## 3 Results and Discussion  
### Moisture Content, Cooking Loss, and pH  
Moisture content is one of the important physicochemical characteristics in meat which plays a basic role in the palatability of meat. Moisture content of raw chicken breast fillet 24 h post-mortem is presented in Table 2. Raw meat showed a moisture content of 72.4%. These results were consistent with those obtained by [PERSON] et al. [40]. The moisture content of sous vide chicken breast fillets cooked at different temperature and time combinations ranged from 68.25% to 71.89% (Table 3). Moisture content was affected by cooking temperature, cooking time, and interaction between temperature and time (\(p<0.05\)). As expected, there was a reduction in moisture content by increasing temperature from 60 \({}^{\circ}\)C to 80 \({}^{\circ}\)C. Control treatment cooked at 100 \({}^{\circ}\)C for 60 min showed the lowest moisture content with 68.25% (\(p<0.05\)). Increasing cooking time from 60 min to 150 at higher temperatures (70 and 80 \({}^{\circ}\)C) caused a reduction in moisture content (\(p\) < 0.05). During cooking, the fluid is released as water and other ingredients such as fat and soluble proteins. Releasing the sarcoplasmic fluid from the muscle fibers results in lower water content at higher temperatures [6, 8, 41]. [PERSON] et al. [42] reported that the denaturation of myosin and actin at higher temperatures caused structural changes and changes in porosity of the chicken breast patties which can directly affect the moisture content. This result is in accordance with those obtained for chicken and beef [28, 43]. Cooking loss is an important factor to consider because it is directly related to juiciness which could influence the consumer's perception of the final product [25]. The cooking loss is defined as total liquid and soluble matter lost from the meat during cooking and it is influenced by different factors such as the quality of the raw meat, genetics of the animals, and cooking conditions. This loss relies on the mass transfer process during heat treatment [44]. In this study, cooking loss ranged from 10.23% to 28.08%. Control samples cooked at 100 \({}^{\circ}\)C showed the highest cooking loss (\(p<0.05\)). Cooking loss was affected by both cooking temperature and cooking time and it was increased by increasing cooking temperature and time (\(p<0.05\)). Increasing temperature causes denaturation of myofibrillar proteins and the actomyosin complex, resulting in shrinkage of the muscle fiber. Thus, less water can be captured within the protein structures kept by capillary forces [41, 45]. Our result is in agreement with previous studies on sous vide cooking on chicken [28], beef [25, 43], pork [23], and lamb [7]. According to [PERSON] et al. [46], the cooking loss is mainly determined by the shrinkage of myofibrillar proteins (40-60 \({}^{\circ}\)C), shrinkage of collagen (60-70 \({}^{\circ}\)C), and denaturation of actin (70-80 \({}^{\circ}\)C). Denaturation of proteins occurs with increasing temperature which causes structural changes and the release of fluid from muscle fiber leading to a decrease in the water holding capacity and higher cooking loss [47]. The pH of raw chicken breast fillet 24 h post-mortem was 5.8 (Table 2). The pH value of sous vide chicken breast fillets cooked at different temperature and time combinations slightly increased and ranged from 6.07 to 6.3. The pH was affected by temperature and the interaction between temperature and time. Increasing temperature from 60 \({}^{\circ}\)C to 80 \({}^{\circ}\)C caused an increase in pH value. Similarly, [PERSON] et al. [26] reported that increasing cooking temperature from 65 \({}^{\circ}\)C to 75 \({}^{\circ}\)C and cooking time from 20 min to 60 min caused an increase in the pH of sous vide turkey cutlet. [PERSON] et al. [20] reported that increasing temperature caused an increase in pH mainly due to the protein denaturation and the change in protein charge.