| Heilongjiang province was a bigger province of kidney bean planting area. Major kinds of kidney bean in Hei long jiang province were En, Zi hua, Bai Sha ke, Japanese red, Spain White, and the British red kidney bean. Kidney bean of Heilongjiang province was as raw materials, evaluated the nutritional value of kidney bean protein, kidney bean antioxidant peptide purification and the determination of antioxidant activity carried on the thorough research, by ultrafiltration and Sephadex G-25 gel chromatography.1 The white Bai Sha ke, En, British red, Zi hua, Japanese red and Spain White kidney bean seeds main nutrients were determinated. The results showed that, six kinds of kidney bean protein were 20.4%, 20.33%, 22.03%, 17.91%, 17.91% and 19.17%, their fat were 8.04%, 8.46%, 5.51%, 8.12%, 7.27% and 2.56%, total sugar contents of the six kinds of kidney bean were 4.52%, 5.42%, 5.22%, 4.93%, 4.51% and 4.50%.2 Kidney bean protein isoelectric points were around p H 4.0, extraction rate of protein around 90%, the molecular weight of proteins main focused 51.39 k Da. En, Zi hua, Bai Sha ke, Japanese red, Spain White,and the British red kidney bean were graded extraction four kinds of protein by Osborne, the protein was determined by kjeldahl determination content, the results showed that, in the kidney bean protein, content of albumin were 70.61%, 66.40%, 72.54%, 69.16%, 72.98% and 65.79%, globulin were 11.14%, 14.93%, 9.81%, 12.71%, 12.82% and 12.09%, prolamine were 6.71%, 7.73%, 7.88%, 5.78%, 6.41% and 6.03%, gluten were 7.29%, 8.17%, 8.67%, 7.50%, 7.32% and 6.70%. Instructions albumin is the main protein in kidney bean protein.3 The British red, Bai Sha ke and En kidney bean were selected, their protein content were high, the composition of amino acids and evaluated nutritional value of the protein were analyzed. The results showed that, the British red, Bai Sha ke and En kidney bean varieties amino acids, contains essential eight kinds of amino acids; the British red, En and Bai Sha ke kidney bean protein essential amino acid scores were 31, 40, 51; the essential amino acids index(EAAI) of them were 70.34, 48.47 and 67.32; the score of ratio coefficient of amino acids(SRCAA)of them were 65.46, 72.48, 77.16; the biological value(BV) of them were 64.97, 41.13 and 61.18; the nutrition index(NI) of them were 67.41, 44.72 and 62.98. Kidney bean nutrition evaluation analysis showed that kidney bean protein composition of essential amino acids in accordance with FAO/WHO standard mode, explain kidney bean protein is a kind of nutritional value, easy to digest the rich high quality protein resource.4 Kidney bean antioxidant peptides were preparated by enzyme hydrolysis, the highest levels of kidney bean protein was the British red kidney beans were chose as raw materials, with the British red kidney bean protein as the research object, kidney bean protein were hydrolyzed by a variety of protease enzymolysis, with total antioxidant capacity as indicators, ultimately alkaline protease in the preparation of antioxidant peptides optimal protease were selected. Under these conditions, enzyme solution temperature, solution time, solution p H, and enzyme content, total antioxidant capacity was used as indicators, the best condition of alkaline protease enzymolysis the British red kidney bean protein were determined. The results showed that, when the temperature was 55 ℃, enzymolysis time was 2.0 h, p H was 10, enzyme content was 4000 u/m L, at this point, the total antioxidant capacity reached maximum value, the total antioxidant capacity was 186.97 U/mgpro.5 The kidney bean antioxidant peptides were obtained through ultrafiltration and Sephadex G-25 gel chromatography, then their antioxidant activity were determinated. Experiments isolated six components average molecular weight were 11407.75 Da, 5214.35 Da, 4821.70 Da, 3311.31 Da, 375.66 Da, 119.78 Da. For the removal of the 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical scavenging activity were 74.44%, 78.85%, 80.24%, 82.49%, 83.02%, 84.99%; total antioxidant capacity were 197.17 U/ mgpro, 208.78 U/ mgpro, 216.51 U/ mgpro, 245.04 U/ mgpro, 221.56 U/ mgpro, 215.31 U/ mgpro; superoxideantion radicalswere 205.09 U/ mgpro, 219.87 U/ mgpro, 226.03 U/ mgpro, 251.64 U/ mgpro, 233.62 U/ mgpro, 216.55 U/ mgpro; hydroxyl radicals scavenging activity were 135.55 U/ mgpro, 155.43 U/ mgpro, 166.35 U/ mgpro, 181.59 U/ mgpro, 170.53 U/ mgpro and 165.20 U/ mgpro, the experiment results showed that the average molecular weight of 3311.31 Da component was the strongest antioxidant activity.6 The six groups of average molecular weight, respectively were 11407.75 Da, 5214.35 Da, 4821.70 Da, 3311.31 Da, 375.66 Da, 119.78 Da, they were determined through the ACE inhibitory, the results were 19.24%, 18.55%, 15.76%, 13.62%, 14.23% and 17.76%. The results could be seen, antioxidant peptides of kidney bean also had a certain ACE inhibitory, but the main performanced for antioxidant activity. |
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