New Procedure Analyzes Fat Structures in Foods

By Linda McGraw
July 5, 2000

A new analytical technique developed by Agricultural Research Service scientists simplifies the complex, time-consuming task of predicting how certain fats will change during processing and storage. This could lead to margarines, shortenings and cooking oils with good taste and a longer shelf life--good news for consumers and food manufacturers alike.

Food manufacturers have to determine how certain fats, called triglycerides, will act in food formulations and during storage. That's because these fats play a key role in flavor and texture. Now, costly trial-and-error analytical procedures for triglycerides can take months.

As an alternative, ARS chemist William E. Neff and Florida-Atlantic University researcher W. Craig Byrdwell, formerly with ARS, developed an analytical technique to help food manufacturers shave months off product development. The two researchers worked together at ARS' National Center for Agricultural Utilization Research in Peoria, Ill.

The new technique is a scientific mouthful--reversed-phase high-performance liquid chromatography (HPLC)/atmospheric pressure chemical ionization (APCI) with mass spectrometry (MS). It sounds complicated, but HPLC/APCI-MS actually simplifies identifying triglycerides.

Seed oils--canola, corn, soybean and sunflower--are a complex mixture of triglycerides. Mass spectrometry helps the researchers identify each individual triglyceride. APCI-mass spectrometry breaks fat molecules into a few large pieces. The researchers can see intact triglycerides before they break down to form negative byproducts during storage or high- temperature frying. The technique is especially helpful for evaluating sunflower and soybean oils, which have no standard reference for their chemical composition.

Using the new technique, the scientists identified 35 to more than 100 triglycerides in just two hours. The technique also correlate triglyceride composition with the physical properties it imparts to food: melting range, mouth-feel and reaction to refrigeration. This should be good news for food manufacturers and to consumers in their quest for healthful, better-tasting foods.

ARS is USDA's chief scientific research agency.

Scientific contact: Gary R. List, Food Quality and Safety Research, ARS National Center for Agricultural Utilization Research, Peoria, Ill.; (309) 681-6388, fax (309) 681-6679, listgr@mail.ncaur.usda.gov.