# Physicochemical Properties and Volatile Profile of Chito: A Traditional Dry-Cured Goat Meat Product
## 3 Results and Discussion  
### Physicochemical Characteristics  
The physical and chemical characteristics (pH, a\({}_{\mathrm{w}}\), proximate composition, heme iron, NaCl, and water-soluble nitrogen) of chito are shown in Table 1.  
For each different year, pH, moisture, fat, heme iron, and NaCl were significantly affected by pressing (\(P\) < 0.05), except for moisture, fat, and heme iron in 2021. For each year, the pH values of P showed a small but significant increase (\(P\) < 0.05) compared to NP. The pH values ranged from 5.08 to 5.28 in NP and from 5.65 to 5.75 for P. Due to the short processing period, the increase in P could be partially attributed to the effect of drying and pressing. [PERSON] et al. [4] reported that the pH of dried meat products is affected by drying procedures due to protein denaturation. In this sense, the increase in pH values in P could be attributed to the reduction of acidic groups present in meat due to conformational changes associated with protein denaturation (through moisture loss) [19] and the force applied to the meat by pressing. Thus, the average values of pH for NP and P are partially in agreement with [PERSON] et al. [4], who reported that the pH of commercial dried meat samples ranged from 5.4 to 5.8. Moreover, in this study, pH values below 5.4 were observed; a low pH is important for avoiding the denaturation of protein in the meat. On the other hand, the mean \(\mathrm{a_{w}}\) values of NP and P (\(\mathrm{a_{w}}\) < 0.70) fall within the range reported for so-called intermediate moisture meat products (0.60-0.90) [9]. Values under 0.75 are relatively safe against microorganisms during storage at ambient temperature [20]. In general, the salting processes not only help with drying but also reduce the \(\mathrm{a_{w}}\) values of meat. Salt penetration into the meat along with water loss from the tissue are simultaneous processes. Furthermore, for the years 2022 and 2023, the pressing significantly (\(P\) < 0.05) decreased the moisture content and heme iron, whereas the fat and sodium chloride (salt) content increased. The fall in moisture content is initially attributed to the pressing, which could have released tissue fluids to the exterior of the meat, promoting drying and water loss. Additionally, chito thickness could have contributed to the diffusion of salt and facilitated drying. Salt is used for dehydrating meat, which involves removing water from the meat in a non-thermal manner [4], which implies a reduction in the water activity and myoglobin concentrations [21], leading to a decrease in heme iron content. The sodium chloride content found in the chito was comparable to that reported in beef cecina (10% NaCl), which is an intermediate meat product produced and consumed mainly in Mexico [5]. Regarding the reduction in heme iron content in pressed chito, it may have implications for its nutritional value, as iron from animal foods is more bioavailable than iron from plant sources. In similar studies, [PERSON] et al. [12] noticed that, during hot air drying of beef jerky, the heme iron content decreased. This effect has been attributed to oxymyoglobin oxidation and a reduction in metmyoglobin. Furthermore, [PERSON] et al. [22] observed that adding salt and then spices reduced heme iron content in dried ostrich meat. Furthermore, statistical analysis showed that, in 2022, NP and P exhibited higher (\(P\) < 0.05) fat content and heme iron content than in the years 2021 and 2023. In the case of fat, particularly in P treatment, the pressing and a higher loss of moisture could have had an impact on the highest fat content; a decrease in the humidity allows the concentration of fat. However, for the year 2021, the fat content in the chito (NP and P) is comparable to that reported by [PERSON] et al. [6] and [PERSON] et al. [21], who found values of 7.14% and 6.03% from salted-ripened goat thigh and cured goat legs, respectively. Finally, for WSN, NP and P showed higher values in 2021 than in 2022 and 2023.