Non-crystal freezing storage assisted by alternating electric field on fresh yak meat quality

Abstract

Ice crystallization has been the main cause of the deterioration of frozen meat quality, because ice crystal expansion causes mechanical damage to the muscle tissue. Thus, in this study, an innovative non-crystal freezing (NCF) technology, which can achieve non-freezing at temperatures below the ice nucleation point (−4.5 °C for yak), was proposed, and corresponding equipment was designed to prolong the shelf life and increase the logistics distance of yak meat. The non-frozen stability and quality of yak meat with NCF were investigated and compared with those of traditional sub-frozen (−4.5 °C) and chilled (4 °C) yak meat. Results of thermal imaging and temperature curves indicate that ice nucleation and phase transition were observed in the −4.5 °C samples during 1–3 days, whereas the icing phenomenon was not found in the NCF samples during the entire 28-day storage period. The microstructure of the NCF samples was differed from that of the −4.5 °C samples, which avoided ice-induced freezing damage and maintained the original integrity. Compared with the −4.5 °C and 4 °C samples, the weight loss of the NCF samples was reduced by 5.33 %–6.94 % and 1.42 %–3.16 %, respectively. Microbial analysis and physicochemical results indicate that compared with 4 °C treatment, NCF extends the shelf life of yak meat by at least twice. NCF breaks down the line between chilling and freezing, combining advantages of low temperature and a non-freezing state, which makes the long-term storage and long-distance, cross-regional logistics of fresh yak meat possible.