Effects Of Sterilization Treatments On Nutrition Quality And Allergenicity Of Pacific White Shrimp(Litopenaeus Vannamei)

Pacific White shrimp(Litopenaeus vannamei)is widely loved by consumers due to its delicious taste and rich nutrition.Therefore,the issue of food allergy has shown a sustained growth trend,which has been widely concerned.It has been demonstrated that the major allergen of shrimp is tropomyosin(TM),a myofibrillar protein composed of two identical subunits with molecular weight of about 36 kDa.Food processing has been found to influence the allergenicity by inducing the conformational changes of food protein.Sterilization treatment is an essential procedure in processing cycle,which contributes to inhibiting the growth of microorganism,increasing the shelf life of food as well as decreasing the food allergenicity.In addition,food processing always causes the loss of nutrition value.In order to investigate the effect of sterilization treatments on the nutrition value and the allergenicity,this research treated shrimp muscle and balls from Pacific white shrimp(Litopenaeus vannamei)with 4 sterilization treatments including boiling,autoclaved sterilization,microwave irradiation and high hydrostatic pressure.Nutrition properties of processed shrimp samples were detected to investigate the effect of sterilization treatments on the nutrition quality.The soluble protein concentration of shrimp sample extractions was quantified by BCA protein quantitative method.The change of protein composition and the allergenicity of tropomyosin(TM)were analyzed by immunoassays.This paper provides certain theoretical basis and data support for the manufacture of cooked shrimp products with low nutrition damage and low allergenicity.The main research content and results are as follows: 1.Effects of sterilization treatments on nutrition quality of Pacific white shrimpThe moisture,crude fat,protein and amino acid content of processed shrimp samples were detected and analyzed.It showed that the moisture content of all treated shrimp samples decreased,and the result of the microwave samples was the lowest.The crude fat content of shrimp samples with microwave irradiation and high hydrostatic pressure were significantly increased(p<0.05).The protein content of shrimp ball samples was lower than the corresponding muscle samples.The protein content of high hydrostatic pressure ball sample under the pressure of 500 MPa had the maximum decline rate(24.22%).The amount and change of total amino acid of samples matched the protein content of corresponding samples.According to the ideal protein pattern recommended by FAO/WHO,shrimp samples with boiling and autoclaved sterilization treatments and high hydrostatic pressure ball samples had high protein quality.Methionine was the first limiting amino acid of shrimp samples with sterilization treatments.In accordance with the essential amino acid index(EAAI),boiled and autoclaved muscle samples,ball samples with autoclaved sterilization and high hydrostatic pressure treatments had higher nutrition value of amino acids.Compared with boiled samples for 10 min,all treated samples kept good flavor.Therefore,boiled and autoclaved shrimp samples and high hydrostatic pressure ball samples had good nutrition quality.2.Effects of sterilization treatments on TM content of Pacific white shrimpBCA protein quantitative method,SDS-PAGE and Western-blotting were used to detect the content of soluble protein(TM)from extractions.It was showed that the protein solubility of treated samples was significantly reduced(44.23%-81.82%).There were significant differences in the concentration of soluble protein between corresponding shrimp muscle and ball samples(p<0.05).The results of SDS-PAGE showed that the TM content of autoclaved shrimp samples and HHP ball samples had great reduction and that the result of other treated samples decreased significantly.The Western-blotting result was similar to SDS-PAGE result.3.Effects of sterilization treatments on TM allergenicity of Pacific white shrimpInhibition ELISA was used to detect the change of TM allergenicity from extractions.The results showed that the TM of all treated samples eliminated except for the boiled muscle sample for 5 min.The effect of autoclaved samples on TM reduction was the best and the elimination rate was over 90% after treating for 20 min.Followed was the high hydrostatic pressure ball samples and the elimination rate was up to 77.10%.Therefore,treating shrimp samples with autoclaved sterilization and treating shrimp balls with high hydrostatic pressure could significantly reduce the allergenicity of TM.In conclusion,our results indicated that the nutrition quality of autoclaved samples increased and that the allergenicity of these samples significantly reduced.The result of shrimp balls with high hydrostatic pressure was similar.Hence,the above results can be used as a reference to provide theoretical basis for the processing of low allergenic shrimp products.