Studies on frozen yoghurt 3-effect of using high levels of fat with different inocula of starter

ABSTRACT

Two levels of fat contents along with 2 levels of starter were added to the mixture of frozen yoghurt as follows 7% fat + 3% starter culture, 7% fat + 5% starter culture, 10% fat + 3% starter culture and 10% fat + 5% starter culture. Increasing fat content and starter inocula during preparation of the frozen yoghurt resulted in increases in titratable acidity and total volatile fatty acids after one day and until 30 days of storage and decreases in pH values. Acetaldehyde and organic acids [propionic acetic lactic and formic] increased until 15 days and 60 days of storage, respectively. The increasing viscosity of the frozen yoghurt mix resulted from increasing the starter and fat content. The highest viscosity occurred in treatment. Viscosity has a clear effect on overrun, which increased with increasing fat content, but decreased with increasing the starter concentration. The meltdown was improved with increasing the starter concentration after one day of storage, and increasing the fat and starter levels. The increasing of fat content in the mixtures improved the meltdown of frozen yoghurt during storage