Isolation and Purification of Antifreeze Polysaccharides from Flammulina velutipes and Their Effect on the Quality of Frozen Beef

Antifreeze polysaccharides with ice recrystallization inhibiting activity were protective for quality preservation of frozen food. In order to investigate the effects of Flammulina velutipes antifreeze polysaccharides (FVAP) with ice recrystallization inhibitory activity on the quality of frozen beef, the heat hysteresis activity of FVAP polysaccharides after cold training was determined by DSC, and the optimal antifreeze activity was determined to be FVAP-1, and the composition of monosaccharides, molecular weight, and the effect of FVAP-1 on the color difference, thawing loss, cooking loss, moisture distribution, texture and microstructure and other indexes. The results showed that FVAP-1 was composed of 55.7% glucose, 21% mannose, 17.1% galactose, 0.9% fucose and 5.3% glucuronic acid, with a number-averaged relative molecular mass (Mn) of 3.73×105 Da, a weight-averaged relative molecular mass (Mw) of 5.90×105 Da and a peak relative molecular mass (Mp) of 1.68×105 Da. Its heat hysteresis activity was 0.47 ℃ and ice crystal content was 19.62%. The thawing loss (26.22%) and cooking loss (33.56%) of FVAP-1-treated beef were better than those of alginate (28.76%, 35.14%) in terms of protection after five freezes and thaws. Meanwhile, the TBARS value of FVAP-1-treated beef was 0.718 mg/kg, while the TBARS of alginose- and antifreeze-protein-treated beef were 0.766 and 0.741 mg/kg, respectively, with the strongest ability of FVAP-1 to inhibit fat oxidation. Afterwards, it was observed by scanning electron microscopy that myogenic fibers were more compact and structurally complete in FVAP-1treated beef. In summary, FVAP-1 could improve the water holding capacity of beef, the color, hardness and other properties of beef after freezing, providing a reference for the application of golden mushroom antifreeze polysaccharide as antifreeze agent.