Alternative sweetening of yoghurt

The influence of different sweeteners on the quality of yoghurt was studied using a sucrose sweetened yoghurt as the reference. The alternative sweeteners used were xylitol, sorbitol, fructose, cyclamate and saccharin. The sweeteners were added to the yoghurt either prior to or after incubation. The influence of xylitol and sorbitol were studied more closely by investigating their growth retarding effects on the yoghurt culture. The quality of the yoghurt varieties was evaluated by pH, titratable acidity, viscosity, microbiological quality, sensory properties and storage stability.
All the sweeteners used were suitable for sweetening of yoghurt after incubation. However, saccharin could be used only when mixed with xylitol to cover its disturbing bitter aftertaste when used alone.
Sweetening with sorbitol prior to incubation was problematic. To obtain a suitable sweetness of the yoghurt 15% of sorbitol had to be added. This amount retarded the growth of the yoghurt culture so greatly that no acid, aroma or coagulation was formed in the product. Even a concentration 7% made the yoghurt significantly different from the normal yoghurt. The sweetness of yoghurt prepared with less than 7% of sorbitol is very slight. Consequently, sorbitol is not suitable for use as the only sweetener in pre-sweetened yoghurt. However, its use was possible in combination with sucrose. Xylitol proved to be a good yoghurt sweetener for pre-incubation sweetening, in spite of a slight retarding effect on the growth of the bacteria. At 8% concentration, which was the most preferred, the retarding effect of xylitol was negligible.