ANTIOXIDANT PROPERTIES OF PROCESS CHEESE SPREAD FORTIFIED WITH ACID CASEIN HYDROLYSATE

Acid casein hydrolysates were prepared by enzymatic hydrolysis using pepsin for 40 min with constant agitation.  The acid casein hydrolysate was added at different levels (0, 10, 20, 30, 40 and 50%) into process cheese spread blends made from young Cheddar cheese (15 days storage) just before processing. The chemical composition, radical scavenging activity, total free amino groups and sensory properties of the products were evaluated. The results showed that the radical scavenging activity of the resultant cheese increased with increasing the concentration of casein hydrolysate. Also, free amino groups were estimated in process cheese while fresh and during storage )20,40 and 60 days) at 7°C ± 1°C, the results were represented as the increase in optical densities (O. D).  The obtained O. D.  values increase with increase the concentration of casein hydrolysate. The O.D values increased to 0.976, 0.986, 1.023, 1.137, 1.164 and 1.203 after 60-day storage in the same order. Moreover, cheese preparations underwent sensory evaluation for appearance, aroma, taste, mouth feel, color, overall quality and total score. In general, no significant differences (P <0.05) were observed between control sample and treated samples with 10, 20 and 30% casein hydrolysate for total scores therefor, these samples can be grouped together. However, the cheese made with 40 and 50% casein hydrolysate received significantly (P < 0.05) lower scores and water phase separation was observed after 60 days storage with 50% treatment.