Optimization of incorporation of low-molecular-weight cryoprotectants into intact fish muscle

Chunks of freshwater trout muscle were immersed in sorbitol solutions (0% to 60%), under different vacuum conditions, for up to 30 min at 5 degrees C. Moisture loss, weight change, and sorbitol uptake were measured or calculated by mass balance, and cryoprotection during subsequent freezing and thawing was monitored as change in myosin Ca(2+) ATPase activity. Vacuum treatment had no effect on measured parameters. Initial sorbitol uptake and weight loss were greater at higher sorbitol concentrations, but adequate cryoprotection was achieved by all treatments when diffusion time following immersion was extended sufficiently. Injection of 60% sorbitol was faster in achieving desired levels of sorbitol in fish meat and induced excellent cryoprotection.