Improving the rheological properties of low-fat Iranian UF-Feta cheese by incorporation of whey protein concentrate and enzymatic treatment of transglutaminase

Ultrafiltered Feta Cheese has the highest per capita consumption amongst cheese varieties in Iran; however, there is mounting concern about the adverse health effects associated with high fat content of such products. On the other hand, fat reduction in cheese is usually accompanied by loss of rheological quality. The present research was thus aimed at improving the rheological properties of low-fat Iranian UF-Feta cheese by incorporation of whey protein concentrate (WPC) (0-16 per cent replacement of WPC
solution with retentate, V/V) and enzymatic treatment of transglutaminase (0-2 units/g protein). The results revealed that lowering the fat content adversely influenced the textural characteristics of UF-Feta cheese through increasing rheological parameters including fracture stress and Young’s, storage and loss moduli. Incorporating the whey protein into the cheese matrix significantly promoted the moisture to protein (M: P) ratio which in turn led to improving the rheological properties of low-fat Iranian UF-Feta
cheese. It was observed that enzymatic treating of the retentate particularly at the higher concentration of transglutaminase would result in cheese samples with firmer texture in terms of investigated rheological parameters. Response surface optimization showed that desired rheological properties for low-fat Iranian UF-Feta cheese were obtainable using 5.53% fat, 0.405 TG and 12.75 WPC. The low-fat Iranian UF-Feta
cheese with optimum formulation exhibited the rheological properties similar to full-fat control cheese (containing 16% fat) and had a more porous structure in comparison with low-fat control sample. Sensory evaluation revealed that the optimized sample was considerably more appreciated by consumers than its low-fat counterpart.