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Food Science
FOOD 2010
Massimo Marcone

Food 2010 Notes Unit 1 Chp 1 Food science education and careers: University of Guelph food science department, Includes information about undergraduate studies in food science through the Department of Food Science at Guelph. Standards for undergraduate degree programs in food science. Minimum standards for undergraduate education as outlined by the Institute of Food Technologists. Specifies the types of physical and administrative resources which should be available at educational institutions offering degrees in food science, and recommendations for curricula. Professional associations: Institute of Food Technologists (IFT) is a large international organization based in the United States. Canadian Institute of Food Science and Technology (CIFST) is an organization representing the interests of food scientists in Canada. Institute of Food Science and Technology (UK) (IFST): an organization based in the United Kingdom representing the interests of food scientists and technologists. International Union of Food Science and Technology (IUFoST): a global organization consisting of national food science organizations. Selected food industry trade association and stakeholder links: Brewers Association of Canada and Food and Consumer Products of Canada Overviews of food sectors in Canada: Summaries of various sector trends in the Canadian food industry compiled by Industry Canada. Selected trade magazines: Food In Canada and Prepared Foods Global trading blocks: North American Free Trade Agreement (NAFTA) is a website of the NAFTA Secretariat which arbitrates trade disputes involving Canada, the United States and Mexico. European Union (EU consists of 15 member countries in Europe. (Website in various languages). Asia-Pacific Economic Co-operation (APEC) consists of 21 member countries around the Pacific rim. Food security: Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO) Notes Chp 1 and 2 Additives include everything from color stabilizers to anti-staling agents, emulsifiers and fat substitutes to preserves. Health depends upon the nutritional quality, safety and balance of the food we eat. Food Science is the scientific study of raw food materials and their behaviour during formation, processing, packaging, storage and evaluation as consumer food products. Different from nutrition in that food science is concerned with the food’s safety before the person consumes them and nutrition is how the body relates to those foods. Food science consists of the following aspects of agricultural, avian, mammalian and marine food materials: food processing and manufacture, food preservation and packaging, food wholesomeness and safety, food quality evaluation, food distribution and consumer food preparation and use. Food Technology is the application of food science to the selection, preservation, processing, packaging, distribution, use of safe, nutritious and wholesome food. The importance of food technology is that is takes in to consideration possible long term effects on people and the environment. Food Manufacturing is the mass production of food products from raw animal and plant materials utilizing the principles of food technology. Biology and Food Science: Food scientist must know how the edible tissue of these food sources is organized on the cellular level. The microbiological action of these organisms can be harmful (causing food borne illness through infections and intoxication), can ne detrimental to food (microbial enzymatic reactions causing it to rot and smell), or can be useful for baking, by adding yeast. Chemistry and Food Science: Food Scientists want to know the molecular structures of these food components and to study the changes to them that might affect food quality. This can be shown by the different chemical structures of the food, oxidized verses unoxidized. Peanut butter odour example. Food Chemistry examines the chemical composition and physical properties of foods. • Chemical reactions during all stages of the food, processing and storage • Food analysis • Physical behaviour of foods • Food toxitiy • Functional properties of proteins, carbs, fats, water, vitamins, minerals, flavours, colours and enzymes Physics and Food Science: Thermodynamics seeks to explain the properties of matter such as which is the optimal physical state is best for the food, solid or liquid. Also, it’s important to know the melting points of different foods and know how they will react and final product texture. They also, test the effect of microwave cooking and the safety of eating that food. Engineering and Food Science: Food Scientist apply the science of engineering to understand the interaction of physical and energy transfer operations with food material. Describes ‘how’ food is transformed when cooked, frozen and packaged. Food Processing is the technology in which raw food ingredients are converted into specific foods for consumption. Food Market Factors a food science discipline. Provides vital information to ensure marketability of food products. • Sensory evaluation • Communications • Food industry trends • Food laws and regulations • Consumer behaviour Scientific Agriculture in Europe, involving crop rotation and improved soil fertilization, meshed with improved livestock feeding and management. History of the Food Industry: In the decades of the 1800s and early 1900s. The urbanization and industrialization of Europe and America allowed for a rise in the standard of living for more people, who were better able to afford to feed themselves and their families. Canning is the idea that grew from the knowledge 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. Refrigeration before that, there were ice houses. Mid 1800’s ice making tech was made. 1873, first meal made from frozen food. Cost Efficient food technologies include microwave pasteurization, ultra filtration and reverse osmosis. Basic Research food scientists obtain fundamental information from food research, while applied food scientist apply the information to food product development and testing. Product Development is where food scientist collaborate with test kitchen staff, engineers, microbiologists, flavour experts, sensory experts, packaging specialists, statisticians and marketing professionals, Quality assurance is when food scientists sample and check raw products to see if they are fresh and conform to purchasing specifications. It checks for sanitation, temperature, humidity and a microbial analysis. Stakeholders Nutraceutical has been given to a proposed new regulatory category of food components, a food that in whole or part is able to provide health improvements or disease prevention. Phytochemical are plant derived, not proteins or parts of proteins, not carbohydrates or any of the macro or micro molecules. They can benefit in protection against cardiovascular disease, certain cancers. Food Guide Pyramid has been developed as an educational tool to remind people which sources of food components (as nutrients) we need to consume on a daily basis, and in what relative amounts. Food Science Education North American Universities focus on diary science. Working on developing new and more effective sterilization procedures. Enology the science of winemaking. Serving Size the quantity of food recommended by the food guide pyramid is termed servings, product food label specify serving sizes, and tables of food composition employ measures. Nutrition Labelling and Education Act (NLEA) defines a serving size as the amount of food customarily eaten at one time. It uses the metric system. o The degrees Brix of Beverages is how you measures sucrose in beverages. ( Brix) is equal to the weight percent of sucrose in solution (grams of sucrose per 100 grams of sample). Factors that promote sucrose inversion are low storage pH and high storage temperature. Brix/acid ratio varies as the relative proportion of sugar to acid content, and it is critical in selecting certain fruit and vegetables to make juices. Oranges are typical harvested at 12 Brix. Endosperm 83 percent of the kernel Bran layer 15 percent Germ embryonic or sprouting part Biological Value refers to the amount of nitrogen derived from food protein that is used in the body to promote growth. Food high in BV is said to possess high-quality protein, meaning all of the essential amino acids are present. Bioavailability is the degree to which nutrients are digested and absorbed in the body. Fruits and Veggies Quality Indicators: • Viscosity • Colour • pH and titratable acidity • Flavour and Odour • Degrees Brix Myofibrils, actinmyosin and collagen Comminuted meat emulsions contains finely chopped meat mixed with water, fat and sometimes additives such as preservatives and water-binding agents. Haugh Units relate egg weight and the height of the thick white and the higher the Haugh unit value, the better the albumen egg quality. Standards of Identity these federal standards are required for labelling purposes and identify the product name and the type and amount of ingredients that a specific food type must contain, as well as processing requirements. Casein is a major milk protein which is located in the watery part of the milk. The other protein is whey proteins. Unit 2 Chp 7 Intentional Additives they are purposely added, including sugar, salt, corn syrup, baking soda, citric acid and vegetable colouring. Intentional additives must received approval from the Food and Drug Administration before they can be used in foods. Indirect Additives are contaminants that accidentally get into food. Uses of Food Additives 1. To maintain product consistency 2. To improve or maintain nutritional value 3. To maintain palatability and wholeness 4. To provide leaving or control acidity/alkalinity 5. To enhance flavour or impart desired colour Anticaking and free-flowing agents are substances that keep ingredients in a powder form for ease of incorporation into formulations during product manufacture, ex. Silicates and talc. Antimicrobial Agents act to inhibit the growth of the bacteria, yeasts and molds and this function as preservatives. Antioxidants acts to inhibit the oxidation of fats and pigments, which would otherwise result in product rancidity and altered colour, ie ascorbic acid. Colourants or food colours are added to certain foods to offset colour loss due to storage or processing of foods, or to correct for natural variations in food colour. Curing Agents for meats contain sodium nitrite, which helps retain the pink colour of cured meats, as well as acting as a preservative. Dough Strengtheners are substances used to improve the machinability of bread dough during processing. Emulsifiers keep fat globules dispersed in water or water droplets dispersed in fat. Enzymes are biological catalysts that occur naturally in the foods, are used by the food industry for use as beneficial food additives. Flavourings may be natural or synthetic and are added for flavour production or modification. Humectants are substances that attract water within a food product, which may lower the product’s water activity. Leavening Agents such as baking powder are used to enhance the leavening effect, rise, of oven spring of dough in baked products. Nutritional Additives are included in foods such as breakfast cereals, baked goods, and drinks to boost nutrient intake and provide for a more balanced diet. Nonnutritive Sweeteners are compounds that provide much great sweetness intensity per amount when compared to sucrose. Nutritive Sweeteners are compounds that provide significant calories from carbohydrates in addition to a level of sweetness intensity. Processing Aids include not only acidulants and alkalis, but also buffers and phosphates. Sequestrants act to combine with metal elements, such as copper and iron, which are active in oxidation reactions. Stabilizers and thickeners combine with water in foods to increase product viscosity, to form gels, and to prevent product crystallization. Surface Active Agents or surfactants act as wetting agents, lubricants, dispersing agents, and emulsifiers, by affecting the surface tension of materials present on food systems. Oxidizing Agents occur in food mainly as residuals from application as sanitizing agents of food processing equipment. pH control Agents are acidulants, which lower food pH, and alkalis or alkaline compounds, which increase food pH. Code of Federal Regulations (CFR) is a yearly codification of rules published in the Federal Register by agencies of the Department of Health and Human Services (HHS) and the Department of Agriculture. Aflatoxin is a powerful mycotoxin produced by the Aspergillus mold, which is associated with crops such as seeds, peanuts, corn, rice, cottonseed meal, oats, hay, barely, sorghum, cassava and millet that are stressed by drought. Cyclamates is an alternative sweetener that in 1968, was banned as a food ingredient when testing showed that a saccharin/cyclamate mixture caused cancer in experimental laboratory mice. Saccharin additive taken off the market in 1972. The Concept of Margin of Safety Margin of safety, or “extra padding” that scientists Toxic amount of use to help protect the substance public. Consuming this Maximum of amount of substance amount probably wouldn’t that a person can consume without suffering ill effects be harmful, but researchers overestimate the risk just to be on the Reference dose or the amount of safe side. substance the EPA or FDA deems acceptable Sometribove is a recombinant bovine somatotropin (BST) product for increasing milk production in diary cows Food and Agriculture Organization (FAO) Mandated a raise in levels of nutrition and standards of living, to improve agricultural productivity and better condition of rural populations. World Health Organization (WHO) • Directing and co-ordinating international health activities • Strengthening existing health services • Furnishing appropriate technical assistance, and providing necessary aid during emergencies upon the request or acceptance of Governments • Stimulating and advancing work on the prevention and control of epidemic, endemic and other diseases • Promoting the improvement of nutrition, housing, sanitation, recreation, economic or working conditions and other aspects of environmental hygiene in co-operation with other specialized agencies. Codex Alimentarius Commission helps facilitate world trade. The Joint Expert Committee on Food Additives (JECFA) sets standards for purity of food additives at the international level. The standards are set for the nations within the EEC (European Economics Community). The United States Department of Agriculture (USDA) is involved with food processing and marketing and employs specially trained inspectors to carry out its functions. Food Safety and Inspection Service (FSIS) Food and Drug Administration (FDA) regulates all foods except meat and poultry which is under USDA. It develops standards for composition, quality, nutrition and safety and enforces federal regulations on labelling, food and colour additives, food sanitation and food safety. • Class 1 – recalls are for dangerous or defective products that predictably could cause serious health problems or death. Ex, is a food that is found to contain botulinium toxin. • Class 2 – recalls are for products that might cause a temporary health problem. • Class 3 – recalls are for products that are unlikely to cause any adverse health reaction, but that violate FDA regulations. Ex, food packages that contain less than the amount stated on the label. Australia New Zealand Food Authority (ANZFA) Hazard Analysis Critical Control Point (HACCP) Ministry of Agriculture Forestry and fisheries (MAFF) Ministry of Health and Welfare (MHW) Quality Management Program (QMP) DFO’s risk-based food safety and quality inspection system Food Product Labeling guide to food labeling and advertising – make sure everything in the product is on the label and it’s not falsely advertised. Must have: (Canadian) • The common name of the product • The net quantity in metric units • Name and address of the manufacturer • List of ingredients by weight in the product • Durable life • Nutrition Labelling Must have: (US) • Product name • Net quantity • Ingredients by weight, sweeteners must be included • Name and address of the manufacturer • Nutrition Facts Label Teratogen refers to a substance that causes abnormal fetal development and birth defects. Mutagen is a substance that causes a change (mutation) in that base sequence of a cell’s DNA. Carcinogen causes cancer in a test animal. Furthermore, a mutagenic substance can induce tumours and other forms of cancer in an organism. Ames test is to identify the mutagenic potential of chemical substances. Using radiation to eliminate microorganism. Nutrition Labelling and Education Act (NLEA) mandated a change in nutrition labelling, standardized key label features and use of terms and authorized health claims for specific foods and ingredients. Dietary Supplement Health and Education Act (DSHEA) expanded the definition of the term dietary supplement beyond essential nutrients to include such substances as ginseng, garlic, fish oils, herbs and safety testing is not required before marketing these substances. Unit 3 Chp 4. Water Activity and Moisture Solution – homogenous mixture of two or more components Food colloids – surface active ingredients in which their particles are too large to dissolve so instead they become components of colloidal dispersion. Amphiphilic molecoles – contain both hydrophilic and hydrophobic regions in their structure Free Water is water that is trapped in food. It is lightly entrapped and therefore easily pressed from food matter, when this is done, the water can be seen and felt. Free water acts as s dispersing agent and solvent, and can be removed by drying foods. Adsorbed Water (structural water) is water that associates in layers via intermolecular hydrogen bonds around hydrophilic food molecules. Bound Water is water in a tight chemically bound arrangement in food that does not exhibit the typical properties of water. Water Activity is the availability of water molecules to enter into microbial, enzymatic or chemical reactions.(Determines shelf life of a food) P aw= P is calculated is a ratio of water vapour pressure of the substance divided by vapour 0 pressure of pure water at the same temperature. P= is the vapour of food and Po= is the vapour pressure of pure water at the same temperature (1.0). RH = (relative humidity in equilibrium in food) 100 x a w Moisture sorption isotherms are graphs of data that interrelated the water content of a food with its water activity at a constant temperature. Plasticizer is a substance that lowers the glass transition temperature when added to a polymer food system. 4.5 (chemical and functional properites of food acids) Typical food acid contains the (COOH) group attached to the molecule. Functional properties of food acids include: antimicrobial agent, buffering system component, chelating agent, dough softening agent, hygroscopicity agent, leavening system component, gelation promoter, sourness agent Hygroscopicity is the ability of a substance to attract moisture. Organic salts are compounds formed from organic acids in which the hydrogen atom of the acid group is replaced by a metal ion(COOH to COONa example) Leavening is the production of gas by yeast fermentation or the production of gas caused by the reaction of an acid with baking soda, in batter and dough products that contributes to the volume achieved during baking and to the final aerated texture. Leavening acid is a substance that generates hydrogen ions and facilitates the release of carbon dioxide from baking soda, causing the expansion of a baking dough or batter product. Chp 5 5.1 food carbs All carbs contain elements carbon, hydrogen, and oxygen Monosaccharides: SINGLE sugar molecules, main ones for food are glucose C6H12O6, fructose, and galactose(all have the same chemical formula C6H12O6 but different structures). Simple sugars also termed organic alcohol because they contain carbon atoms attached to – OH(alcohol) groups. Ring formation more common than straight line structure due to cyclization(joins C1 and C5 together to form a closed ring) Disaccharides: sucrose (glucose+ fructose), lactose (glucose + galactose); maltose (glucose + glucose) Functional group is the –OH, for sweetness and solubility in water Carbonyl group -C=O is important for the reducing activity (reducing agent – loses/donates an electron, making it oxidized) All mono and disacc are reducing sugars(reducing agents that contain the carbonyl group) Maillard browning: creates brown colour pigments when reducing sugars react with amino acids (dried egg whites, baked goods, instant mashed potatoes (details p124) Caramelization: formation of brown caramel pigments by applying heat to sugars (200C) C24H36O18 =caramelen, colour in colas Crystallization: sugars can be soluble (syrup) or crystals…negative when lactose crystallizes in ice cream to form a gritty texture. Positive: hard candy needs crystalliazation Humectancy something that has an affinity to moisture. Carbs are humectant and can draw water to themselves and away from food preventing bacterial growth ie they act as a preservative. Inversion convert sucroseglucose and fructose so it will be sweeter is an inversion and needs a n enzyme invertase. Oxidation and reduction: Oxid of a sugars makes it less sweet Eg Glucose + oxygenglucuronic acid Reduction makes it more sweet eg glucose + hydrogen sorbitol Sugars control sweetness and texture as they control water activity Polysaccharides (40 or more units of both reducing ends as well as non reducing areas) eg starch and Oligosaccharides (10 or fewer units) eg raffinose (dried beans) Enzymes are used in food industry to enhance functionality in foods such as starches Sugars exist in alpha and beta forms. If OH group attached to carbon 1 projects downward it is alpha if it projects upwards its beta. Beta Glucans – polysaccharide, similar to cellulose From Cell wall of yeast, lowers cholesterol and activate macrophage cells of immune system Cellulose – most abundant polysaccharide, comes from plant cell walls, can replace fat in foods Dextrins - is a Polysac…can replace fat found in tapioca..used in salad dressings, puddings, spreads, frozen desserts. and Maltodextrin is a polysac, fat replacer and bulking agent. Eg corn starch Fructooligosaccharides: aka prebiotics and promote growth of probiotics which are bacteria beneficial to health…eg acidophilus, bifidus, faecium Inulin: is a Fructooligosaccharide that functions as a soluble dietary fibre. Occurs in chicory root, onions, asparagus, artichokes. When added to foods forms a viscous solution.(non-digestable) Pectics are polysacch. In the cell walls of plants. Pectin gels are formed when an acid and sugar are present. The acid lowers repulsive forces and sugar interacts with water lowering water activity for pectin. This allows pectin:pectin interactions which results in the gel. Starch is a polysacch. Eg corn, potato, rice, wheat. Starch gel is starch and water that has properties of a solid. Vegetable gums: polysacch, are plant hydrocolloids(derived from plants that act in water as colloidal dispersions). They are fat replacers, no calories. Smooth texture, act as thickeners and water binders…eg carrageenan, guar gum, xanthan gum Lipids: Organic substances that are nonpolar. Lipophilic. Fats and oils are triglycerides(three fatty acids one glycerol). Saturated fat – does not contain any carbon to carbon double bonds. Unsaturated if it does contain double carbon to carbon bonds. Unsaturated have cis and trans formations. Cis – hydrogen atoms bonding to the carbon-carbon double bond are located on same side of the double bond. Trans – hydrogens attached to carbon atoms are on either side of the double bond Polar Lipids - have a polar group and so have some solubility. Because of their amphiphilic structure they can function as emulsifiers in foods. Eg glycerophospholipid eg lecithin Waxes – esters of fatty acids that coat plant leaves and fruits. Used as protective coatings in food industry for fruits and vegetables to increase shelf life and flavour quality(fat coating/barrier prevents moisture into or out of food. Ex. Beeswax, carnauba wax, etc. Reactions of Lipids • Fractionation(splits oil into higher and lower melting point components) • Hydrogenation(addition of hydrogen atoms to saturated bonds in unsaturated fat. Used to harden liquid oils into semisolid fats and raises saturated fat level)(Increases life of oils since less oxidation occurring) • Hydrolysis(Separate fatty acids from glycerol portion of a triglyceride molecule) • Interesterification(Removal of fatty acids from glycerol, applied to hard fats like lard to produce improved creaming) • Oxidation(oxygen reacts with double bonds of unsaturated fatty acids, generating bad odors in fat foods and loss of nutritional value) • Polymerization Properties of Lipids: • Aeration(air bubbles formed during mixing of batter that are needed for expansion during baking) • Crystallization • Emulsification(homogeneous dispersions of an oil and water phase ex. Cake batter) • Flavour • Heat transfer • Mouthfeel • Plasticity • tenderization Proteins – Polymers(repeating units) of amino acids and are referred to as polypeptides due to the peptide bonds joining the amino acids.(2 amino acids bonded = dipeptide) Conjugated proteins means protein combined with nonprotein substances. Nonconjugated just protein. Globular proteins – spherical, soluble in water(ex. Myoglobin) Fibrous proteins – elongated(long), insoluble (ex. Collagen) Proteins are amphoteric substances(they can behave as an acids thru carboxyl group or as bases thru amino group) Proteins Reactions: • Denaturation – unfolding of protein structure due to H bonds breaking without disrupting protein covalent bonds(enzyme function stops, solubility in water decreases, bad for protein) • Hydrolysis – protein + water + protease enzyme = amino acids.(non enzymatic hydrolysis is breaking apart of molecles due to extreme heat or pH. Functional properties: • Emulsification – proteins can stabilize emulsions by acting at the oil-water interface. Since protein molecules are amphilic molecules, they can stabilize between the two phases • Enzymes – protein that function to speed up chemical reactions without being used up in the process.(affected by temp. pH, moisture) • Fat reduction • Foaming – foams are colloidal dispersions of gas in liquid(ex. Egg, milk, soy proteins to make ice cream, whipped toppings, etc) • Gelation – gel formed by balancing protein protein and protein solvent interactions(ex. Bread dough, tofu, yogurt). • Buffering – preventing a pH change by undergoing an ionization reaction(function of amino acid) • Solubility(effected by pH, and temp.) • Water holding capacity Unit 4 Chp 6 Colour: rods – light and dark Cones- colour red, green, blue Chroma (saturation): purity of colour Intensity: range from light to dark Pigment or chromophoretic compounds give food their colour 5 major pigments: • Chlorophylls • Carotenoids • Anthocyanins • Betalains • Heme protein (animals) Red Meat: • Red Meat fresh, Oxymyoglobin • Brown meat not fresh metmyoglobin • Oxygenation (not oxidation) • Nitrate cured meats…nitric oxide myoglobin- bright pink-red • Green and yellow can occur due to bacterial action on the myoglobin Fruits and Vegetables Colour is due to the resonance in the double bonds of the porphyrin rings Phenolic based pigments: anthocyanins, antoxanthins and betalains Anthocyanins: water soluble, deep purple to orange-red, related to flavonoids, pH sensitive, red in acid, blue at neutral and colourless at a pH 4 Antoxanthins: colourless or white can turn yellow, slight contribution to food colour Betalains: water soluble violet –red pigments, yellow, bind to glucose Carotenoids: fat soluble, carotenes and xanthophylls, eg beta-carotene in carrots, lycopene in tomatoes Cholorophylls: lipid soluble, green, similar to myoglobin (magnesium instead of iron) Cholorophyll a and b, as you heat the green goes into the water, magnesium leaves and it goes gray brown Colourant: pigment used to give colour to food; there were 100 colourants (from natural sources like turmeric, carotenoids, paprika and synthetic. All colourants are additives, FD&C colourants are certified safe by the FDA. Dyes are water soluble chemicals used to colour the entire food like a lollipop. Lake is an insoluble powder by precipitation of a water soluble food colourant used to colour the surface of food or fat based products including chocolate Exempt colourants are exempt from certification, eg cochineal from insects used to colour the lips red 5000 BC and caramel colour from 19th Century, burnt sugar. Flavour: Taste and aroma, receptors taste and smell. The 6 flavours are sweet, salty, sour, bitter, umami and astringency. Must be water soluble, therefore hydrophilic groups. Food acids are sour, salts are salty, alkaloids are bitter, astringency-puckering due to tannins and olyphenols and umami- savory and delicious sensation. Pungency: spicy heat, chili peppers, capsaicinoids, capsaicin Cooling: spearmint, peppermint, menthol, polyols (sugar alcohols) Bread: fresh baked smells good, smell is gone when it cools…volatile aroma molecules Additive flavours: Enzyme-produced flavours, eg meat flavour. Fermentation. Flavour enhancers: eg protein hydrolysates , Hydrolyzed vegetable protein (HVP) Encapsulation: stability, convenience and time release Thermal processing conditions: baking, deep frying, extrusion, retorting Storage conditions: low temp, high temp oxidation, pH Consumer conditions: cooking, freezing, refrigeration, reheating Flavour deterioration: Rancid- lipids, free fatty acids, hydrolytic rancidity, oxidative rancidity. Fishy- trimethylamines. WOF warmed over flavour-stale taste, reheated meats. Rheology: flow of matter in response to force Polysaccharides make food seem creamier richer, eg chocolate milk Fat replacers: mimics fat. For creaminess Sugars: compete with protein and starch for water. Collagen and gelatin: viscosity, thickening Food Additive is any substance, the use of which results, or may reasonably be expected to result in it or its by-products becoming a part of or affecting the characteristics of a food. • Maintain nutritional quality (antioxidants retard oxidation in fats) • Food preservation (mold inhibitors) • Improve product appearance (food colours) • Aid during processing, packaging or storage (humectants used to maintain soft texture in ‘chewy’ cookies) Adulteration is an intentional or unintentional misrepresentation of the composition of a product. Market Surveillance routinely test products sold on the market to help ensure compliance with food and packaging regulations. Food Composition – test samples of the product in a laboratory and calculating the nutrient content using available information contained in nutritional databases. Unit 5 Chp 10 Gram negative bacteria have thin cell wall and membrane Gram positive have a thick cell wall and no outer membrane Shape: coccus, bacillus, spirillum 1. Bacteria 2. Spores 3. Fungi a. Molds-mycellium, hyphae b. Yeasts 4. Protozoa Microbial Growth Phototrophs: need light Chemotrophs: need chemicals • Lithotrophic-need minerals • Organotrophic-need organic matter Temperature thermophiles Mesophiles Psychrophiles: low temp Proteins can produce a buffering effect to modify the ph Hurdle concept: apply 2 or more hurdles to impede bacterial growth, eg dairy products: low ph AND refrigeration Vaccuum packaging AND refrigeration Pepperoni cooking AND adding curing agents AND lowering water activity…result in a shelf stable product Foodborne Microorganisms 1. those that spoil food 2. pathogenic (cause disease 3. useful for food production Muscle food: 10 ^3 total organisms per gram; bacteria, yeasts, molds, viruses and parasites. Inside is sterile. Contact with knoves leads to contamination Pseudomonas cause spoilage Salmonella Lactic acid bacteria Fruits and Vegs: Low ph so acid tolerant bacteria like lactobacillus and Leuconostoc Dairy: Lactic acid bacteria, Psudmonas Food Spoilage Pectinase: breaks down pectin, causes spoilage in fruits and veg Cellulase
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