The research results are published in the September issue of the Journal of Agricultural and Food Chemistry and on the journal's Web site at http://pubs.acs.org/journals/jafcau/index.html.
"This study brings analytical chemistry, food science, nutritional sciences and consumer interest together," said Lisa Mauer, assistant professor of food science. "Consumers want the salad dressing brand they buy to taste the same every time. The same is true for special types of oils, which are more expensive than a general cooking oil. You expect what you buy to be high quality and contain what is on the label."
Consumers are concerned about purity because of taste, safety, health benefits and cost, she said. While oils that are less pure may be less expensive, they may lose the flavor or health benefits, and some can even be detrimental to health. In addition, consumer demand for food and food additives is increasingly for organic or 100 percent natural products.
Manufacturers of health supplements and drugs are concerned with purity because of quality control issues that impact safety of the substances and company economics.
To address these concerns, scientists search for fast, effective, inexpensive ways of differentiating between different ingredients - in this case dietary supplement oils.
Purdue researchers used infrared spectroscopy and statistical analysis to classify samples of 14 dietary supplement oils and five common food oils. The scientists profiled the chemical makeup of at least two different brands of each.