Yield and Curd Characteristics of Cottage Cheese Made by the Culture and Direct-Acid-Set Methods1

Abstract

We compared yield and curd characteristics of cottage cheese made by the short-set culture and direct-acid-set methods using three skim milk protein concentrations. 3.1, 3.5 and 3.9 ± .1%. For each method of manufacture, approximately 380 kg of the same skim milk were set per experimental vat. Representative samples of whey, wash water and curd were analyzed and the total quantities of each were measured. Solids and protein recovered in whey, wash water and curd were related to yields for each method. The same curd samples also were used to measure curd size distribution, curd firmness and dressing retention. Analysis of variance showed highly significant differences in curd yield between the two methods when the three protein concentrations were considered. There was approximately 5% more yield when cottage cheese was made from skim milk containing 3.1 or 3.5% protein, using the direct-acid-set method. This yield advantage was less than 1% when the skim milk contained 3.9% protein. Curd firmness did not differ significantly between methods (p < .01). Curd from the 3.1% protein-skim milk, however. was firmer (p < .01) than that from either 3.5 or 3.9% protein-skim milk. Direct-acid-set curd was more uniform in size than that of the short-set culture curd. It retained dressing better only when made from 3.1% protein skim milk, and when 1.25 × the normal amount of dressing was used.