Inulin, isomalt lead to yogurt ice cream alternative.

Yogurt ice cream offers sensory and physical properties that are similar to those of ice cream and yogurt. Yogurt adds a pleasing liveliness to ice cream and makes it very refreshing too.

The aim of Turkish scientists was to develop a yogurt ice cream with acceptable quality and sensory attributes using such additives as inulin, isomalt, polydextrose and synthetic sweeteners. Their effort could lead to a new dairy alternative to ice cream with improved functional properties.

The researchers examined the composition of various yogurt ice cream products--their total solid, fat, protein, ash and carbohydrate content, as well as their viscosity, acidity, overrun, melting rate, heat shock stability, lactic acid bacteria and total bacteria count. Using aspartame-acesulfame K, the researchers made two different yogurt ice creams at pH 4.8 and 5.2. They tested them using consumer preference and acceptance tests with 88 judges. The most preferred sample at pH 5.2 was used as the control sample in additional experiments.

The researchers then produced five samples. Sample A contained sugar and whole fat; sample B: sugar and reduced fat; sample C: 8% inulin, 5% isomalt and 5% polydextrose; sample D: 6.5% inulin, 6.5% isomalt and 5% polydextrose; and sample E: 5% inulin, 8% isomalt and 5% polydextrose. Samples C, D and E were sugar-free and reduced-fat products. The sugar was replaced with 0.065% of aspartame-acesulfame-K in those samples.

The viscosities of the five formulations were statistically different. The viscosity of the reduced-fat control sample was significantly lower than that of whole-fat control sample. The melting rate of B was greater than that of D, which was greater than that of E, which was greater than that of C, and which was greater than that of A.

The melting rate of the samples increased as the fat and total solid amounts decreased. Lactic acid bacteria counts were between 8.12 and 8.49 log values. A 43% reduction in energy value was obtained compared to the control sample. The sample containing 8% inulin (the highest) and 5% isomalt (the lowest) was the most successful diet product due to its melting characteristics and sensory properties, which made it somewhat similar to the control, we're told.

Further information. Prof. Dr. Dilek Boyacioglu, Department of Food Engineering, Istanbul Technical University, 34469 Maslak Istanbul, Turkey; phone/fax: +90 212 285 6039; email: boyaci@itu.edu.tr.