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

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.