Trans fat content to appear on nutritional labels

STILLWATER, Okla.–The nutritional attributes of trans fatty acids has been the subject of concern among food scientist, nutritionists and consumers.

“Recent events have prompted the Food & Agricultural Products Center’s efforts to optimize methods for determining trans fat in foods and provide accurate nutritional labeling concerning fat types,” said Guadalupe Davila El-Rassi, analytical chemist for the FAPC.

A National Cattlemen’s Beef Association article, Nutrient Facts/Trans Fatty Acids, reported that there are two basic categories of trans fatty acids: "naturally occurring" and "man made." The main structural differences between these two categories are position and number of double bonds. These differences result in very different health effects.

The man-made trans fats are produced during partial hydrogenation of vegetable oils. Partial hydrogenation, a process that solidifies or semi-solidifies fatty acids, increases the shelf life and flavor stability of these fats. It also reconfigures some double bonds where the hydrogen is placed on a different side of the chain.

Low amounts of trans fatty acids occur naturally in animal products such as beef, lamb and dairy products, stated in the NCBA article.

The most prominent fatty acids are vaccenic acid (VA 18:1, trans 11) and two conjugated linolenic acids (18:2, cis 9-trans 11 and 18:2, trans 10-cis 12). Unlike the man-made trans fatty acids, conjugated linolenic acids appear to present beneficial health effects.

According to the article, Determination of Total Trans Fatty Acid in Food, trans fat, such as saturated fat, raises the serum level of low-density lipoprotein cholesterol, LDL-C or “bad” cholesterol, increasing the risk of developing coronary heart disease.

“As a result of these alarming findings of suspected adverse health effects of trans fatty acids, the food industry is trying to develop new hydrogenation techniques without the development of man-made trans fats,” El-Rassi said. “In addition, a requirement has emerged from the Food and Drug Administration’s trans fatty acid final rule, which will go into effect on Jan. 1, 2006.”

Silliker Inc., testing laboratories serving the food processing, retail, foodservice, pharmaceutical and cosmetic industries, reported that the changing of the Nutritional Fact panel is one of the requirements listed in the new trans fats FDA ruling.

The panel must specify the contents of trans fat in grams on a separate line below saturated fat. This requirement has emerged from the recent finding of the adverse health effects of trans fatty acids. Three examples for listing trans fats are:

• The nutritional facts panel for all food and dietary supplements, unless exempt, must include trans fat content on a separate line below saturated fat.
• Labels must declare trans fat content in grams, rounded to the nearest 0.5 gram below 5 grams and rounded to the nearest 1 gram above 5 grams. 
• Products containing less than 0.5 gram of total fat per serving and do not make fat, fatty acid or cholesterol claims are exempt from declaring trans fat on a separate line in the nutrition facts panel. However, products must include the statement, “Not a significant source of trans fat,” at the bottom of the nutrition facts panel.

The ability to identify and quantitate trans fatty acids has improved dramatically over the past decade. This has prompted the FDA to include trans fat as one of the core nutrients. Trans fats will be deemed misbranded if the nutrient content of composite samples exceeds 120 percent of the label value, according to Silliker.

“The FAPC is committed in providing entrepreneurs with dependable technical assistance in analytical chemistry,” El-Rassi said. “The FAPC has recently established a gas chromatography method to determine trans fatty acids in food products.”

The determination of trans fatty acids content is normally carried out by either infrared spectroscopy or capillary gas chromatography. The FAPC analyzes samples by gas chromatography because it offers better sensitivity and can separate the different trans fatty acids isomers present in polyunsaturated fats. This method could be applied to a wide array of sample matrices.

Fat extraction and methylation from processed food samples are performed according to the Official Method of Analysis of the Association of Official and Analytical Chemists. Most of the trans fatty acids consumed in American diets come from processed snacks such as chips, cookies, vegetable shortening and commercial baked goods as well as fried foods.

The methods involved include fat extraction, methylation and gas chromatography analysis. The procedure begins with food preparation. The prepared food samples are thawed and finely ground and homogenized in a Cuisinart mini-prep plus food processor. Thawed dough aliquots are then taken at different sample locations, and products are analyzed within 48 hours of homogenization.

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CONTACT:

Guadalupe Davila El-Rassi
Analytical Chemist
Robert M. Kerr Food & Agricultural Products Center
148 FAPC
Stillwater, OK 74078
Phone: 405-744-6071
Fax: 405-744-6313
E-Mail: guadalupe.davila_de_el_rassi@okstate.edu

Oklahoma State University, U.S. Department of Agriculture, State and Local Governments Cooperating. The Oklahoma Cooperative Extension Service offers its programs to all eligible persons regardless of race, color, national origin, religion, sex, age, disability, or status as a veteran, and is an equal opportunity employer.

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