الفهرس | Only 14 pages are availabe for public view |
Abstract The main objective of this study was to evaluate the effect of different heat treatments (thermization and pasteurization), natural whey culture and black cumin oil as a natural preservative on the physicochemical, textural, free amino acids, organic acids, volatile compounds, microbiological, and sensorial properties of Edam cheese during the ripening period. The study consists of three main parts. The first part aimed to evaluate the effect of raw, thermized (65°C/15sec), pasteurized (72°C/15sec) milk on the physicochemical, free fatty acids, volatile compound, textural, microbiological and sensory characteristics of Edam cheese ripened for 45days. Heat treatment had a significant effect on the physiochemical, proteolysis, volatile compounds and free fatty acids of experimental Edam cheese. The second part aimed to investigate the effect of different levels of Natural Whey Culture (NWC) (2, 3 and 4%) on the quality of Edam cheese made from heated milk (72 oC/15 sec.). The results showed that the titratable acidity, moisture, ash, WSN/TN, NPN/TN%, free amino acids and organic acids were significantly higher while protein and fat contents were lower in experimental cheese. Edam cheese with NWC showed higher values in textural evaluation. Overall, Edam cheese made with 4% NWC was higher in quality characteristics than that with starter culture and was similar to control cheese made of raw milk. The third part of this study aimed to evaluate the physicochemical, microbiological and sensorial characteristics of Edam cheese produced by three different concentrations of black cumin oil (0.2, 0.4 and 0.6%). Significant differences in physicochemical and ripening indices between treated cheese samples and control cheese were observed in all examined parameters. Incorporation of black cumin oil in Edam cheese reduced the total viable counts, Yeast & Molds at the end of ripening period and inhibited the growth of coliform groups. Panelists accepted the taste of Edam cheese with high concentration of black cumin oil (0.6%) with no complains on appearance and smell, while they favored the texture of Edam cheese with higher percentage of oil. Keywords: Edam cheese, heat treatments, natural whey culture, starter culture, Black cumin oil. |