Fast freezing, slow tempering: The key to tuna (Thunnus albacares) quality retention

Summary There is a debate on the optimal tempering rate for preserving the quality of aquatic muscle products. An adjustable and uniform tempering method is required to address this. Radio frequency (RF) heating, with its rapid and volumetric heating characteristics and adjustable tempering rate, has shown great potential in frozen food tempering. In this study, we utilised a developed improved RF heating method with controlled heating rates and uniformity to investigate the quality attributes of yellowfin tuna flesh samples subjected to two freezing rates (0.35 and 0.47 cm h −1 ) and three tempering rates (0.5, 1.0, and 1.5 °C min −1 ), respectively, to reveal the influence of freezing and tempering rates influence on tuna quality attributes. In the majority of treatment groups, the differences in drip loss, TBARS, TVB‐N, MetMb, colour, and protein solubility between the high‐speed freezing and slow‐thawing groups were minimal. It was found that fast freezing allows smaller‐scale ice crystal generation, which has the least influence on muscle fibre, and a low tempering rate could gently regulate the influence of ice crystal size on muscle structures.