Preconcentration of yoghurt base by ultrafiltration for reduction in acid whey generation during Greek yoghurt manufacturing

The feasibility of applying ultrafiltration (UF) to concentrate a yoghurt base prior to fermentation during Greek yoghurt manufacturing was studied as a way of minimising acid whey (AW) generation. Two Greek yoghurts were prepared by concentrating a milk base through UF to 13.8% and 17.5% (w/w) (GY-2, GY-3). Production of GY-3 resulted in zero AW discharge, while the GY-2 production discharged 78% lower AW compared to the control (GY-1). GY-2 exhibited a hard gel structure, low syneresis, maximum rheological properties and a high protein and fat content. Applying both, UF and straining, resulted yoghurts with required structural attributes while substantially reducing the generation of AW.