Produce low-fat frozen dessert with dietary fibers and dairy proteins as fat replacers.

Ice cream, as a high-energy and tasty dessert, is enjoyed by young and old worldwide. Its basic classification is based upon its fat content. To answer consumer demands for healthier low-fat foods, the fat substitution approach using dietary fibers and proteins offers an appropriate solution.

Scientists at Australia's Victoria University wanted to assess the feasibility of producing low-fat frozen desserts with characteristics resembling full-fat ice cream. They used carbohydrate and protein-based fat replacers, which have potential health benefits, and found that producing low-fat frozen dessert appears feasible using a combination of dietary fibers. However, the manufacturing process may require modifications to improve certain technological characteristics.

The scientists prepared mixes using an ice cream formulation with 10% fat as a control and with fat subsequently replaced by up to 75% with combinations of barley beta-glucan-high polymer inulin or barley beta-glucan-whey protein isolate. The researchers measured the titratable acidity, pH, total solid, fat and protein content, whippability and rheological properties of the mixes.

The samples, frozen in a batch ice cream freezer, were analyzed for overrun, meltability and textural characteristics. An untrained panel evaluated samples for appearance, firmness, smoothness, mouthfeel and overall acceptance using a hedonic scale. All of the mixes contained more than 36% total solids, which satisfied local regulatory requirements. The fat and protein content depended on the level of fat substitution.

Fat replacement caused approximately a 30-fold decrease of apparent viscosity and up to a four orders of magnitude decline of storage modulus of the various dairy mixes, indicating that structural changes had taken place. Higher levels of the substitutes resulted in poor whippability and consequently lower overrun and short melting times in comparison to the control.

Sensory evaluation revealed that the samples supplemented with higher levels of whey protein scored significantly lower for several parameters than the control or carbohydrate-based substitutions. Surprisingly, we're told that the best accepted sample was a 75% fat-reduced frozen dessert produced with the beta-glucan-inulin combination.

The researchers are still elaborating all the aspects of the process but it is certain that many technological parameters are greatly affected by fat substitution. More recently, they used protein-based fat mimetics to improve the overrun and melting behavior of low-fat frozen dessert. This approach also required modifying the heat treatment and homogenization regime.

Further information. Todor Vasiljevic, Ph.D., Senior Lecturer, Department of Food Science and Technology, School of Molecular Sciences, Victoria University, P.O. Box 14428, Melbourne VIC 8001 Australia; phone: [phone]; fax: [phone]; email: [e-mail].