Study on Technique of Protein and Starch Extracted from Wheat Bran
|School||Nanjing Agricultural College|
|Course||Crop Cultivation and Farming System|
|Keywords||wheat bran protein starch isolation|
Wheat bran, main byproduct of wheat flour milling, contains various types of the function compound. Some compound had a unique physical chemistry property. A study was conducted to establish the technique of main function compound extracted from wheat bran, characterize the physical chemistry property of some compound. Primal function compound was extracted from wheat bran by enzyme and ultrasonic treatments. Based on these studies, physical chemistry property of wheat bran starch were further characterized; the comprehensive processing of flavonoid, protein, starch, diet fiber from wheat bran was analyzed systematically, condition of processing were demonstrated elementarily. The main results were summarized as follows:1. Craft of protein production from wheat branWheat bran (10 g, as is) was mixed with deionizer water (100 ml) in a 500 ml beaker, the slurry was conduct for 9 min with ultrasonic sound, then the temperature was maintained at 52.5℃with a circulator, and the pH of the slurry adjusted to 6.9 with Tris and HCl. a-amylase at3.8 g/L was added to the slurry and reacted for180 min with constant stirring. The slurry was centrifuged at 2000 rpm for 10 min. The top layer was carefully removed and then adjusts isoelectric point (pH 4.0), dries. Under these conditions, the experimental yield was 90.05%, which is well matched with the predictive yield.2. craft and property of starch production from wheat bran2.1 Craft of starch production from wheat branWheat bran (100 g, as is) was mixed with deionizer water (1000 ml) in a 5000 ml container, the temperature was maintained at 45℃with a circulator, and the pH of the slurry adjusted to 7.0 with Tris and HCl. Neutral protease at3.0 g/L was added to the slurry and reacted for 60 min with constant stirring, the slurry was conduct for 9 min with ultrasonic sound, After the protease digestion, The slurry was passed though a 325 screen and washed with deionizer water three times. Then the flour slurry was centrifuged at 2500g for 10 min. The solid was dryings to obtain starch. Under this condition, starch production is 14.86g, while protein content is 0.25%.2.2 Property of starch production from wheat bran Content of protein content and damaged starch in wheat bran starch was 0.25%,0.93%, separately, lower than that in starch isolated from flour. Bran starch contained lower A-type starch content, while B-type starch and C-type starch (d<1.5 um) was increased obviously, peak value is at 14 um. Compared with the starch isolated from flour, bran starch contained lower amylose content, and the pasting value was lower, the degree of crystallinity was smaller, while the swelling power was higher. and the pasting value was lower, the degree of crystallinity was smaller, while the swelling power was higher. X-ray chromatogram showed: bran starch has not A-type chromatogram, but flour starch has. which is different from flour starch.3. Comprehensive processing of flavonoid, protein, starch and diet fiber from wheat branThe results showed that the optimal conditions for extraction of wheat bran protein by alkali-processing were:pH 8.5, extracting time 75min, and extracting temperature 45℃, Solid/liquid 1:15, and extracting rate are 54.8%, and pH value of acid-depositing was 4.0, with yield rate 43.71%. The optimal conditions for hydroxylation of wheat germ protein by neutral protease were:extracting time 75min, extracting temperature 44.5℃, and concentration of neutral protease 3.1g/L, with protein content is 0.648±0.04%, which is well matched with the predictive yield. Flavonoid ratio, starch and diet fiber content is 2.3‰,12.64% and 38.27%, separately.