Relationship between glass-transition and textural evolution of batter-coated meat analog

Glass-transition is a crucial phenomenon to control the quality and stability of food materials. This study aimed to characterize the thermo-mechanical transitions of meat analog (MA) based batter coated fried foods for understanding their textural evolution. Wheat and rice flour-based batters were used to coat the MA and fried at 180°C in canola oil for 2, 4 and 6 minutes. Thermal and mechanical glass-transition-temperature of the fried coatings were assessed by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA), respectively. Mechanical texture analyzer and X-ray microtomography were employed to assess textural attributes and internal microstructure, respectively. Results showed that batter-formulation greatly impacts both the thermal (Tg) and mechanical (Ts) glass-transition-temperature of fried batter coatings. Fried batters Ts value (°C) was higher than corresponding Tg value. Both Tg and Ts of fried batters are positively correlated with frying-time and internal microporosity (%), whereas negatively correlated with moisture content. Internal microstructure greatly influenced the textural attributes (i.e., hardness, brittleness, crispiness) of batter coated fried meat analogs. However, textural stability was considerably impacted by both the Tg and Ts. Negative Tg and Ts values could explain the textural changes (hard-to-soft, brittle-to-ductile, crispy-to-soggy) of meat-analog based fried batter coated products at room-temperature (25°C). • Batter formulation and frying time significantly affected thermal (Tg) and mechanical (Ts) glass-transition temperature. • Mechanical glass transition temperature (Ts) exceeded thermal Tg • Moisture reduced Tg and Ts, acting as a dominant plasticizer • Microporosity and frying time increased Tg, Ts, and crust rigidity • Glass transition governed crispness and post-frying textural stability