Summary Principles of Food Science SW: complete PDF

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Ch.1- Summary Notes

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Principles of Food Science – Chapter 1: Introduction to Food Science and Technology 1.1 Dimensions of Food Science Food is critical for our physical and mental functioning, termed health. Our body notifies us of this need through physiology (e.g. growling, grumbling, and the feeling of emptiness). In turn, we must depend on the nutritional quality, safety and balance of these foods in order to maintain our body’s requirements. Foods we have access to have been influenced by technology which makes it possible to have a large variety and availability of frozen, baked, dried, pickled, canned, fresh, fermented refrigerated and packaged foods. Part of the technological equation is related to the numerous nonfood substances that are formulated into manufactured foods as processing aids. These food additives include colour stabilizers to anti-staling agents, emulsifiers and fat substitutes to preservatives. Food science is the scientific study of raw food materials and their behavior during formulation, processing, packaging, storage, and evaluation as consumer products. This differentiates food science from the science of nutrition. Overall, food science is concerned with all quality and safety aspects of foods before a person consumes them, while nutrition is related to how the body uses foods after we eat them to promote and maintain our health. The field of food science and technology is concerned with the following aspects of agricultural, avian, mammal and marine food materials; food processing and manufacturing, food preservation and packaging, food wholesomeness and safety, food quality evaluation, food distribution, and consumer food preparation and use. Institute of Food Technologists (IFT) of United States identifies food technology as “the application of food science to the selection, preservation, processing, packaging, distribution and use of safe, nutritious and wholesome food”. Food manufacturing as “the mass production of food products from raw animal and plant materials utilizing the principles of food technology”. The difference between science and technology in general is that technology is what people can make happen through today’s technological expertise whereas an understanding of science and consequences of those technologies (e.g. long term effects on people and the environment) may belong to the future. An example of this is the development of nutraceutical food products.

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Food Science and Nutrition •

The American Medical Association (AMA) has defined nutrition as the nutrients and other substances in food, “their action, interaction and balance in relation to health and disease, and the process by which the organism (body) ingests, digests, absorbs transports, utilizes and excretes food substances”.

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Food science deals with food manipulations and their consequences on the food components themselves, where as nutrition deals with the consequences the food components have upon the humans who consume them. Food science overlaps nutrition, biology, chemistry, engineering and physics. Food science is not a traditional scientific discipline but an application or combination of these other sciences, meaning that food science is an interdisciplinary field of study.

Biology and Food Science •

Biology is the study of living things and their life-sustaining systems. Foods are derived from living organisms, either animal or plant origin, therefore food scientists must know how the edible tissue of these food sources is organized on the cellular level. This foundation is needed to understand changes that occur during processing, storage etc. Living organisms such as bacteria, yeast, and molds can contaminate living tissue, creating a lot of consequences. The microbial action of these organisms can be harmful (causing food borne illness through infections and intoxications), can be detrimental to food (microbial enzyme reactions causing it to rot and smell), or can be useful (purposely added yeast to bread flour, causing the desired leavening effect in baking). One branch of biology, genetics, is the scientific foundation of food biotechnology.

Chemistry and Food Science •

Chemistry is the study of atoms and molecules that make up the substances present in the universe, their arrangement into structures and the reactions they participate in. Food such as meats, fruits and vegetables, and breads and cereals contain carbon, hydrogen and oxygen atoms. These and other atoms listed in the periodic table of the elements exist in foods as combined structures forming the characteristic proteins, carbohydrates, vitamins, minerals, pigments and fat molecules found in every food. Food scientists want to know the molecular structures of these food components and to study the changes to them that might affect food quality. These changes can be represented by chemical equations, e.g. opened jar of peanut butter sits on the shelf long enough the chemical reaction will occur to the peanut oil in the product that results in an undesirable odor. Food scientists recognize this reaction as oxidation of unsaturated fatty acids in the peanut butter and can use chemical structures to describe it.

Physics and Food Science •

Physics is the study of matter and energy and is concerned with the physical changes that matter experiences under certain conditions. Many branches of physics are important to food scientists, e.g. thermodynamics seeks to explain the properties of matter such as the solid or liquid state of the food. For example, in the manufacturer of solid chocolate, it is critical to understand the concept of the melting point behavior and how it relates to the

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final product texture. Food scientists use the physics of the electromagnetic energy spectrum as a basis for understanding how food colour is detected, how microwave cooking works, and how the application of irradiation makes foods safe. Engineering and Food Science •

Engineering is the discipline traditionally devoted to the study of momentum, heat and mass transfer. Food scientists apply the science of engineering to understand the interaction of physical and energy transfer operations with food materials. The unit operations of the food industry invoke engineering principles applied to food processing (heat transfer during thermal processing), packaging, refrigeration, freezing, evaporation and drying. The manner in which a raw potato slice dropped into hot oil is transformed into a hot French fry or a crisp potato chip is explained by discussing the concept of heat and mass transfer from the cooking oil to the potato. Despite our familiarity with such food products, explaining “how” a food is transformed presents a challenge to food scientists, who must be simultaneously knowledgeable in the basics of biology, chemistry, physics and engineering.

1.2 The Food Processing Industry •

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Food processing in technology, in which raw (animal or plant) ingredients are converted into specific foods for consumption, has a long history. For thousands of years people have been salting, drying, smoking, pickling, and chilling their foods. Canned and frozen foods are a recent development of the food processing industry. Over the years, researchers have found new and better ways to process, package and preserve foods from the time of harvest to the time they get consumed. Historically, the human race has met challenges via breakthrough efforts new developments and discoveries in turn generate further discoveries and developments with the gradual passage of time. However, with the industrial era, the speed of change was startlingly and dramatically swift. A minor technological improvement in one field often has resulted into a cascade of unforeseen progress in others. E.g. advances with optics and lenses enabled the development of microscopes, which permitted the birth of the science of bacteriology, which profoundly influenced the areas of health, medicine, food safety and food preservation. Food processing industry is vital to the global economy; more nutritious food is available to the American public, to consumers in developing countries and to countries suffering famine, thanks to modern food processing. Food processing is the largest manufacturing industry in the United States. Food processing areas include; food ingredients of all kinds, milk dairy products, meat, poultry, seafood, eggs and legumes, fruits and vegetables, cereal, grains and baked goods, beverages, sugar and alternative sweeteners, fats, oils and substitutes, and confection and chocolates.

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History of the Food Industry •

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Food, clothing and shelter are the necessities of life. Food (including water and other water based beverages) is the most essential. People cannot live without food, and the need for a continuous food supply has led to the development of the modern, organized food industry that feeds the world. How did this industry arise? In Europe during the mid 1700s, machines and power tools replaced the simple hand tools used in agriculture and in manufacture. This advance allowed the development of large scale industrial production of consumer goods and had profound economic and social effects. The industrial revolution had a bearing on the development on the food industry as well. Historical problems such as food shortages and starvation became less frequent with the advent of more efficient mechanized food production and distribution. A specialized dairy industry developed in Holland, became famous for exporting Edam and Gouda cheeses during the eighteenth century. In Europe, scientific agriculture involving crop rotation and improved soil fertilization, meshed with improved livestock feeding, and management. Later scientific advances, the science of genetics and use of chemical fertilizers further expanded agricultural output. Growth of towns into cities and transitions from paths to roads and railways paved the way for goods transport and marketing opportunities. In the decades of the 1800s and early 1900s, urbanization and industrialization of Europe and America allowed for a rise in the standard of living for more people who were then better able to afford to feed themselves and their families.

Canning •

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The idea of canning grew from the knowledge (circa 1700) that cooked meats could be preserved for a limited time if they were covered with a layer of fat, which kept the meat from contact with the air. One hundred years later, Europeans were storing substances like fruit syrups and preserves in glass bottles. In response to help Napoleon’s needs to feed his troops, Frenchman Nicolas Appert (b.1752) combined these ideas by placing foods like cooked meat, vegetables and even milk into glass bottles that were closed off and heated, the idea being to drive the air off by heating. A series of food spoiling mishaps taught preparers that the heating steps had to be standardized for different can sizes. Heat killed the spoilage bacteria and thus prevented spoilage, not driving off the air as thought. Englishman Brian Donkin took the essential next step substituting an unbreakable “tin” can for the breakable glass bottle. The canning industry was born in 1812 with Donkin’s canning factory. In 6 years it had a canned product lineup that included beef, carrots, mutton, vegetable stew, veal and a soup. Gail Borden in the United

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States developed a canned version of milk that used added sugar to help extend the shelf life. This product was so popular with the armies in the Civil War, that men carried their taste for it back to the civilian market. By the end of the 1800s, the Massachusetts Institute of Technology created a chart showing the effective pasteurization times and temperatures for a wide variety of foods. Positive results of canning revolution included consumer convenience, low food cost, variety and safety. Refrigeration Technology •

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Before refrigeration was developed, “ice houses” were used to maintain a supply of ice. In the United States, the shakers in particular were icehouse adherents. An icehouse was a heavily insulated room with a carpeted floor and insulated roof designed to store blocks of natural ice obtained from the cold northern lakes. By mid 1800s ice making technology had arrived and ice machines were patented. An improved compressor designed by Scotsman James Harrison allowed for the development of an ice factory and a refrigerating machine. The latter was exploited by the Australian brewing company. Manufactured ice was also helpful to the fishing industry. An unheard of dinner event took place in Australia in 1873, at a public banquet, meat, poultry, and fish had been frozen for 6 months using the new technology were cooked and served to the highly impressed guests.

The Discovery of Vitamins •

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In 1846 Justus von Leibig, writing his report in Chemistry and its Application to Agriculture and Physiology, established the foundation of modern human nutrition by demonstrating that living tissue (and foods) was composed of carbohydrates, fats and proteins which were of differing biological value. Dutch physician Christiaan Eijkman’s investigations into beriberi treatment using rice polishings and the work of European scientists including A.C. Pekelharing, and Wilhelm Stepp paved the way for isolation and discovery of vitamins. In the 1930s, British doctor Harriet Chick and colleagues proved beyond all doubt the value of vitamin D in relieving the symptoms of rickets in a large number of artificially fed babies in pre World War 2 Austria.

Adulteration of Foods •

Some wholesalers and retailers in the 1800s extended food profits and supply by adding cheap bulk ingredients to certain foodstuffs thus coining this practice as adulteration. E.g. adding “pepper dust” to pepper which may have consisted of pea flour, mustard husks and even floor sweepings. Tea was adulterated with a substance called “smouch” which was made from dried ash leaves mixed in with the tea leaves. Used tea leaves were

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recycled by unscrupulous merchants who revitalized them with gum solutions and coloured them with black lead. Commercial bread flour was extended with alum, a mineral salt whitening agent; coffee diluted with chicory or acorns and cocoa powder often contained an addition of brick dust. These ingenious but deceitful and potentially dangerous practices were exposed in the 1850s in England which drafted its first British Food and Drugs Acts in 1860 and 1872 to regulate food purity. In the United States as early as 1785, Massachusetts enacted the first general food adulteration law. A 1905 book penned by Upton Sinclair, entitled The Jungle detailed unsanitary practices in the meat industry; it’s publication lead to the enactment of the 1906 Foods and Drugs Act and The Meat Inspections Act The Work of a Food Scientist Today •

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Food scientist or food technologist is a person who applies scientific knowledge and technological principals to the study of food and their components, in a research setting (university, industry or government) or manufacturing setting. Research food scientists are skilled at making observations, which lead to an understanding of how biological, chemical and physical factors affect food. In manufacturing, food scientists focus on analyzing product quality and safety, creating new products and investigating new manufacturing methods. E.g. ideas of fruit roll ups, fat free yogurt, coffee singles, microwavable brownies, flavored water or high fiber cereal came from the minds of food scientists. Need for trained food scientists has grown in pace with consumer demands for convenient, safe and nutritious foods and beverages with currently more emphasis placed on the safety of the food supply. Manufacturers are undergoing a transition to adopting food to new processing/quality assurance strategies. Current investigations of energy and cost efficient technologies in the processing of foods including microwave pasteurization, ultrafiltration and reverse osmosis. Health conscious consumers and food companies with marketing savvy are also paying attention to development of nutraceutical foods, foods that provide health benefits beyond those due to essential nutrients. The skilled food scientist will need to exhibit a combination of technological expertise and consumer awareness. Food scientists use the laws of science and engineering to produce, process, evaluate, package and distribute foods. The kind of work they do depends on the company they work for and the products they develop. Food scientists may concentrate on basic research, product development, quality assurance, processing, packaging, labeling, technical sales and research. They may work in production or technical management, they check on food standards, laws and safety.

Basic Research

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Food scientists in basic research study the chemical microbiological, physical and sensory properties of food and their ingredients. E.g. chemical property; colour change in canned vegetables during storage. E.g. microbiological study; check on the stability of baked muffins to spoilage by mold. E.g. of important physical property; hardening of gummy bear candies. E.g. of critical sensory property; identification of altered flavor in an ultra high temperature heat treated dairy beverage. Basic food scientists obtain fundamental information from food research while applied food scientists apply information to food product development and testing. Research is an activity driven by questions that are answered through experimental testing and observation, thus considered an iterative process such that a single question that receives an answer can lead to a multitude of successive questions requiring answers. Through this systematic process of inquiry, new information is constantly attainable and previous knowledge can be refined.

Product Development •

Most large food processing companies have test kitchens and food scientists work with test kitchen staff. They also work with engineers, microbiologists, flavor experts, sensory evaluation experts, packaging specialists, statisticians and marketing professionals. Also interact with buyers, production line workers and warehouse staff.

Quality Assurance •

Food scientists in QA sample and check raw products to see if fresh and conform to purchasing specifications. QA personnel ensure that operators monitor each processing step to make sure the product meets government, company and industry standards. Check warehouses and storage space for sanitation, temperature and humidity. Of major importance is food safety testing including microbial analysis where food is sampled and tested for specific biological, chemical and physical hazards including microorganisms of significance in terms of food safety.

Research Tools and Scope •

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Tools of the research food scientist are similar to that of other research scientists, well established analytical methodologies and instrumental techniques are useful in the study of changes to foods and food components especially during production and storage. Research food scientists are usually specialists in one of the focused areas previously mentioned e.g. food chemistry, food engineering etc. Experim...