Natural ingredients are in and artificial ones are out, but how natural are some and how artificial are others? Regulations make this question even more complex. Life is complicated, and we look for shortcuts. We are particularly risk averse, but it takes time to adequately assess risk. In How Risky is it Really, David Ropeik explores many of the terms that we use as shortcuts to connote wholesomeness and safety. Unfortunately, these buzzwords are not always accurate or helpful. “Natural” is one of those terms Ropeik mentions that can give us a false sense of security. In this day and age, both Big Food and food pundits have so badly misused the term that it has become almost meaningless. Artificial is also a misleading term as most “artificial” additives or ingredients are either derived from natural sources or are synthesized in a laboratory to reproduce chemicals found in nature. This post will provide some perspective on why those differences may not be as stark as portrayed by the advertisement of a new food product or the author of the latest avoid-processed-food book on the shelves.
My introduction to food flavor and to scientific research came in my Senior year as an undergraduate due to a course conflict. Two courses that I needed to graduate, Food Biochemistry and one that escapes my memory, were taught at the same time. My Food Bochemistry professor allowed me to write a research paper on some aspect of biochemical reacitons in foods. I chose the topic of the biogenesis of fresh fruit flavor. It was fascinating. Instead of viewing fresh fruits as merely healthy, delicious foods to eat, I started thinking of them as specialized plant tissues that were active reaction vessels. I was primarily interested in the volatile (capable of evaporating and creating distinct odors) compounds which contributed to the characteristic odor of a particular type of fruit. Many major changes were occurring as a fruit ripened such as a change in color, softening and accumulation of sugar.
Natural fresh-fruit flavors are a miracle of biochemistry. Large flavorless molecules are being turned into smaller, volatile chemicals through biochemical pathways. Very specific enzymes are responsible for converting one molecule in the pathway to the next molecule. The molecules at the end of a pathway start to accumulate at the same time many other reactions in that fruit induce other profound changes in the attached organ such as softening and developing a desirable color. As the fruit becomes riper, molecules at the end of the pathway contribute to the overall impression associated with being an apple, grape, papaya, tomato or any other enticing fruit. Molecules accumulate within each pathway and at its end gradually become too predominant signaling that the fruit is becoming over-ripe with a less desirable flavor. Years later I learned through the research of one of my graduate students that there are distinct differences in how individuals perceive the flavor of fresh fruit. For some consumers it is all about the distinct aroma of a specific fruit like a peach or a mango. For others, it’s all about the sugar—the sweeter the better.1
Anytime a food is prepared by mixing ingredients, whether in a food processing plant, at a restaurant or in the home, flavor molecules are combined and new flavors are generated. Different criteria are used in determining whether such flavor ingredients are natural or not natural. One set of criteria is that any flavor “out of its natural environment” cannot be considered natural. Using this statement as our guide only fresh, whole foods or those cut up without further modification would qualify. Unexplained is that the act of extraction, a common food process, can remove aromatic chemicals from a plant part such as a vanilla bean and still be considered a natural flavor. In a restaurant or home kitchen, recipes call for a combination of several ingredients. When making a processed food, formulations also call for the combination of several ingredients. Recipes and formulations are prepared by humans to create new flavors which may or may not be considered natural.
Food processors put raw materials (e.g. whole foods) through a series of steps that change the flavor of foods, particularly when heat is involved. Heating speeds up chemical reactions within a food to create new flavor molecules*. Some of these changes can be beneficial; others, detrimental. For example, even before adding any cinnamon or sugar a baked apple does not have the same flavor as a raw apple. Likewise, a medium rare steak is very different in flavor than one that is well done. The loss of water during drying of a food breaks down cells within a whole food, bringing together molecules that can react to form new flavor sensations. Similarly, macerating a whole food brings together flavor compounds that Mother Nature never intended. One of the most-gentle processes is freezing, which helps maintain the natural flavors in a whole food as long as the natural enzymes are controlled during and after the process. Dramatic changes in flavor occur in the presence of microbes. The flavor of yogurt is not the same as that of milk; kimchi as its raw ingredients; wine as grapes etc. Off-flavors can develop in processed foods due to oxidation such as in rancid fish or nuts.
There is no such thing as natural cooking. When we cook a food, we are clearly taking it “out of its natural environment.” Humans are the only animals who have developed the skills to use technology to modify its food supply. The discovery of Fire changed the food experience for humans and may be as fundamental to our existence as language and agriculture. Cooking is a form of home-food processing. Other food processing done in the home include drying, putting it into a blender, freezing, and wine-making. Yes, Jane Goodall pointed out that other primates can use tools, but the technology from fire to modern kitchen appliances available to humans is not comparable.
Analytical chemists working in the food industry search for compounds that convey a specific flavor. They do this by isolating and identifying specific chemicals that are tied to specific taste or aroma sensations. As mentioned earlier in this post, fresh fruits are loaded with many molecules which contribute to flavor. Some of these molecules are called character-impact compounds such as isoamyl acetate, the chemical a fresh banana uses to tell us it is ripe. Other molecules can either modify, enhance or mute the impact of ones that predominate. To contribute to taste such as sweet or sour, the compound must be able to react with the taste-buds. To contribute to aroma the chemical must be volatile.
Food chemists can use processing techniques such as solvent extraction, separation and concentration to capture the essence of a natural flavor, but “out of its natural environment.” They can also synthesize “nature-identical” molecules in the laboratory that are less likely to contain contaminants than the natural extracts. It is not always clear whether a natural flavor is safer than a synthetic (artificial) one, but it sure sounds less risky when promoted in diet books or television commercials. Particular criticism is brought against “artificial” sweeteners and monosodium glutamate (MSG). The dangers to health of overconsumption of sugar and salt are well known, although current popular warnings may be overblown. Alternative sweeteners are being used to reduce sugar consumption in food products. MSG is an ingredient added to restaurant foods that do not require an ingredient statement to reduce salt content without compromising flavor.
Summing up and a new year’s resolution
Flavor is complex—much more complex than many writers would have us believe! The line between natural and artificial flavors is not as clear as many of us would like it to be. Unless a flavor is present in a food in the chemical form it is found in nature, I do not consider it to be a natural flavor. Flavors from accidental fermentations of whole foods would be considered natural if I were dictator but not flavors in fermentations controlled by humans in any way. The use of the term, “natural flavors” by governmental regulations makes little sense to me. Any use of technology from fire to extraction to temperature control takes us into the land of processing, and processing of food is what makes us and what we eat human.
Finally, when I wrote my book In Defense of Processed Food, I was looking for a term to describe writers who encouraged us to avoid processed food despite a lack of formal training in food science or nutrition. I chose the term food pundit. The term was probably overused in the book and used too pejoratively. I have refrained from its use, for the most part, on this blogsite. I have now discovered a new term that is being used and more accurately describes what I have been trying to convey–food evangelist.** Food eVangelists are members of “a powerful global group who want to impact the way a food is raised, packaged, sold and are committed to sharing their opinions with others.” I respect the right of these food evangelists to proclaim their beliefs, some of which I share, but I reserve my right to criticize those beliefs I reject.
1 Malundo, T.M.M. 1996. Application of the quality enhancement approach to mango (Mangifera indica L.) flavor research. Ph.D. dissertation, University of Georgia, Athens GA.
* As explained in an earlier post this month, “Note that I use the terms chemical, compound and molecule interchangeably throughout this post. Although there are distinctions between the three terms in chemistry, in the popular food literature chemical usually has a negative connotation, molecule a positive one and compound more neutral.”
Next week: Bejeweled watches and non-GMO labels