Effect of ultrasonic pretreatment with synergistic microbial fermentation on tenderness and flavor of air-dried duck under low nitrite process

The tenderness and flavor of meat products are critical factors influencing consumers' purchasing decisions. This study investigated the effects of ultrasonic pretreatment with synergistic microbial strain fermentation on tenderness and flavor of air-dried duck under low nitrite process. The results demonstrated that ultrasonic pretreatment combined with microbial strain fermentation improved water retention and tenderness of duck meat by disrupting the muscle microstructure, increasing muscle fiber spacing, and facilitating water migration and distribution. This primarily concerns the cavitation and mechanical effects of ultrasound and the role of lactic acid bacteria and yeasts in muscle protein hydrolysis. A total of 34 and 55 volatile flavor compounds were detected by HS-SPME-GC-MS and GC-IMS, respectively. The results indicated that acetaldehyde (stimulating, fruity, green apple), ethyl acetate (sweet, fruity, pineapple), and 3-hydroxy-2-butanone (sweet, creamy) were responsible for the improved flavor during this process, which was primarily related to the increased activity of neutral lipase (0.38 U/g protein), acidic lipase (0.48 U/g protein), and phospholipase (0.09 U/g protein). This study provides valuable insights into the synergistic effects of ultrasonic pretreatment and microbial co-fermentation, offering a theoretical basis for optimizing air-dried duck production and enhancing flavor quality.