Quality Characteristics Changes of the Fat Portion of Chinese Bacon During Processing Based on Physicochemical Properties and Microstructure Studies

In order to elucidate the development of quality properties in the fat portion of Chinese bacon during low-temperature smoking (LTS), raw pork was cured for five days, followed by infusion with smoked liquid and a subsequent ten-day smoking period characterized by alternating high and low-temperature conditions. The physicochemical characteristics and microstructures of the fat portion of the Chinese bacon were examined at three stages: the raw meat stage (Control), the curing stage (C3d and C5d), and the smoking stage (S5d and S10d). The results showed that LTS increased the hardness, transparency, and b* value of bacon fat. The increased contents of neutral lipids and free fatty acids, increased activities of neutral lipase and lipoxygenase, and increased peroxide and thiobarbituric acid reactive substance value indicated significant lipolysis and lipid oxidation of bacon fat during LTS. After the treatment, a decreased melting point and increased β'- and β-type fat crystal formation were observed in the fat portion. Moreover, the treatment led to disruption of the adipocyte membrane structure. Therefore, the destruction of adipocytes after lipolysis and lipid oxidation during low-temperature smoking treatment might contribute to the development of quality properties of bacon fat portions. Precise control of temperature and time enhances the stability of the fat portion of bacon, thereby improving quality characteristics such as texture and appearance.