Study On The Preparation Of Sesame Peptides And Their Antioxidant Activity From Solid-state Fermented Sesame Meal

Suma seed meal is a by-product of the production of Suma oil.It has high protein content and rich amino acids,which is a high-quality plant protein resource.However,at present,the processing and utilization of Suma meal is single,and it is mainly used as feed,fertilizer,fuel and other cheap processing or directly discarded.This not only greatly wastes the protein resources in it,but also affects the economic value of Suma meal and its industrial development.Suma peptide is a small molecule peptide obtained by hydrolysis of Suma seed meal protein.It has better processing characteristics and richer biological activity than Suma protein.The microbial fermentation method hydrolyzes the protein in the fermentation substrate through the protease produced by the microorganism during the growth and metabolism process,and decomposes it into amino acids and small molecule peptides.Since the microbial fermentation method can make the enzyme production and enzymatic hydrolysis continuously proceed,it has become a research hotspot in the preparation of biologically active peptides.In this paper,the by-product of Suma oil produced Suma seed meal is used as a raw material,and solid-state fermentation technology is used to ferment it,in order to obtain Suma polypeptide with higher yield and better antioxidant activity as a natural antioxidant.The main research contents and conclusions are as follows:(1)Aspergillus oryzae was used as the fermentation strain,and the solid-state fermentation method was used to ferment the sesame meal.And the response surface optimization test was performed on the basis of single factor experiments to obtain the best solid-state fermentation process conditions: fermentation time 48 h,fermentation temperature 28 ?,inoculum amount 5.56%,liquid-to-battery ratio 1:1,under these conditions,the peptide content of the fermented Suma seed meal was(58.75±1.12)mg/g,which was 2.66 times higher than that before fermentation.(2)After fermented with the best fermentation process,the crude protein content of the Suma seed meal increased by 1.69%,the crude fat content decreased by 1.65%,the moisture content decreased by 2.64%,the total phenols increased by 18.36 mg/L,and the total flavonoid content Increase 0.39 mg/m L.Later fermentation,the Suma seed meal has 17 kinds of amino acids,of which glutamic acid is the most abundant.The total amount of essential amino acids in the fermented Suma seed meal was 82.61 mg/g,which was higher than the unfermented Suma seed meal(80.40 mg/g).Using Headspace Solid-phase Microextraction combined with GC-MS(HS-SPME-GC/MS),it was identified that the main component in the Suma seed meal was(+)-limonene(23.50%),followed by piperonone(13.49%)and linalool(7.34%),N-hexanal(5.25%).The main components of fermented Suma seed meal are acetic acid(25.20%),2-methylbutyric acid(23.90%),ethyl nitrite(8.69%),isobutyric acid(5.42%).The types of acids,ketones,hydrocarbons,pyrazines,pyridines and amine compounds increase after fermentation of the Suma seed meal.(3)The ultrafiltration method was used to separate and purify the crude extract of the Suma peptide prepared by the best fermentation process,and the relative molecular mass distribution of the Suma peptide was determined by high-efficiency size exclusion chromatography.After ultrafiltration,the peptide fraction with a molecular weight smaller than 1000 Da was 98.8%,indicating that the ultrafiltration had a very good purification effect on the Suma peptide.Different ultrafiltration products are obtained by ultrafiltration: PSMP1(more than 10 k Da),PSMP2(3 k Da?10 k Da),PSMP3(less than 3 k Da).Among them,the ABTS free radical,DPPH free radical,hydroxyl free radical scavenging ability and reducing ability of PSMP3(less than 3 k Da)component are stronger than the other two polypeptides.The three components have a balanced ratio of amino acids and are rich in variety.Among them,the content of amino acids such as Glu and Asp is the highest among the three components.The hydrophobic amino acid Met is only detected in the PSMP3 component,and none of the other two components are detected.(4)By establishing a D-gal-induced aging mouse model,the mice were given different doses of PSMP3 components by gavage.Suma polypeptide can increase the activity of SOD,CAT,GSH-Px and T-AOC in the serum and liver of mice,reduce the content of MDA,and delay the aging of mice.It shows that Suma polypeptide can reduce body damage,and significantly improve the antioxidant status of D-gal-induced aging mice.The effect of intragastric administration of 400?800 mg/(kg·d)Suma polypeptide is equivalent to that of intragastric administration of 100 mg/(kg·d)Vc,revealing that Suma polypeptide has strong antioxidant capacity.These results show that the Suma peptides have good application value in the food fields,and provide a reference for the high-value utilization of the by-products of Sume seed meal.