Effects of reconstitution rate and hydration time on the yield of fresh cheese from reconstituted milk

Resumo

Powdered milk, due to its versatility, extended shelf life, and ease of transport, serves as a viable alternative for cheese production, especially in regions with limited access to fresh milk. However, the cheese yield from reconstituted milk may vary depending on factors such as the concentration of milk powder in the solution and the degree of casein hydration. This study aimed to evaluate the effects of reconstitution rate and hydration time of powdered milk on cheese yield. A 3 × 3 factorial design with three replicates per treatment was employed, testing reconstitution rates of 10%, 20%, and 30%, along with hydration times of 0, 1, and 2 hours. Cheeses were prepared by reconstituting whole milk powder in heated water, followed by the addition of calcium chloride and Ha-la^® chymosin. The mixture was incubated at 37 °C for coagulation, then the curd was cut and stirred, concluding with hot-water syneresis and moulding. The resulting cheeses were evaluated based on yield parameters, including weight yield, adjusted yield, protein losses in whey, and protein retention in cheese. Results showed that higher concentrations of milk powder significantly increased yield, rising from 17.5% at 10% concentration to 22.6% at 30%, whereas hydration time had no notable effect. This may be due to the rapid solubilization of casein or the possibility that hydration periods longer than 2 hours are necessary to influence protein interactions. Protein retention in cheese improved from 58.4% to 78.5%, while protein losses in whey decreased from 41.6% to 21.5% with increasing concentration. Production costs remained consistent across treatments; however, the 30% concentration yielded more cheese per batch, thus enhancing the cost–benefit ratio for processors. These findings support the use of reconstituted milk for cheese production in areas where fresh milk is scarce, offering a practical and economical option for the dairy industry. In conclusion, increasing the concentration of milk powder in reconstituted milk enhances cheese yield, while hydration time does not significantly influence these parameters.