Preparation And Functional Activities Of Protein Peptides From Juglans Mandshurica Maxim. Kernel In Changbai Mountain

Juglans mandshurica Maxim Nuts are rich in nutrients, especially high content of protein, which is the main component of in-depth development and utilization of Changbai Mountain walnuts. In this paper, the Juglans mandshurica Maxim. Kernel protein isolate（referred JMKP） was taken as raw material, single-factor experiment and response surface method were used to conduct research on enzymatic hydrolysis processes. Response surface methodology analysis results showed that the optimal enzymatic hydrolysis conditions were: neutral protease: reaction time 2h, substrate concentration 2.6g / 100 mL, pH 7.2, enzyme dosage 9000U/g, hydrolysis temperature 52.5 ℃, alkaline Protease: hydrolysis time 3h, enzyme dosage 7000U/g, pH 8.4, hydrolysis temperature of 55.5 ℃, the degree of hydrolysis of 32.23% under this condition. Followed by a response surface under optimal conditions obtained digested by ultrafiltration enzymatic preparation of polypeptide crude extract（Juglans mandshurica Maxim. Kernel protein isolate active peptides, MWHP） were isolated and purified, it will be divided into> 10 kDa, 10-3 kDa, <3 kDa three components of active peptides.Through experiments in mice swimming in swimming time fatigue index, and measured blood lactate（BLA）, glycogen（GLU） and malondialdehyde（MDA） content and glutathione peroxidase（GSH-Px）, catalase（CAT） and superoxide dismutase（SOD） activity and other biochemical markers explore JMKP and MWHP alleviate physical fatigue and antioxidant effects in vivo. This test confirms the preliminary JMKP and MWHP（<3 kDa） are to make swimming time was significantly longer, and with the extension of the increase intragastric dose and time, swimming time increase is more significant. Each dose group can reduce the accumulation of lactic acid in the blood, reducing glycogen consumption, lower production of MDA. They can improve the body of GSH-Px, CAT and SOD levels, particularly at high doses four weeks, compared with the control group were significantly raise the level（P <0.01）. This indicates JMKP and MWHP（<3 kDa） can play a role to alleviate physical fatigue in mice and improve the body’s antioxidant capacity.Receptors in mice by gavage JMKP and MWHP（different molecular weights）, measured the immune organ index mouse peritoneal macrophages phagocytic activity, the small intestine soluble substance s-IgA concentration, spleen lymphocyte proliferation and other immune index immunomodulatory effects on mice of different doses JMKP and MWHP. This test validated that the JMKP and MWHP（<3 kDa） could increase the spleen index and thymus index, increase phagocytic activity of macrophages and splenic T lymphocyte proliferation ability, and significantly increase the concentration of IgA in the intestinal contents. This indicates JMKP and MWHP（<3 kDa） are able to increase the body’s immune function in mice.Passed Sephadex G-25, Sephadex G-15 RP-HPLC determination of antioxidant peptides obtained were isolated and purified, for isolated components were superoxide anion, ABTS, hydroxyl radical, reducing power and Fe²⁺ vitality and and selects the most active next step separation. After three-step purification, and ultimately determine the antioxidant activity of the strongest components of C₄.