Impact of freezing methods on the quality and flavor characteristics of Preprepared dishes

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This study analyzed the effects of different freezing methods on the flavor characteristics of preprepared green pepper and shredded pork dishes using electronic-nose (E-nose), electronic-tongue (E-tongue), and Headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) technologies. It explored the correlation between flavor changes and freezing rate, microstructure, water distribution, and texture. Results showed significant effects of freezing methods on flavor profiles. Principal component analysis confirmed that E-nose and E-tongue effectively distinguished odor and taste characteristics, with liquid nitrogen freezing yielding sensory quality closest to fresh samples. HS-GC-IMS determined 31 key markers via Orthogonal partial least squares discriminant analysis (OPLS-DA). Correlation analysis revealed that rapid freezing shortened ice crystal formation time, preserved myofibrillar structure, and inhibited bound water migration, retaining beneficial flavors like acetic acid-D and acetic acid ethyl ester while suppressing undesirable ones. This study confirms that higher freezing rates maintain sensory quality and characteristic flavors, providing a basis for optimizing freezing processes. • The quality and flavor of dishes were investigated at different freezing methods. • Liquid nitrogen freezing (LF) maintained the muscle fiber structure of dishes. • LF preserved flavor and quality properties of dishes due to its rapid freezing rate. • Refrigerator freezing(RF) reduced the quality and flavor of dishes. • LF inhibited the production of pungent odor compounds.