Effect of acidification temperature and acid on the yield and quality of cheese produced from UF-concentrated whey

Unconcentrated and ultrafiltration (UF)-concentrated whey were used for cheese manufacture with lactic, citric or hydrochloric acid as acidification media. The effect of the acidification temperature combined with the concentration level and the type of acid on the process yield, the protein and solids retention as well as on the quality characteristics of the product was examined. Unconcentrated whey resulted in 3.8% cheese yield, 20.0% whey solids retention and 79.3% protein retention in the cheese. Whey concentrated to 5:1 and 20:1 resulted in 2.3% and 1.7% cheese yield, 12.2% and 8.2% solids retention and 57.0% and 37.7% protein retention, respectively. Both, the texture and the flavor of the products were negatively affected by the increase of the concentration level of the whey. Cheese produced from UF-concentrated whey had poor sensory characteristics not affected significantly by the type of acid. The acidification of the whey at the final stage of heating resulted in products with the most acceptable flavor. Lactic acid addition to unconcentrated whey resulted in lower product yield (2.8%) compared to citric and hydrochloric acid (4.8% and 3.8%, respectively), attributed to lower solids retention. However, UF-concentrated whey presented similar yields not depending on the acidification medium.