3. Basic Food Chemistry
• All foods, including people, consist of one or more of six basic
nutrient groups (CHNOPS):
• Carbon
• Hydrogen
• Nitrogen
• Oxygen
• Phosphorus
• Sulfur
4. Elements combine to form molecules or compounds
• Molecule: a unit composed of one or more types of atoms held
together by chemical bonds
• Compound: a substance whose molecules consist of unlike
atoms
Basic Food Chemistry
7. • Water content in foods
• Foods have water content of 0 to 95%
• Fruits and vegetables: 70 to 95% water
• Whole milk: 80% water
• Most meats: average just under 70%
• Least water: vegetable oils and dried foods such as grains and
beans
Water
10. • Freezing Point: The temperature at which a liquid changes to a
solid
• Solute: solid, liquid, or a gas compound dissolved in another
substance
• Melting Point: The temperature at which a solid changes to a
liquid state
• Boiling Point: The temperature at which a heated liquid begins to
boil and changes to a gas.
• The boiling point of water is 212°F
Water
11. Water – Hard vs. Soft
• Minerals in water determine whether it is hard or soft
• Hard water contains greater concentration of calcium and magnesium
compounds
• Soft water has a higher sodium concentration
12. • Transfer medium for heat
• Acts as a solvent
• Important agent in chemical reactions
• Factor in perishability and preservation of food
Functions of Water
13. • Food preservation decreases microorganisms
• Dehydration occurs in warm temperatures; hydration in cool
temperatures
• Water activity (aw) determines how quickly food decays
• More water means quicker decay
• Solutes reduce water activity via osmosis
Water
14. Carbohydrates
• Sugars, starches, and fibers of food
• Mostly found in plants
• Made in plants during photosynthesis
• Milk is an animal food that contains the carbohydrate “lactose”
• Made up of carbon, hydrogen, and oxygen
16. • Glucose: starch and sugar; called dextrose when refined
• Fructose (fruit sugar)
• Galactose: rare in nature; part of lactose
Carbohydrates: Monosacharides
17. • Sucrose: table sugar
• One glucose and one fructose molecule
• Lactose: milk sugar; not digestible by some
• One glucose and one galactose molecule
• Maltose: malt sugar; found in beer, cereal, some infant formulas
• Two glucose molecules linked together
Carbohydrates: Disaccharides
19. • Starch
• Amylose and amylopectin
• Stored energy for plants
• Digestible by humans
• Glycogen
• Stored energy for animals
• Digestible by humans
• Turned into lactic acid during slaughter
Carbohydrates: Polysaccharides
21. • Undigestible by humans
• Only found in plant-originated food
• Soluble fiber vs. insoluble fiber
• Cellulose
• Hemicelluloses
• Pectic substances
• Others (vegetable gums, inulin, lignin)
Carbohydrates: Fiber
22. Lipids: Fats vs. Oils
• Fats are solid at room temperature
• Oils are liquid at room temperature
• Fats are usually derived from animal sources
• Oils are derived predominantly from plants
23. • Animal sources include:
• Meats, poultry, and dairy products
• Plant food sources include:
• Nuts, seeds, avocado, olives, and coconut
Foods High in Lipids
24. Triglycerides
• Three fatty acids attached to a glycerol molecule
• 95% of lipids in foods
Fatty acids
• Length determined by number of carbon atoms
• Saturation determined by number of double bonds between carbon
atoms
• Saturation = no double bonds
Lipids (Fats)
26. • Contains phosphorus, which makes them water soluble
• Used as emulsifiers (e.g., lecithin)
• Emulsifier: compound that possesses both water-loving and
water-fearing properties so that it disperses in either water or oil
Phospholipids
27. Proteins
• Contain nitrogen
• Made from amino acids
• There are twenty-two amino acids
• Nine are essential (must be obtained by diet)
• Complete vs. incomplete proteins
• Most animal proteins are complete
• Most plant proteins are incomplete (protein complementation)
29. Vitamins and Minerals
• Vitamins
• Organic (carbon-containing)
• Can be destroyed by heat, light, or oxygen
• No kcalories
• Minerals
• Nonorganic; found on periodic table
• Cannot be destroyed by heat, light, or oxygen
• No kcalories
30. • Enrichment and fortification
• Enriched: modified by the addition of certain nutrients in order to
replace those lost during processing (refers to refined grain products)
• Fortified: modified by the addition of nutrients that were not present in
the original food
• Antioxidants
• Sodium: preservation, flavoring
Functions of Vitamins and Minerals
31. Vitamins
Water Soluble Fat Soluble
B complex: Vitamin A
Thiamin (B1) Vitamin D
Riboflavin (B2) Vitamin E
Vitamin B6(pyridoxine) Vitamin K
Vitamin B12(cobalamin)
Niacin
Folate
Pantothenic acid
Biotin
Ascorbic acid (vitamin C)
TABLE 3-6 Major Vitamins and Minerals in Foods Vitamins
32. Minerals
Macrominerals (minerals present in the
body in relatively large amounts)
Microminerals (minerals present in the
body in relatively small amounts)
Calcium (Ca) Iron (Fe)
Phosphorous (P) Zinc (Zn)
Potassium (P) Selenium (Se)
Sulfur (S) Manganese (Mn)
Sodium (Na) Copper (Cu)
Chlorine (Cl) Iodine (I)
Magnesium (Mg) Molybdenum (Mo)
Chromium (Cr)
Fluorine (F)
TABLE 3-6 Major Minerals in Foods
33. • Food additive: any substance added to foods
• Over 3,000 food additives, including:
• Sugar
• Salt
• Corn syrup
Nonnutritive Food Components
34. • Improve appeal
• Color compounds, natural colors, flavor compounds, texture
compounds
• Extend storage life
• BHA and BHT
• Maximize performance
• Protect nutrient value
Purpose of Food Additives
35. Plant compounds:
• Beneficial
• Phytochemicals: a nonnutritive “chemical” in plants that is considered
beneficial to health
• Harmful
• Natural toxins
• Caffeine in excess
• Caffeine
• Natural stimulant
Nonnutritive Food Components
36. Nonnutritive Food Components
Phytochemical Family Major Food Sources
Allyl sulfides Onions, garlic, leeks, chives
Carotenoids Yellow and orange vegetables and fruits; dark green, leafy vegetables
Flavonoids Most fruits and vegetables
Indoles Cruciferous vegetables (broccoli, cabbage, kale, cauliflower, etc.)
Isoflavones Soybeans (tofu, soy milk)
Isothiocyanates Cruciferous vegetables
Limonoids Citrus fruits
Lycopene Tomatoes, red grapefruit
Phenols Nearly all fruits and vegetables
Phenolic acids Tomatoes, citrus fruits, carrots, whole grains, nuts
Plant sterols Broccoli, cabbage, cucumbers, squash, yams, tomatoes, eggplant, peppers, soy products, whole grains
Polyphenols Green tea, grapes, wine
Saponins Beans and legumes
Terpenes Cherries, citrus fruit pee
TABLE 3-8 Phytochemicals: Potential Cancer Protectors
