Insights into myofibrillar protein denaturation during freezing: The impact of ice-water interface area

This study investigated the impact of the ice-water interface area on the denaturation of myofibrillar protein (MP) over 1, 3, and 5 freeze-thaw cycles. Experimental systems designed to generate ice-water interfaces with two distinct surface areas were established by employing rapid freezing at -80 °C and slow freezing at -25 °C, resulting in surface areas of 64.63 m²/100 mL and 54.05 m²/100 mL, respectively. Following three freeze-thaw cycles, the process of rapid freezing, characterized by formation of a larger ice-water interface area, was found to significantly influenced the functional properties of MP. The impact was evidenced by a reduction in solubility, total sulfhydryl content, and thermal denaturation temperature. Structural modifications in MP suggested that the larger ice-water interface led an accelerated rate of protein unfolding during freezing. Interfacial pressure and confocal laser scanning microscopy (CLSM) results demonstrated that the larger ice-water interface area could be more able to reduce protein interfacial adsorption and enhanced protein emulsion aggregation. The addition of 0.1 % surfactant Tween 80 prior to freezing markedly enhanced protein stability throughout both the freezing and subsequent freeze-thaw cycles. The findings suggested that to further inhibit MP frozen denaturation, it is important to consider limiting the expansion of ice-water interface area.