Optimization of strawberry-longan bar formulation using response surface methodology.
Optimization of a strawberry-longan bar was done using response surface methodology (RSM). Ten strawberry-longan bar formulations were formulated by mixing three basic ingredients: dried strawberry (25-35%), dried longan (25-35%) and mixed crisp; mixture of dried almond, dried cashew nut and dried banana (10-25%). All formulations contained 10% glucose syrup, 13% strawberry syrup and 2% sunflower oil. The sensory qualities (overall liking, appearance, flavor and texture), texture measurements (hardness and stickiness), moisture content, water activity and color parameters were evaluated. Parameter estimates were determined by performing regression analysis with no intercept option. Area within the response surface plots having predicted acceptability scores of at least 5.6 (on a 9-point hedonic scale) for appearance and texture were selected to derive a predicted optimum formulation range. The prediction models generated in this study were verified as adequate to predict the sensory and physical qualities of strawberry-longan bar. The selected optimal formulation of strawberry-longan bar consisted of 28% dried strawberry, 27% dried longan, 20% mixed crisp, 10% glucose syrup, 13% strawberry syrup and 2% sunflower oil.