Cold plasma-assisted protease hydrolysis modulates antigenicity, antioxidant properties, and bitterness of bovine casein

Abstract

Enzymatic hydrolysis has been proven to be an effective approach to reduce the allergenicity of casein; however, its hydrolysates are usually associated with a strong bitter taste. Thus, this study adopted a two-step approach to prepare casein hydrolysates, involving initial alkaline protease hydrolysis followed by cold plasma (CP) treatment. This CP-assisted enzymatic treatment achieves higher hydrolysis efficiency, along with improved palatability and functional properties of casein hydrolysates. Spectroscopic and ELISA data revealed that CP-assisted enzymatic hydrolysates exhibited reduced endogenous fluorescence intensity, enhanced surface hydrophobicity, and a 29.1% additional reduction in IgE-binding activity relative to sole enzymatic hydrolysis. Moreover, in vitro antioxidant assays demonstrated that sequential treatment has the potential to improve the antioxidant activity of casein hydrolysates. Meanwhile, electronic tongue analysis indicated an 11.3% lower bitterness intensity in CP-assisted enzymatic hydrolysates compared with the sole enzymatic hydrolysis group. These results were further validated by mass spectrometry and free amino acid analyses. Overall, this sequential treatment may provide a useful reference for developing casein hydrolysates with reduced residual antigenic reactivity and bitterness.

Keywords

Cold plasma-assisted hydrolysis / Antigenicity reduction / Protein structure / Antioxidant activity / Bitter peptides

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