Food Science & Consumer Document Essentials

Consumer Documents: Audience & Design

• Purpose: Engage general public; not academic/scientific.

• Audience profiling essential (students, seniors, new moms, business people, general mix).

  • Triggers:

  • Students—fast food, low-cost, trendy/international flavours.

  • Seniors—low cost, convenience, comfort.

  • New moms—time-saving, healthy.

  • Business—on-the-go, non-messy.

• Layout guidelines:

  • Generous white/coloured space; avoid small fonts.

  • Consistent fonts/colours; avoid red–green, red–black combos.

  • Bold/underline for emphasis; ALL-CAPS = online “shouting”.

  • Graphics: eye-catching but not cluttered.

  • Break into sections for accessibility & scannability.

• Information triage: research reliable sources; include citations (APA for Langara).

Milk – Definition & Physical Nature

• Multifaceted dispersion: solution (lactose), colloid (proteins), emulsion (fat globules).

• Fat naturally rises → cream; agitation → butter; warming → fermentation → yoghurt; draining → cheese.

• Composition affected by species, breed, feed, season, health.

  • Fat = most variable; protein = 2nd most variable.

Gross Composition

• Typical cow’s milk (by mass):

  • \approx 87\% water, 3.25\% fat, 3.3\% protein, 4.9\% lactose, 0.7\% minerals (ash).

Carbohydrate (Lactose)

• Disaccharide (glucose + galactose); \frac15 sweetness of sucrose.

• Least soluble common sugar → crystallisation (“sandy” condensed milk/ice-cream).

• Lactic-acid bacteria (Lactobacilli/Lactococci) hydrolyse lactose → lactic acid ↓pH → inhibits spoilage microbes.

Milk Fat

• Short-chain saturated FA (butyric, caproic) dominate; carries vitamins A, D, E, K.

• Globule membrane (phospholipid + protein) keeps droplets separate & protects against lipases.

• Rancidity ↔ free FA release.

Proteins

• 82 % casein (curd), 18 % whey.

• Casein micelle stabilized by calcium phosphate & kappa-casein “hairy layer”.

  • Acidification to pH\;\approx4.7 or rennet (chymosin) cleaves kappa-casein → coagulation.

  • Heat stable: needs >12 h boiling to precipitate.

• Whey proteins (esp. \beta-lactoglobulin) denature \approx66\,^\circ C; form “skin”, contribute to foams.

Colour & Flavour

• Whiteness: light refraction by casein & salts; skim milk bluish (less fat scattering).

• Flavour sources: lactose (sweet), minerals (salty), fat (mouth-feel), feed-derived volatiles.

• Maillard reactions during high-T pasteurisation/boiling → butterscotch notes.

Milk Processing

• Pasteurisation: LTLT 62\,^\circ C 30 min or HTST 72\,^\circ C 15 s; UHT 138\,^\circ C 2 s.

• Homogenisation: high-pressure ↓globule size; casein coats droplets → stable, whiter, more viscous.

Nutritional & Health Aspects

• Rich in protein, lactose, Ca, P, Vit A & D (fortified); low Fe & Vit C.

• Whole milk 3.25\% fat; 2 %, 1 %, skim <0.5\%.

• Lactose intolerance: deficiency of lactase → osmotic diarrhoea & gas; managed by enzyme pills, fermented dairy.

• Milk allergy (protein) in 1–10 % infants.

Fluid & Concentrated Milk Products

• Evaporated: 60 % water removed; sterilised; Maillard browning.

• Sweetened condensed: 50 % water removed + ≈55 % sugar (preservative by osmotic pressure).

• Powdered: 2–3 % moisture; mostly low-fat; instant rehydrates cold.

• Buttermilk: cultured skim; pH\approx4.5.

• Fermented (yogurt, sour cream, kefir) – lactic cultures coagulate casein.

Frozen & Heated Dairy Applications

• Ice cream: semi-solid foam (ice crystals + air + fat globules); churning adds air; sugar lowers T_f.

• Re-freezing → grainy (large ice) & rubbery (broken membranes).

• Heat: whey proteins denature; Maillard browning; skin/boil-over from steam under protein film.

  • Mitigate scorch with double-boiler, pre-wet pan.

• Acidic or tannin-rich ingredients (tomato, coffee) curdle milk—add milk to acid or use fresh milk.

Milk Foams

• Thin protein layer stabilises bubbles; best at 70\,^\circ C when whey proteins denature.

• Skim foams easiest (more protein); whole milk gives richer texture.

Cheese Fundamentals

• Three core inputs: milk, rennet (chymosin), microbes (starter, ripening).

• Steps: acidification → rennet coagulation → whey drainage → salting/pressing → ripening (proteolysis & lipolysis).

• Moisture determines style: fresh >55 % (cottage, feta), soft-ripened ≈50 % (Brie), semi-soft 35–45 %, hard 20–35 % (Cheddar), very hard \<20 % (Parmesan).

• Processed cheese: natural cheese + heat + emulsifying salts (e.g.
  \text{Na}2\text{PO}4) → melt-without-separation.

Plant-Based “Milks”

• Not true milks (no mammary origin) but beverages from soy, almond, oat, rice, coconut, cashew.

• Industrial process: clean/soak → wet-grind in water → heat/inactivate enzymes → filter out fibre & oligosaccharides → homogenise → add oils, gums, flavours, vitamins/minerals → pasteurise or UHT.

• Nutrition vs 250 mL cow milk:

  • Calories: 35–67 %.

  • Fat: ≈50 % (except coconut high sat-fat).

  • Protein: 0–7 g (only soy = complete).

  • Ca: fortified 20–25 % RDA (check label).

  • B12: added; naturally absent.

• Culinary: lower protein/fat → thinner sauces; add at end or thicken with starch; oat milk froths best.

• Environment: 9× less land than dairy; water use high for almonds, methane for rice paddies; soy/oats risk deforestation.

Legumes

• Terminology: legume (plant), pulse (dried seed), bean (individual seed).

• Nutrients per 100 g dry → 300 g cooked: 340–400 kcal, 20–34 g protein, 60–64 g CHO, 10–20 g fibre.

• Nitrogen fixation in root nodules → high protein.

• Limit AAs: methionine & tryptophan; complement with grains rich in those.

• Anti-nutrients: oligosaccharides (gas), phytates, lectins; mitigated by soaking, discard water, germination, fermentation.

• Soaking ratios: 4:1 water:bean; no salt until tender; hard water or acids slow softening.

• Quick-soak: boil 2 min, soak 1 h.

• Cooking: pressure/Instant Pot 20–30 min from dry; avoid baking soda (>vitamin loss).

• Popular species: soy (tofu, miso, tempeh), chickpea, kidney/lima, lentil, peanut.

Nuts & Seeds

• Botanical distinctions: true nuts (hazelnut), drupes (almond), legumes (peanut), seeds (sunflower, chia).

• High energy: ~600 kcal/100 g; 50–65 % oil (macadamia 75 %, chestnut \<5 %).

• Lipids mostly MUFA/PUFA; walnut high in \alpha-linolenic acid (ALA).

• Allergies: peanut/tree nut among top anaphylactic triggers (1–2 % pop).

• Rancidity risk → store airtight, cool, dark; freeze for months.

• Culinary: toasting enhances Maillard flavours; nut butters, oils, milks.

  • Coconut milk/cream: fat-rich, used in tropical cuisines.

  • Pesto: pine nuts as thickener/flavour.

Eggs

Structure & Composition

• Shell (CaCO$_3$) with bloom; membranes; albumen; yolk; chalazae.

• Whole egg: \approx75\% water, 12\% protein, 10\% fat.

• Yolk: 50 % water, 33 % fat (TG + phospholipids), 17 % protein; pigments lutein/zeaxanthin.

• Major white proteins: ovalbumin 54 % (heat-susceptible, S-groups), ovotransferrin 12 % (sets \approx60\,^\circ C), ovomucin 11 % (thick white), lysozyme (antibacterial), avidin (binds biotin).

Quality & Grading

• Candling checks air cell, yolk position, defects.

• Canada A (retail), B (baking), C (processing).

• Sizes: Jumbo \ge70 g → Peewee <42 g.

• Aging effects: pH rises (white up to 9.7), thinning albumen, enlarged air cell.

Storage & Safety

• Refrigerate <4\,^\circ C; keep in carton.

• Freeze: whites freeze well; yolks need sugar/salt to inhibit gelatinisation.

• Pasteurised liquid eggs (2 L ≈ 33 eggs) used for safety & labour.

• Salmonella mitigation: cook to \ge70\,^\circ C for \ge1 min.

Functional Roles

1. Structure via coagulation (custards, quiches).

2. Thickening/binding (meatloaf, breading).

3. Emulsification (lecithin in yolk → mayonnaise).

4. Leavening by foams (soufflé, angel cake).

5. Colour/flavour/shine (egg wash).

6. Clarification (consommé).

7. Interfering agent in ice-cream/candy.

Coagulation Science

• Whites: start 63\,^\circ C, set 65\,^\circ C.

• Yolks: start 65\,^\circ C, set 70\,^\circ C.

• Whole egg mixtures (custard) \approx73\,^\circ C but diluted increases setting \uparrow.

• Sugar ↑coagulation T (tender), acid/salt ↓T (quicker set, but tender).

Foams

• Beating unfolds proteins; incorporates air; stages: foamy → soft peak → stiff peak → dry/over-beaten.

• Factors: fresh > aged; room T faster; no fat; copper/stainless bowls; acid (cream of tartar) stabilises; sugar added once soft peaks formed.

• Applications: soft/hard meringue, sponge cakes.

Custards & Creams

• Gentle heat (water-bath) prevent curdling; stirring vs non-stirred defines cream vs baked custard.

• Overheat → syneresis (weeping), sulphur-iron green ring.

Meat & Poultry

Structure

• Muscle fibres (myofibrils) + connective tissue (collagen—softens to gelatin; elastin—tough).

• Marbling (intramuscular fat) adds juiciness.

Post-mortem & Aging

• Rigor mortis (actin–myosin cross-linking) → stiff; aging 14–21 d enzymes tenderise, develop flavour.

Tenderness determinants

• Cut location (loin tender, chuck tough), age, species, fat, marination (acid/enzyme), mechanical (grinding).

Classification & Cuts

• Beef: steer/heifer; primals—chuck, rib, loin, round, flank; grades determine marbling.

• Pork: youthful <12 m; cured→ham/bacon.

• Lamb (\<14 m) vs mutton (>20 m); “break joint” age test.

• Poultry labelled by age/weight: broiler/fryer, roaster, capon, stewing hen; turkey – fryer, hen, tom.

Storage & Safety

• Refrigerate <=4\,^\circ C; ground meats 1–2 d; freeze -18\,^\circ C; avoid cross-contamination.

• Cooking safe internal temps (examples):

  • Poultry \ge74\,^\circ C, ground beef \ge71\,^\circ C, pork \ge71\,^\circ C.

• Carry-over cooking: center temp rises 5–10\,^\circ C after oven removal.

Cooking Methods

• Dry heat (roast, grill) for tender cuts; moist (braise, stew) for tough.

• Shrinkage: rare ~10 %, medium 15 %, well 25 % (water/fat loss).

• Freezing → ice-crystal damage, freezer burn (dehydration) if poorly wrapped.

Fish & Seafood

• Lean (<5 % fat) vs fatty (>5 %) fish; shellfish = molluscs/crustaceans.

• High-quality protein, long-chain \omega3 (EPA/DHA); glycogen → sweet after autolysis.

• Spoils rapidly—store on ice 0\,^\circ C, use within 2 d.

• Cooking: minimal connective tissue → quick; overcooking dries/flakes; shellfish toughen with high heat.

• Sushi-grade: parasite-controlled (deep-frozen); shellfish should not be eaten raw in food service.

Game & Novel Proteins

• Game meats (venison, elk, rabbit, wild fowl) lean, low sat-fat, require marination/low-fat cooking.

• Only farm-raised game allowed in Canadian commercial kitchens (except NL).

• Insect protein (entomophagy): >2 000 edible species; high protein, fibre, minerals; sustainable (cricket farming, “flour”, bars).

Vegetable & Cereal Proteins

• High-protein grains: quinoa (complete), teff, kamut, wild rice.

• Combine plant sources for complete AA profile: beans+rice, PB + whole-grain toast, hummus+pita.

• Ultra-processed “plant-based meats” (Impossible, Beyond): formulated from pea/soy proteins, heme, coconut/canola oil; fortified B12; high Na, sometimes high sat-fat.

Lipids: Chemistry & Properties

• Triglyceride = glycerol + 3 FA; saturated (no double bonds) vs cis-unsaturated (natural) vs trans (industrial hydrogenation).

• Phospholipids (lecithin) amphiphilic → emulsifiers.

• Sterols: cholesterol (animal), phytosterols, Vit D precursors.

• Physical: insoluble in water, plasticity (spreadable), flavour carrier.

• Melting point ↑ with saturation & chain length; smoke point = T where acrolein smoke forms; choose high >220\,^\circ C oils for frying.

Processing

• Hydrogenation: add H$_2$ → solid fat, create trans-fat (now banned in Canada).

• Winterisation: chill & filter to remove waxes → salad oils remain clear.

Rancidity

• Oxidative: O$_2$ attacks double bonds → hydroperoxides → aldehydes (off-odour). Accelerated by light, heat, metals; retarded by antioxidants (BHA, BHT, tocopherol, \text{EDTA}).

• Hydrolytic: lipase + heat splits TG → free FA (butyric rancidity).

• Flavour reversion: early “fishy” from oxidising linolenic.

Deep-Fat Frying

• Ideal frying range 177–191\,^\circ C.

• Smoke point declines with food particles, emulsifiers, reuse.

• Quality fried product: golden, crisp surface, cooked interior, minimal oil uptake.

• Extend oil life: filter daily, avoid water/salt, use narrow fryer, cool/store dark, discard when dark/foamy.

Emulsions & Salad Dressings

• Emulsion: dispersion of immiscible liquids (oil-in-water O/W or water-in-oil W/O).

• Emulsifier (surfactant) lowers surface tension: lecithin, casein, mono-/diglycerides, gums.

• Stability factors: viscosity of continuous phase, droplet size (↓), emulsifier concentration, phase ratio.

Mayonnaise

• O/W emulsion: \ge65\% oil by wt; egg yolk = emulsifier; typical ratio 1 yolk : 200 mL oil : 30 mL vinegar/lemon.

• Breaks with overheating, freezing, fast oil addition; can be re-emulsified with new yolk/water.

Vinaigrette (“French dressing”)

• Temporary emulsion; classical 3 parts oil : 1 part vinegar; mustard, paprika, gums can increase stability.

Foams

• Gas dispersed in liquid/solid (egg white foam, whipped cream, sponge cake). Stability needs low surface tension, proteins/fats to form film.

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