Extrusion And Synergistic Enzymatic Hydrolysis Of Pea Protein Peptide Optimization And Anti-fatigue Effect Research

Pea is an important legume crop in the world.It has comprehensive and balanced nutrition,high biological price,high efficacy ratio,and high protein content,which is one of the good sources of plant protein.Although pea resources are abundant in my country,they are often used in the preparation of starch,and the utilization rate of the by-product pea protein is not high.It is often used in feed production or directly used as production waste,resulting in a great waste of resources.In addition to its high nutritional value,pea protein also has good functional properties and is a good source of plant protein peptides.Studies have shown that pea peptides have a variety of functional properties,of which the antioxidant properties are more prominent and their functional properties It is closely related to the preparation method.At present,most studies on the antioxidant activity of pea peptides focus on the detection of in vitro antioxidant indicators.There are few studies on whether it still exerts its biological activity in the body,and the mechanism of action is still unclear.In this study,pea antioxidant peptides were prepared by physical combined enzymatic method,including extrusion combined with enzymatic method to modify pea protein and enzymatic hydrolysis to prepare pea antioxidant peptides,and then separated and purified by chromatography,and in vitro antioxidant indicators Finally,to explore the anti-fatigue effect of pea peptide in vivo.The main findings are as follows:(1)The combination of single factor and orthogonal experiment was used to optimize the process of preparing modified pea protein by extrusion combined with enzymatic method,and the structure of the modified protein was analyzed.As a result,when the water content of the material is 30%,the barrel temperature is 80?,the die diameter is 8 mm,and the screw speed is150 r/min,better modified pea protein can be prepared.The results of infrared spectroscopy showed that the content of?-helix and?-sheet of the modified pea protein was significantly reduced,the content of?-turn and random curls were significantly increased,the stability of the protein was deteriorated,and the structure was looser.The results of electrophoresis showed that the modified pea protein mainly contained 7S and 11S globulins,and a small amount of new bands appeared,indicating that there may be new structures.(2)Enzymatically hydrolyze modified pea protein to prepare antioxidant pea peptide.The single factor and response surface method were used to optimize the process parameters for preparing pea antioxidant peptides by alkaline protease.The results showed that the p H value was 8.1,the enzymatic hydrolysis time was 3.8 h,the enzymatic hydrolysis temperature was50?,and the substrate concentration was 6.75%,the DPPH clearance rate of the prepared pea peptide reached 48.64%,which was close to the theoretical value.The verification found that the parameters of the conditions are stable,easy to operate,and can be used to prepare pea antioxidant peptides.(3)The prepared pea antioxidant peptides were separated and purified by macroporous resin chromatography adsorption and gel chromatography,and three peptides with different molecular weights were collected,and then enriched by in vitro antioxidant indexes to obtain three different The molecular weight peptides are screened for the main functional peptides.As a result,peptides of different molecular weights all showed good O₂·,·OH and DPPH free radical scavenging abilities,and their free radical scavenging rates were 76.52%,66.48%,52.89%,respectively,indicating that the prepared pea peptides all have good Antioxidant,and among them,the antioxidative ability of the molecular weight less than 2 k Da is the strongest,and the peptides less than 2 k Da account for 52.72%of the total content,which are the main functional peptides.(4)The anti-fatigue study of pea antioxidant peptides was carried out using in vivo experiments in mice.Results Pea peptide had no significant difference in the body weight and organ weight of the mice;in the exhaustive swimming experiment,the swimming time of the mice in the high-dose pea peptide group and the middle-dose pea peptide group was 47.81%and35.16%longer than the control group,and showed A certain dose time dependence;pea antioxidant peptide high,medium,and low dose groups gradually increase liver glycogen content;significantly reduce the serum urea nitrogen content in mice,indicating that it may participate in energy metabolism in mice and can improve mice's energy metabolism.Exercise endurance;the lactic acid content in mice also decreased significantly and was dose-dependent.The high-dose group had the best effect.The lactic acid content was 5.24 mmol/L,which was35.86%lower than the control lactic acid content,indicating that it has the effect of relieving fatigue;It can also reduce the content of malondialdehyde in the serum of mice.By measuring the content of SOD and GSH-PX in the serum of mice,it is found that different doses of pea antioxidant peptides can improve the activity of antioxidant enzymes in the body and eliminate the excess in cells.Oxide,in order to achieve the effect of relieving fatigue.In summary,the pea protein is modified by extrusion combined with enzymatic method first,and then the modified pea protein is enzymatically hydrolyzed to prepare the antioxidant active peptide.The purified pea antioxidant peptide not only exhibits good in vitro anti-oxidant properties.The oxidation effect can also exert anti-fatigue effect in the body through its characteristics,and the effect is remarkable.However,there are few reports on the antioxidant properties of pea peptides in vivo,and the mechanism of its antioxidant and anti-fatigue effects in the body is still unclear.In this study,pea antioxidant peptides were prepared by physical and enzymatic methods,optimized its preparation process,and explored its functions in the body,which can provide theoretical support for the research of pea antioxidant peptides,and is of great significance to the application and deep processing of pea protein.It also provides a reference for the source of plant protein active peptides.