| Pork is rich in high-quality protein,fat,and vitamins,which can provide the necessary nutrients for human growth and development.Chilled fresh pork looks moist,has a soft and elastic texture,is easy to process,tastes smooth and tender,and is easy to digest.It is favored by consumers and has become the mainstream of consumption.From processing to transportation to consumption,chilled fresh pork can only be keep fresh for about 6 days in an environment of 0 to 4℃.Therefore,people usually use food additives,irradiation,ultra high pressure treatment,vacuum packaging,and other methods to extend the storage period of pork.With the improvement of people’s living standards and the enhancement of their health awareness,using safe,broad-spectrum,and easily degradable natural preservatives to extend the storage life of pork has gradually become a research hotspot.Therefore,this experiment take chilled fresh pork as the main research object,using the characteristic resource products of Guizhou Province,such as tannic acid,propyl gallate,and synergistic agent Citric acid,to conduct a mixture,and then determine the TBARS value and sensory evaluation to determine the best formula for chilled fresh pork preservation.At the same time,explore the effects of complex antioxidants on chilled fresh pork protein The effects of lipids and microorganisms are intended to provide theoretical basis for the preservation technology of chilled fresh pork,extend the storage period of chilled fresh pork,and reduce waste caused by corruption.The main contents and conclusions of this experimental study are as follows:(1)This experiment used single factor and orthogonal experimental results,combined with response surface analysis,to determine the optimal process for the effect of gallnut extract and its derivatives composite antioxidants on the quality of chilled fresh pork: the mass concentration of tannic acid is 5.16 mg/m L,the mass concentration of citric acid is 4.35 mg/m L,and the mass concentration of propyl gallate is 0.48 mg/m L.The TVB-N of chilled pork treated with composite antioxidants was 14.373 mg/100 g,the total bacterial count was 5.438 lg CFU/g,and the juice loss was 10.397% after being stored in vacuum at 4 ℃ for 16 days.Compared with the control group,the TVB-N of chilled pork decreased by 5.311mg/100 g,1.985 lg CFU/g,and 3.629%,respectively.All indicators had significant inhibitory effects.The muscle fiber structure of chilled fresh pork remained intact,and the shelf life of chilled fresh pork was extended by more than 6 days compared to the control group.(2)A total of 1291 proteins were identified from chilled fresh pork produced by the above compounding process using label-free proteomics methods,including 195 differential proteins.The results of GO enrichment and KEGG enrichment analysis of differential proteins showed that in the dt13-VS-dc1 control group,changes in the ubiquitin dependent protein catabolism process of the differential proteins were mainly concentrated in tight junction,regulation of actin cytoskeleton,focal adhesion,and other pathways;In the dt13-VS-dc13 control group,changes in differential proteins were mainly observed during ubiquitin dependent protein catabolism and protein deubiquitin.A0A480LF55 and A0A8D0PPC9 were enriched in the RNA transport pathway and protein expression was downregulated.(3)It was detected by GC-MS that the fatty acid composition of the treatment group and the control group during the entire storage process was similar,but there were significant differences in the fatty acid content with the prolongation of storage time,including myristic acid,palmitic acid,stearic acid,oleic acid,linoleic acid,palmitic acid,isooleic acid Arachidonic acid is the main fatty acid in chilled fresh pork samples of each group.Compared with the control group,there was no significant change in myristic acid and palmitoleic acid,while unsaturated fatty acids,isooleic acid,and arachidonic acid were significantly downregulated,and the content of unsaturated fatty acid was significantly downregulated.Studies have shown that gallnut extract and its derivatives complex antioxidants significantly inhibit the synthesis of unsaturated fatty acids in chilled fresh pork.(4)Using 16 S rDNA amplifiers for high throughput sequencing,it was found that the dominant bacteria in the entire storage process of chilled fresh pork include Actinobacteria,Firmicutes,and Proteobacteria,while the dominant bacteria include Psychrobacter,Acinetobacter,and Pseudomonas.KEGG function prediction analysis found that at the first level,it mainly involves metabolism,the second level mainly involves amino acid metabolism and carbohydrate metabolism.Meta Cycle functional prediction analysis found that at the first level,functional pathways mainly involve biosynthesis,at the second level,it mainly involves amino acid biosynthesis,carbohydrate biosynthesis,cofactors,prosthetic groups,electron carriers,and vitamin biosynthesis,fatty acid and lipid biosynthesis Nucleoside and nucleotide biosynthesis,TCA cycle. |
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