The science of food

Ribs on a grill, cold beer and chips. The perfect makings for a tailgate.

Yet that puffy bag of chips has a lot of science behind it. It’s a remarkable device to protect the chips from the major ways the chips can go bad. Manufacturers fill this plastic bag with chips, then inject it with dry nitrogen and seal it. Now the chips have crush resistance. Chips can go bad by absorbing water, but there’s no water to absorb, so it stays crispy. If there’s oil in the chips, it can go rancid. But the oil needs oxygen to go rancid, and there’s no oxygen. So the chips stay fresh.

This is the field of food science. Each food has its own unique food problem. And food scientists are responsible for designing ways to manufacture and preserve the quality and safety of those foods throughout its lifecycle.

Richard Ludescher, Ph.D., is a professor of food science with expertise in biophysics, protein chemistry, and optical luminescence at Rutgers University’s School of Environmental and Biological Sciences. He teaches food chemistry and physical chemistry.

Ludescher primarily practices optical spectroscopy. For parts of 2018 and 2019, he is on loan as a visiting scientist at the Department of Physics at the University of Oxford in England. His purpose is to learn how to identify food markers on the molecular level using single molecule optical spectroscopy.

Much of food science is dedicated to food safety and quality. Ludescher said food manufacturers hire Rutgers graduates to bring this information in-house. It’s not just about keeping the food safe but improving the quality and understanding the raw materials.

“Companies that want to be known as making the best cookies in the world will have an expert in flours, which are stored and shipped the right way,” Ludescher said. “That knowledge comes from food science.”

Ludescher’s research is more abstract. He studies fluorescence. Ludescher focuses on naturally occurring molecules in the food we eat that fluoresce, and are sensitive under optical spectroscopy to the physical and chemical properties that are relevant to food science.

“My research is based on when you have fluorescent molecules in solution, their fluorescence properties are often influenced by particular properties of the solution,” he said. “It tells you if they are sensitive to the pH, polarity, temperature, pressure or viscosity. This way you now have a sensor, a chemical that is sensitive to that property. You can now measure pH by a signal from that molecule.”

pH, polarity, temperature, pressure or viscosity all affect food quality and safety.

In his New Brunswick, New Jersey lab, Ludescher uses a HORIBA steady-state fluorescence fluorometer to measure this fluorescence.

pH is an important property for food. Manufacturers have to be careful how it changes in meat, for example, since the wrong pH can create undesirable products or properties. Ultimate pH, the pH measured 24 hours after slaughter, can determine the meat’s tenderness, according to studies published by the National Institutes of Health.

“That’s what I focus on,” Ludescher said. “We identify naturally occurring fluorescent molecules in food, that is, edible fluorescent molecules. We are identifying which of those molecules have a fluorescent property that can tell us about a physical or chemical state, which in turn can tell us about that property and safety.”

Ludescher is using fluorescing molecules as food sensors.

“We are identifying possible sensor molecules and characterizing them. No one else is doing this,” he said.

At Oxford University, he is learning how to measure fluorescence one molecule at a time.

“This is a technique has been around for 15 to 20 years, and has become extremely important in biomedicine and biophysics,” he said. “I have begun to apply the technique to food problems.”

Something food scientists do is develop new foods. Each one has problems that need to be solved. Questions arise, like how is it made? That’s just the beginning. The next step is figuring out how to manufacture it to be safe and keep it safe.

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