Effect of molecular migration on texture of high-protein intermediate-moisture foods

• 1、State Key Lab of Food Science and Technology, Jiangnan University, Wuxi, 214122, China

Abstract：The objective of this study was to evaluate the influence of molecular migration on the texture of high-protein intermediate-moisture foods. Texture analyzer, confocal laser scanning microscopy (CLSM) and low-field nuclear magnetic resonance (LF-NMR) were used to monitor the changes in texture, microstructure and T2 relaxation time of model systems during storage for 24 hours at 25℃. Sodium caseinate (NaCN) model system was thermodynamically unstable and showed significant increase in hardness during storage. Formation of cross-network and migration of low molecular weight compounds from lipid phase to insoluble protein powders were found, which may contribute to the firm texture of NaCN system. In contrast, Whey protein Isolate (WPI) model system showed little molecular migration or microstructural changes and kept soft texture all the time. NMR experiment of NaCN heavy water system showed that glycerol and sorbitol had lower mobility than water and their existence could delay moisture migration to keep the system softer. These results confirmed that molecule-migration-induced changes in microstructure and molecular mobility were the key factors of the hardening of high-protein intermediate-moisture foods.

Keywords： high-protein intermediate-moisture foods hardening molecular migration CLSM LF-NMR