Basic Foods Reviewer PDF

BASIC FOODS  By location INTRODUCTION TO FOOD SCIENCE Mediterranean, European, Italian, French, African, Asian, Indian,...

BASIC FOODS  By location INTRODUCTION TO FOOD SCIENCE Mediterranean, European, Italian, French, African, Asian, Indian, Chinese, Mexican, Filipino  Food is anything people eat to provide nourishment. Psycho-socio-cultural: as in comfort food, ethnic food, traditional LEGAL DEFINITION OF FOOD foods, gourmet foods, food taboos in some religions  food is anything taken into the body by mouth which includes drinks, bubble gum, any substance or Physiological: as in heart-healthy foods, vegetarian, low carb, ingredient needed in the preparation of food. lactose-free, gluten-free, and other dietary modifications for  Drugs and medicine taken into the mouth are not metabolic disorders. considered as food. Designer food: foods designed by biotechnology or genetic FOOD SELECTION DETERMINATION modification  Geography Functional foods, nutraceuticals, probiotics, prebiotics, synbiotics;  Soil phytochemicals, and organic foods.  Climate  Production technology NUTRITION FUNCTION OF FOOD  Transport system  Storage and preservation facilities  Nutrition is the primary function of food.  Nutritional sense food is defined as anything which  Economic condition of community when taken into the body will perform one or more of the following: build and repair body tissues, HISTORY OF FOOD AND CIVILIZATION provide energy and regulate body processes.  1.75 million years ago (rats, mice, frogs, snakes, Main nutrients: Water, Proteins, carbohydrates, fats, minerals tortoise and antelopes were part of the human diet). and vitamins  Discovery of fire (making food more digestible, sanitary and better tasting) PHYSICAL AND CHEMICAL PROPERTIES OF FOOD  Early 40,000- drying of meat, fish were practiced  12,000 BC (Egypt) making of flour  Basic food chemistry  6,000 years ago – cultivation of rice  Water  4,000 years ago- bread making  Carbohydrates  Civilization progressed  Lipids  Variations in food preparation developed  Proteins  The age of exploration made possible the distribution of produce. Basic Food Chemistry  1960’s increasing production through pesticides and fertilizers then new varieties of food by cross breeding  A basic principle of biochemistry is that all living things and gene modification. contain key elements (or atoms): carbon, hydrogen,  GMOs- genetic make-up had been altered for quality, nitrogen, oxygen, phosphorous and sulfur (CHNOPS). yield or resistance to diseases.  These are building blocks of organic material, carbon- containing compounds that are often living material. CLASSIFICATION AND KINDS OF FOOD  All the elements have the capacity to join together with similar or different elements to produce  According to source: molecules or compounds, which then combine to create all the substances on earth, including FOOD and Plant: grains, cereals, pulses, dried legumes, fruits, vegetables, BEVERAGEs. tubers, nuts, fungi (mushrooms), oilseeds, seaweed  This chapter focuses on both organic and inorganic compounds by covering the six nutrient groups found Animals: muscle, entrails, milk, poultry, eggs, fish, shellfish in people: water, carbohydrates, fats, proteins, vitamins and minerals.  According to level of manufacturing method involved:  Nutrients serve as the foundation underlying all principles in food and nutrition. Primary processed: the derived basic commodities from  Focused on what foods contain them, their chemical operations such as milling, oil extraction or animal slaughter composition, and their functions in foods. Preserved foods: those food items that still retain the natural form but are treated to lengthen shelf life Manufactured food: bears little or no resemblance to the physical form of the original source. WATER WATER CONTENTS IN FOOD  Many foods contain more water than any other nutrients.  Water content of food 0 to 95% greater.  Fruits and vegetables 70-95%  Whole milk – over 80%  Most meats- average just under 70% COMPOSITION OF WATER  At even higher elevations such as Mt. Everest, the  boiling point of water drops at 690C.  3 atoms – 1 O and 2H (H2O) FORMS OF WATER HARD AND SOFT WATER  Free or bound water  Free water- the largest amount of water present in  Hard water contains a greater concentration of foods, is easily separated from food. Calcium and Magnesium compounds.  Soft water has a higher sodium concentration Example- found in fruits  How to tell?  Hard water leaves a ring in the bath tub, a grayish  Bound water- Incorporated into the chemical structure sediment on the bottom of the pans, and the grayish of nutrients cast in washed whites Example - Found in breads FUNCTIONS OF WATER IN FOOD. Bound water is not easily removed and is resistant to freezing, it is also not readily available to acts as a medium for dissolving Heat Transfer: Moist-heat cooking methods salts, acids, or sugars.  Boiling SPECIFIC HEAT  Simmering  Steaming  The presence of hydrogen bonding between water molecules-means that it takes more energy to heat Dispersions: These are mixtures containing particles (solid, liquid, water than it does any other known substance. or gas) that are dispersed within another substance (solid, liquid  Water’s high specific heat makes it unique among the or gas) known as the continuous phase (dispersion medium). compounds on earth. Three types of dispersions:  This important characteristic of water enables animals,  Solutions including people, with a high water content to  Colloidal dispersions (sol, gel, emulsions and foams) withstand the very hot and very cold temperatures  Coarse dispersions sometimes found on earth. SOLUTION  The molecules of solute are so small that they are SURFACE TENSION completely dissolved by the solvent. Example: sugar in water  Water has a very high surface tension.  A solution is a homogenous mixture composed of only  This is indicated by the fact that, water molecules tend one phase; the solute will not precipitate from its fluid to clump together to form drops rather than spread medium and can’t be separated by filtering, but out in a thin film. sometimes can be removed by distillation.  This surface tension is observed when water is placed in a cylinder, the surface tend to be concave instead of flat.  Read water volume at the lower meniscus. FREEZING POINT COLLOIDAL DISPERSIONS  320F/00C pure water  Lowered temperature decreases water’s kinetic  Not all particles readily or homogeneously dissolve. energy, or the energy associated with motion, which  Some particles, called “colloids” (starches, gums and slows the movement of water molecules until they some proteins), never truly dissolve in a solvent finally set into a compact configuration. because of their large size.  Water expands and becomes less dense when  They remain in an unstable colloidal dispersion and do completely frozen (float) not noticeably change the dispersion’s freezing or  Expansion of frozen water ruptures pipes and boiling point. containers filled with water.  Emulsion- a liquid-in-liquid mixture.  Adding anything else to the water changes freezing point. Food examples include water-in-oil or oil-in-water emulsions. Neither water nor fats will dissolve in each other, creating an BOILING POINT emulsion.  2120F/ 1000C at sea level Milk, cream, ice cream, mayonnaise, gravy, sauces, salad  The water will not get any hotter (evaporate). dressings, and butter.  The food will not also be cooked faster no matter how much more heat is added. SOL AND GEL  Slow boil is more recommended because it is more gentle on the food and results in less evaporation.  A sol is a liquid gel.  When salts or sugars are added, the boiling point of  This is exemplified by gelatin or gums dissolved in hot water is increased. water. ELEVATION AND BOILING POINT Gel point: a point in the sol-gel transformation when the liquid begins to take a semisolid character  Increasing the elevation decreases the boiling point of water Gel: a liquid-in-solid dispersion (Jam, gelatin, cheese)  Sea level is 212 0F/ 100 0C but drops to 10F for every 500-ft increase in altitude. Foam: A gas-in-liquid (whipped egg white or whipped cream  Water boils in the mountains at lower temperature foams) or gas-in-solid dispersion (marshmallows). because of atmospheric pressure.  Example: At 7,000 feet, water boils at 920C.  Lipids or Fats  The fats and oils belong to a group called lipids.  Commonly called fats  Fats are solid at room temperature, derived from animal source  Oils are liquid, derived from plants.  Except: coconut and palm oils which are solid at room temp and fish oils which are liquid. Composition of Lipids COARSE DISPERIONS (SUSPENSION)  Composed of carbon, hydrogen, and oxygen atoms but in differing proportions.  Unlike colloids, coarse dispersions or suspensions will  One way to test is by dipping in water eventually settle out.  lipids are not water soluble but can be dissolved in  Generally, mechanical agitation (stirring) is necessary organic solvents not used in food preparation such as to create a suspension. benzene, chloroform, ether, and acetone.  Edible lipids are divided into three major groups: Example: When cornstarch is mixed into water, the starch triglycerides (fats and oils), phospholipids, and sterols. grains float within the liquid rather than dissolve. Triglycerides  Cornstarch suspensions are often used in Chinese cooking to give food its particular shiny appearance  Type of fat that circulates in your blood. and smooth mouthfeel.  About 95% of all lipids are triglycerides , which consists of three (tri) fatty acids attached to a glycerol WATER ACTIVITY molecule.  Fatty acids with one double bond present is called  Aw- or available water determines its perishability. monounsaturated fatty acid.  Bacteria need water to grow.  If there are two or more double bonds in the carbon  Aw 1.00 is pure water chain of fatty acids – polyunsaturated  Aw below.85 do not support bacterial growth.  The degree of unsaturation of the fatty acids in a fat  Thus, foods high in water content, such as milk, meat, affects the temperature at which it melts. vegetables, and fruits are more prone to microbial  The more unsaturated a fat, the more liquid it remains spoilage than dried foods. at room temperature.  In contrast, the more saturated a fat, the firmer its CARBOHYDRATES consistency.  Thus, vegetable oils are liquid at room temperature Functions  Saturated animal fats are solid. Fatty Acids in Foods  Provide energy  Protein-sparing action  Saturated- animal fats, coconut and palm oils  Normal fat metabolism  Monounsaturated- olive, canola  Provide fiber  Polyunsaturated- fish oils and vegetable oils  Stored form is called glycogen. –found in the liver and muscles. Also called animal starch. Phospholipids CLASSIFICATION  Similar to triglycerides in structure, in that fatty acids are attached to the glycerol molecule. The difference is  Monosaccharides that one of the fatty acids is replaced by a compound  Simple sugars containing phosphorous, which makes the  Disaccharides phospholipids soluble in water.  Polysaccharides  Component of cell membranes  Complex carbohydrates  They assist in moving fat-soluble vitamins Carbohydrates and hormones in and out of the cell.  Are the sugars, starches, and fibers found in foods.  Food sources: egg yolks, liver, soybean,  Plants are the primary source with the exception of wheat, germ, and peanuts. milk which contains a sugar called “lactose”.  The muscles from animals can also contain some carbs Uses of phospholipids in the food industry in the form of glycogen.  Common food sources: grains, rice, wheat, rye, barley,  Emulsifiers- allow hydrophobic and hydrophilic corn; legumes such as beans, peas, and lentils; fruits compound to mix. and some vegetables such as carrots, potatoes, and  Beverages, baked goods, mayonnaise, and candy bars. beets.  Lecithin is the best known phospholipid which is found in egg yolks. COMPOSITION OF CARBOHYDRATES Sterols  Composed of Carbon, Hydrogen, and Oxygen.  CHO are synthesized in green plants through the  Large, intricate molecule consisting of interconnected process of photosynthesis. rings of carbon atoms with a variety of side chains  The carbon, hydrogen, and oxygen atoms making up attached. the carbohydrates are arranged in a basic unit called  Cholesterol, bile, testosterone, estrogen hormones and “saccharide” vitamin D.  Most significant in food is cholesterol  Found only in animal origin  Non-essential Plant Sterols Enzymatic Reactions  Sterols are found in small amounts in many fruits,  Enzymes (or biocatalysts) are one of the most vegetables, nuts, seeds, cereals, legumes (beans, peas, important proteins formed within living cells because and lentils) including soybeans, and other plant source. they act as biologic catalysts to speed up chemical reactions. Functions of Lipids in Foods  Hastens chemical reaction without itself undergoing change  Heat transfer during food preparation  All enzymes are specific, i.e. they act only on specific  contributing to the tenderness substances called substrates  mixing (emulsifying)  Usually ends with an “-ase”  Texture (melting, plasticity, solubility)  Examples:  Flavor of foods  Lipoxidases- rancidity of fats  Increasing one’s feeling of fullness after eating  Proteinases- e.g. bromelin (pineapple), papain (satiety). (papaya), rennin (stomach lining of certain animals) PROTEINS Browning  From the Greek word proteos, of “prime importance”.  Through maillard reaction and enzymatic browning  Amino acids- building blocks of proteins.  Maillard reaction: The reaction between a sugar and protein resulting in the formation of brown complexes. Protein Quality in Foods The brown color produced during the heating of many different kinds of foods.  Most proteins are from animal sources – meat, poultry,  Also contribute s to flavors and golden crust fish, and shellfish, milk (cheese, yogurt, etc.) and eggs – of baked products, browning of meats and complete protein. dark color of roasted coffee.  Plant proteins except from soybeans and certain  grains are incomplete and will support maintenance Enzymatic browning: occurs when the enzyme tyrosinase oxidizes but not growth. the amino acid tyrosine to result in dark-colored melanin  Protein complementation- are two or more incomplete compounds such as those observed in dark teas and vegetables protein sources that together form a complete protein. HEAT IN FOOD PREPARATION and COOKING METHODS The best sources of proteins from plants are the legumes-beans, peas and lentils- which are often combined with grains. Purpose of Cooking Composition of Proteins Definition of cooking is the application of heat and transfer of energy to food”. The purposes of cooking food are to:  Protein differs from CHO and fat because it is the only one containing Nitrogen.  Improve palatability and digestibility  CHON  Render it safe from parasites and microorganisms Protein Functions in Food  Alter color, texture and flavor of food  Inactivate enzymes  Hydration  Prolong shelf life of food  Denaturation/ coagulation  Enzymatic reactions Heat Transfer in Food  Browning  Involves two things: Hydration  Temperature – represents the amount of thermal energy available  The ability of proteins to dissolve in and attract water  Flow of heat- represents the amount of  Capability to form gels (an intricate network of protein thermal energy from place to place. strands that trap water)  Aid in dough formation Mechanism of Heat Transfer Denaturation  Convection  Radiation  is a process in which proteins or nucleic acids lose the  Induction quaternary structure, tertiary structure, and secondary structure which is present in their native state, by Most foods are cooked by a combination of at least two heat application of some external stress or compound transfer processes, not just one.  When subjected to heat, pH extremes, alcohol, and physical and chemical disturbances  When proteins are denatured they can result to coagulation (the curdling or congealing of proteins)  Irriversible Uses of denaturation in the food industry Foam formation: once the foam forms, adding sugar to beaten egg whites helps to stabilize the delicate denatured protein; therefore, sugar is often added near the end of whipping Cheese production relies on coagulation of proteins, which is speeded up by adding salt. Cheese is made by creating a curd composed of denatured milk proteins that collapse together.