Effect of Adding Different levels of Azanza grackeana Fruit Juice on the Chemical and Sensory Characteristics of Stirred Yoghurt

Abstract

This study was conducted in the Dairy Science and Technology Laboratory, College of Animal Production Science and Technology, Sudan University of Science and Technology, during 2022 to determine effect of different levels of Azanza juice on chemical and sensory properties of yoghurt. Cow's milk obtained from farm of College of Animal Production Science and Technology, Sudan University of Science and Technology. In this study four treatments were carried out. Four liters of milk were pasteurized at 80°C for 1 hour , then cooled to 40°C, the starter culture (Streptococcus thermophilus, Lactobacillus delbrueckii ssp.bulgricus) was added at the rate of 2%, then incubated at 45°C until coagulation occurred, then the yoghurt was divided into four equal portions , the first treatment was control without Azanza fruit juice while in the second, third and fourth treatment Azanza juice(Azanza juice at a concentration of 60%.) was added at the rate of 10%, %15 and % 20, respectively. All the treatments were subjected to chemical analysis (fat, protein, total solids, ash, acidity) and sensory evaluation (colour, flavour, taste, texture and general appearance). Then the obtained results were subjected to statistical analysis ANOVA using the least significant difference (LSD) test to find out the difference among the treatments. The results showed a significant difference in the percentage of ash and total solids, and there were no significant differences in the percentage of fat, protein and acidity. The highest percentage of total solids and ash were in the fourth treatment, which contains 20% Azanza juice.The results showed that there were high significant difference in color, flavour, texture and taste for sensory evaluation, while there was no significant difference for the general appearance. It was concluded from the study that Azanza juice had an effect on the chemical and sensory properties of yogurt.