Research On The Effect Of Thermal Processing On Immune Binding Activity Of Allergens From Litopenaeus Vannamei

Litopenaeus vannamei has the highest yield in China because of its delicious meat and rich nutrition.In recent years,the allergic events caused by the consumption of L.vannamei have increased,so the research to reduce the allergenicity of L.vannamei has become a hot spot.In this study,L.vannamei was selected as the object to explore the effects of thermal processing on the digestive stability and immune binding activity of shrimp muscle allergens,analyzed the reasons for the thermal processing changed allergenicity of shrimp muscle allergens,provided a theoretical basis for the research of thermal processing affecting the allergenicity of shrimp muscle allergens.Above all,the effects of boil and high-temperature combined with pressure treatment on the structure,digestive stability and protein composition of shrimp muscle proteins were evaluated.Selected buffers with different salt concentrations to extract shrimp muscle protein,the result showed that the buffer solution contained 0.5 mol/L NaCl could significantly improve the extraction rate of shrimp muscle protein.Scanning electron microscope results showed that the shrimp muscles were densely arranged after boiled,but after high-temperature combined with pressure treated,it has showed a loose bundle structure with large pores.After boiled and high-temperature combined with pressure treated,the particle size of the digested product decreased by 53.4 ± 4.5% and 74.8 ± 2.4%,respectively.Moreover,the maximum absorption peak of the digested product processed by high-temperature combined with pressure treatment was obviously red-shifted,at the beginning of digestion,the protein band was completely degraded,and the digestibility increased by 27.3 ± 3.4%.Secondly,the digestive stability and immune binding activity of allergens in digested products after boiled and high-temperature combined with pressure treated were analyzed.Western-blot results showed that the immunoglobulin(Ig)G binding activity of the heat-stable allergens sarcoplasmic calcium-binding protein(SCP)and tropomoysin(TM)after boiled decreased by 51.9 ± 2.5% and 60.1 ± 0.1%,while the IgG binding activity of SCP and TM in the high-temperature combined with pressure treated products decreased by 77.1 ± 0.2% and 85.7 ± 0.6%.ELISA results showed that the IgE binding activity of TM after boiled and high-temperature combined with pressure treated decreased by 67.0 ± 4.5% and 81.6 ± 4.1%,respectively.Using the boiled and high-temperature combined with pressure treated products to stimulate human mast cells(LAD-2),the degranulation release rate was reduced by 49.3 ± 2.1% and 52.3 ± 2.2%,respectively.It showed that high-temperature combined with pressure treatment can reduce the digestive stability and immune binding activity of shrimp allergens.Finally,the compound processing technology of high-temperature and pressure combined with Maillard reaction was used to process shrimp,and optimized the processing temperature(110 °C,115 °C,121 °C),the texture was evaluated by texture profile analysis.The results showed that at 115 °C,the IgG binding activity of SCP and TM in the continuous digestion products decreased by 97.4 ± 0.3% and 94.9 ± 2.1%,the IgE binding activity decreased by 98.5 ± 0.1% and 96.3 ± 0.2%,and the texture quality such as elasticity and nozzle resistance were better,on this basis,a hypoallergenic shrimp food was developed.In summary,this study found that high-temperature combined with pressure treatment changed the microstructure of shrimp muscle tissue,increased the digestibility of muscle protein,and reduced the digestive stability and immune binding activity of SCP and TM.On this basis,the processing method was optimized,and a hypoallergenic shrimp was developed to provided a reference for the development of hypoallergenic shrimp food.