Cryoprotective effect of low-sweetness additives on protein denaturation of threadfin bream surimi (Nemipterusspp.) during frozen storage

摘要

The cryoprotective effects of lactitol, maltodextrin, palatinit, polydextrose, trehalose on the protein denaturation of threadfin bream surimi during six months of frozen storage were investigated. The characteristics analyzed were Ca2þ-ATPase activity, protein solubility, sulfhydryl (SH) content, electrophoresis, surface morphology, and thermal stability. The effectiveness of all cryoprotectants generally decreased as the storage time increased. Polydextrose was able to maintain Ca2þ-ATPase activity, protein solubility, and SH content of 33.5%, 71.3%, 71.8%, respectively. Sucrose was able to maintain Ca2þ-ATPase activity, protein solubility, and SH content of 32.4%, 68.1%, 75.6%, respectively. Electrophoresis showed that the myosin heavy chain (MHC) and actin band intensity almost disappeared by the end of storage. Analysis by scanning electron microscopy (SEM) demonstrated that the number of pores formed increased after storage. Thermal stability analysis showed a decrease in myosin but no significant change in actin content. This study suggests that polydextrose as a cryoprotectant is able to maintain protein from denaturation as the same as sucrose.