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Keywords:

  • fat structure;
  • fat substitute;
  • ice cream;
  • oleogel;
  • rice bran wax

Abstract

The development of structure in ice cream, characterized by its smooth texture and resistance to collapse during melting, depends, in part, on the presence of solid fat during the whipping and freezing steps. The objective of this study was to investigate the potential application of 10% rice bran wax (RBW) oleogel, comprised 90% high-oleic sunflower oil and 10% RBW, to replace solid fat in ice cream. A commercial blend of 80% saturated mono- and diglycerides and 20% polysorbate 80 was used as the emulsifier. Standard ice cream measurements, cryo-scanning electron microscopy (cryo-SEM), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) were used to evaluate the formation of structure in ice cream. RBW oleogel produced higher levels of overrun when compared to a liquid oil ice cream sample, creating a lighter sample with good texture and appearance. However, those results were not associated with higher meltdown resistance. Microscopy revealed larger aggregation of RBW oleogel fat droplets at the air cell interface and distortion of the shape of air cells and fat droplets. Although the RBW oleogel did not develop sufficient structure in ice cream to maintain shape during meltdown when a mono- and diglycerides and polysorbate 80 blend was used as the emulsifier, micro- and ultrastructure investigations suggested that RBW oleogel did induce formation of a fat globule network in ice cream, suggesting that further optimization could lead to an alternative to saturated fat sources for ice cream applications.

Practical Application

The objective of this study was to investigate the potential application of 10% rice bran wax (RBW) oleogel, comprised 90% high-oleic sunflower oil (HOSO) and 10% RBW, to replace solid fat in ice cream. This would provide ice cream manufacturers with an alternative to solid fat sources, which could expand the potential for fat source selection beyond either natural saturated fats or hydrogenated oils, and reduce saturated fat intake for consumers. It was found that RBW oleogels created better structure than HOSO alone but not as good as milk fat. Further optimization of the oleogel manufacture and mix composition may improve product structure.