Food Science and Human Nutrition

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Food Science Study Guide

Food Science- the discipline in which biology, physical sciences, and engineering are used to study the nature of foods, the causes of their deterioration, and the principles underlying food processing

Food Technology- the application of food science to the selection, preservation, processing, packaging, distribution, and the use of safe, nutritious, and wholesome food

Aspects of Food Quality
-Appearance
-Size and shape
-Color
-Structure
-Transparency or turbidity
-Dullness or gloss
-Wholeness or damage
-Texture
-Felt with fingers, palette, or teeth
-Crunchy, crispy, chewy, creamy, tender
-Loss of water, stale, thawed/freezing
-Flavor
-Nutritional Value
-Provide energy
-Carbohydrates, proteins, lipids, cell membranes
-Safety
-Harmful microbes, natural toxins, contaminants, additives, allergens Water
-Abundant in all living things
-Impact on texture of foods
-Crisp texture to fruits/veggies
-Juiciness to meats
-Chips, cereals, and crackers (lack of water is important)
-Bacteria: need water for growth

Food Processing Techniques:
-Increase shelf life and inhibit bacterial growth
-Freezing
-Drying
-Heating and cooling medium

Chemistry of Water:
-O-H bonds are covalent bonds, electrons shared
-Polar molecule:
-Oxygen atoms attract electrons strongly than hydrogen bonds
-Hydrogen: slight positive charge
-Oxygen: slight negative charge
-Hydrogen bonds: weak bond between polar compounds
-Each water molecule can form 4 hydrogen bonds
-Water is a liquid rather than a gas at room temperature
Freezing:
-Water forms highly ordered crystalline structure
-Volume increases, density increases

Phase Changes of Water:
-Ice to water at 32 degrees (melting point)
-Water to steam at 212 degrees (boiling point)
-1 cal/g per C
-Latent of fusion: 80 cal
-Latent of vaporization: 540 cal
-Large amounts of energy needed to heat water

Sublimination: frozen foods placed in vacuum, food is heated, ice is converted to steam without going through liquid phase

Water as a Dispersing Medium
-Water dissolves small molecules to form a true solution
-Ionic solution:
-Molecules that ionize (break apart) in water
-Salts, acids, bases
-Molecular solution:
-Polar molecules associate with water through hydrogen bonding
-Sugars
-Clear solution
-Molecules that are too big to form true solutions
-Particle size: 1-100nm
-Individual particles cannot be seen
-Ex. Cellulose, cooked starch, pectic substances, gums
-Molecules that are too big to form colloidal dispersions
-Particle size: 100nm <
-Uncooked starch

Carbohydrates
-Organic compounds containing carbon, hydrogen, and oxygen
-Source of energy
-Source of fiber
-Provide important functional properties
-Sweeteners, thickeners, stabilizers, gelling agents, fat replacers

Simple Sugars:
-Naturally present in fruits
-Use to make candies and desserts

Complex Carbohydrates:
-Starch
-Fiber in fruits and vegetables
-Not really digestible

Monosaccharides:
-Sugar composed of 5 or 6 carbons
-Fructose, glucose, galactose
Disaccharides:
-Sugar composed of 2 monosaccharides joined by eliminating H2O
-Ex. Milk sugar, sugar, starch component

Glycosidic Bond
-Formed between carbonyl group and a hydroxyl group
-Covalent bond

Properties of Sugars
-Sweetness
-Body and mouthfeel (increases viscosity)
-Fermentation (use sugars for energy)
-Preservatives (prevent growth of bacteria and reduce water activity)
-Caramelization and browning

Relative Sweetness of Sugars
1. Fructose (115-170)
2. Sucrose (100)
3. Honey
4. Glucose
5. Galactose
6. Maltose
7. Lactose (30)

Caramelization
-Sucrose heated at high temperature
-Color change from colorless to golden brown to deep brown
-Development of caramel-like aroma
-Overheating of burnt sugar aroma

Sugar Alcohols
-Sweet...
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