Fatty Acid Analysis And Polypeptide Preparation And Activity Study Of Hickory Kernel

Hickory is a famous high-quality nut food in Zhejiang Province,and it is also a unique economic crop in Lin'an,Zhejiang Province.Since ancient times,hickory has been loved by people in Zhejiang Province and even the whole country for its unique taste,physical fitness and intellectual benefit.Studies on hickory kernel have shown that hickory kernel contain a large amount of unsaturated fatty acids and abundant proteins.However,few further studies have been done on these peptides.Therefore,this paper focuses on the composition of fatty acids and amino acids in hickory kernel,and applies mechanochemical technology to the preparation of hickory polypeptide.Research on its antioxidant and immunological activities provides a practical and reliable research basis for the utilization and development of hickory resources.The specific content of this article is as follows:Firstly,the content of fat and protein in hickory kernel was measured and the composition of fatty acids and amino acids was analyzed.The hickory were compared with walnut and pecan to analyze the difference between hickory and other two kinds of nuts.The chloroform-methanol extraction method was used to obtain the maximum oil in the nut,and the optimum extraction conditions for the hickory seed oil were as follows: extraction temperature was 65 °C,extraction time was 60 min,and the ratio of material to liquid was 1:12,the volume ratio of methanol and chloroform was 1:2.The oils of hickory,walnut and pecan were obtained under better conditions,and the composition and content of fatty acids were studied by gas chromatography.The results showed that all the three nut oils contained 11 fatty acids and their composition was significantly different.The highest content of hickory and pecan nuts were oleic acid,which were 68.92% and 57.30%,respectively.The highest content of walnut kernel is linoleic acid with a content of 62.31%.And the content of hickory unsaturated fatty acids is significantly higher than the other two nuts,which can reach 92.92%.The protein content and the composition and content of the amino acids in the three nut kernels were determined.The results showed that the content of hickory protein was 8.11%,but the content of essential amino acids accounted for 29.89% of the total,which was larger than that of walnut and pecan.In addition,the highest content of amino acids in the three nut kernels is glutamic acid,followed by arginine and aspartic acid.Secondly,the main research on mechanochemical assisted method for the preparation of hickory polypeptide.Polypeptide is the main form of absorption of protein in the human body.The polypeptide of a certain molecular weight can be absorbed through the intestinal tract more quickly and after entering the human body,it works.Therefore,studying the polypeptide derived from hickory and its preparation method can help to improve the economic value of hickory.Among them,the single factor investigation of the enzymatic hydrolysis method determined that the preferred process for the preparation of hickory polypeptide by enzymatic hydrolysis was as follows: alkaline enzyme added enzyme amount was 2.5%,substrate concentration was 2%,temperature was 55 °C,pH was 9.0.The enzymatic hydrolysis time is 3 h.Then the mechanochemical assisted preparation of hickory polypeptide was established by mechanochemical assisted technique combined with response surface analysis.The optimal process conditions were as follows: sodium hydroxide dosage was 14%,filling rate was 10.7%,ball milling time was 43 min,ball milling frequency was 22 Hz.By comparing and analyzing the above two methods for preparing hickory polypeptide,the microstructure of hickory defatted powder was observed according to scanning electron micrograph.It can be seen that the hickory defatted powder after mechanochemical treatment showed a significant decrease in particle size and uniform particle size.The degree of improvement is favorable for the enzymatic hydrolysis reaction,and the yield of the hickory polypeptide prepared by mechanochemical assisted method is improved by 42.91% compared with the enzymatic hydrolysis method.In addition,mechanochemical assisted ball milling can help to obtain a polypeptide with a small weight average relative molecular weight,and the weight average molecular weight distribution of the polypeptide is better.Finally,the anti-oxidation and immunological activities of the hickory polypeptide prepared by mechanochemical assisted method were studied.The results showed that the scavenging ability of hickory polypeptide in DPPH and ABTS free radical scavenging experiments was comparable to that of Vc and had strong free radical scavenging.ability.Through the experimental study of spleen lymphocyte proliferation,it was found that hickory polypeptide can promote the proliferation of spleen lymphocytes,which provides a scientific basis for the hickory to have physical fitness.