Exploitation of pig by-product: physicochemical properties and flavor of Dachang Tang: effect of cooking time

Objective: The objective of this study was to determine the optimal cooking time for Dachang Tang in order to promote Chinese cuisine culture and to improve the utilization of pig large intestines, thereby reducing resource waste.Methods: The raw pig large intestines were cleaned with water and flour, then boiled with selected spices for 40 mins to reduce off-odors. Subsequently, the large intestines were stir-fried with oil, garlic, and <i>Zanthoxylum bungeanum</i> for a specified duration, before being added to the original broth. The pig large intestines were then cooked for 10 mins, 20 mins, 40 mins, and 60 mins, respectively. Samples were collected at each cooking times to analyze their basic nutritional components (moisture, protein, fat), texture, color, water state, fatty acids, volatile compounds, microstructure, and sensory characteristics.Results: With the increase in cooking time, the moisture and fat content decreased significantly, and the ratio of unsaturated to saturated fatty acids increased (p<0.05). At 20 mins, pig large intestines exhibited optimal chewiness, color, surface integrity and sensory scores. Meanwhile, volatile flavor compounds mainly derived from spices, such as 4-methoxybenzaldehyde, benzaldehyde, 3-ethyltoluene, estragole, and ethyl decanoate effectively masking the off-flavor caused by p-cresol and indole in pig large intestines, and provided fruity, spicy, fennel and citrus aromas to Dachang Tang.Conclusion: A comprehensive analysis concluded that 20 mins was the optimal cooking time.