## 3 Results and Discussion
### Cooking Loss and WBSF  
Table 2 summarizes the CT, _CL_, and WBSF changes of ST muscle cooked using various methods. CT corresponded to the duration required to reach a core temperature of 70 \({}^{\circ}\)C. The exception was the SV treatments, for which the duration was determined based on preliminary experiments. The shortest process was boiling in water (47.24 min), while the longest, excluding SV, was \(\Delta\)T20 (135.25 min). Increasing \(\Delta\)T from 20 to 40 reduced the heat treatment time by 53 min. The lowest _CL_ values were observed in samples treated with \(\Delta\)T20 (18.78%) and \(\Delta\)T40 (19.54%), whereas the CON heat treatment resulted in the highest _CL_ (37.12%; \(p\leq\) 0.05) (Table 2). The lower cooking losses observed in the \(\Delta\)T methods may be explained by the gradual and more controlled heating process, which minimizes instant protein denaturation and structural damage, thereby better preserving the water-holding capacity of the meat [40]. In the SV method, an increase in heat treatment temperature led to a significant rise in _CL_ (\(p\leq\) 0.05). However, increasing \(\Delta\)T from 20 to 40 did not cause significant changes in _CL_. The observed effect may be attributed to the increase in internal temperature, which induces protein denaturation, reducing water-binding capacity and leading to protein network shrinkage. Consequently, this shrinkage increases internal pressure within the product, forcing excess water to be expelled from the surface through convective mass transfer. Additionally, the unbalanced pressure contributes to further shrinkage, resulting in greater water loss from the meat structure [1; 41]. The boiled sample (CON) had the highest shear force value (44.29 N), which was significantly higher than that of the other samples (\(p\leq\) 0.05). In contrast, the samples treated with the SV55 and SV65 methods showed the lowest WBSF values (26.47 N and 28.26 N, respectively; \(p\leq\) 0.05). These samples also exhibited the highest tenderness among all those tested. Lowering the \(\Delta\)T (the temperature difference between the product's center and the oven interior) from 40 to 20 led to a significant (\(p\leq\) 0.05) reduction in WBSF values, from 33.68 N to 29.65 N, respectively. The difference in tenderness between \(\Delta\)T20 and \(\Delta\)T40 results from the duration of exposure to higher temperatures. Using a higher \(\Delta\)T value (\(\Delta\)T40) in roasting may have contributed to reduced tenderness, as a higher final temperature was reached in the oven. This could be caused by the fact that \(\Delta\)T20 samples were exposed to a maximum temperature of 90 \({}^{\circ}\)C (a final core temperature of 70 \({}^{\circ}\)C + \(\Delta\)T20 = 90 \({}^{\circ}\)C in the oven). In contrast, \(\Delta\)T40 samples were exposed to temperatures above 90 \({}^{\circ}\)C, resulting in a reduction in their tenderness. The slowest roasting samples, \(\Delta\)T20 and R75, had similar tenderness (\(p>\) 0.05), while the \(\Delta\)T40 sample had a comparable WBSF value to the SV75 sample. According to [PERSON] and [PERSON] [42], consumers find beef tenderness acceptable when the WBSF value is below 39 N. Based on these findings, it can be concluded that ST muscle products processed using LTLT methods demonstrated a considerably high and acceptable level of tenderness.