Study On The Extraction Optimization And Antioxidant Activity Of Seedlings Protein From Selenium-Enriched Peanut

As an essential element of human body, selenium was enriched in the cultivation of peanut, which is one of the basic crops largely planted in China. The process of by-products of peanut industry into plant protein could not only increase the added value of peanut industry, but also bring huge social and economic benefits.In this study, selenium-enriched peanut seedling was treated as the object of the study, and the extraction of its protein was optimized to test the protein content and selesnium content of peanut seedlings under different selenium-rich ways and selenium concentrations, and the antioxidant activity of the samples with non-selenium,low-selenium and thigh-selenium was determinated as well. The results showed that:1. The single factor tests and response surface methodology (RSM)were used to optimize the protein extraction process from peanut stem and leaf , and the extraction rate of peanut stem and leaf protein was determined under the optimal conditions. In terms of the extraction rate of peanut stem and leaf protein, the effects of pH, solid-liquid ratio and extraction time on the protein extraction rate were investigated and these three factors’ significance could be ranked in a decreasing order of pH value > extraction time > solid-liquid ratio. The optimum conditions for protein extraction were as follows: pH value 9, solid-liquid ratio 1:20 (w / v) and extraction time 34 min. The protein extraction rate was 49.08% and the purity was 63.83%.2. Through the addition of exogenous selenium (Na2Se03), the content of selenium in the stem and leaf and peanut leaf protein can be improved, and the selenium-enriched method of spraying on the leaf surface was the best. When the exogenous selenium concentration was 4 mg/mL, the total selenium content of peanut stem and leaf can reach to 26.7951 μg/g. The selenium-enriched concentration had a huge effect on the selenium content. For the selenium-rich method of spraying on the leaf surface, the appropriate exogenous selenium concentration was about 2 mg / mL. For the method of selenium enrichment in soil,the reasonable concentration of selenium was about 1.6mg / mL. With regard to the mixed selenium-rich way, 4mg /mL of the concentration of exogenous selenium was enough. After selenium enrichment, the total protein content of the plant increased compared with the control, and the most obvious increasing was under the method of spraying on the leaf surface. There were small differences of the changes of content of soluble protein between sample group and control group.3. The antioxidant activity of the samples with non-selenium, low-selenium(0.4 mg /mL) and high-selenium(2 mg / mL) was determinated, ard the results showed that the ability on scavenging DPPH,·OH and ·O2- all enhanced with the increase of selenium concentration. The selenium-enriched sample will increase the initial value of each clearance rate, and each sample had better effect on scavenging DPPH and ·O2- . The consequence reflected the nature of selenium, especially under the high selenium concentration. However, the · OH scavenging ability was lower.