ARS | Publication request: Solid fat content as a substitute for total polar compounds analysis in edible oils

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2012
Publication Date: N/A

Interpretive Summary: In this research, we determined that solid fat content measurements are a good alternative to measurement of total polar compounds. One of the major problems with frying oils is that they degrade over time. It is essential to monitor the extent of this degradation so that the oil can be discarded at the appropriate time. There are a number of methods available to monitor the quality of frying oils, including total polar compounds analysis and triglyceride concentrations. One of the most widely used indicators, total polar compounds, has two main drawbacks: first, this method is very time consuming, and second, it involves the use of large quantities of laboratory solvents. In some settings, such as in a quality control or quality assurance environment, there may already be equipment available that measures solid fat content. Equipment that measures solid fat content is very user-friendly and measurements can be achieved in less than ten seconds. In this study, we demonstrated that solid fat content measurements are correlated with total polar compounds. We studied six different oils, including soybean oil, two grapeseed oils, walnut oil, sunflower oil, and canola oil. For five out of the six oils, the correlations between solid fat content and total polar compounds were statistically significant. This was also the case for correlations between solid fat content and triglyceride concentration. We have generated equations that can be used to convert solid fat content measurements to either total polar compounds or triglyceride concentrations. The rate of increase in solid fat content over time was also correlated with the oxidative stability of the oil. These findings are important because this provides a simpler method for monitoring the quality of frying oils.

Technical Abstract: The solid fat contents (SFC) of heated edible oil samples were measured and found to correlate positively with total polar compounds (TPC) and inversely with triglyceride concentration. Traditional methods for determination of total polar compounds require a laboratory setting and are time intensive. Therefore, SFC analysis represents a viable user-friendly alternative to measuring polar components in environments where low resolution NMR may already be in use, for example, in quality assurance environments. The slope of SFC measurements versus time was also found to correlate with the oxidative stability index of the edible oils studied.