Studies on Alum as Milk Coagulating Agent in the Manufacture of Paneer – An Indian Cottage Cheese

Abstract

Alum is a white crystalline double sulphate of aluminum and potassium that is commonly used as an astringent. Utilising its protein binding property, alum was studied as coagulating agent of milk in the preparation of paneer. Paneer is a soft variety of cottage cheese very popular in Indian sub-continent, used in various culinary dishes. Its preparation essentially involves acid coagulation of hot milk and pressing of the hot coagulum to form a compact block which is then cooled by immersing in chilled water. Citric acid and vinegar are commonly used as coagulating agents of milk during paneer manufacture. However, when alum was used as a coagulating agent, it was observed that most of the proteins were amalgamated during coagulation process resulting in enhanced yield of paneer. It also resulted in reduced solids losses in whey. However, use of alum resulted in a slight astringency in paneer, hence it was recommended to be used in combination with common coagulant i.e. citric acid. The solids content (losses) in whey were 6.62, 6.08, and 6.32 %, respectively for citric acid, alum and citric acid + alum mixture used as coagulating agents. Similarly, the yields of paneer were 16.42, 19.04 and 16.99 %. The alum coagulated paneer looked glossy and attractive which was indicated by reflectance values of 83.75% as against 79% for control paneer sample. The paneer made by alum coagulation had slightly brittle texture.