Quality Analysis And Process Improvement Of Traditional Spanish Mackerel In Dalian

Dried spanish mackerel is a special food that has been passed down from generation to generation by fishermen in coastal areas and is very popular among consumers.In the process of natural air drying,beneficial bacteria and harmful bacteria coexist,and spanish mackerel is a high histamine fish.Improper processing and storage can easily produce a large amount of histamine,causing serious food poisoning incidents and endangering people's life and health.There is a hidden danger in the edible safety of dried spanish mackerel.The main reason for the deterioration of fish is the growth and reproduction of microorganisms.The anti-corrosion methods used in the past are mostly to increase the amount of salt,but this method will affect the taste of fish and cause adverse effects on human health.Some lactic acid bacteria can be used as preservatives to inhibit the growth of spoilage bacteria and prevent food spoilage because of their broad-spectrum antibacterial activity and food safety.In this paper,the microbial composition and physical and chemical indicators of commercially available dried spanish mackerel were studied,and the edible safety was evaluated.The beneficial lactic acid bacteria in the commercially available dried spanish mackerel were applied to the preservation of low-salt dried spanish mackerel and the processing technology was optimized.The results of this study are as follows:1.Physical and chemical detection and bacterial phase analysis of traditional spanish mackerel.Through the physical and chemical indicators of the dried spanish mackerel purchased in five markets in Dalian,it was found that the volatile base nitrogen was kept within 30 mg/100g.According to GB 10136-2015 "Food Safety National Standard Animal Aquatic Products",the upper limit of volatile base nitrogen of prefabricated aquatic products(excluding dry and salted products)is 30 mg/100g.The dryness did not exceed the highest limit of the volatile base nitrogen of the national standard;the histamine content of the 5 groups of dried spanish mackerel in this experiment was 7-17 mg/kg,according to GB 10136-2015 "Food Safety National Standard Animal Aquatic Products" Spanish mackerel The histamine content is specified to be within 400 mg/kg,and the histamine content of this experimental sample is much smaller than the standard range.In summary,all the 5 groups of spanish mackerel dried in this experiment have food safety.Analysis of microbial diversity of dried spanish mackerel purchased in five markets revealed that the dominant bacteria were at the level of the door:Proteobacteria,Firmicute,and Actinobacteria.The dominant genus at the genus level is Lactobacillus,Psychrobacter,Ralstonia.2.Screening for biologically fresh-keeping active Lactobacillus.Eight suspected lactic acid bacteria selected from commercially available dried spanish mackerel were used as test strains.The pathogenicity test of sterilized fish juice and sterilized fish pieces showed that the strain X23 had the least erotogenic ability and was found by electronic nose analysis.The sterilized fish pieces of strain X23 were placed at room temperature for 48 h,96 h,and 144 h,and the odor was the closest to that of 0 h sterilized fish.Therefore,X23 was selected as the strain with biopreservation potential.It was identified by 16S rDNA as Lactobacillus plantarum and named L.plantarum X23.3,the effect of different curing methods and L.plantarum X23 bacteria treatment on the physical and chemical indicators of spanish mackerel.Firstly,the effects of different salt content and curing methods on the physical and chemical indicators of dried spanish mackerel were tested.It was found that the sensory evaluation score of dried spanish mackerel with a salt content of 16%salt for 10 min was 92.24,which was significantly higher than other sensory scores.(p<0.05);physical and chemical test results showed that 16%saline wet marinated spanish mackerel had a salt content of about 3%,good sensory,TBA content of 3.00 mg/kg,the lowest content and significant difference compared with other groups(p<0.05),the free amino acid content was 3.13 mg/g,the highest content,histamine content was 24.35 mg/kg,compared with other groups,the lowest content and significant difference(p<0.05),far lower than the national standard 400 mg/kg is within safe limits,so this curing method was chosen for the next experiment.The spanish mackerel were treated with 16%salt water and L.plantarum X23.It was found that the L.plantarum X23 treatment group reduced the histamine content from 24.35 mg/kg to 2.16 mg/kg compared with the saline-free marinated spanish mackerel.A significant difference(p<0.05),the acid value decreased from 5.61 mg/g to 3.93 mg/g,which was significantly different from the dry acid value of the untreated bacteria(p<0.05),and the free amino acid was 3.13 mg/g.Increasing to 3.70 mg/g,there was a significant difference(p<0.05)in the dry acid value of the spanish mackerel treated with the unused bacteria,and the sensory was good.Conclusion:After inoculation with L.plantarum X23,the content of histamine and putrescine in dried low-salt spanish mackerel was significantly lower than that of homemade spanish mackerel dried only with salt water,and its value was significantly lower than that of commercially available high-salt spanish mackerel.The content of histamine and putrescine in the dry.