Optimisation of low calorie mixed fruit jelly by response surface methodology

Response surface methodology (Box-Behnken design) was used to evaluate and model effects of three factors (sweetener, low methoxyl (LM) pectin and calcium content) at three levels each, on the overall acceptability of a tropical mixed fruit (pineapple, banana and passion fruit) jelly, determined by 100 consumers. Results showed that the model fit was significant (p = 0.014) and there was satisfactory correlation between actual and fitted values (R-2 = 0.940 and adjusted R-2 = 0.832). The model presented no significant lack of fit (p = 0.253). Calcium level had a significant effect on overall acceptability, but LM pectin and sweetener levels did not. The statistical model was used to optimise the factors' levels for highest acceptability, to obtain a jelly that provided less than 12 calories per serving, allowing the product to be labelled as "low calorie". (c) 2007 Elsevier Ltd. All rights reserved.