This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from the USDA’s rich science and research portfolio.
Food chemistry is the study of the chemical processes and interactions that happen within our foods. By examining different components like water, starches and fats found in foods, we can learn how to enhance or prevent different natural and unnatural chemical reactions from happening in our food.
For instance, food chemistry helps us understand natural processes like the fermentation that turns milk protein into yogurt or the use of different freezing speeds to preserve color and flavor in vegetables. Carbohydrates, fats and proteins are some of the main food components studied by food chemists, but we also examine the water, vitamins, minerals, additives, flavors, colors and enzymes, found in foods.
A lot of the work we do at the National Science Laboratory (NSL), a part of USDA’s Agricultural Marketing Service (AMS), involves checking the quality of food products to make sure certain specifications are met. As with many areas of science and research though, each of our food chemists bring their own perspectives to the field of food chemistry.
“I personally find the samples with human impact most interesting,” says Lauren Shoemaker, a molecular biologist/chemist. “For instance, we began testing milk products for melamine and cyanuric acid after several deaths were associated with these chemicals.” These tests were added to the analysis of fat, salt, protein, moisture, mineral and vitamin content already being conducted by the lab.
Examining the water content and its influence on the quality of food is also a key piece of the work done by food chemists. Our food is made up of mostly water—with meats being about 50% water and some fruits and vegetables being made up of 95% water.
“It is water that supports the growth of micro-organisms,” says Dr. Kouassi Dje, lead chemist. “Water is also the solvent for other biochemical reactions that influence spoilage in foods, and the level of water in any food affects its long term stability. Efforts to preserve food products are driven by the control of water through drying, freezing, or manipulating water activity with preservatives.”
By determining the moisture content of food, our food chemists can look at the wholesomeness of products throughout their shelf life, and can make sure U.S. companies meet the regulatory requirements needed to market foods domestically and internationally.
“We strive to provide our customers—the U.S. Military, the American public and international customers—with the most accurate information and food testing,” says Jonathan Barber, Chemist in Charge at NSL. “We take pride in delivering quality test information to our customers and our role in ensuring the quality of foods we eat.”
