Effects of freeze-thaw cycles on the quality and flavor profiles of stir-fried ZhiJiang duck.

To investigate the effects of four freeze-thaw (F-T) cycles on the quality, protein properties, and volatile flavor compounds of stir-fried Zhijiang duck meat, providing a scientific basis for mitigating deterioration. The results indicated that the pH value, water-holding capacity, chewiness, and total sulfhydryl content decreased significantly with more F-T cycles. Conversely, the content of thiobarbituric acid-reactive substances (TBARS), acid content, carbonyl content, and total volatile basic nitrogen (TVB-N) increased significantly with increasing F-T cycles. After 3 cycles, TVB-N reached 20.83 mg/100 g, above the spoilage limit. The α-helix content decreased from 17.87 % to 7.73 %. Hematoxylin and eosin (HE) staining showed that more F-T cycles caused irreversible cellular damage. The odor profile changed significantly after 3 cycles. The relative contents and diversity of alcohols, aldehydes, and ketones increased with the number of F-T cycles. Octanal, nonanal, and (E, E)-2,4-decadienal contributed to flavor at early, middle, and late stages of F-T cycles.