Research On Extraction Of Peptides From Fagopyrum Tatayicum And Antihypertensive Activity

This paper use Fagopyrum Tataricum flour as raw material. The response surface software are used to optimize the extraction condition, with Protein extraction rate as index. Then determine the best enzyme hydrolysis of buckwheat protein by orthogonal experiment, with the degree of hydrolysis and antihypertensive activity as index. Finally, we will obtain high purity antihypertensive peptides after isolation and purification of enzyme products. In this section, ultrafiltration, ion exchange chromatography and gel-permeation chromatography are used. Finally, we analyzes the size of molecular weight, amino acid composition.(1) Fagopyrum tataricum composition analysisIn this paper, the nutritional components of Buckwheat nutrition are evaluated by physical and chemical methods. We confirm the contents of Protein, fat, moisture and flavonoids are 13.04%,1.36%,3.54%,3.14%, respectively.(2) Research of Fagopyrum tataricum protein extractionFirstly, we obtained the best protein extraction technology by single-factor (solid-liquid ratio, extraction temperature, extraction time and pH) and response surface experiment. The results as follows:extracting time 50min, so lid-liquid ratio 1:12, extraction temperature 55℃, pH 10.0. The protein content is 85.19%, under this condition.(3) Research of enzymatic hydrolysis conditions to prepare Fagopyrum tataricum antihypertensive peptidesFirstly, alkaline protease is confirmed as the optimum hydrolytic to prepare fagopyrum tataricum antihypertensive peptides, with antihypertensive activity asindex. Then, we obtained the best enzymatic hydrolysis conditions by orthogonal test. The results are as follows:the substrate concentration 2%, enzyme dosage 20 ku/g (in terms of the substrate concentration), temperature 50℃, pH 9.0. And the enzymatic hydrolysis product (1g/mL) after hydrolysis of 2 h has the highest antihypertensive activity. The ACE inhibitory rate and the degree of hydrolysis are 75.85%,58.44% respectively, under this condition.(4) The separation and purification of Fagopyrum tataricum antihypertensive peptidesFirstly, we learned that the peptides with molecular weight< 5000Da has the highest activity of antihypertensive, after separation and purification with ultrafiltration membrane (5000Da). Subsequently, ion exchange chromatography (DEAE-25) is used to further purification. Received two components (F1 and F2) and Fl has the higher antihypertensive ability, for 46.52%.which is 1.16 times higher than before purification. After that, we continue to purify component 1 by gel chromatography method (SephadexG-25), also obtained two component (F1-1 and F1-2) and component F1-1 has the higher antihypertensive ability, for 77.61%.which is 1.66 times higher than before purification. Finally, we analyze size of molecular weight of F1-1 by LC-MS technique. The size of molecular weight is about 1048～2329Da, mainly concentrated on 1000～1500Da. Due to the average relative molecular weight of amino acids in human body is 128 Da, we confirm the antihypertensive activity peptide may composed by 7～12 amino acid. And thin-layer chromatography showed that the composition is rich in Aspartic acid, tyrosine, phenylalanine. But what the the specific amino acid have and the connection between amino acids has yet to be explored.