Meet the Curd Nerd - Dr. Michael Qian

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In this installment of "Meet the Curd Nerd," we talk to Dr. Michael Qian, Assistant Professor in the Food Science Department of Oregon State University. Dr. Qian's research interests are in flavor chemistry and technology, and he has done a lot of work with cheese as well as wine and fruits. He also served as a technical judge at this year's American Cheese Society Competition, held in July of this year in Portland, Oregon.

CN: Tell us a little about your background as a Food Technologist, and what originally sparked your interest in the field?

MQ: My background is in chemistry, and as a chemist most of my work is associated with analytical chemistry and food chemistry. Originally I was focused more on the general chemistry side, but after I came to the States in 1997, I began to study and work more in the area of food chemistry. I got my masters degree at the University of Illinois, Urbana-Champaign, and later on I began to work on a PhD at the University of Minnesota. I got interested in food chemistry because it's really kind of a unique area. There are a lot of people working in chemistry, but only a limited number working in food chemistry. Also I like studying food because it is something that's directly associated with daily life; it's something you can touch, something that's visible.

CN: What can chemistry tell us about the foods we eat?

MQ: Well actually a lot! If you look at food chemistry in general, you can think about the fact that when we are eating food, we are eating the actual chemical molecules. When you look at that way, on a small scale, you can begin to understand the chemical composition of the food, the nutrition, and the chemical changes that take place due to processing and storage. Those chemical changes can affect the food both positively and negatively. For flavor chemistry, it's again about the chemical composition, but the difference is that the concentrations are so small. A unique chemical in trace amounts (in the parts per million or parts per billion level) really can impact the aroma & flavor--the human sensory system is very, very sensitive. That's what I'm working on: to understand the contributions of those trace amounts of compounds to flavor and aroma; to understand their changes during preparation, processing, and storage. This area is very poorly understood.

CN: You've done lots of work with flavors and aromas in Parmigiano- Reggiano cheese. What drew you to this variety of cheese specifically, and what have been the fruits of your research?

MQ: I've been trying to understand Parmigiano-Reggiano cheese is because it's a good cheese, so powerful, so unique. It's a cheese that has very complex, very persistent flavor. Also, the technical approach provides the basics to understand other cheeses as well. In terms of Parmigiano-Reggiano, there are many, many compounds that contribute to the flavor. And all of those compounds probably interact with each other, to give it a complex flavor. In general cheese flavor is very complex, it's not one or two compounds; it's the interaction of a group of compounds. For example there are a lot of short-chain fatty acids in Parmesan, basically from the lipids from fats breaking down. Those short-chain fatty acids make a big contribution to the flavor. In addition, there's a very high concentration of esters, which gives it a very nice, fruity, apple/banana-type of flavor. Amino acids, which are from the proteins breaking down, also contribute to the savory flavor of cheese, but they don't contribute as much on the aroma side.

CN: You also do work with flavors and aromas in berries and wines; do you see any overlap between this research and your cheese research?

Esters, which are important contributors to the flavor of Parmesan cheese, are also present in wine, and are the primary compound in fruit (especially ripe fruit). But even though a lot of compounds are commmon to cheese & wine, the concentrations are different, and when you put different compounds together at different concentrations, they give a very different perception. In wine you also have alcohol and other kinds of compounds, which added together give you a totally different flavor than cheese. In terms of the actual research techniques, a lot of flavor isolation techniques are very similar, but they're also unique based on what types of compounds you are looking for.

CN: In your capacity as a judge in the ACS Cheese Competition, what qualities are you looking for in each cheese? What separates the award-winning cheese specimen from the runners-up?

MQ: The ACS competition was a wonderful experience for me, quite fun and interesting. We went through so many different kinds of cheeses. I was a technical judge and when we judge cheese quality, we are judging if there are any defects, any off-flavors, and whether the flavor and aroma fit into whatever the category happens to be. In addition, we are judging how unique the flavor is--that's typically the difference between the award-winners and the runners-up. They're all great cheeses, they're beautifully-made, but a lot of times I'm looking for the cheese that is unique, that has a complex, balanced flavor.

CN: How would one train oneself to taste cheese the way you might taste it?

MQ: That's very difficult, very hard. It takes a lot of training, learning from others. Someone describes something and you ask yourself, "Do I detect that flavor too?" It's a difficult process to describe. I typically smell it first, get a good whiff, and then I put a small chunk of cheese into my mouth and begin to taste it. Is it savory? Is it bitter? And then I evaluate the aroma again to see whether it has changed over time.

CN: What are your plans for future research? Where do you see the field of Food Science heading in the next 5, 10, 20 years?

MQ: Right now we are still working on Cheddar cheese, which is a very complex flavor system. Many people have been doing research in this area for many, many years, but nobody yet understands what are the key compounds for Cheddar cheese flavor. At this point we are focusing on the contribution of sulphur compounds, trying to understand how those flavor compounds change during the aging process, or what parameters will make for the most significant changes during aging. We are specifically studying the difference in the flavor development in pasteurized-milk cheese vs. heat-shocked cheese.

In terms of the future of academic Food Science, it always depends on funding. Right now federal funding has really switched to the health benefits, and flavor chemistry is kind of ignored. I see very little funding available at the federal level really supporting flavor research, unfortunately. That makes it very hard to predict at this point where the flavor research is going to go in the next 10 or 20 years. If you suddenly see the inflow of funding, then you will see a lot of progress. However, on the commodity side, there are a lot of industry groups who are really interested in flavor, as a quality concern. If the flavor of a product is not good, regardless of the nutritional benefits, the consumer may not buy it or eat it. So the commodity groups are really trying to understand and support this kind of research. They really want to understand flavor development and formation, and how to enhance the positive flavors and diminish the negative ones, because that translates directly to how well the product sells.

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