Effects Of High Hydrostatic Pressure And Its Assisted Enzyme Treatment On The Immunoreactivity And Structure Of Peanut Allergenic Protein Ara H 1

The prevalence of food allergy has been on the rise in the world for nearly 20 years,which has been a food safety issue and attracted more and more attention.Peanuts were generally recognized as one of the eight most sensitive foods,and about 1%of children worldwide are peanut sensitized patients.Ara h 1 is a major allergenic protein in peanuts,with stable structure and resistant to high temperature and enzymatic hydrolysis.Thus it is not easy to eliminate its immunoreactivity in food processing.High hydrostatic pressure(HHP)is an emerging food processing technology.In recent years,studies have been shown that it can change the structure of proteins and thus reduce the allergenicity of proteins.Therefore,the present study investigated the effects of HHP and HHP assisted enzyme treatment on the immunoreactivity and structure of Ara h 1 protein.The results are as follows:(1)HHP had no significant effect on the immunoreactivity of Ara h 1 protein at 200 MPa.However,the immunoreactivity decreased by 32.1%～50.9%with the increase of holding time under the pressure of 400 MPa.The maximum reduction of 74.32%was achieved at 600 MPa for 1200 s.Therefore,a higher high hydrostatic pressure(≥400 MPa)can significantly reduce the immunoreactivity of Ara h 1 protein,and its immunoreactivity is closely related to the change of protein structure.(2)HHP had no significant effect on protein Ara h 1 structure at 200 MPa.However,Ara h lhad been significantly changed the secondary/tertiary structure when the pressure was more than 400 MPa.High pressure(>400 MPa)changed the tertiary structure of the Ara h 1 protein,which resulted in the formation of new polymers,and some immune reaction sites in the protein were embedded,thereby reducing immunoreactivity.Changes in secondary structure destroyed some immune reaction sites and further reduced the immune reactivity of the protein.Therefore,high hydrostatic treatment on Ara h 1 protein can effectively reduce its immunoreactivity by changing its secondary/tertiary structure and formation of multimers.(3)The treatment of high hydrostatic pressure assisted hydrolase(a-chymotrypsin,flavourzyme,papain,alcalase,trypsin)can not effectively reduce the lmmunoreactivity of Ara h 1 protein.However,HHP assisted cross-linking enzyme(TG)treatment can reduce the immunoreactivity of Ara h 1 protein.TG-HHP treatment had the best effect on the mmunoreactivity with 68.1%decrease at 200 MPa.HHP-TG treatment was most effective at 400 MPa and the immunoreactivity was reduced by 60.7%.The change of immunoreactivity of Ara h 1 protein is related to the primary structure of the protein and multimers formed,which destroyed or embedded some immune reaction sites and resulted in the reduction of the immunoreactivity of Ara h 1 protein..In conclusion,HHP can effectively reduce the immunoreactivity of Ara h 1 protein.This technology is expected to be applied in production of hypoallergenic peanut products.