Food Science Exam 2 Simple

oligosaccharides functions in food

• prebiotic

• fructo = mild sweetness + improves mouthfeel

• low caloric value

polysaccharides

starch (digestible) and fiber (non-digestible)

starch

• digestible

• made of glucose

• sources = cereal grains, legumes, potatoes

• break down in small intestine to be used as an energy source

• thickeners and stabilizers

starch gelatinization

starch granules are heated, absorb water, and lose their crystalline structure (irreversible + forms pudding/custard when cooled)

dietary fiber

• resist digestion in small intestine

• cellulose = plant cell walls

• hemicellulose

• pectin = fruits + jam making

• extends feeling of fullness

• regulates blood glucose levels

• improves digestion + regular bowel movement (gut health)

• fermentation substrate

• sources = fruits, vegetables, whole grains

• water-holding + fat-binding

• thickener, emulsifier, gelling agent

• prebiotic + adds volume to food

ways to increase fiber intake

• whole-grain breads, pastas, crackers, cookies

• food with 3+ grams per serving

• skin of fruit and vegetables

• fruit over fruit juices

• sprinkle ground flaxseed on food

• limit white flower intake

proteins

• polymers of amino acids

• one or more polypeptide folding into a functional structure (3D)

• second role = energy source

structural support of proteins

muscle, skin, hair, nails (collagen, keratin, actin)

enzymes

speed up chemical reactions

transport proteins

move substances across membranes

hormones

chemical messengers

insulin

regulates blood sugar levels

peptide bonds

crucial for forming primary structure of proteins

side chains

• amino acid sequence (properties are key to protein folding)

• determine chemical properties of amino acids

• affect solubility and stability

• contribute to proteins ability to bind to other molecules

formation of proteins

1. primary = linear polypeptide chain

2. secondary = helix, b-sheet

3. tertiary = 3D folding

4. quaternary = two or more tertiary structures assemble

9 essential amino acids (THose, HILLs, VALleys, and TRees are My Phevorite)

1. threonine

2. histidine

3. isoleucine

4. leucine

5. lysine

6. valine

7. tryptophan

8. methionine phenylalanine

9. phenylalanine

cysteine

when two link they form disulfide bonds and influence the texture of gluten (dough springiness)

monosodium glutamate (MSG)

• enhances umami taste

• not found in nature

• salt from glutamic acid

• produced through fermentation

protein denaturation

• alternation of structure without breaking peptide bonds (unfolding)

• changes in solubility, firmness, viscosity

• “practically irreversible”

• more digestible

• emulsification, foaming, and gelling functions

hydrolysis of peptide bonds

peptide bonds are broken and amino acids are released

proteases

protein hydrolysis depending on temperature and pH

animal proteins (highly digestible)

1. meat (complete proteins)

2. milk + dairy (casein + whey)

3. eggs (egg whites = gold standard)

4. fish and seafood (omega-3)

plant proteins

1. legumes (fiber + minerals)

2. cereals (lower in protein)

3. soybeans + soy products = comparable to animal protein quality

PDCAAS

based on content of amino acids, digestibility, and ability to supply essential amino acids

functional properties of proteins

• solubility (increased by pectin)

• water-holding complex (influences moisture, juiciness, texture)

• emulsification

• foaming and generation

allergies

happen from proteins that are not broken down by digestive tract

(eggs, fish, shellfish, dairy, wheat, tree nuts, peanuts, soy)

lipids

• mostly water insoluble

• energy source (9kcal/g) → excessive = fat

• structural component in cell membrane

• insulation and protection

• carrier of fat-soluble vitamins

• promotes fullness

• sources = oil, margarine, butter, shortenings, meats, nuts, ice cream, milk, mayo, eggs, etc.

triglyceride

basic structure of lipids (glycerol + 3 fatty acids)

simple lipids

• oil and fats

• formed of triglyceride

• primary form of energy storage

complex lipids

• additional functional groups

• phospho- = phosphate group (egg yolks)

• glyco- = sugar groups

derived lipids

from hydrolysis of lipids

saturated fatty acids

• linear structure

• higher melting point

• solid at room temp

• crystalize more easily

• less prone to oxidation

• no double bonds

unsaturated fatty acids

• bends/kinks in structure (lose)

• lower melting points

• liquid at room temp

• vulnerable to oxidation

• smooth mouthfeel

• one or more double bond

cis fats

H atom on same side (health promoting)

trans fats

H atom on opposite sides (unhealthy)

• raises LDL and lowers HDL (heart disease risk)

lipid functions

• absorbs + retains flavor

• texture/mouthfeel

• improves palatability

• carrier for fat soluble vitamins

• source of omega-6 and omega-3 fatty acids

• act as emulsifiers

lipid oxidation

• chemical reaction of unsaturated fats and oxygen, light, heat, or metals

• results in rancidity

• reduces shelf-life

lipid oxidation prevention methods

• add antioxidants (vitamin E and C)

• packaging techniques (vacuum, modified atmosphere, and light blocking)

• storage conditions (cool (0-4 C), dry, dark)

vitamins

• organic compound

• carbon-based

• don’t produce energy

• must be obtained in diet (not synthesized)

• water solube = B and C

• fat-soluble = A,D,E,K

minerals

• inorganic compound

• naturally occurring elements (from Earth)

• structural components and vital processes in bodies

vitamin A

• sources = orange fruits + vegetables (carrots)

• main function = vision

• deficiency = night blindness and embryo defects

• toxicity = organ damage

vitamin D

• sources = sunshine + milk

• functions = assist in bone making + maintenance

• deficiency = osteomalacia

• toxicity = calcium deposits

vitamin E

• sources = seeds, nuts, oils

• toxicity + deficiency = rare

vitamin K

• sources = green leafy vegetables

• functions = blood clotting and bone health

• toxicity and deficiency = rare

vitamin C

• sources = fruits and vegetables (oranges)

• functions = immune support + act as antioxidant

vitamin B family sources

whole grains, leafy greens, legumes

water-soluble vitamin deficiencies

1. thiamin = beriberi

2. niacin = pellagra (4Ds)

3. vitamin c = scurvy

mineral functions

• bone health

• blood health

• fluid balance

• energy metabolism

• antioxidant

make-up of bones

• calcium = 99%

• phosphorus

• magnesium = regulator

iron (blood health)

• 70% = heme iron = absorbed by body (higher in meat)

• green leafy = non-heme

• sources = clams, beef, spinach, beans, lentils, chickpeas, mushrooms

• deficiency = fatigue, headaches, shortness of breath

sodium

• fluid and electrolyte balance

• regulates blood pressure

• nerve transmission and lowers blood pressure

potassium

• fluid balance

• lowers blood pressure

• heartbeat + muscle contractions

• normal nerve transmission

iodine

energy regulation, reproduction and growth

selenium

antioxidant

reasons for hydrogenation

• improved oxidative stability (extends shelf life + reduces rancidity)

• enhanced heat tolerance (high-heat cooking)

• higher melting point

issues of hydrogenation

• unsaturated bonds are reversible and the double bonds can be cis or trans fat

retrogradation

• starches firm and baked goods lose soft, fresh texture

• refrigeration accelerated process

  • 4 C for bread

  • 15-20 C for cake

ways to reduce retrogradation

1. control storage temp

2. adjust moisture content

3. use additives (emulsifiers and enzymes)

4. use modified starches

role of cysteine in baked goods

forms sulfur bonds which contribute to the development of gluten network, essential for texture and structure of dough