Food processing may reduce the allergenicity of shrimps

Friday, 16 March 2007 00:09

Tropomyosin, a myofibrillar protein, has been identified as the major allergen in shrimps, and the protein has been shown to retain its activity even when degraded to peptide fragments during normal manufacturing processes.

Simple heat treatment does not reduce the allergenicity of this major allergen, however new research by scientists in China has indicated that in combination with heat, irradiation can reduce shrimp immunoreactivity.  While the allergenicity of irradiated shrimp was stronger than untreated shrimp, the immunoreactivity of gamma-irradiated, heat-treated shrimp decreased with increasing dose of radiation.

The results could be explained by a destruction of shrimp allergens by radicals formed during irradiation and subsequent heat treatment. Some epitopes (ie. the part of a protein molecule that is recognised by the immune system) that are buried in the interior of the protein molecule can be exposed by irradiation. This denaturation might result in unfolding of the protein’s secondary structure. Subsequently, the epitopes that become exposed can then be destroyed by heat.

The full article “Impact of irradiation and thermal processing on the immunoreactivity of shrimp (Penaeus vannamei) proteins” is currently in press in the Journal of the Science of Food and Agriculture.