## 3 Results and Discussion
### Thermal Treatment Parameters Optimization  
RSM was used to assess the influence of temperature, humidity, and fan rotation on the heat treatment of goose breast fillets (Pectoralis major). This modeling technique enabled the observation of trends in the outcomes as the independent variables were altered. The regression coefficients outlined in Table 2, along with the 3D plots depicted in Figure 5, demonstrated that all three independent variables exerted a statistically significant effect on the denaturation levels of individual proteins, encompassing myosin, collagen, actin, and cooking loss in the goose samples. However, the extent of this impact varied depending on the specific response and the level of the independent variable. The myosin denaturation level was notably impacted by temperature and humidity in linear terms (\(p\leq 0.001\)). Similarly, a linear impact was observed for fan rotation speed (\(p\leq 0.05\)) on myosin denaturation. Additionally, the interaction between temperature and humidity had a significant influence on myosin denaturation (\(p\leq 0.001\)). Nevertheless, there were no significant effects of temperature, fan speed, and humidity in quadratic terms (\(p>0.05\)). The interaction between fan speed \(\times\) temperature and fan speed \(\times\) humidity did not exert a significant influence on myosin denaturation (\(p\leq 0.05\)). The study  
Figure 5: The 3D surface charts generated using the RSM model at fan rotation of 700 rpm illustrate the impact of factors and their interactions on output data: (**A**)—myoglobin denaturation [%], (**B**)—collagen denaturation [%], (**C**)—actin denaturation [%], and (**D**)—cooking loss [%]. carried out by [PERSON] et al. [43] sheds light on the intricacies of myosin denaturation during thermal processing, particularly in masseter and cutaneous trunci muscles, which exhibit distinct characteristics. The research highlights significant differences in quality, chemical composition, and histological properties between the two muscle types. The masseter muscles exhibited elevated pH levels, as well as higher total and soluble collagen content, and shorter sarcomere length in comparison to the cutaneous trunci. Notably, myosin denaturation was found to occur at a lower temperature (54 \({}^{\circ}\)C) in cutaneous trunci compared to masseter (63 \({}^{\circ}\)C), where it coincided with collagen and sarcoplasmic protein denaturation. This lower transition temperature of myosin in cutaneous trunci was identified as a key factor contributing to a greater cooking loss and shrinkage in this muscle type compared to masseter at temperatures up to 65 \({}^{\circ}\)C. Additionally, the intense transverse shrinkage observed in the masseter at 60-70 \({}^{\circ}\)C coincided with the later onset of myosin denaturation in this muscle [43]. The study conducted by [PERSON] et al. [44] delves into the intricate effects of thermal processing on the conformational and digestive properties of myosin, a crucial protein in meat. The findings reveal that increasing heating temperatures lead to notable changes in the structural integrity of myosin. Specifically, higher temperatures result in the exposure of internal groups to a polar environment while simultaneously causing a decline in the study \(\alpha\)-helix structure of myosin. Tryptophan fluorescence analysis confirms that myosin's tertiary structure appears to unfold at 70 \({}^{\circ}\)C. Furthermore, excessive heating, exemplified by treatment at 100 \({}^{\circ}\)C for 30 min, induces greater protein denaturation, evidenced by elevated sulfhydryl contents and turbidity, ultimately leading to the formation of irregular aggregates. Importantly, the study highlights the impact of heating temperature on myosin's digestibility by pepsin, a key digestive enzyme. Mild heating at 70 \({}^{\circ}\)C enhances the exposure of active sites for pepsin, thereby improving digestibility.