Development of a freeze‐dried mixture of Nile tilapia (Oreochromis niloticus) croquette using a GA‐based multiobjective optimisation

BACKGROUND: The mechanically separated meat (MSM) of Nile tilapia is an example of a by‐product that can be used in the development of new foods. The aim of this study was to optimise the mixture of different flours in the development of a freeze‐dried mixture of fish croquette using Nile tilapia MSM. Flavour, texture and overall acceptance of seven formulations were evaluated by an acceptance test. A genetic algorithm (GA) with desirability functions was combined with a multiobjective optimisation of the response surface models. RESULTS: The combination of flours was chosen to minimise cost and maximise overall acceptance and fibre content. Overall acceptance showed a statistically significant correlation (P?0.05) with flavour (r = 0.67) and texture (r = 0.61). The GA‐based approach indicated that the highest overall acceptance was obtained when using wheat and rye flours in equal parts. This formulation had an overall acceptance of 7.52, a fibre content of 11.50 g kg^?1 and a cost of US$ 2.21/kg. After 24 h of freeze‐drying, the water activity of the mixture was 0.11. CONCLUSION: The GA‐based approach was able to optimise the croquette formulation. The freeze‐drying process contributed to the development of a value‐added product with high quality and long shelf‐life. © 2012 Society of Chemical Industry