The effects of trehalose synergy with NaCl on the textural, water distribution, and microstructure of snakehead fish filets induced by freeze–thaw cycles

Abstract

In this study, we investigated the effect of trehalose in concert with NaCl on the flesh of snakehead fish that had undergone freeze-thaw cycles. Four groups of treatments were compared in this study, including distilled water, 3% NaCl, antifreeze (4% wt/vol) with 3% NaCl, and 4% trehalose (wt/vol) with 3% (wt/vol) NaCl. The results showed that the addition of 4% trehalose (wt/vol) with 3% (wt/vol) NaCl reduced the cracks between muscle fibers and the pores on muscle fiber bundles caused by freeze-thaw cycles during frozen storage of snakehead fish, thus reducing mechanical damage to the fish tissue structure. Moreover, the treatment was able to reduce the thawing loss of snakehead fillets, reduce cooking loss, and help maintain the color of the fish. Further, 4% trehalose (wt/vol) + 3% (wt/vol) NaCl (T) could slow down the reduction of hardness, elasticity, and chewiness of fish fillets during frozen storage. This study provides a theoretical basis for reducing the freeze-thaw cycle on the quality changes of snakehead fish during transportation and marketing.freeze-thaw cycles, microstructure, myofibrillar protein content, snakehead fish, trehalose, water-holding capacity | INTRODUCTIONSnakehead (Channa argus) is an important freshwater fish in China with a wide market due to its adaptability, fast growth, high protein, and low-fat characteristics (Cao et al., 2020;Song, Munian, Abd Rashid, & Bhassu, 2013). Currently, snakehead fish are mainly processed and marketed as fresh fish. With the improvement in living standards, frozen snakehead filets have become a high-quality choice for prepared foods due to their tender meat and high protein content (Hongmanee, Wongmaneeprateep, Boonyoung, & Yuangsoi, 2022;Sinh, Navy, & Pomeroy, 2014). Temperature fluctuations during frozen storage and distribution can lead to repeated freezing and thawing of frozen filets (Ali et al., 2015), a process that inevitably results in damage to the tissue structure of the fish, which in turn reduces the water-holding capacity (WHC) of the product and affects its quality (Zhang, Li, Diao, Kong, & Xia, 2017). To suppress the effect of temperature fluctuations on the quality of frozen fish fillet products, in addition to controlling temperature changes during frozen storage, products can be added with cryoprotectants (Nikoo, Benjakul, & Rahmanifarah, 2016;Tan, Ding, Yang, & Xie, 2022). It has been shown that salting can promote the recovery of tuna meat microstructure and optimized salting can achieve enhanced WHC, high yield, and good freezing stability .Carbohydrates have also been widely used as cryoprotectants, including cellobiose (Tan et al., 2022), kappa-carrageenan oligosaccha-