Allergenic response to squid (Todarodes pacificus) tropomyosin Tod p1 structure modifications induced by high hydrostatic pressure.

The structural and allergenic modifications of tropomyosin Tod p1 (TMTp1) in fresh squids induced by high hydrostatic pressure (HHP) were investigated. The α-helix in TMTp1 decreased along with increasing pressure from 200 to 600 MPa, where almost 53% α-helix was converted into β-sheet and random coils at 600 MPa. The free sulfhydryl group dropped significantly as pressure went up, but the surface hydrophobicity increased at 200 and 400 MPa, while it slightly decreased at 600 MPa. Based on in vitro gastrointestinal digestion test, digestibility of TMTp1 was promoted by HHP treatment, in which 400 and 600 MPa were more effective in reducing the allergenicity than 200 MPa based on indirect ELISA. This study suggested that HHP can decrease allergenicity of TMTp1 by protein unfolding and secondary structure modification, thus providing potential for alleviating allergenicity of squid.