Study on the influences of ultrasound on the flavor profile of unsmoked bacon and its underlying metabolic mechanism by using HS-GC-IMS.

For exploring the influence of ultrasound on the flavor characteristic of unsmoked bacon, sensory evaluation combined with E-nose and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) were performed to analyze the overall flavor profile and specific volatile flavor compounds (VFCs), respectively. Furthermore, the metabolic pathway of VFCs affected by ultrasound was also investigated. Results demonstrated that ultrasound improved the flavor characteristic of unsmoked bacon by raising the levels of nonanal, heptanal, octanal, 3-methylbutanal n-hexyl acetate and n-propyl acetate. Enzymatic oxidation was found to be an important metabolic pathway responsible for the development of flavor characteristic after ultrasound treatment, which could be attributed to the increased activities of lipases and lipoxygenase and the higher concentration of polyunsaturated free fatty acids. The increased level of lipid oxidation after ultrasound treatment was also confirmed by thiobarbituric acid reactive substances. Consequently, ultrasound is an effective approach to enhance the flavor characteristic of unsmoked bacon.