Effect of boiled-water-cooking time on quality and characteristic of flavor components in pig large intestines

Fresh pig large intestines have a heavy initial off-flavor and a strong pungent smell that may cause discomfort to the consumer. To examine how boiled-water cooking of the pig large intestines affects the quality characteristics and flavor profiles, changes in shear force, cooking loss, volatile flavor compounds, and other physical and chemical indexes were measured in pig large defatted intestines using gas chromatography-odor-mass spectrometry detector (GC-O-MS), and electronic nose (E-nose) and texture analyzer. The results showed that indole, 3-methylindole, and 4-methylphenol were the characteristic volatile substances that caused visceral off-odor to the pig large intestines. After boiled-water-cooking, the content of acids decreased, while the aldehydes increased. Group B20 boiled for 20 min showed the highest volatile substance content in pig large intestines. However, the contents of the off-odor components 4-methylphenol, indole, and 3-methylindole in the samples decreased by 56.5%, 45.5%, and 20.4%, respectively, after continuous boiling for 10 min. The odor of the late stage samples (mainly after B20) was significantly different from the control group (R0) and those of the early stage of boiling (B0, B5). As cooking time was increased, the texture of intestines became tender, the shear force decreased, and the fat percentage initially decreased before stabilizing. This study provides a theoretical support for the quality change of pig large intestines during heating.