Effect of Heat Treatment on Milk Prepared for Cheese Making

Abstract

This study was conducted to evaluate the effect of heat treatments on milk based cheese manufacture. The milk was divided into four groups. Each group had 5litters However, group one (comparative group), had no subjected to any heat treatments, whereas, group two was pasteurized to 72oC for 15 sec, while group three was boiled to 100.17oC for 6 min. Group four was used reconstituted dry milk, the total solids as the same to natural milk. Cheese samples were subjected to physical, chemical, microbial and sensory evaluation analysis. The study showed that, group four occurred the highest yield 1300g, then boling1000g followed by pasteurized milk group 950g and the lowest raw milk group 680g. The analysis show that, coagulate time was 2hr and 30min for milk powder group, 1hr and 50min boiled milk , 1hr. and 40min pasteurized milk , and 1hr. and 15min raw milk respectively. The analysis showed that, the taste was 8.55 for milk powder, 7.60 for boiled, 6.60for pasteurized and 5.25for raw milk respectively. The texture was in acceptance score 8.40 for milk powder, 7.90 for boiled, 6.50 for pasteurized, 6.55 for untreated one respectively. Flavor score was an acceptance score 8.05 for dry milk, 7.15 for boiled, 6.90 for pasteurized and 5.80 for untreated one respectively. For chemical analysis we observed that the cheese from dry milk was the highest one in all chemical composition except Acidity than all type of cheese under study, on the other side cheese from boiling milk was the lowest one in all chemical parameters except Acidity it was the highest On the other hand untreated cheese had highest Total Viable Bacterial count TVBC; obesities the cheese making by treated milk with boiling had lowest Total Viable Bacterial count TVBC. The panelists preferred cheese based milk powder when compared with other different treatments finally the cheese mad by Dry milk was the best one.