Using HPMC to improve crust crispness in microwave-reheated battered mackerel nuggets: Water barrier effect of HPMC

Mackerel nuggets used in this study were coated with HPMC prior to battering or coated with batter containing HPMC in order to improve crust crispness through the formation of a thermal gel barrier preventing the diffusion of water from meat into the crust during microwave reheating. A physical properties assessment and sensory analysis showed that S- and SH-pattern products exhibited a firm and brittle texture, while W- and WC-pattern batters exhibited crispy crust texture. Water molecule diffusion from fish meat into the crust was inhibited during microwave reheating in HPMC-coated products. Nevertheless, a slight toughness was observed in HPMC-coated products still hot following microwave reheating. This may relate to the thermal gelation HPMC film adhering to the crust. Nonetheless, HPMCʹs ability to serve as a barrier to water diffusion effectively improved the crispness of HPMC-coated mackerel nuggets that had been reheated in a microwave in comparison with non-HPMC-coated nuggets.