Study On Modification And Application Of Tartary Buckwheat Bran

The purpose of this paper was to study the modification and application of tartary buckwheat bran. The results were showed in Chapter Two to Chapter Five.1. The content of nutrients in tartaty buckwheat and the optimal enzymatic extraction conditions were studied. Protease N was chosen as the best protease to hydrolyze buckwheat protein. The preparation conditions were optimized by MINI TAB Release 14 through Center composite design: hydrolysis of starch: RTW 1:20.68, temperature 25℃, pH 7.0, pasting time 5.0min, amylase addition 5000U/100g, amylase hydrolysis time 91.48 min; hydrolysis of protein: protease addition 3%, temperature 55℃, protease hydrolyzing time 120min. DF1 and DF2 were obtained from grinded tartary buckwheat bran and extruded tartary buckwheat bran, respectively. The purity of DF1 rose from 44.2% to 83.5%, while the purity of DF2 grew from 35.58% to 70.62%. The contents of SDF in DF1 and DF2 were 1.03% and 3.97%, respectively. The SEM photograph of DF1 and DF2 showed the flaky ultrastructure. And the preparation did not change the size of the scatters of DF1 and DF2 in nano-structure.2. The effect of cellulase on DF1 and DF2 was studied. The optimized modification conditions were: pH 4.6, temperature 55℃, cellulase addition 0.3%, hydrolyzing time 2h. The products of DF1 were DF3 (IDF) and DF5 (SDF). And the yield of DF5 was 18.03±0.56%. Under the same condition, DF4 (IDF) and DF6(SDF) were obtained from DF2. And the yield of DF6 was 21.17±0.42%. This increase changed by 26 to 27 times. The infrared spectrum of DF5 and DF6 showed they had the properties of polysaccharides. The composition and content of monosaccharides in DF5 and DF6 were determined by HPLC. Results showed that xylose and glucose were the main monosaccharides. Results of SAXS analysis showed that there was a decrease in the diameter of scatterer. Therefore, the polymerization degree of DF declined. These characterizations showed that SDF could be applied in beverage, and has abilities to regulate the balance of flora in intestine and the content of blood sugar.Comparison of water retention capacity and swelling capacity between bran and DFs showed that DF3>DF1>GTB, ETB>DF2>DF4. This means that the ability of DF holding water in body was increased, thus DF could cure the constipation.3. Antioxidant activity of brans and DFs were researched by the in vitro methods. Results showed that flavonoids and phenolics mainly existed in bran and IDF, while few existed in SDF. The research indicated that there was a significant increase in iron(III) chelating activity and hydroxyl radicals-scavenging activity after extraction and modification treatments. However, uperoxide anion radical-scavenging activity decreased slightly. Because hydroxyl radical is one of the most toxicant radicals, the enzymatic extraction modification treatments were important to antioxidant activity of tartaty buckwheat bran.4. Chapter Five researched on the application of modified TDF from grinded tartary buckwheat bran (DF3+DF5) in cakes and its effect on quality. The study showed that the addition of the modified TDF would lead to increases in hardness and chewiness and a decrease in springiness of the cake. The content of the dietary fiber cake was defined through the orthogonal test: 12.5% (the soft flour as equivalent). This reduced-calorie baked cake did not only contain higher dietary fiber, but was also rich in flavonoids. The antioxidant activity of DPPH scavenging capacity was equivalent with BHT at the same amount.