Stability of major allergen tropomyosin and other food proteins of mud crab (Scylla serrata) by in vitro gastrointestinal digestion

Stability in simulated gastric fluid is regarded as an important parameter for the estimation of food allergenicity. In this study, the digestive stability of allergenic protein tropomyosin (TM) and other food proteins from mud crab in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) digestion assay system was investigated and compared by SDS–PAGE and Western blot. In SGF system, proteins such as actin and the original band of myosin heavy chain (MHC) were rapidly degraded within a short period of time, while TM was relatively resistant to pepsin digestion. In SIF system, MHC was easily decomposed, while TM and actin were similarly resistant to digestion. Further study by IgE-immunoblotting and inhibition ELISA using sera from crab-allergic patients indicated that allergenicity of TM was partially decreased, suggesting proteinase digestion is effective in reducing the allergenicity of crab TM.