Improving the quality of Ras-type cheese made from recombined milk containing high levels of total solids

Abstract

Ras type cheese was made from recombined milk (RM) containing normal (12·5%) or high levels of Total Solids (TS) (25%, 32% or 40%) using fresh or recombined cream. Cheese curds obtained from RM containing high TS levels were moulded directly or after washing with warm water (50°C) for 10 min before moulding. The cheeses were matured at 7°C or 15°C. Cheese made from fresh milk was better in flavour and consistency than any of the cheeses made from RM. Use of RM in which fresh cream was used gave cheeses of better quality than those made from RM containing recombined cream. Washing the curd made from all RMs resulted in cheeses with better flavour and body characteristics than those made from unwashed curd. Cheese made from RM containing 25% TS with or without washing of the curds was of better quality than those made from RM containing 32% or 40% TS. The changes of nitrogenous fractions, degradation of α sI- and β-caseins, accumulation of free amino acids and the formation of free fatty acids were reduced as the level of TS in RM was increased. All cheeses made from washed RM curd showed greater proteolysis and lipolysis compared with those made from unwashed curd. Storage of RM cheese at 15°C accelerated its ripening and improved cheese quality compared with ripening at 7°C.