Effects of sucrose and trehalose on the stability of pork myofibrillar protein during freeze-drying

This study investigated the effects of sucrose and trehalose on pork myofibrillar proteins (MP) subjected to freezing and freeze-drying. Differential scanning calorimetry showed that the addition of sucrose and trehalose increased the glass transition temperature (T′_g1) of myofibrillar proteins, while T′_g1 was not detected in samples without additives. Scanning electron microscopy revealed that freeze-dried samples containing sucrose or trehalose formed uniform and stable porous structures, whereas samples without additives exhibited irregular morphologies. Structural analyses indicated that freezing and freeze-drying of samples without additives significantly increased surface hydrophobicity and reactive sulfhydryl exposure compared with the Raw sample (p < 0.05). In contrast, no significant differences were observed between the Raw sample and samples containing sucrose or trehalose (p > 0.05). After freeze-drying, carbonyl content analysis showed that MP without additives and the sample containing sucrose exhibited significantly higher carbonyl contents than the Raw sample (p < 0.05), whereas no significant difference was observed for the sample containing trehalose compared with the Raw sample (p > 0.05). After freeze-drying, samples containing sucrose or trehalose showed significantly higher NaCl-soluble protein solubility than samples without additives (p < 0.05). These results indicate that sugar-based excipients influence the structural, oxidative, and functional responses of myofibrillar proteins during freezing and freeze-drying.