Studies On Preparation And Antioxidant Activities Of Rapeseed Peptides

Rapeseed is a kind of important oil plants in china.Rapeseed meal which is only used for animal feed and fertilizer,thus leading to the waste of resources. Therefore,it's significant to work on the value-added process of ra-peseed meal.Defatted meal of double-zero rapeseed was used as material in this study.Rapeseed albumin was extracted from rapeseed meal.The parameters of step enzymic hydrolysis of alcalase and papain were studied and optimized by Single-factor experiments and orthogonal experiments.The antioxidant activities of papeseed peptides was also studied. The main conclusions of the experiments were as follows:(1)Preparation of rapeseed albumin:from 100g dry defatted rapeseed meal in 2L beaker,and then add 1000mL distilled water at 40℃under the conditions of extraction 1h,then 6000rpm,4℃centrifuge 20min,filter the supernatant to be precipitated,by the above steps extracting 3 times repetitions,merger the Supernatant liquid of four times,using 1mol/LHCl for rapeseed albumin deposition, the pH adjusted to 4.0,then 6000rpm,4℃centrifuge 10 min,got the sediment, placed it in distilled water in dialysis 24h,and in the 8h,16h,replace the distilled water,and then vacuum freeze-drying to be albumin.(2)Rapeseed albumin the main function characters are as follows:326.88%for the absorbent,oil absorption for 4.30mL oil /g albumin,66.00%for foaming, emulsifying and emulsion stability were 29.80%and 35.53%.(3)In this paper,alcalase and papain were selected to have a step study of enzymatic hydrolysis on rapeseed albumin.Based on the single-factor,then through orthogonal experiment,the best conditions of dual-enzymatic hydrolysis were got as follows:rapeseed albumin of 3.5%concentration was hydrolyzed by 4000U/g of alcalase at 8.0 of pH value and 55℃for 3h,and then by 3000U/g of papain at 5.5 of pH value and 50℃for 3 h.The degree of hydrolysate is 40.17%.(4) Rapeseed peptide had a strong deoxidize ability.The deoxidize ability increased with the increase of concentration showed that rapeseed peptides antioxidant ability increases with the concentration of the increase.Rapeseed peptide has a clear inhibition of superoxide anion and a role of restraining action on hydroxyl radicals,and showed a certain degree of dose-effect relationship,and its anti-oxidation were increased with the concentration increased,and their superoxide anion IC₅₀ value was 6.60mg/mL.Rapeseed peptides through gavage for 40 days,tests have shown to improve antioxidant capacity of mice to mouse liver and kidney enhance the activity of SOD,while MDA content in mice significantly reduced.