Textbook Notes (367,976)
Canada (161,540)
Food Science (205)
FOOD 2010 (197)
Chapter

Unit 8 Notes.doc

16 Pages
96 Views
Unlock Document

Department
Food Science
Course
FOOD 2010
Professor
Massimo Marcone
Semester
Winter

Description
Chapter 9 (p. 249 – 278): Understanding Fat, Sugar, Beverage, and Plant Product Processing 9.1 Processing of Fats and Oils - Lipids that have a relatively high melting point and are solid at room temperature are called fats - Lipids that have lower melting points and are liquid at room temperature are called oils - All food lipids are mixtures of triglycerides, usually with 2 or 3 different fatty acids attached to each triglyceride o Melt over a range of temperatures - Processing of fats means the removal or extraction of a fat or oil from its natural source, such as a kernel of corn, the carcass of a hog, or a cottonseed - Refining: refers to the removal of impurities from the extracted fat or oil o Oxidative stability of oils is generally improved by refining, as are colour and flavour o Toxicants are also removed during this process - Crude oil: when food lipid matter is obtained via pressing and rendering o Subjected to a number of commercial refining processes to remove compounds that may contribute especially to flavour and colour instability o RBD oil: crude oil that has undergone refining, bleaching, and deodorizing - Basic production methods: o Rendering – heating of fatty meat scraps in water o Pressing – mechanical squeezing of oil from oilseeds o Solvent extraction – separation of oil from cracked seeds using a nontoxic fat solvent such as hexane  Solvent is distilled off and recovered for reuse o Deodorization – application of steam heat in a vacuum chamber to strip away certain odor-causing low molecular weight compounds from oils o Degumming – first refining steps for oils such as soybean oil and others high in phospholipids o Neutralization – removes free fatty acids from a fat o Bleaching – refers to the removal of coloured substances from oil o Hydrogenization – process to saturate double bonds and make an oil more solid and more resistant to oxidative rancidity o Winterizing – refrigeration treatment of oils for a specific purpose o Plasticizing – softening a hard fat, which changes the fat’s consistency - Processing of specific fats: o Milkfat is a mixture of glycerides found in milk, milk products, and butter – processed by fractionation (to yield butter fractions of varying melting points)  Process generates solid and liquid phases that are easily separated by vacuum or pressure filtration o Interesterification: refers to the removal of fatty acids from the glycerol portion of food triglycerides, such as those occurring in large, and their subsequent recombination into numerous configurations  Contain a random distribution of the fatty acids within a glyceride molecule  Ester bonds break and reform during this reaction  Can change lard into one with a lower melting point, finer crustal size, more plastic, and smoother texture and mouthfeel  Also produces fats with reduced calories - Chemical and physical testing of fats: o Must be tested to gain information regarding specific food applications, to measure deterioration, to check performance vs. purchase expectations, and to examine physical properties o Iodine value: used to measure the degree of unsaturation of a fat or oil o Peroxide value (PV): used to measure lipid oxidation, and it too uses iodine o Acid value: measure of the number of free fatty acids present in a fat  Refers to the splitting of glycerides into component parts: glycerol and free fatty acids o Saponification value: test that gives the average molecular weight of the fatty acids in a fat  Molecular weight influences physical firmness  Potential to produce odour, with short-chain or low molecule weight fatty acids being most odorous o Smoke point: temperature at which smoke emanates continuously from the surface of a lipid heated under standard conditions  If higher temperatures – sample will flash and further burn 9.2 Sugar Processing - Most common sugar is sucrose – disaccharide found in almost all plants o Highest concentration in sugarcane and sugar beets - Cane sugar: refers to the sucrose product obtained from sugarcane and is generally produced in two stages o Manufacturing in cane-growing countries o Refining into food-grade products in sugar-consuming countries - Sugar beets are processed into white sugar in one stage - Extraction: o Cane is chopped into chips to expose the tissue and open the cell structure o Crushed cane proceeds through series of roll mills, where it is forced against a countercurrent of water (water of maceration) o Mixes with maceration water and combines into a dilute juice - Neutralization and clarification: o Mixed juice from the extraction mills is purified by addition of calcium hydroxide and heat - Concentration and crystallization: o Clarified juice is pumped to a series of devices called evaporators o Steam is used to concentrate the juice into evaporator syrup o Further evaporated under vacuum to achieve supersaturation o Crystallization: yield an “A” sugar, leaving behind a residual mother liquor known as A molasses o A molasses is concentrated to yield B variety, and low-grade B molasses is concentrated to yield C sugar o Left with molasses, known as blackstrap - Separation and drying: o Crystals and mother liquor are separated via centrifugation o Washing process is performed in an effort to produce high-purity raw sugar o Washed sugar dries and cools and is placed in bulk storage - Sugar refining: refers to the production of high-quality sugars from remelted raw cane sugars o Produces white sugar cubes, powdered and granulated white sugar, and light and dark brown sugars 9.3 Beverage Processing - Drinking (or potable) water: water that is intended for human consumption and sealed in bottles or other containers with no added ingredients, except optional antimicrobial agents - Bottled water: includes natural mineral waters, carbonated waters, and sweetened, flavoured waters that are typically carbonated o To ensure a safe product and to preserve the properties ascribed to the water, such as mineral content or flavour, up to the point of consumption - Ozone: an unstable, colourless gas that acts as a powerful oxidizer and a potent germicide o Controls the growth of bacteria in water o Does not leave a residual taste o Higher disinfection potential than chlorine - Soft drink beverages: o Soft drinks: non-alcoholic carbonated or noncarbonated beverages, usually containing a sweetening agent, edible acids, and natural or artificial flavours  Includes cola beverages, fruit-flavoured drinks, ginger ale, and root beer o Superchlorination: water is treated through this process to remove colour, chlorine, and any other tastes or odors that may be present  Water is exposed to a high concentration of chlorine and to a flocculant that removes microorganisms o Carbonation: the saturation of water with carbon dioxide under pressure in which the CO g2s dissolved in the water becomes carbonic acid  Water or the finished beverage mixture is chilled and cascaded in thin layers over a series of plates in an enclosure containing carbon dioxide gas under pressure - Special beverage categories: o Noncarbonated soft drinks: produced with much the same ingredients and techniques as those for carbonated soft drinks  Not protected from spoilage o Powdered soft drinks: made by blending flavouring material with such ingredients as dry acids, gums, and artificial colour o Nutraceutical beverages: drinks formulated with special functional ingredients that promote some aspect of health or reduce the risk of certain diseases 9.4 Processing of Cereal Grains - Conversion of cereal grains into food products or ingredients - Classified as dry fruits, derived from the seeds of plants in the grass family - Cereal: refers to any grain used for food - Grain: refers to a small hard seed produced by plants that are grasses - Barley, buckwheat, corn, millet, oats, rice, rye, sorghum, and wheat are grass plants that produce the common cereal grains - Milling – grinding of grain into a form that is easily incorporated into foods or cooked o Methods are dry and wet, depending on the particular grain - Wheat milling: o Hard and soft wheat describe the firmness of the kernels and relate to the strength of the gluten developed when doughs are made from milled flours o Strong gluten: higher protein content, elastic gluten suited to breadmaking o Weak gluten: low in protein, weak, fragile gluten producing a softer, more fragile dough for cakes and biscuits o Semolina: result of milling certain hard grains  Generally used to make pasta  Doughs made from it are strong but do not have the same level of elasticity o Wheat flour processing consists of grinding rollers, sieves, and purifiers - Breadmaking: o Bread: product of baking doughs from a mixture of flour, water, salt, yeast, and other ingredients o Patent flour: the purest flour, selected from the purest flour streams released in the mill  Very low mineral content, devoid of bran specks and other impurities o Basic breadmaking:  Flour, water, other ingredients (sugar, yeast, emulsifier)  Mixing (kneading) • Until the flour is converted into stiff dough, followed by baking the dough into a loaf • Want to produce dough that will rise easily and have eating properties desired by consumer • Must be extensible (relax/stress) and elastic, having strength to hold the • gases produced during fermentation, and stable to hold shape and cell structure • gluten is formed from two proteins present in flour: gliadin (stickiness) and glutenin (elasticity) • Natural flour lipids (glycolipids) bound to carbohydrate associate with gluten proteins in the dough matrix • After making, forms a crumb structure • Heating causes gluten proteins to strength and expand as the gas cells in the dough increase in volume • Overmixing reduces elasticity properties • Undermixing may create small, unmixed dough areas that will remain unrisen  Fermentation (29°C, 84°F for 4 hr) • Changes the dough to a smooth, extensible dough with good gas- holding properties • Each yeast cell forms a nucleus around which carbon dioxide bubbles form  Proofed dough  Sheeting, molding, and panning • Dough is sheeted after the first rise o Gentler process than mixing, less energy • Use an action roller system for sheeting – pair of rotating rollers shuttle back and forth over two separate belt conveyors • Dough is panned and returned to the fermentation cabinet  Baking (215°C, 419°F for 20 minutes) • Gas cells increase in size •
More Less

Related notes for FOOD 2010

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit