a certain amount of starch which was not hydrolysed, and the content of dietary fiber was 33.02%.