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FOOD- Unit 1.docx

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School
University of Guelph
Department
Food Science
Course
FOOD 2010
Professor
Massimo Marcone
Semester
Winter

Description
FOOD SCIENCE Unit 1 Chapter 1 (pages 1-14) The first chapter provides a general introduction to the major disciplines in food science. You will read about the scope of the work of food scientists and their educational training. Food science is truly multi-facetted and interdisciplinary as the following schematic illustrates: The textbook was written from anAmerican perspective; therefore, there will be information that differs from Canadian and international contexts. IFT and IFST (mentioned on pg. 2) are 2 examples of professional associations that promote food science. Asimilar professional association in Canada is the Canadian Institute of Food Science and Technology (CIFST). There are links to these organizations in the Web Resources page for this unit. The Food Guide Pyramid (pgs. 10-11) was developed by the USDAfor theAmerican population. Canada’s Food Guide for Healthy Eating differs slightly from the pyramid concept. At this point, we will not ask you to read the Challenge! section which accompanies chapter 1. The articles are interesting, but they may be more relevant later as you learn about specific areas of food science. You will not be tested on material in chapter 1 of the textbook. Chapter 2 (pages 21-55) introduced to applications of food composition information. You will learn more about the importance of food composition in the next unit of the course. Chapter 2 revisits the Food Guide Pyramid, which is used in the United States. Canada’s Food Guide for Healthy Eating is similar in principle, but is based on a rainbow rather than a pyramid concept. Since this is not a course specifically devoted to nutrition, you are not required to learn about the food guide pyramid or Canada’s food guide. Concentrate your reading for chapter 2 on the remaining sections which focus on characteristics of beverages and specific commodities (sections 2.2-2.10). Also read the Challenge! section at the end of chapter 2 which discusses a popular trend in the development of products for the health conscious consumer. You do not need to memorize tables 2.21 or 2.22, but you should know about functional foods. Read unit 1 of the course manual. You may be tested on this supplemental information. 2.1 Food Composition Tables (No emphasis on this for exam) - food composition = substances/components found in a beverage or food - larger molecular substances: prot, fat/lipid, carbohydrate (starch, sugars, fibre) and smaller molecules of water, vitamins, minerals and phytochemicals - raw foods – naturally occurring substances - processed foods – usually contain specific, functional additives Food Categories and the Food Pyramid - commodity: a useful consumer good, a product of agriculture, produced and delivered for shipment o usually refers to raw product but USDAlists some that are processed products o red meats, poultry, fish and shellfish, eggs, dairy products, beverage milks, fats and oils, fruits (fresh, canned, dried, frozen and juices), vegetables (fresh, canned, dried, frozen and pulses), shelled peanuts and tree nuts, flour and cereal products, caloric sweeteners, coffee and cocoa. - processed commodity: value-added commodities derived from agricultural commodities that offer convenience, longer shelf life and sometimes add nutrients. - food categories discussed throughout this book are used w/in the food industry - food in food guide pyramid aren’t exactly the same (there are additional foods like bacon and sausage… made using processing aids) - processing aids: stabilizers and emulsifiers, as well as flavors, preservatives, and other additives, are important components of their manufacture - this course strives to teach the student how these additives function and their regulated limits of additions to food Serving Sizes - how much food we eat 2.2 Beverages - drinkable liquid - consumed bc: 1. thirst quenching ie. water 2. stimulant effect ie. caffeinated drinks (cocoa, coffee, tea) 3. alcoholic content ie. beer 4. health value ie. milk, fruit/veg juices 5. enjoyment ie. carbonated soft drinks - nutrient density: concept that applies to foods and beverages, how much supply it has of protein, complex carbs, vits, minerals without xs fat and calories - pic top page 25 milk and OJ have greater nutrient density compared to soft drinks - water- major constituent of beverages (compare in table page 26 bottom left) The Degrees Brix of Beverages - naturally sweet or have sweeteners (sucrose/sugar, high-fructose corn syrup) added - sucrose is part of the total soluble solids content of a beverage - sucrose concentration of beverages is measured as degrees Brix ( B) equal to the weight percent of sucrose in solution (g of sucrose per 100g of sample) - sucrose inversion: process in which sucrose molecules in solution come apart and yield the 2 component sugars (sucrose is a disaccharide) glucose and fructose - can affect the final sweetness and flavor bc fructose is super sweet (frut can increase sweetness of anything) - this process can occur… o low storage pH o high storage temperature o in some products this process is desired and done so by enzyme invertase or by an acidulant The Important of Brix/Acid Ratio - fruit juice beverage flavor is a function of sugar content and natural acid content, so flavor depends on Brix/acid ratio o varies as the relative proportion of sugar to acid content o can also vary based on location 2.3 Cereals, Grains and Baked Products - among the world’s major crops; cereal grains, corn, rice, wheat, barley, millet, rye, sorghum and oats - cereal grains: high in carb content such as starch and the sugars gluc, maltose, and fructose as well as fibre (table bottom of 27) - consumed directly or milled into flours and processed into many dif food prods - some grains (corn) used to feed livestock as well as being used by humans - 2 noncereal crops; sugar cane and beets, also processed into sugars and syrups - wheat = prime example of typical cereal grain seed or kernel - cereal grains composed of 3 nutrition parts/structures: endosperm (83% of the kernel), bran layer (15% of the kernel), germ (remaining. embryonic or sprouting part). - avg, unprocessed cereals are 75% carbohydrate, 10% protein, up to 2% fat - prot is of lower biological value than prot found in animal prods and has low bioavailability - biological value (BV): amt of nitrogen derived from food prot that is used in the body to promote growth. o related to the aa content of a protein o hen’s egg is used as a reference standard as a food complete in high- quality prot (thus high BV) o high BV high quality prot, all of the essential aa present - plant prot sources (cereals and legumes) are deficient in lysine and methionine = incomplete protein sources (table bottom pg 28) - but a mix of these can be adequate for diet - bioavailability: degree to which nutrients are digested and absorbed in the body o influenced by food source (animal vs. plant), food processing (certain nutrients are destroyed by heating) Leavening of Baked Products - leavening: production of gases in dough that contributes to the volume achieved during baking (leavening effect) and the final aerated texture (pic top pg 29) o typical leavening agents added to foods: yeast (biological leavening agent), baking soda (sodium bicarbonate), baking powder and ammonium bicarbonate o produce CO2 as the specific leavening gas o steam also produced during baking and contributes to oven spring - see table bottom page 29 for examples of products 2.4 Fruits and Vegetables - fruit: fleshy or pulpy plant part commonly eaten as a desert due to its sweetness o botanical termed: ripened ovary of a plant, which means that it contains the seeds (thus tomatos, squash and avocado are actually fruit) - vegetable: plant or plant part that is not sweet, usually served with the main course of a meal o herbaceous plant containing an edible portion such as a leaf, shoot, root, tuber, flower or stem - table top left pg 30 - table bottom pg 29 (high in water content, low in prot and low in fat) - contain minerals - good sources of digestible carbs (sugars/starches) and indigestible carbs (fibre, including cellulose and pectic substances) - good sources of some vits: vitaminAprecursor (beta carotene), vit C - table bottom page 30 Health Benefits - protective effect against heart disease and cancers - fermented grape juice, red wine, contains resveratrol which could lower blood cholesterol, prevent cvd, and anticancer substance - food scientists strive to incorporate and identify such substances - see table page 52 Maturity and Ripeness - ripeness: optimum or peak condition fo flavor, colour and texture - maturity: condition of a fruit when it is picked (could be at or just before the ripened stage) - fruits that continue to ripen after theyre picked may become overripe if picked at peak ripeness - harvesting: collection of fruits/vegs at the specific time of peak quality in terms of coloru, texture and flavor in order to market them - senescence: decline in quality of stored, respiring fruits and vegs that occurs after harvesting. fruit/veg may pass the period of peak quality after harvest (ie. sweetness of corn decreases dramatically during storage bc up to half of sugars may convert back to starch, which is not sweet). Quantitative and Qualitative Quality Considerations - qualitative characteristics: size, colour, blemishes/bruises, flavor, firmness, presence of extraneous matter (unwanted stems, pits or leaves) o viscosity- if it can flow (ie. apple sauce…). indication of solids content, particle size and pectin or starch content o colour- typical of this fruit/veg in its ripened state. o pH and titratable acidity (indication of amt of acid present) o flavor and odor (fresh, unspoiled state) o degrees Brix (other than sugar can also refer to salt and acid) - quantitative: degree Brix, microbiological information, moisture content, pH and viscosity Dried Fruits - proessed category of fruits created by dehydration - dehydration: removes moisture from fruits to prevent microbial and enzymatic deterioration - concentrates the nutrients as well – bottom table pg 32 - can be done to fruits thatAREN’T fragile-skinned - sun dried or dried in chambers - must be in very ripened state so they can have highest possible amt of sugar - infusion: process used to create dehydrated fruit. usring heat and pressure, fruct is forced into a fruit piece and this sugar replaces the water in the fruit o adds flavor, colour, to achieve a certain texture 2.5 Legumes and Nuts - legumes: edible seeds and pods (as beans and peas) of certain flowering plants, include beans, lentils, soybeans and peas - offer good quality prot - low in fat, low sodium, high fibre, vitamin, mineral and prot - green, lima and wax beans - red, kidney, navy , pinto, black, white, garbanzo/chickpeas - higher fat legumes: soy beans, cottonseed, sesame seed, sunflower seed, peanut seed = oilseeds - peanuts: ground to produce peanut butter, pressed to extract peanut oil, come in 3 major varieties- Spanish peanuts (small, used in nut clusters and peanut brittle), Runner peanut (medium sized and incorporated into confectionery prods), Virginia peanuts (larger, longer and used for roasted nuts) Common Soy Products - legume with a dual role as an oil bean and a food bean bc of the fat and protein content - various products in table on the right of page 33 - when pressed soybean oil removed and used for food-grade oil and in margarine formulations - beans that remain can be processed into soy flour - protein in defatted soybean flakes can be concentrated to produce even more soy prods ie. soy protein concentrate (70% prot)/soy prot isolate (90% prot) - soy milk: made by soaking soybeans in water, grinding to produce a slurry, which is then cooked and filtered - soy milks used to have a flavor defect called “beany” or “grass
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