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Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/5/2011 Publication Date: 10/27/2011 Citation: Hwang, H., Kim, S., Singh, M., Moser, J.K., Liu, S.X. 2012. Organogel formation of soybean oil with waxes. Journal of the American Oil Chemists' Society. 89:639-647. Interpretive Summary: The hydrogenation process is used to convert a liquid vegetable oil to a solid fat. The solid fat is used in oil-based food products such as margarine and spreads to have the desired texture. However, the solid fat consists of trans-fats and saturated fats that are known to have adverse effects on health. This research was conducted to find a way to give the similar texture of the food product without using the unhealthy solid fat. Seventeen plant wax samples from different suppliers were screened for their gelation ability towards soybean oil and found that several waxes are effective to make a gel with soybean oil. Sunflower wax showed the best results and could make a gel at the concentration as low as 0.5%. The firmness of the gel containing 1-6% sunflower wax in soybean oil was measured to be similar or greater than the gel containing 18-30% of hydrogenated soybean oil. The properties of the soybean oil gels were also studied to facilitate the utilization of this method in the food industry. This research showed that the small amount of a plant wax such as sunflower wax can be used in soybean oil to give a desired texture as a alternative to the hydrogenated oil containing trans-fats and saturated fats. Technical Abstract: Many waxes including plant waxes and animal waxes were evaluated for the gelation ability toward soybean oil (SBO) and compared with hydrogenated vegetable oils, petroleum waxes and commercial non-edible gelling agents to understand factors affecting the gelation ability of a gelator. Sunflower wax (SW) showed the best results and all SW samples from three different suppliers could make a gel with concentrations as low as 0.5 wt%. Candelilla wax and rice bran wax also showed good gelation properties, which, however, varied with different suppliers. Gelation ability of a wax is significantly dependant on its purity and detailed composition. A wax ester with longer alkyl chains has significantly better gelation ability toward SBO than that with shorter alkyl chains indicating that the chain length of a component in a wax such as wax ester is an important factor for gelation ability. The SW-SBO organogel showed increased melting point with increased SW content, showing the melting point range from about 47 to 65 °C with 0.5 to 10 wt% SW. The effects of cooling rate on crystal size and firmness of a gel were investigated. The dependence of firmness on cooling rate was so significant that the desired texture of an organogel could be achieved by controlling the cooling rate in addition to controlling the amount of gelling agent. This research reveals that a small amount of food grade plant waxes including sunflower wax may replace a large amount of the hardstock containing trans-fat or saturated fat. |
