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136 Cards in this Set

  • Front
  • Back
What is Food Science?
It is a multidisciplinary study.
It integrates the knowledge within various disciplines: chemistry, biology, physics, engineering, microbiology, toxicology, among others, to study the nature of foods, causes of their deterioration and the principles underlying food processing.
Food Science integrates and applies the knowledge within these various disciplines to the
Production,
Processing
Packaging
Distribution, Preparation
Evaluation of foods.
There are several areas of specialty
Food analysis, Food Composition
Quality Assurance
Food safety
Food processing
Food packaging
Sensory Evaluation
Development of New Products
Careers in Food Science and Technology
Food Industry
Academia
Basic/applied research
Government agencies in charge of food regulations.
Hunger
Millions of people regularly suffer from hunger; most are women and children. One child dies every 6 seconds for hunger-related causes.
Challenges to feed the world:
Population growth (world population today is almost 7 billion)
Differences in agricultural output in arious regions of the world.
Poverty
Cost of food
Oil price increases transport costs
Use of food crops for biofuel production
Others, such as war, natural disasters
Is there enough food to feed everyone in the world?
Yes, but many people don't have access to it.
Food Insecurity
Limited or uncertain availability of food or money to buy food. According to the Food and Agriculture Organization of the United Nations(FAO), IN 2013 there were 842 million undernourished people in the world.
Food security
Food security exists when all people, at all times, have access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life.
In 2012 how many percentage of American households were food secure throughout the entire year?
85%
Undernutrition
Failing health that results from a diet (long duration) that is not enough to meet nutritional needs. Undernutrition is common when food supplies are low and the population is large. It leads to nutritional deficiency diseases.
How many people worldwide suffer from micronutrient deficiencies?
2 Billion.
Which food deficiencies are the top causes of death from disease in developing countries?
Iron, iodine, vitamin A and zinc.
Micronutrients:
Vitamins and minerals.
Vitamine A deficiency
Severe vitamin A causes blindness. Each year, 250,000 to 500,000 children become blind from lack of vitamin A Vitamin A supplements given a few times a year could prevent it.
Iodine deficiency causes
Causes goiter. Currently, 2 billion people are at risk for iodine deficiency. In India about 500 million people get too little iodine, 54 million have goiter. Moreover, inadequate intake of iodine during pregnancy may lead to infants that develop mental retardation,
Over weight and obese
Over 1.4 billion people in the world
Obesity in the U.S.
During the past 20 years there has been a dramatic increase in obesity in the United States. This raises concern because of its implications for the health of Americans. Obesity increases the risk of many diseases and health conditions, such as coronary heart disease and type 2 diabetes.
What is hunger?
Being malnourished means you don't have the strength or energy to do even the simplest tasks.
Food insecurity
A situation that exists when people lack secure access to sufficient amounts of safe and nutritious food for normal growth and development and an active and healthy life.
On average, how many Kcal does a person need per day as a minimum energy intake?
1800
Causes of hunger
Natural disasters, conflict, poverty, poor agricultural infrastructure and over exploitation of the environment and financial crisis.
Hidden hunger?
Micronutrient deficiencies, which make people susceptible to infectious diseases, impair physical and mental development, reduce their labour productivity and increase the risk of premature death.
Chronic malnutrition
Lack of proper nutrition over time. It weakens the immune systems of young children, which can lead to malaria, diarrhea and pneumonia, akk of which can result in death.
Iron deficiency
Reduce the work capacity of individuals and entire populations, bringing serious economic consequences and obstacles to national development.
Iodine deficiency disorders
Iodine deficiency is the world's most prevalent, yet easily preventable, cause of brain damage.
Serious iodine deficiency during pregnancy
It can result in stillbirth, spontaneous abortion, and congenital abnormalities such as cretinism, a grave, irreversible form of mental retardation that affects people living in iodine-deficient areas of Africa and Asia.
The response towards iodine deficiency
Iodized salt.
VDA in pregnant women
It causes night blindness and may increase the risk of maternal mortality.
The best way of preventing micronutrient malnutrition is to
ensue consumption of a balanced diet that is adequate in every nutrient.
Food fortification
Food fortification refers to the addition of micronutrients to processed foods.
Which method is a valid technology for reducing micronutrient malnutrition?
Fortification of food with micronutrients.
Nutrients
Chemical substances present in food that provide
Energy.
Materials to build and maintain the body.
Macronutrients
Needed in gram quantities
Micronutrients
Needed in milligram or microgram quantities.
There are 6 classes of nutrients
Carbohydrates, lipids, proteins
Vitamins, Minerals, and water.
Minerals
Include a range of elemental, inorganic substances that are required from foods in small amounts, but have diverse roles in the body.
-Major minerals (ex. calcium, phosphorus, potassium)daily needs>100mg.
-Trace minerals(e. iron, iodine, zinc, etc.); daily needs< 100mg.
Vitamins have diverse functions in the body
-Help regulate and support chemical reactions in the body
-are required in very small amounts in the diet.
There are 13 vitamins, and that are classified as
-Fat soluble vitamins: A, D,E,and K
-Water soluble: B vitamins, C.
Vitamin A
Is found only in foods of animal origin (beef liver, chicken liver, fish, fortified milk, etc.)
Plant foods contain provitamin A (precursors of vitamin A) carotenoids.
Carotenoids
Carotenoids are natural pigments with colors varying from yellow to orange to red; they give color to carrots, tomatoes, etc.
Soem carotenoids (ex. beta-carotene and alpha-carotene) can be converted to vitamin A in the body; these are called provitamin A carotenoids (vitamin A precursors )
Which carotenoid is the highest provitamin A activity?
Beta-carotene
Vitamin C
Some good sources are : citrus fruits, green peppers, kiwi, strawberries, etc. Deficiency of vitamin C causes scurvy, disease characterized by bleeding gums, loose teeth, and weakness, among other symptoms. In the past it afflicted many people on long sea voyages. Today , it is rare in developed countries.
There are 8 B vitamins.
They have key roles in energy metabolism.
Folate: a B vitamin; the term folate corresponds to several chemical forms of the vitamin. Folic acid is a synthetic form added to foods and supplements. Good sources of folate are green leafy vegetables, bean, orange juice.
Food enrichment:
Nutrients lost during processing are added back. An example is all purpose flour enriched with vitamins Bi, B2, folic acid, Iron.
Food fortification
Nutrients added to a food where they were nit originally present. An example is orange juice with added vitamin D and Calcium.
Energy content of foods is often expressed in_____.
Calories.
One calorie is the amount of heat it takes to raise the temperature of 1 gram of water by_____.
1ºC.
One kilocalorie is the amount of heat it takes to raise the temperature of 1000 grams of water by 1ºC. 1 kcal or Calorie=
1000 cal.
The International System of Units(ISU) uses the ______ as unit of energy.
joule(J)
1kcal+4.184 kJ.
Energy-yielding nutrients:
Carbohydrates: 4kal/g
Lipids: 9 kcal/g
Proteins: 4 kal/g.
Calorie content of foods can be measured using instrument called
a bomb calorimeter.
A common method to estimate the caloric value of foods is by
Determining the amount of carbohydrates, lipids, and protein in the food, and the calculating the total energ based on the number of calories each nutrient yields(4-9-4 method).
Note: Alcohol is not an essential nutrient, but it also supplies energy: ~7 kcal/g.
Water
H2O is a vital nutrient. Our body contains ~60% water.
Water functions in the body
Solvent,
Component of body fluids
Reaction medium
Vehicle for transporting nutrients to cells
To remove waste products
Temperature regulation; etc.
Water is a polar molecule.
Water forms hydrogen bonds with other water molecules. Ice melting and water vaporization involve hydrogen bonds breaking
Scurvy
Scurvy is a rare condition that you don't have enough vitamin C in your diet.
Vitamin C(ascorbic acid) is vital for the body as it is needed to make collagen.
Collagen is a type of protein found in many different types of tissue, such as skin, blood vessels, bones and cartilage (which covers the surface of joints)
Symptoms of scurvy
Muscle and joint pain
Tiredness
The appearance of red dots on the skin
Bleeding and swelling of the gums.
What is folate and what does it do?
Folate is a B-vitamin that is naturally present in many foods. A form of folate, called folic acid, is used in dietary supplements and fortified foods.
Our bodies need folate to make DNA and other genetic material. Folate is also needed for the body’s cells to divide.
What happens if I don't get enough folate?
Neural tube defects
Preterm birth,
congenital heart defects,
and other birth defects,
Cancer,
Heart disease and stroke
Dementia, cognitive function, and Alzheimer's disease
DepressionW
What is on the label?
Serving Size
Amount of Calories
Limit these nutrients
Get enough of these nutrients
Percent(%) Daily Value
Footnote with daily Values (DVs)
Empty Calories
C alories from solid fats and/or added sugars. Solid fats and added sugars add calories to the food but few or no nutrients
Microwaving
Microwave ovens transfer heat via electromagnetic radiation.
Microwaves tend to affect only polar molecules, whose electrical imbalance gives the radiation a kind of handle with which to move them.
Advantages and disadvantaging of microwaving
It cooks food much faster.
However, speedy heating can cause greater fluid loss and so a drier texture, and makes it more difficult to control doneness.
Also microwaves cannot brown many food unless they essentially dehydrate them, since the food surface gets no warmer than the interior.
Carbohydrates
The most abundant organic compounds on earth
Major source of energy for the body
Provide >50% of calories for most people'Have important functions in foods, such as sweetening, thickening, gel formation, among others.
Carbohydrates are classified as
Simple Sugars (mono- and disaccharides)
Oligosaccharides and
Polysaccharides
Monosaccharides
Monosaccharides are the simplest carbohydrates; they can have a backbone of three to eight carbon atoms.
The most common monosaccharides in foods are
glucose, fructose and galactose; all are 6-carbon sugars/
Disaccharides
Formed by 2 units of monosaccharides joined together through a glycosidic bond.
eg. Sucrose (table sugar)= Glucose-Fructose
Lactose=Glucose=Galactose
Oligosaccharides
Carbohydrates containing from 3 to 10 sugar units.
Polysaccharides
Contain >10 sugar units up to thousands.
Starch
A common energy reserve of plants
Celulose
Structural component of plant cell walls
Pectin
Component of plant cell walls and between cells, binding cells together
Various gums from plants and seaweeds.
Starch
Starch is a polymer formed by glucose units. It consists of two types of chain:
amylose (linear chain) and amylopectin (branched chain). Both occur together in
starch granules. Starch is abundant in seeds, roots, and tubers. Starch is digested by
humans and supplies 4 kcal/g.
Cellulose
Cellulose is also a polysaccharide formed by glucose units, but composed only of
linear chains. Cellulose cannot be digested by humans. It is a component of the
dietary FIBER.
Pectin
Pectins form gels in food products such as jams, jellies, preserves.
Alginates
Alginates are used as food additives, frequently for their gel‐forming properties.
Pectins and alginates, guar gum, carrageenan, gum arabic ______ be digested by
humans.
cannot
DIETARY FIBER
It is found in plant foods. It is composed mainly of complex
carbohydrates: ‐ cellulose, hemicellulose, pectins, , and
‐ Lignin (noncarbohydrate)
Dietary fiber
Dietary fiber cannot be broken down during digestion. Fiber adds bulk to feces.
Promotes bowel regularity.
Inulin
Inulin is a polymer of fructose sugars, from a handful to hundreds per molecule.
Two primary uses of sugars
The storage of chemical energy.
To provide building blocks for physical structures, especially in plants.
Glucose
The most common sugar from which living cells directly extract chemical energy.
Fructose
Fructose is the sweetest of the common sugars, the most soluble water and absorbs and retinas water most effectively.
Sucrose
Table sugar.
Made of glucose and fructose.
Lactose
Composite of two simple sugars, glucose and galactose.
Okra
Okra mucilage can be exploited as a thickener in soups and stews, or its qualities can be minimized by using dry cooking methods.
Carrageenan
From certain red algae, has long Dietary fiber cannot be broken down during digestion. Fiber adds bulk to feces.
Promotes bowel regularity.
Alginates
Dietary fiber cannot be broken down during digestion. Fiber adds bulk to feces.
Promotes bowel regularity.
Gellan
Gellan, an industrial discovery, is a carbohydrate secreted by a bacterium, and in the presence of salts or acid forms very clear gels that release their flavor well.
Fiber
Fiber is defined as the material in our plant foods that our digestive enzymes can't break down into absorbable nutrients.
Four main compounds of fiber: Cellulose, lignin, pectins and hemicellulose.
Advantages of fibers?
Heart diseases, Diabetees, Digestive Problems, Weight Gain.
Lipids
Chemically diverse group of organic compounds that are essentially insoluble in water. They include: Fats and oils, sterols (eg. cholesterol); Waxes, among others.
Oils
Liquid at room temperature. ex. corn oil, soybean oil, olive oil, etc.
Fats
Solid or semi-solid at room temperature. Usually from animal sources. e.g.. butter, lard.
Fats and Oils-functions in foods
Source of energy(9 kcal/g)
Carriers of fat soluble vitamins (A,D,E,K)
Flavor, Texture
Cooking medium (frying)
Although lipids comprise a variety of chemical structures, most food lipids are
Triglycerides= Triacylglycerols
Contain 3 Fatty Acids linked to a backbone of glycerol
Simple triglycerides:
Contain only one type of fatty acid
Mixed triglycerides
Contain at least 2 types of fatty acid.
Most natural fats and oils are
Mixture of simple and mixed triglycerides.
Fatty acids
Carboxylic acids with hydrocarbon chains generally ranging from 4 C to 24C atoms; most have an even number of C atoms.
Fatty Acids can be
Saturated fatty acids contain no carbon-carbon double bonds.
Unsaturated are subdivided in
Monounsaturated: contain one carbon-carbon double bond.
Polyunsaturated fatty acids: contain two or more double bonds.
Essential fatty acids:
Cannot be made by the body must be obtained from foods.
They are: ‐ LINOLEIC Acid (ω‐6); which has 18C and 2 double bonds (18:2)
‐ alpha‐LINOLENIC Acid (ω‐3); which has 18C and 3 double bonds (18:3)
To find out the omega (ω) number,
count from the omega end (=methyl end; opposite to the
COOH) up to the first double bond. Next check examples of ω‐3 and ω‐6 fatty acids.
Common sources of Linoleic acid are
oils from corn, sunflower, soybean
Alpha‐linolenic
sources are flaxseeds, walnuts, and soybean and canola oils. Some fish and fish oils supply
other omega‐3 fatty acids, such as EPA* (20C and 5=) and DHA* (22C and 6=).
are flaxseeds, walnuts, and soybean and canola oils.
Some fish and fish oils
supply other omega‐3 fatty acids, such as EPA* (20C and 5=) and DHA* (22C and 6=).
EPA
Eicosapentaenoic acid
DHA
Docosahexaenoic acid
Based on annual production, currently the major vegetable oils are:
palm oil, soybean, canola and sunflower oils.
Hydrogenation of oils:
addition of hydrogen to double bonds. Some or all double
bonds can be hydrogenated, resulting in partial or complete hydrogenation,
respectively. Hydrogenation is used to convert liquid oils into more solid fats.
Hydrogenation increases the shelf life and stability of fats.
Vegetable oils
margarine, shortening
During partial hydrogenation of oils some trans double bonds can be formed.
cis double bond, trans double bond
Margarine
Modern margarine is now made not from solid animal fats, but from normally liquid vegetable oils.
________ allowed manufacturers to make a butter substitute that spreads easily even at refrigerator temperature, where butter is unusably hard.
Hydrogenation
Trans unsaturated fats
They are less prone to oxidation or heat damage and make cooking oils more stable.
They may contribute to human heart disease,
Functions of Proteins
1. Help build and maintain body structures
2. Enzymes, antibodies, among many others,
3. Can also be used to provide energy (4 kcal/g)
4. In foods, proteins contribute to physical properties of foods, such as gels, foams, cheese curd, bread dough, and others, such as in meat substitutes.
The components of proteins
Proteins are organic molecules composed of amino acids. Amino acids are the building blocks of proteins; all contain C,H, O, and N. Some contain S.
Most proteins contain about___ different amino acids.
20
Based on their nutritional role, amino acids are classified as
Essential (9 amino acids)
Nonessential
Essential amino acids
must be obtained from foods (cannot be made by the body)
Amino Acids basic structure
Amino group (H2N), carboxyl group (COOH)
Protein amino acids are joint together by________.
peptide bonds.
Proteins have up to __ levels of structure
Primary, Secondary, Tertiary and Quaternary.
Which protein structure is the linear sequence of amino acids?
The primary one. It determines the folding of a protein.
Protein reactions:
Denaturation.
Protein unfolds (loss of the three-dimensional structure)
-Proteins can be denatured by heat, acids, detergents, etc.
-Primary sequence is maintained
-Protein properties are significantly altered.
Coagulation
Aggregation of denatured protein
Ex. Egg white proteins denature and coagulate during cooking.
Hydrolysis
-Cleavage of peptide bond
-Shortens peptide chain
-can be caused by acid and enzymes.
eg. meat tenderizers.
Enzymatic activity
‐ enzymes are biological catalysts
‐ many enzymes are important in Food Science
‐ some have detrimental effects, such as
Polyphenol oxidases, which cause enzymatic
browning on the surface of fruits and vegetables
‐ others have desirable effects, such as invertase use in
some kinds of candies:
SUCROSE ------Invertase-----GLUCOSE + FRUCTOSE
Amino Acids and Peptide Contribute Flavor
Amino acids participate in the browning reactions that generate flavor at high cooking temperatures.
Many single amino acids and short peptides have tastes of their own.
Proteins can be denatured in many ways
By exposing them to heat, to high acidity, or to air bubbles, or to combination of these.
Marshmallows
Marshmallows were first made in France from the gummy root juice of the marsh mallow, a weedy relative of the hollyhock. The juice was mixed with eggs and sugar and then beaten to a foam.
Today, marshmallows are made by combining a vicous protein solution, usually gelatin, with a viscous protein solution, usually gelatin, with a sugar syrup concentrated to about the caramel stage, and whipping the mixture to incorporate air bubbles.
Meat Tenderizers
Meat tenderizers are protein-digesting enzymes extracted from a number of plants, including papaya, pineapple, fig, kiwi, and ginger.
All the tenderizing action takes place during cooking.
Problems with tenderizers
They penetrate into meat even more slowly than acids, so that the meat surface tends to accumulate too much and get overly mealy, while the interior remains unaffected.
It can be improved by injecting the tenderizer into the meat.
Celiac Disease
Having celiac disease means a person can't eat gluten, a protein found in wheat, rye, and barley, and in some medicines.
Over time, celiac disease can cause anemia, infertility, weak and brittle bones, and other health problems.