Freezing is an important way to maintain the quality and safety of meat and meat products, but freezing-thawing process can take place repeatedly during their long-term processing, transportation and sale. The repeated formation of ice crystals will cause a series of problems for meat and meat products such as oxidative denaturation, reduced water-holding capacity, declined functional quality and loss of nutrients, which can seriously affect the stability of meat system. Quality deterioration caused by repeated freeze-thaw cycles has become a hot topic in meat science. In this paper, the formation process of ice crystals and the influence of ice crystal morphology on the microstructure, juice loss, product quality and oxidation stability of meat system are reviewed, aiming to lay a foundation for studies to improve the stability of frozenthawed meat system and provide a theoretical basis for improving the quality of frozen meat.

In order to explore the effect of substituting Chinese baijiu with brandy on the quality of traditional air-dried sausages, sausage samples were formulated with mixtures of mulberry brandy and baijiu in different proportions, and the amount of alcohol added to the sausages was 0.03 mL/g. Air-dried sausages were evaluated for volatile components, biogenic amine content, thiobarbituric acid reactive substances (TBARS) content, total volatile basic nitrogen (TVB-N) content and sensory evaluation after air-drying and ripening. In total 63 volatile components were detected in the samples by headspace-solid phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and 45 known volatile components were detected by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). Benzaldehyde, decyl aldehyde, ethyl acetate, ethyl octanoate, ethyl phenylacetate, ethyl nonanoate and isoamyl acetate were found to be the major typical flavor components in the sausages with brandy. The flavor and overall acceptability of the sausage with complete replacement of baijiu by brandy were best. The TBARS value and TVB-N value were 0.92 mg/kg and 7.15 mg/100 g, respectively, which were significantly lower than those of the control and liquor groups (P < 0.05). In addition, the formation of histamine, tryptamine and 2-phenylethylamine was controlled during the ripening process, and the effect was significantly better than that in the control and liquor groups (P < 0.05). However, the inhibitory effects of baijiu and brandy on the formation of total biogenic amines were not significantly different (P < 0.05). Overall, mulberry brandy imparts a distinct flavor to air-dried sausage, inhibits oxidative deterioration and accumulation of biogenic amines, and improves its quality.