Effect of ball-milling treatment on the structure, physicochemical properties and allergenicity of proteins from oyster (Crassostrea gigas)

This study was focused on the effect of ball-milling treatment (0, 5, 10, 15, 20 min) on the structure, physicochemical properties and allergenicity of oyster protein (OP). The results showed that ball-milling affected the secondary structure of OP, in which the contents of α-helix and β-turn increased and the contents of β-sheet and random coil decreased. The surface hydrophobicity and free sulfhydryl groups increased in ball-milled OP. The best foaming capacity (25.50%) was obtained for OP treated for 5 min, whereas the highest foaming stability (99.32%) and lowest solubility (3.00%) were observed for OP treated for 10 min. Compared to the control, the particle size decreased continuously, and maximum uniformity was found in OP treated for 15 min. The highest thermal deformation temperature (38.32 °C) and water holding capacity (97.50%) as well as the lowest oil holding capacity (380.00%) were obtained for OP treated for 20 min. Moreover, ball-milling significantly (p < 0.05) increased the digestibility and decreased the allergenicity of OP. In summary, the improvement of processing properties, digestibility and safety of ball-milled OP mainly resulted from changes of structure and decrease of particle size. The results suggested a way to improve the structure and physicochemical properties of an aquatic product.