The Role of Egg Whites and pH Increase on the Shelf Life and Viscosity of Chocolate Milk Drinks

Today, a variety of milk-based products are made with flavored beverages, because many people, especially children, are reluctant to consume unpasteurized milk. On the other hand, eggs are placed in higher degree than other sources of protein nutritionally, that they are added to most food products to increase their nutritional value as well as improve their functional properties. Therefore, in this study, Egg white protein and chocolate milk were used for making protein beverage. Microbiological count, sensory attributes and pH changes were investigated during 10 days of refrigerated storage. At the tenth day, the total numbers of bacteria were between 4.05- 5.77 (Log10 CFU/ml). It was concluded that when egg white amount increased, the number of bacteria significantly decreased. No coliforms, E-coli, salmonella, mold and yeast were observed. Also, pH levels increased to 8.3-8.7 and reduced acidic spoilage. Also, there was a direct relationship between increasing egg white amount and decreasing the amount of cocoa and sugar in increasing the viscosity and the viscosity values ​​of the samples with higher egg white content decreased  during storage time and samples with lower percentages of egg white increased.