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In order to reduce the environmental pressure caused by petroleum based packaging materials, the development of natural and environmentally friendly soybean protein based food packaging film has become a hot research topic. This paper searched research papers on soy protein based food packaging films from 1990 to 2021 in the Web of Science (WOS), visualized 1318 related articles by using scientific knowledge mapping tool CiteSpace5.8.R3, deeply discussed and analyzed the research hotspots and development trends of soybean protein based food packaging film combined with the method of literature and quantitative analysis. The results showed that the research process of soybean protein based food packaging film could be divided into three stages: Initial, steady and accelerated development, and now it was in the accelerated development stage. China ranked first in the number of publications, reflecting its huge development potential in this field. The betweenness value of the United States was 0.59, indicating that it had a strong scientific research strength. Food Hydrocolloids was a leading journal in this field. The modification of soybean protein based food packaging film and its application in food packaging are the promising research topics, and it tends to develop green food packaging film with natural bioactive compounds in the future.

In order to improve the comprehensive utilization rate of walnut, the technology of synchronous producing oil and polypeptide from walnut by aqueous enzymatic method was optimized, and the fatty acid composition of the oil was analyzed. By comparing the effects of four different proteases and cellulase on oil extraction rate and polypeptide yield of walnut, the optimal enzyme combination was then determined. On this basis, the effects of pH, enzymolysis temperature, enzymolysis time, solid-liquid ratio and dosage of enzyme on the oil extraction rate and the yield of polypeptide from walnut were studied by single factor and L18(35) orthogonal experiment, and the optimal extraction conditions were finally obtained. The fatty acid composition of walnut oil was analyzed by gas chromatography. The results showed that the combination of papain and cellulase (2:1, w/w) was the best enzyme combination. The optimal synchronous extraction process of oil and polypeptide were as follows: Dosage of enzyme 3.0%, solid-liquid ratio 1:5 (g/mL), pH5, enzymolysis time 3.0 h, enzymolysis temperature 60 ℃. Under these conditions, the oil extraction rate of walnut could reach 53.37%, and the yield of polypeptide was 4.01 mg/g. The determination results of gas chromatography indicated that five fatty acids were detected in walnut oil, including linoleic acid (62.26%), oleic acid (18.64%), α-linolenic acid (10.57%), palmitic acid (6.00%), stearic acid (2.53%). Walnut oil was rich in unsaturated fatty acids. The total content of unsaturated fatty acids in walnut oil was up to 91.47%, in which the contents of polyunsaturated fatty acids and monounsaturated fat acids were 72.83% and 18.64%, respectively. The process could provide reference for the industrial application of synchronous producing oil and polypeptide from walnut by aqueous enzymatic method.