Optimization of rheological properties of labane (concentrated yoghurt) produced by wheyless process using firefly algorithm

Production methods of concentrated yoghurt (labane) varied from traditional methods, which are tedious, such as separation of whey by fabric bags, to complicated methods. These raise demand to establish more suitable methods such as “wheyless process” by dried milk, concentrated milk protein or concentrated whey protein. So the influence of different ingredients such as milk protein concentrate (MPC), whey protein concentrates (WPC) and konjac gum (KG) on rheological properties of labane was investigated through mixture-process design methodology and optimized these properties by firefly algorithm. The results of the combination of back extrusion and texture profile analysis (TPA) indicated that increasing KG significantly increased hardness, adhesiveness and adhesiveness force especially for samples with high amount of CWP but increasing MPC and decreasing CWP decreased cohesiveness in samples with high amount of KG. Strain sweep test of the labane indicated that all sample had gel-like structure (weak gel) at 1 Hz and 20˚C. Rheological results also showed that increasing KG significantly increased G’LVE, G” LVE, γc, τy, τf and Gf especially for samples with high amount of CWP. The optimal results of different gum percentages to achieve maximum Hardness, Cohesiveness, G΄LVE, γc, τy, tan δ LVE, Gf and minimum Adhesiveness, Adhesiveness force, G˝LVE using the firefly algorithm in PC space, it has been shown that the optimum amounts of KG and MPC were close to each other and had more variance of the data which shows the similarity of the effect of these two component on the rheological parameters.