| Recently, traditional soup-stock has got more and more attention because of its obvious flavor advantage. However, few researches are related to this issue. The degradation of pork bone and chicken meat soup under thermal treatment was studied. On the basis of this study, the effects of different pork bone/chicken meat ratio, solid/liquid ratio and time of thermal treatment on the quality of soup-stock were also studied. Based on the experiment results, we obtained the following conclusions:The physico-chemical properties, nutrients and flavoring substance of pork bone and chicken meat soup increased with the increase of thermal time. At the beginning of thermal treatment, the contents of crude protein, water-soluble protein, total sugar, TCA-soluble nitrogen, amino nitrogen and free amino acids increased significantly. However, at the late stage of thermal treatment, nutrients and flavor substance gradually accumulated to a certain level, and the change was insignificant (p≥0.05). After9h thermal treatment, glutamic acid contents in pork bone and chicken meat soup reached the maximum, which were94.22g/mL and 113.41g/mL respectively. The total free amino acid content increased significantly during thermal treatment (p≤0.05). It was interesting that total free amino acid content in chicken meat soup was4times higher than that in pork bone soup under the same thermal condition. However, the contents of crude protein, water-soluble protein and total sugar in chicken meat soup were lower than those in pork bone soup. It was showed that the chicken meat soup had lower content than the pork bone soup.Different pork bone/chicken meat ratio not only affected the sensory index such as color, viscosity, smell and taste of soup-stock, but also influenced the nutrients and flavor substance of soup-stock. Consequently, it would affect the quality characteristics of final product. Our experiment found that the pork bone/chicken meat ratio at2.5:1was the most favorable for soup-stock. On the other hand, solid/liquid ratio not only affected the sensory characteristics of the product, but also influenced the nutrients and flavor components of soup-stock. Finally, we revealed that the optimum ratio of solid to liquid was1:2.5. Furthermore, at the beginning of thermal treatment, the contents of nutrients and taste substance were at a low level, and reached a higher level after9h thermal treatment then remained stable. At the same time, the sensory evaluation of soup-stock after thermal treatment of9h,12h,15h and18h was studied. The result indicated that products by thermal treatment12h obtained a higher score. |
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