Create performance gels by adding canola oil.

The U.S. Army is developing high-carbohydrate, energy-enhancing, easily-consumed gel products. There is a desire to further fortify these ration items with lipids in order to increase their caloric density, but at the same time not compromise their texture and stability.

So Army scientists determined the effect of oil concentration on the rheological and various physical properties of the gels. Their research showed that performance gels can be formulated with up to 8% added oil with little effect on their flowability or syneresis.

The investigators determined the maximum feasible amount of oil that could be added to fortify the gels. The formulation for an orange-flavor gel that was thickened with konjac, gellan and xanthan gums was varied to develop samples containing up to 16% (by weight) added canola oil. The gels were analyzed using rotational viscometry at temperatures ranging from 30 C to 80 C. They were fitted to Bingham and power law flow models.

The researchers determined the effects of oil content on gel color and extent of syneresis. Furthermore, the effect of four weeks storage at 49 C on flow parameters was assessed. Multivariate regression was used to determine the significance of oil concentration and storage on gel properties.

Both initial yield stress and initial flow coefficient increased with increasing oil content. The gels also became less shear-thinning as oil content increased. Greater temperatures reduced the magnitudes of all rheological parameters. There was a significant interaction between oil concentration and temperature for the Bingham coefficient.

Storage did not significantly affect flow properties. Oil separation was minimal up to 8% of added oil, but noticeable beyond that concentration. Oil content had an insignificant effect on gel color.

Further information. A. H. Barrett, U.S. Army Natick Soldier Center, U.S. Army Research, Development and Engineering Command, Combat Feeding Innovative Science Team, Kansas Street, Building 36, Room E-108, Natick, MA 01760; phone: [phone]; URL: www.natick.army.mil.