Antioxdant Capacities Of Whole Tartary Buckwheat Grains And Dietary Fiber Of Tartary Buckwheat Bran

Buckwheat is not a cereal but is usually grouped with cereals due to its ways of cultivation and utilization,it has been used both as a food and a traditional medicine.Buckwheat is abundant in nutrients,such as protein,amino acids,and minerals.According to the published reports , buckwheat has been shown to exhibit antioxidative,anti-inflammatory,anticarcinogenic,hypoglycemic and hypolipidemic effects for its abundance in flavonoids and phenolic compounds.The content of flavonoids and phenolic compounds in buckwheat is higher than most plants,especially in tartary buckwheat,so we studied the distribution of tartary buckwheat antioxidants and its activities.Tartary buckwheat bran is the mainly byproduct in tartary buckwheat processing, 23%～27% in grain. Tartary buckwheat bran is abundant in nutrients, the content of dietary fiber is 25.97%.But generally, tartary buckwheat bran is used as feedstuff and waste.In order to improve the utilization rate of the tartary buckwheat bran, both tartary buckwheat bran nutritional power and dietary fabre were synchronously produced by combining water extraction with enzymatic hydrolysis, and their nutrient components were analyzed. And in this paper, an in vitro experiment was taken to test the antioxidative activity of dietary fibre from tartary buckwheat bran before and after fermentation.The main results of this paper:(1) The distribution of tartary buckwheat phenolic was different from which of wheat. 60~80 mesh total phenolic content was highest(3410.21mg GA eq/100g DW).The average phenolic content of tartary buckwheat was 1751.54 mg GA eq/100g DW, which 6~25 times than apples, bananas and other daily fruit and 5~16 times than corn, wheat, oats and rice grains.(2) The content of bound phenolic in tartaty buckwheat was generally reduced from outer to inner. 40 mesh bound phenolic content has the highest proportion(27.47%) in total phenolics.Significant and positive linear correlations were found between phenolic contents and scavenging ability of DPPH? (R2 = 0.8514) and ABTS?+ (R2 =0.9793).(3) Better processing conditions of water extraction of tartary buckwheat bran were as follows:ratio of tartary buckwheat bran to water 1︰5,extraction temperature 70℃,extraction time 30 min. In this process, the rate of tartary buckwheat bran nutritional powder was 32.83%,dietary fibre content of fibre powder was 38.79%.The tartary buckwheat bran residue was then hydrolyzed byα-amylase.Better enzymatic hydrolysis conditions of tartary buckwheat bran were as follows:α-amylase concentration 1.5%, and enzymatic hydrolysis time 30 min. In this process, the rate of tartary buckwheat bran nutritional powder was 53.98%,dietary fibre content of fibre powder was 55.65%.(4) The protein content of tartary buckwheat bran nutritional powder was highest(40.44%),lysine content of which was 0.63%.The content of sugar was 32.77% ,fat was 11.19% and dietary fibre was 6.94%. Components of tartary buckwheat bran dietary fibre powder were mainly dietary fibre, sugar, protein and fat, and the content of dietary fibre was 55.65%. The content of protein was 18.78%,sugar was 9.46% and fat was 6.54%.(5) Tartary buckwheat bran dietary fiber showed antioxidant activity not cause polysaccharide, but the bound antioxidants in them. 76.8% (4.25 mg/g) and 89.7%(1.67 mg/g) of ferulic acid and 70.5% (769.37 mg GA eq/100g DW)and 77.4%(936.23 mg GA eq/100g DW)of phenolics were released from IDF and SDF respectively after 24h fermentation.