Purification, characterization and immunoreactivity of β′-component, a major allergen from the roe of large yellow croaker (Pseudosciaena crocea)

Fish roe, a nutritious food, is favored by consumers, but has also been confirmed to be allergenic in salmonid fish. However, little information is available in other fish species. To determine the allergen in the roe of large yellow croaker (Pseudosciaena crocea), crude extracts were incubated with sera of allergic patients. The major allergen was purified by column chromatography methods, revealing a single band with 16 kDa and was confirmed as β′-component (β′-c) by mass spectrometry. The results of physicochemical characterization showed that β′-c was a glycoprotein and was relatively stable following thermal or acid/alkali treatment. Furthermore, β′-c was easily degraded by pepsin, but was resistant to trypsin and α-chymotrypsin. After treatment with different processing methods, including Maillard reaction (MR), ultraviolet radiation (UVR), ultrasound-heat (UH), and retorting (RT), the IgG-binding activity of β′-c decreased obviously by MR, but decreased slightly by UVR and UH. Cross-immunoreactivity results of the allergens in the roes of different species revealed that β′-c was a specific allergen in teleostean, and the cross-immunoreactivity between the roe of large yellow croaker and other kinds of fish roe was relatively strong.