Study On Preservation Technology Of Penaeus Vannamei Based On Volatile Substances From Pomelo Peel

Penaeus vannamei is favored by consumers because of its rich nutrition,thin shell,thick meat and delicious taste.However,due to its high protein and moisture content,it is easy to be attacked by bacteria and spoilage in the process of fishing,sales,storage and transportation,which seriously reduces the nutritional value and economic value of penaeus vannamei.To this end,scientists have developed a variety of preservation technologies.However,the current preservation technology has some defects due to chemical residues or complicated technology.Pomelo peel is often thrown away as a waste in daily life.Many studies have shown that pomelo peel has antibacterial and antioxidant functions.This paper studies the pomelo peel volatile substances of refrigeration effect of preservation of penaeus vannamei,soaking with 1% of grapefruit essential oil in penaeus vannamei,or penaeus vannamei with pomelo peel without contact,storage at 4 ℃ environment,testing different storage period of the improvement of the various indicators of prawns,the change of the electronic nose was used to study the flavor quality,using GC-MS analysis of volatile components of change,The results are as follows:(1)Both 1% pomelo essential oil and pomelo peel treatment can reduce the speed of the body softening,keep the color of the shrimp,reduce the stench of the shrimp,and alleviate the deterioration of the sensory quality of the shrimp.However,prawns treated with essential oil had a strong flavor of pomelo,which could affect the sensory receptance of prawns,while pomelo peel treatment had little effect on the smell(2)Image J software was used to analyze the color changes of Penaeus vannamei during storage,and the gray values of the body surface color of fresh Penaeus vannamei were mostly distributed around 80.Pomelo essential oil treatment group had the most obvious effect on preserving the natural color of shrimp on day 2,and almost no effect on shrimp on day 4.Pomelo peel treatment group could significantly inhibit the melanosis of prawn in the first 4 days,but the effect was not obvious after 6 days.Pomelo peel treatment group could maintain the color of prawn better.(3)The p H,thiobarbituric acid reactants(TBARS),polyphenol oxidase(PPO)and volatile base nitrogen(TVB-N)of shrimp were inhibited by 1% pomelo essential oil and volatile substance of pomelo peel.The TVB-N value of the control group was 33.95mg/100 g on day 4,which exceeded the edible standard(30 mg/100g),and the pomelo peel treatment group exceeded the limit value on day 6,which extended the shelf life for 2 days.In 1% pomelo essential oil treatment group,the TVB-N value of 1% pomelo essential oil treatment group was 33.85 mg/100 g at 8 days,which exceeded the edible standard and extended the shelf life for 4 days.(4)1% pomelo essential oil and volatile compounds from pomelo peel had significant inhibition on microbial growth during storage.The total number of colonies in the control group exceeded the edible standard(6.0 lg CFU/g)on day 6,while the total number of colonies in the 1% pomelo essential oil treatment group was only 4.83 lg CFU/g,and the total number of colonies in the pomelo skin contactless wrapping treatment group was 4.99 lg CFU/g,both of which belonged to the first-grade freshness of prawns(5)The results of electronic nose analysis showed that inorganic sulfides and nitrogen oxides were the main compounds affecting the flavor of shrimp during cold storage.Loading analysis found that sensor W1W(sensitive to inorganic sulfide)and sensor W5S(sensitive to nitrogen oxides)contributed the most.The results of principal component analysis(PCA),linear discriminant analysis(LDA)and radar map showed that the smell of pomelo skin treatment group was similar to that of fresh shrimp after 4 days of storage,and the smell of 1% pomelo essential oil treatment group was similar to that of control group after 6 days of storage.Both can effectively maintain their inherent flavor;(6)Main volatile Components of penaeus vannamei under Different Storage times and Treatments: Penaeus vannamei in unrefrigerated and refrigerated for 4 days,6 days,8days the dominant volatile compounds of were heptadecane and(+)-limonene,cetaldehyde and trimethylamine,indole and oleol,2-amino-5-methylbenzoic acid and(1,13-tetradecanodiene).Pomelo peel volatile matter treatment had a great effect on the species and relative content of volatile matter of prawn.After pomelo essential oil treatment,the main volatile compounds were changed into(+)-limonene,α-terpineol,linalool,photolene,etc.After pomelo peel volatiles treatment,the dominant volatiles of penaeus vannamei were(+)-limonene,hexanol and isoamyl alcohol.In addition,the treatment of volatile compounds in pomelo peel reduced the production or relative content of volatile compounds such as trimethylamine,indole,dimethyl trisulfur and so on,and effectively reduced the rotten smell of shrimp during storage,which was an effective measure to improve the flavor of shrimp.In conclusion,this study found that volatile substances from pomelo peel can effectively produce fresh-keeping effects and prolong the shelf life of penaeus vannamei during cold storage.