The Effect of Lipids on Recognition Thresholds and Intensity Ratings of the Five Basic Tastes

In addition to the contribution of lipids to food texture and aroma, the effect of lipids on taste perception is now commonly studied. It has been found that lipids may affect taste perception through lipid composition (i.e., cis-polyunsaturated fatty acids). This study assessed the effect of lipid composition on the recognition thresholds of the basic tastes (i.e., sour, umami, bitter, salty, sweet) in emulsion model systems as well as taste intensities perceived at low suprathreshold concentrations. Taste thresholds and intensities in corresponding aqueous systems were determined for comparison. To evaluate the effect of lipid chemical composition on tastant detection, 20% oil emulsions were formulated with either anhydrous milk fat, soybean oil, or a blend comprised of a 1:1 ratio (by weight) of milk fat and soybean oil. Prior to taste testing, emulsions were deemed to have the necessary physicochemical characteristics (i.e., stability, pH, droplet size, viscosity) for use in taste experiments. Thresholds were determined according to the ASTM forced-choice ascending concentration series method using 11 trained panelists. Taste intensities were rated on a numerical scale of zero to 15 by 10 trained panelists. As expected, aqueous thresholds were generally lower than those of respective emulsions; however, these differences were not always found to be significant. Though lipid composition affected emulsion thresholds slightly for all tastes except bitter, a significant relationship between thresholds and fat composition was not established. Taste intensity appears to increase proportionally to increases in tastant concentration at suprathreshold concentrations near recognition threshold. Some results from taste intensity experiments indicate that fatty acid composition may be influencing results, but the implications are unclear based upon these experiments. These results suggest that the role of lipids in taste perception is more complex than simply correlating with an increase in polyunsaturated fatty acids in general