Production of quarg by ultrafiltration

Abstract

The increased protein concentration in UF concentrate caused some problems in achieving the desired pH for quarg making when yogurt and mixed lactic cultures were used. Yogurt culture could ferment concentrated milk to a lower pH than the mixed culture. With the increasing concentration during UF, levels of total ash, calcium and phosphorus in the concentrate increased, but these increases were much lower at pH 4.6. Quarg obtained from UF concentrated sour milk was rated close to conventional quarg and had no bitter taste. A high heat treatment of milk before lactic fermentation and subsequent UF concentration resulted in a quarg with a smoother texture. Diafiltration of UF concentrated milk did not result in significant elimination of excessive calcium. The quality of the quarg was also poor with respect to taste, body and texture. Thus diafiltration would be of little use in quarg making.