Optimization of the gelatinization conditions to improve the expansion and crispiness of fish crackers using RSM

Fish crackers were prepared by blending lean fish (Nemipterus japonicus) along with tapioca, corn and sago in the proportion 40:60 (cooked fish: starch) to optimize the gelatinization conditions in order to improve the expansion and crispiness using Response Surface Methodology (RSM). The process variables were steaming time (20, 40, 60 min), gel setting time (12, 18, 24 h) and drying temperature (40, 50, 60 °C). The responses taken were linear expansion, bulk density and crispiness. The average values ranged from 51.295 to 71.135% for linear expansion, 0.241-0.4 g/cm3; for bulk density and 2.710-9.011 N (hardness value) for crispiness of the products. The optimum condition predicted by RSM to have high linear expansion of products was at a steaming time of 40 min, a gel setting time of 24 h and a drying temperature of 40 °C. To have a maximum crispiness, the steaming time has to be increased as 60 min. This study enabled to optimize few important process conditions that are not examined earlier to improve the expansion and crispiness of the fish crackers.