Foods that haven't been processed at all don't last forever — think about fruits, vegetables and proteins such as chicken or eggs. Therefore, food manufacturers typically use monoglycerides and diglycerides to extend a product's shelf life, though monoglycerides occur naturally in some foods that contain plant or animal fats or oils. These additives serve as emulsifiers, which combine ingredients containing fat with those with water, which naturally repel each other. Made in part of fatty acids, mono- and diglycerides are similar to triglycerides, the predominant fat in food, according to the Harvard T.H. Chan School of Public Health, except they are classified as emulsifiers rather than lipids.
Read more: Advantages & Disadvantages of Food Additives
Foods Containing Mono- and Diglycerides
Monoglycerides and diglycerides in food are typically in those that are processed and packaged, some of which are the least healthy food products on the market. This includes baked goods, soft drinks, candy, gum, whipped cream, ice cream, margarine and shortening. In fact, a 2017 study published in the Journal of Experimental Food Chemistry noted that monoglycerides and diglycerides are around 70 percent of emulsifiers used in the U.S. food industry.
The Risk of Trans Fats
Trans fats have been associated with increased risk of numerous diseases, including heart disease, stroke and diabetes. They promote inflammation and obesity, raise LDL cholesterol levels and lower HDL cholesterol levels. Made up in part of fatty acids, mono- and diglycerides may contain trans fats, either when manufactured in a lab, or if they come from an animal or vegetable sources, when exposed to heat for processing into packaged and prepared foods.
FDA Labeling Laws
In 2006, the U.S. Food and Drug Administration began requiring that all food manufacturers list a food's trans fat content on the label. This law applies to lipids, like triglycerides, but not to emulsifiers like mono- and diglycerides. Therefore, even though mono- and diglycerides may contain trans-fatty acids, they do not fall under these labeling requirements. This means a food may be labeled as possessing "0 percent trans fat" yet still contain trans-fatty acids from mono- and diglycerides.
Other Additives in Food
Many different chemicals may be used in the process of manufacturing mono- and diglycerides that are still present in the final product. Among the most prevalent is hardened palm oil, or palm oil exposed to hydrogen and high temperatures, a process that forms trans fats. Other possible compounds added in the making of mono- and diglycerides include nickel, tartaric acid, synthetic lactic acid, ricinus fatty acids and sodium hydroxide, each of which may pose health risks. However, an insufficient number of studies have been done on the potential health dangers of these compounds.
Read more: List of Fully Hydrogenated Oils