WACE ATAR Food Science and Technology cheat sheet

Macronutrients: carbohydrates 17 kJ/g, protein 17 kJ/g, fat 37 kJ/g, alcohol 29 kJ/g, dietary fibre 8 kJ/g (energy factors used in Australian labelling).

Amino acids: nine are indispensable for adults (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine); a protein is complete when all are present at adequate levels.

Maillard browning occurs between reducing sugars and amino groups at roughly 140-165 degrees C; caramelisation is sugar pyrolysis without protein and starts near 160 degrees C.

Gelatinisation: starch granules absorb water and swell, amylose leaches out, and viscosity peaks; on cooling amylose retrogrades and sets a gel.

Emulsions are stabilised by amphiphilic emulsifiers lowering interfacial tension; oil-in-water (mayonnaise) versus water-in-oil (butter) depends on the continuous phase.

Gluten forms when hydrated gliadin and glutenin are worked; gliadin adds extensibility, glutenin adds elasticity, and fat or sugar shortens the network.

Water activity (aw) governs microbial growth more than moisture content: most bacteria need aw above 0.91, most yeasts above 0.88, xerophilic moulds above 0.75.

pH and isoelectric point: casein precipitates near pH 4.6; acids denature proteins and tighten gels, as in yoghurt or ceviche.

Danger zone is 5-60 degrees C; the temperature danger zone rule requires keeping high-risk food out of this range and holding hot food at 60 degrees C or above, cold at 5 degrees C or below.

Two-hour/four-hour rule: food held in the danger zone under 2 hours may be refrigerated or used; 2-4 hours must be used immediately; over 4 hours it must be discarded.

HACCP has seven principles: hazard analysis, CCP identification, critical limits, monitoring, corrective action, verification, and record keeping.

A CCP is a step where control is essential to prevent, eliminate or reduce a significant hazard; a critical limit is a measurable boundary such as 75 degrees C core temperature.

High-risk foods are moist, protein-rich and near-neutral pH (meat, dairy, cooked rice, shellfish); low-risk foods are dry, acidic, high-sugar or high-salt.

Cross-contamination controls: separate colour-coded boards, raw below ready-to-eat in refrigeration, separate utensils, and handwashing before and after raw handling.

Bacterial growth phases are lag, log (exponential), stationary and death; spores of Clostridium botulinum survive boiling and require pressure canning above 116 degrees C.

Allergen management requires declaring the nine Australian priority allergens and preventing undeclared allergen transfer through dedicated equipment and cleaning verification.

Design cycle stages: investigate and define the brief, generate and screen ideas, prototype, test and evaluate, refine, then produce and market.

A product design brief specifies target consumer, need or opportunity, constraints (cost, equipment, time), specifications and success criteria.

Product specification is measurable: mass, dimensions, moisture, pH, aw, texture (e.g. hardness in newtons), colour (Lab*), shelf life and cost per serve.

Sensory evaluation: discriminative tests (triangle, duo-trio) detect differences; descriptive profiling and hedonic 9-point scales measure attributes and liking.

Screening matrices score ideas against weighted criteria such as feasibility, cost, nutrition and consumer appeal to make selection transparent.

Prototyping moves from bench scale to pilot scale to commercial scale; scale-up changes heat transfer, mixing and filling, so formulations often need adjustment.

Shelf-life testing uses accelerated storage (elevated temperature and humidity) with extrapolation, plus microbial, chemical and sensory endpoints.

Packaging functions are containment, protection, preservation (barrier to oxygen, moisture, light) and communication; modified atmosphere packaging adjusts O2 and CO2 levels.

Thermal processing: pasteurisation (typically 72 degrees C for 15 s) reduces pathogens and extends chilled life; sterilisation (e.g. 121 degrees C) achieves commercial sterility.

Blanching inactivates enzymes (peroxidase, polyphenol oxidase) before freezing or drying to prevent browning and off-flavours.

Freezing rate determines ice crystal size: fast freezing gives small crystals and less cell damage; storage should be at -18 degrees C or below.

Drying lowers aw; sun, hot-air, freeze-drying and spray-drying differ in heat exposure and nutrient retention, with freeze-drying best preserving heat-labile vitamins.

Fermentation uses microorganisms to lower pH and produce preservative metabolites (lactic acid, ethanol); examples include yoghurt, sauerkraut, sourdough and wine.

Curing and smoking use salt, nitrite and smoke phenolics to inhibit Clostridium botulinum and develop colour and flavour.

Irradiation and high-pressure processing are non-thermal methods that inactivate microorganisms with minimal heat damage to texture and nutrients.

Extrusion cooking combines heat, pressure and shear to gelatinise starch and texturise protein, producing snacks, breakfast cereals and meat analogues.

Australian Dietary Guidelines emphasise five food groups, variety, limiting discretionary foods, and choosing water as the main drink.

Australian Guide to Healthy Eating plate proportions: vegetables and legumes about 1/2, grain foods about 1/4, lean protein about 1/4, plus fruit and dairy or alternatives.

Nutrient Reference Values include EAR, RDI, AI and UL; the UL is the highest usual intake unlikely to cause adverse effects, not a target.

Energy balance: weight change follows the difference between energy consumed and energy expended; 1 kg body fat approximates 37 000 kJ.

Glycaemic index ranks carbohydrate foods by blood glucose response; low-GI choices improve glycaemic control, and GI is distinct from glycaemic load.

Labelling rules: the Nutrition Information Panel must show energy, protein, fat, saturated fat, carbohydrate, sugars and sodium per serve and per 100 g.

Health Star Rating scores products from 0.5 to 5 stars using a nutrient profiling algorithm balancing energy, saturated fat, sodium and sugar against fruit, vegetable, fibre and protein content.

Consumer choice is shaped by price, availability, culture, habit, marketing, health literacy and label claims such as 'no added sugar' or 'high in fibre'.

Food system stages: production, processing, distribution, retail, consumption and waste; sustainability considers environmental, economic and social dimensions.

Food miles measure distance travelled but ignore mode and production intensity; lifecycle assessment (LCA) quantifies impacts from farm to plate.

Food loss occurs at production and processing; food waste occurs at retail and consumption, with roughly one-third of global food wasted.

Animal production generally requires more land, water and feed per kilogram of protein than plant production, so dietary shifts affect environmental footprint.

Food security has four pillars: availability, access, utilisation and stability; food sovereignty adds community control over food systems.

Ethical issues include fair trade pricing, animal welfare, labour conditions, genetic modification, and marketing of discretionary foods to children.

Policy instruments include the Health Star Rating, food fortification (iodised salt, folate in bread flour), front-of-pack labelling and advertising restrictions.

Circular economy approaches include composting, anaerobic digestion, upcycling by-products and reducing single-use packaging.

Mise en place covers reading the recipe, gathering and weighing ingredients, preheating equipment and setting up a clean work station.

Knife skills: claw grip protects fingers, the guide hand controls thickness, and consistent dice size ensures even cooking.

Measuring accuracy: use dry measuring cups for dry ingredients and liquid jugs at eye level; digital scales are most accurate for baking.

Cooking methods: moist (boiling, steaming, poaching, stewing) versus dry (baking, grilling, frying, roasting) affect texture, colour and nutrient loss.

Standard recipe format lists ingredients in order of use with exact quantities, method steps, yield, equipment and critical control points.

Investigation design: state a hypothesis, identify independent, dependent and controlled variables, and repeat trials to improve reliability.

Evaluation uses sensory and measurable data against the brief's success criteria, then recommends specific improvements with justification.

Occupational health and safety: sharp knives stored safely, panhandles turned inward, hot fat excluded from water, and correct manual handling.

Vitamin classification: fat-soluble A, D, E, K are stored in body tissue and can reach toxicity; water-soluble B group and C are excreted and need regular intake.

Key mineral functions: calcium and phosphorus for bone, iron for haemoglobin, iodine for thyroid hormones, sodium and potassium for fluid balance.

Vitamin C is heat- and oxygen-labile, so minimal cooking water, short cooking time and intact skins reduce loss; it also enhances non-haem iron absorption.

Dietary fibre fractions: soluble fibre (pectin, beta-glucan) lowers cholesterol and slows glucose absorption; insoluble fibre (cellulose) adds bulk and speeds transit.

Fatty acids: saturated (no double bonds), monounsaturated (one), polyunsaturated (two or more); omega-3 and omega-6 are essential and must come from the diet.

Protein denaturation by heat, acid, salt or mechanical action unfolds the structure, altering solubility and texture without changing amino acid composition.

Enzymatic browning by polyphenol oxidase requires oxygen and is controlled by blanching, acidification, or reducing available oxygen.

Colligative preservation: adding sugar or salt lowers water activity by binding water, inhibiting microbial growth as in jam or cured meat.

High-risk pathogen profiles: Salmonella in poultry and eggs, Listeria in soft cheese and chilled ready-to-eat food, E. coli O157 in undercooked beef, Bacillus cereus in cooked rice.

Cooling rule: cooked food should pass through the danger zone quickly, typically from 60 degrees C to 21 degrees C within 2 hours and to 5 degrees C within a further 4 hours.

Cleaning versus sanitising: cleaning removes soil with detergent; sanitising reduces microorganisms with heat or chemical sanitiser on a clean surface.

Personal hygiene controls: clean uniform, hair restrained, short nails without polish, no jewellery, exclusion of staff with vomiting or diarrhoea for 48 hours after symptoms stop.

Pest control and premises design: sealed openings, self-closing doors, smooth cleanable surfaces, adequate lighting and ventilation, and waste stored away from food areas.

Food recall triggers include undeclared allergens, microbial contamination and foreign matter; traceability requires one-step-back and one-step-forward records.

Risk assessment matrix combines likelihood and severity to rank hazards and prioritise controls.

Temperature monitoring must use calibrated probe thermometers, with records kept as verification evidence for HACCP.

Market research methods: surveys, focus groups, sensory panels and competitor analysis inform the brief and validate consumer need.

Concept screening tools include SWOT analysis, cost-benefit analysis and weighted decision matrices with scored criteria.

Formulation substitutions follow functional roles: replace sugar for sweetness, bulk, humectancy and browning; replace fat for mouthfeel, aeration and flavour carrying.

Shelf-life is determined by the first attribute to fail, whether microbial, chemical (rancidity, staling) or sensory (texture, flavour).

Quality assurance versus quality control: QA is the planned system ensuring standards; QC is the testing of samples against specifications.

Intellectual property and labelling compliance include ingredient lists in descending order by weight, allergen declarations, date marking and country-of-origin labelling.

Costing a product includes ingredients, packaging, labour, overheads, wastage and margin; the selling price must cover these plus GST treatment.

Iterative testing uses consumer panels at each prototype stage, with results recorded to justify design changes.

Canning process: raw fill, exhaust or vacuum, seal, retort at 116-121 degrees C, cool rapidly; low-acid foods need pressure processing to destroy botulinum spores.

UHT processing heats to about 135-140 degrees C for 2-4 seconds, giving shelf-stable aseptic products with minimal protein damage.

Concentration by evaporation (e.g. evaporated milk, juice concentrate) removes water and increases soluble solids, lowering aw.

Additive functions by class: preservatives, antioxidants, emulsifiers, stabilisers, thickeners, colours, flavours and anti-caking agents, each with a code number.

Freezer burn results from sublimation of surface ice; it is a quality defect, not a safety issue, and is minimised by airtight packaging.

Fermentation control variables include starter culture, temperature, pH endpoint and salt concentration, as in cheese making and beer brewing.

Minimal processing such as chilling, vacuum packing and high-pressure treatment preserves fresh-like quality but shortens shelf life versus thermal methods.

Extraction and refining (e.g. cold-pressed versus solvent-extracted oils) affect nutrient retention and yield.

Protein quality measures: biological value, net protein utilisation and PDCAAS/DIAAS score foods by amino acid profile and digestibility.

Iron absorption: haem iron from animal foods is well absorbed; non-haem iron needs vitamin C, and phytates, tannins and calcium inhibit absorption.

Calcium bioavailability is affected by oxalates (spinach), phytates and vitamin D status; dairy provides well-absorbed calcium.

Body mass index equals mass in kilograms divided by height in metres squared; adult healthy range is 18.5-24.9.

Chronic disease links: excess saturated fat raises LDL cholesterol, excess sodium raises blood pressure, excess free sugars increase dental caries and energy intake.

Food insecurity affects diet quality; low-cost nutritious choices include legumes, eggs, seasonal vegetables, wholegrains and canned fish.

Marketing and labelling terms such as 'natural', 'lite' and 'source of fibre' have specific regulated meanings; consumers should check the Nutrition Information Panel.

Special diets: vegetarian and vegan diets need attention to vitamin B12, iron, zinc, omega-3 and calcium; coeliac disease requires strict gluten avoidance.

Environmental impacts of food include greenhouse gas emissions, water use, land use, eutrophication and biodiversity loss.

Ruminant livestock produce methane through enteric fermentation; plant proteins generally have lower emissions per gram of protein.

Food waste hierarchy: prevent, redistribute to people, feed animals, recycle (compost, anaerobic digestion), then dispose.

Fair trade certification guarantees minimum prices and premiums for producers, aiming to reduce exploitation in supply chains.

Genetic modification regulation in Australia is overseen by the Gene Technology Regulator; GM foods require safety assessment before sale.

Food policy tools include taxation (sugar-sweetened beverage taxes), subsidies, procurement standards, zoning of fast-food outlets and school food policies.

Water footprint varies widely: producing 1 kg of beef requires far more water than 1 kg of wheat.

Seasonal and local purchasing can reduce transport emissions, though production method often dominates total impact.

Recipe modification for health: reduce sugar by 25 percent, replace saturated fat with unsaturated oils, add vegetables and legumes, and reduce sodium with herbs and spices.

Sensory testing conditions: controlled lighting, coded samples, palate cleansers (water, plain cracker), random order and no discussion between panellists.

Food photography and presentation: balance colour, height, negative space and garnish suitability for the product's purpose.

Data presentation: tables and graphs with labelled axes, units, means and ranges; percentage difference calculations support comparisons.

Reliability versus validity: reliability is consistency across repeats; validity is whether the test measures what it claims.

Hygiene in practical work: wash hands, sanitise benches, use separate boards for raw meat and ready-to-eat food, and clean as you go.

Time and resource planning: sequence tasks by critical path, use dovetailing, and record wastage to evaluate efficiency.

Evaluation criteria should be set before testing and matched to the brief, with evidence cited for each judgement.