Introducing Food Science

Robert L. Shewfelt, Alicia Orta-Ramirez, Andrew D. Clarke

• Publisher: CRC Press
• Year: 2015
• ISBN:
  9781498766647
• Edition: 2
• Topic: Medizin
• Subtopic: Ernährung, Diätetik & Bariatrie

Written as an introductory food science textbook that excites students and fosters learning, the first edition of Introducing Food Science broke new ground. With an easy-to-read format and innovative sections such as Looking Back, Remember This!, and Looking Ahead, it quickly became popular with students and professors alike. This newly r

Section IV

Scientific Principles

Chapter 11

Food Chemistry

As a Chemistry major, Ignacio was more interested in what toxic chemicals the microbes made than in the microbes themselves. He was also interested in all the chemicals that were added to foods, like preservatives, but he wasn’t so sure that he wanted all those chemicals in his mouth. While he was looking for an elective course online during open registration, he came across one called Food Chemistry. It sounded interesting, like it might be a course where he could apply his basic knowledge in chemistry to the real world. He took the course, loved it, and found out that he had much more to learn about the chemicals in his food. Much of what he learned changed his understanding of and appreciation for chemistry in everyday life.

Jennifer, by now a committed vegan, decided to major in Nutrition because she wanted to learn how to eat healthier. We can imagine her shock when she learned that nutrition is mainly about chemicals and how they act in the body. It really doesn’t have much to do with food at all. There was in-depth study of digestion and all the metabolic pathways that occur to food components once they are broken down, but healthy eating wasn’t exactly the main topic of discussion. When her professors talked about a vegetarian diet, they had some good things to say but also a lot of negative things. Mostly, they talked about chemicals. They talked about large chemical compounds like carbs (only they called them carbohydrates), fats (lipids), and proteins. She learned that vitamins are actually organic chemicals and that minerals are elements straight from the periodic table she had memorized (and quickly forgotten) in first-year chemistry. She wanted to know more about nutrients, but she wanted to know about the nutrients in the types of foods she ate regularly.

Kyle is a Food Science major and is learning more about all the chemicals in his foods. He learned about the toxins and preservatives Ignacio was into, as well as about the nutrients that Jennifer was studying. He was fascinated by the many other chemicals in foods and how they all work together to produce the quality of a food. He found out that foods are made of ingredients and ingredients are made of chemicals. Each ingredient has a function in the food, but it is actually the chemical components that give an ingredient its function. The more he learned about pigments and stabilizers, the more he wanted to learn about texturizers and humectants. He thought that the taste of a food was simple, but now he knows that flavor combines taste and aroma. He learned that tens and even hundreds of chemical compounds could be contributing to the aroma of foods. Upon completion of his degree, Kyle plans to go to graduate school to learn more about food chemistry and then to work in the food industry to develop new food products.

11.1 Looking Back

In previous chapters, we looked at general food issues, the types of food products we encounter in the marketplace, and the activities that food scientists perform. In this chapter, we focus on the most basic science we need to know as it relates to foods: chemistry.

The key points that follow were covered in previous chapters and will help prepare us for a basic understanding of the chemical aspects of foods:

• Waste prevention is critical in sustaining our planet, and it becomes more critical the later the waste occurs in the life cycle as the inputs accumulate at each point in the cycle.
• Molecular gastronomy has been developed in Europe to merge food science with the culinary arts to better understand the chemical and physical changes that food materials undergo during cooking processes.
• Stabilizers are added to formulated foods to keep them from breaking down.
• Individual fat replacers cannot perform all functions of lipids.
• A clean label is one that has only clearly recognizable ingredients, none of which sound like chemicals.
• The main function of a package is to preserve the physical and chemical integrity of a product including preventing microbial or chemical contamination.
• The Nutrition Facts part of the label indicates the serving size, how many servings per container, calories per serving, and the fat calories per serving.
• Nutraceuticals are foods specifically designed to act as drugs.
• Although not a true allergic reaction, celiac disease is an autoimmune disorder in which microvilli in the intestinal tract react with gliadin, a component of gluten found in wheat and other grains.
• Preservatives are food ingredients that slow spoilage and help prevent food-associated illnesses.

By now, it should be apparent that all foods are composed of chemicals—edible chemicals, but chemicals nonetheless. All food components, macro- and micronutrients, and any processing additives and preservatives, colors, and flavors are of chemical nature. Proteins, carbohydrates, and fats are chemicals that provide calories. Vitamins and minerals are chemicals that are needed for proper body metabolism. Dietary fiber is a complex mix of chemicals that aids digestion and binds toxins. Even the most important nutrients of all, water and oxygen, are chemicals. People who do not have a background in nutrition, physiology, or food science may not understand or even want to believe that our bodies are complex organisms composed of chemicals and will need chemical replacements to maintain health. Food scientists believe that chemicals are not to be feared but rather to be understood.

11.2 Chemistry of Our Foods

11.2.1 Water

Water, with its simple chemical formula (H2O), is the most abundant compound in the majority of fresh foods although it is not listed on most nutritional labels. Fruits and vegetables are made of as much as 90%–95% water, while full fat cheeses and bread may contain 35%–40% water, and nuts and chocolate, between 0.5% and 1%. Vegetable oils are among the few foods that contain no water.

Water is the only chemical commonly found as a solid, liquid, and gas under normal cond...