MANUFACTURE OF SWEETENED FULL-FAT YOGHURT WITH DIFFER-ENT CALORIES CONTENT

The present study was carried out as an attempt to manufacture and study the properties of sweetened full-fat yoghurt with different calories content by using 9% sucrose (Sug), 0.015% sucralose (Suc), 5% prepared dates powder (DP) and whole cow's milk . Changes in pH values during fermentation period were followed. The resultant yoghurt was analyzed for chemical composition, some physical and sensory properties as well as the energy content for the fresh and stored yoghurt. The results showed that, treatments had insignificant effect on the activity of yoghurt starter culture. Sug and Suc had insignificant effect on the acidity and pH either in fresh or stored yoghurt, whereas the use of DP increased them significantly. No significant increase in acidity or decrease in pH values were recorded during storage period. TS, ash and carbohydrates contents were greatly affected due to adding 9% Sug and 5% DP, whereas fat and protein were not affected by the used additives, while due to storage period the effects were insignificant. Sug and DP treatments had the highest significant energy values (97.26 and 82.76 kcal/100 g in order), while Suc gave an opportunity to prepare sweetened low-calorie yoghurt with insignificant differences compared to the control. The significant increase in curd tension (CT) in Sug-yoghurt was accompanied by lower curd syneresis (CS) in most cases as compared with those of the control samples. Sensory properties were not significantly affected by treatments, but sucralose caused more smoothness and sweetness when compared with sucrose. DP-yoghurt had slightly brown colour which was colour for set yoghurt. In general, all samples were free from bitterness rejected by some panelists and accepted by others, who found it an accepted no, cooked and foreign flavours.