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The commercial sterility standard for low-acid canned food: a heat process delivering twelve decimal reductions of Clostridium botulinum spores.
This is why canned foods like tinned vegetables, meats and soups sit safely on a supermarket shelf for years without refrigeration.
See also: D-value, F-value, Commercial sterility, Clostridium botulinum
Estimating shelf life by storing product under elevated stress, usually temperature, and extrapolating using a kinetic model such as Q10 or Arrhenius.
Lets a food company put a “best before” date on a new snack or sauce within weeks of developing it, instead of waiting out the full real-time shelf life.
See also: Q10, Shelf life, Glass transition temperature
A process contaminant formed from asparagine and reducing sugars during Maillard browning above about 120 °C, classified as a probable human carcinogen.
Forms in fried and baked starchy foods like potato chips, French fries and toast; health advisories recommend cooking them to a golden colour rather than dark brown to limit it.
See also: Maillard reaction, Reducing sugar
A group of highly toxic and carcinogenic mycotoxins produced mainly by Aspergillus flavus and A. parasiticus, commonly in groundnut, maize and spices.
The reason groundnuts, maize and spices are tested and rejected for mould contamination before reaching the market — untreated exposure is linked to liver damage.
See also: Water activity, HACCP
The highly branched fraction of starch, with α-1,4 chains joined by α-1,6 branch points roughly every 20–25 units.
The branched starch that makes rice sticky and gives bread its soft crumb; waxy rice varieties are almost pure amylopectin.
See also: Amylose, Starch gelatinisation
The essentially linear fraction of starch, made of α-1,4-linked glucose units. Typically 20–30% of common starches.
The straight-chain starch behind the firm, separate grains in basmati rice and the hard set of cooled boiled potatoes.
See also: Amylopectin, Retrogradation
A substance that delays oxidative rancidity. Primary antioxidants (BHA, BHT, TBHQ, tocopherols) donate hydrogen to break the radical chain; secondary antioxidants (citric acid, EDTA) chelate pro-oxidant metals.
Added to potato chips, cooking oils and butter — as BHA, BHT or vitamin E — to stop them turning rancid on the shelf.
See also: Rancidity, Peroxide value
Filling a commercially sterile product into a sterilised container in a sterile environment, sealing without further heat.
What lets Tetra Pak milk and juice sit unrefrigerated on a store shelf for months, then spoil within days once opened.
The proportion of absorbed nitrogen retained by the body, expressed as a percentage.
Used to compare protein quality in diet plans and nutrition science — eggs and milk score high, most plant proteins score lower unless combined with each other.
See also: Protein Efficiency Ratio, Limiting amino acid
A short heat treatment, usually 70–100 °C, applied before freezing, drying or canning, primarily to inactivate enzymes.
The quick dip in boiling water before freezing vegetables like peas and beans, so they don't turn mushy or lose colour in the freezer.
See also: Enzymatic browning, Peroxidase test, Polyphenol oxidase
Thermal degradation of sugars in the absence of amino groups, producing colour and flavour compounds. It requires much higher temperatures than the Maillard reaction.
What gives roasted onions, seared steak crust and toffee their brown colour and flavour — distinct from the browning caused by a Maillard reaction.
See also: Maillard reaction
The main phosphoprotein of milk, about 80% of milk protein, existing as micelles stabilised by κ-casein. Precipitates at pH 4.6 or on rennet action.
The protein that curdles when lemon juice is added to hot milk to make paneer or cheese; also why milk clots when it reaches an acidic stomach.
See also: Isoelectric point, Whey protein
Fruit showing a sharp rise in respiration and ethylene production at the onset of ripening — banana, mango, apple, tomato — and able to ripen after harvest.
The reason bananas and mangoes can be bought unripe and left to ripen on the kitchen counter, while grapes and citrus can't.
See also: Respiration rate, Ethylene
An anaerobic, spore-forming bacterium producing botulinum neurotoxin. Proteolytic types do not grow below pH 4.6, aw 0.94 or 10 °C.
The reason home-canned low-acid vegetables need a pressure canner, not just boiling water, and why a bulging or dented can is never opened.
See also: 12D concept, Low-acid food, Water activity
The international collection of food standards, guidelines and codes of practice of the FAO/WHO Codex Alimentarius Commission.
The international reference standards that FSSAI and most national food regulators align with when setting limits for additives, pesticides and labelling.
The slowest-heating location in a container, where lethality accumulates least during thermal processing.
The point inside a can, jar or retort pouch that a food processor measures temperature at, because it's the last place to reach a safe temperature during sterilisation.
The condition in which no microorganisms capable of growing under normal storage conditions remain, though highly heat-resistant spores may survive.
What lets a tin of beans sit in a warehouse for two years at room temperature without spoiling, even though it isn't completely free of microorganisms.
See also: 12D concept, Sterilisation
The first stage of drying, in which free surface water evaporates at a steady rate and the surface stays at the wet bulb temperature.
The early, fast stage of drying fruit, grain or milk powder, before the surface dries out and the process slows down.
See also: Wet bulb temperature, Critical moisture content
Bulk storage in which gas composition is continuously monitored and actively corrected, used mainly for fruit such as apples.
Why apples bought from a supermarket in April can still taste crisp from an autumn harvest — kept in low-oxygen rooms that slow ripening for months.
See also: Modified atmosphere packaging, Respiration rate
A step at which control can be applied and is essential to prevent, eliminate or reduce a food safety hazard to an acceptable level.
The exact step in a food factory — a cooking temperature, a metal detector — where a HACCP plan actually stops a hazard from reaching the consumer.
See also: HACCP, Critical limit
A measurable maximum or minimum value at a CCP that separates acceptable from unacceptable product.
The specific number, like “core temperature must reach 75°C”, that a factory worker checks at a critical control point to know a batch is safe.
See also: Critical control point, HACCP
The moisture content at which drying shifts from the constant rate period to the falling rate period.
Tells a biscuit or snack manufacturer what packaging barrier is needed to stop the product going soft and stale on the shelf.
See also: Constant rate period
The time at a given temperature required to destroy 90% of a microbial population — one log reduction.
Used by canneries and sterilisation engineers to work out exactly how long a product must be heated to kill enough bacteria to be safe.
See also: z-value, F-value, 12D concept
The percentage of galacturonic acid carboxyl groups in pectin that are methyl-esterified.
Determines whether a fruit jam needs added sugar and acid to set (high-ester pectin) or can be made as a low-sugar spread (low-ester pectin).
See also: Pectin
Loss of a protein's secondary, tertiary and quaternary structure without breaking peptide bonds, caused by heat, pH change, salts, solvents or shear.
Why an egg turns solid when fried or boiled, and why milk proteins clump together if boiled with lemon juice.
See also: Isoelectric point, Protein coagulation
Carbohydrate polymers not hydrolysed by human digestive enzymes. Soluble fibre forms viscous gels; insoluble fibre adds bulk.
The reason whole wheat atta, oats and vegetables are recommended over refined flour for digestion and blood sugar control.
A surface-active molecule with hydrophilic and lipophilic regions that lowers interfacial tension and stabilises an emulsion.
What keeps mayonnaise, ice cream and chocolate from separating into oil and water layers while sitting on a shelf.
A dispersion of one immiscible liquid in another, stabilised by an emulsifier. Oil-in-water as in milk and mayonnaise, or water-in-oil as in butter and margarine.
Milk, mayonnaise, butter and salad dressings are everyday examples — mixtures of oil and water that would otherwise separate.
See also: Emulsifier, HLB, Homogenisation
Browning catalysed by polyphenol oxidase, which oxidises phenolic compounds to quinones that polymerise into brown melanins. It requires oxygen, the enzyme, and a phenolic substrate.
Why a cut apple or potato turns brown within minutes, and why a squeeze of lemon juice slows it down.
See also: Polyphenol oxidase, Blanching, Maillard reaction
A gaseous plant hormone that triggers and accelerates ripening and senescence, active at parts-per-million concentrations.
The ripening gas behind the old kitchen trick of storing bananas away from other fruit, so the whole bowl doesn't ripen and spoil together.
See also: Climacteric fruit, Controlled atmosphere storage
A process combining mixing, shearing, heating and forming in a screw barrel, forcing material through a die. High-temperature short-time extrusion cooks and expands.
The process behind pasta, breakfast cereals and puffed snacks like Kurkure — dough forced through a shaped die under heat and pressure.
See also: Specific mechanical energy, Starch gelatinisation
The total lethality of a heat process expressed as equivalent minutes at a reference temperature. F0 is the reference at 121.1 °C with z = 10 °C.
Used by food engineers to design a canning (retort) process that guarantees a can is actually safe, not just cooked through.
See also: D-value, z-value, 12D concept
The controlled use of microorganisms or their enzymes to convert food substrates, producing acids, alcohol, gas and flavour compounds.
What turns milk into curd and dosa batter into a light, sour, bubbly mix overnight.
See also: Lactic acid bacteria, Probiotic
An officer appointed under the FSS Act with powers to inspect premises, take samples and initiate enforcement.
The FSSAI-appointed inspector who checks restaurant kitchens, food factories and street vendors for licensing and hygiene compliance.
See also: FSSAI, FSS Act 2006
The deposition of protein, mineral or burnt-on residue on heat exchanger surfaces during processing, adding a thermal resistance and restricting flow.
The reason a milk pasteuriser or evaporator needs regular shutdowns for cleaning — burnt-on protein and mineral deposits reduce heat transfer over time.
See also: Overall heat transfer coefficient, Pasteurisation
Fatty acids released from triglycerides by hydrolysis, reported as a percentage or as acid value.
Tested in cooking oil to judge how much it has broken down from repeated frying, since high levels mean rancid, lower-quality oil.
See also: Rancidity, Peroxide value
Dehydration by freezing the food and subliming the ice under vacuum below the triple point of water, followed by desorption of bound water.
Why instant coffee dissolves instantly, and why astronaut ice cream and lightweight camping meals keep their shape and nutrients for years.
See also: Sublimation, Spray drying, Glass transition temperature
The Food Safety and Standards Act, 2006 — the umbrella Indian food law that created FSSAI and replaced multiple earlier statutes.
The law that created FSSAI and made food licensing, labelling and safety standards legally enforceable across India.
See also: FSSAI, Food Safety Officer
The apex Indian regulator for food, established under the Food Safety and Standards Act, 2006, responsible for standards, licensing and enforcement.
The body whose logo and licence number appear on every packaged food product sold legally in India.
See also: FSS Act 2006, Food Safety Officer
The temperature at which an amorphous solid changes between a rigid glassy state and a rubbery state.
Why crackers and papad turn soft and lose their snap when left open in humid weather.
See also: Freeze drying, Water activity
Baseline requirements for premises, equipment, personnel and processes to ensure food is consistently produced safely.
The basic hygiene and process rules — clean equipment, trained staff, pest control — a food factory must have in place before it can even attempt HACCP or export certification.
See also: Prerequisite programme, HACCP
A systematic preventive food safety system built on seven principles, beginning with hazard analysis and identification of critical control points.
The food safety system most large food manufacturers and export-focused plants are required to run, especially for meat, seafood and dairy.
See also: Critical control point, Critical limit, Prerequisite programme
An affective sensory scale measuring degree of liking, most commonly the 9-point scale from dislike extremely to like extremely.
What a “rate this product 1 to 9” taste-test survey uses when a company decides whether a new flavour is ready to launch.
See also: Sensory evaluation, Triangle test
Applying isostatic pressure of roughly 400–600 MPa to packaged food to inactivate vegetative microorganisms with little heat.
The technology behind cold-pressed juices sold with a longer shelf life than fresh juice, without heat pasteurisation.
See also: Hurdle technology, Pasteurisation
A number from 0 to 20 describing an emulsifier's relative affinity for water and oil.
Used by food formulators to pick the right emulsifier for a product — a low-HLB emulsifier suits butter-type spreads, a high-HLB one suits salad dressings.
See also: Emulsifier, Emulsion
The section of a continuous pasteuriser that provides the required residence time at process temperature.
The pipe section in a milk pasteuriser that keeps every drop hot long enough to kill harmful bacteria before it's cooled.
See also: Laminar flow, Reynolds number, Pasteurisation
Forcing a liquid at high pressure through a narrow valve to break dispersed droplets into smaller ones, stabilising the emulsion.
Why packaged milk doesn't separate into a layer of cream on top, the way fresh, unprocessed milk does.
See also: Emulsion, Stokes law
The principle that higher temperature for shorter time achieves the same microbial lethality with less loss of nutrients, colour and flavour.
The reason pasteurised milk in a carton tastes fresher and less “cooked” than boiled milk — a shorter, hotter treatment instead of prolonged boiling.
See also: UHT, z-value, Pasteurisation
Combining several mild preservation factors — pH, aw, temperature, preservatives, redox potential — so that their combined effect prevents microbial growth where none alone would suffice.
Why pickles are salty, sour and stored in oil all at once — no single barrier alone would stop spoilage, but combined they do.
See also: Water activity, Preservative
Addition of hydrogen across double bonds of unsaturated fatty acids using a nickel catalyst, raising melting point and oxidative stability.
What turns liquid vegetable oil into solid vanaspati or margarine — and why health advisories now warn about the trans fat it can create.
See also: Trans fat, Iodine value
The equimolar mixture of glucose and fructose produced by hydrolysing sucrose, so called because the optical rotation inverts from positive to negative.
Used in commercial baking and sweet-making, including Indian mithai syrups, to stop sugar crystals forming and keep the product moist.
See also: Reducing sugar
Grams of iodine absorbed by 100 g of fat, measuring total unsaturation.
Tells a cooking-oil buyer or blender how likely an oil is to turn rancid — higher values mean more unsaturated fat and faster spoilage.
See also: Hydrogenation, Saponification value
Exposure to ionising radiation — gamma, electron beam or X-ray — measured in grays, to reduce microbial load, control insects or inhibit sprouting.
The reason some imported spices, onions and potatoes are treated to kill insects and stop sprouting without heat or chemicals — look for the Radura symbol on the pack.
See also: Hurdle technology
The pH at which a protein carries no net electrical charge, so electrostatic repulsion between molecules is minimal.
Why paneer and cheese are made by adjusting milk's acidity — the proteins clump together and separate from the whey at this exact pH.
See also: Denaturation, Casein
Gram-positive, non-sporing bacteria producing lactic acid as the main fermentation product — Lactobacillus, Lactococcus, Streptococcus, Leuconostoc, Pediococcus.
The organisms behind curd, yoghurt, dosa batter and pickles, and the reason probiotic drinks list specific bacterial strains on the label.
See also: Fermentation, Probiotic
Smooth, ordered flow in parallel layers, occurring at low Reynolds number, with a parabolic velocity profile in a pipe.
Used in cleanroom and sterile filling lines at infant-formula and pharma-grade food plants to keep the air free of contamination.
See also: Reynolds number, Holding tube
The essential amino acid present in a protein in the smallest amount relative to requirement, capping the use of all the others.
Why nutritionists recommend eating rice with dal — each is short on a different essential amino acid, and combining them completes the protein.
See also: Biological value, Protein Efficiency Ratio
The logarithmic average of the temperature differences at each end of a heat exchanger, used because the difference varies along its length.
Used by process engineers sizing a heat exchanger for a dairy or juice plant, to work out how much heating surface is actually needed.
See also: Overall heat transfer coefficient
A food with an equilibrium pH above 4.6 and water activity above 0.85, capable of supporting Clostridium botulinum growth.
The reason canned vegetables and meats need pressure sterilisation, while naturally more acidic canned tomatoes or pickles can be processed more simply.
See also: Clostridium botulinum, 12D concept, Pasteurisation
A non-enzymatic browning reaction between a reducing sugar's carbonyl group and a free amino group of an amino acid or protein, producing melanoidin pigments and a wide range of flavour compounds.
What gives bread crust, roasted coffee, fried onions and a seared tandoori chicken their brown colour and flavour — distinct from sugar caramelising on its own.
See also: Caramelisation, Enzymatic browning, Reducing sugar, Acrylamide
Replacing the air in a pack with a controlled gas mixture, typically carbon dioxide, nitrogen and sometimes oxygen, then sealing without further adjustment.
The reason a packet of sliced bread, salad leaves or cut fruit in a supermarket looks puffed up with gas rather than vacuum sealed.
See also: Controlled atmosphere storage, Hurdle technology
The total amount of water in a food, expressed on a wet basis (mass of water per mass of wet sample) or dry basis (mass of water per mass of dry solids).
What determines whether a bag of wheat, rice or spice powder is safe to store long-term or will spoil and grow mould.
See also: Water activity
A fluid whose shear stress is directly proportional to shear rate, so viscosity is independent of shear.
Water and thin syrups behave this way, unlike ketchup or honey — which is why ketchup needs a shake to start flowing but water doesn't.
See also: Rheology, Thixotropy
The combined conductance of all resistances between two fluids — convective films, wall conduction and fouling — used as Q = UAΔTlm.
Used by dairy and beverage plants to design pasteurisers and evaporators that heat or cool product efficiently at scale.
See also: Log mean temperature difference, Fouling
A mild heat treatment that destroys vegetative pathogens and reduces spoilage organisms, without eliminating spores. Milk: LTLT 63 °C for 30 min, or HTST 72 °C for 15 s.
The everyday reason packaged milk, juice and beer are safe to drink without boiling, and why “raw milk” carries extra risk.
See also: Sterilisation, UHT, Phosphatase test
A structural polysaccharide of plant cell walls based on galacturonic acid. High-methoxyl pectin (DE > 50%) gels with sugar and acid; low-methoxyl pectin gels with calcium.
The setting agent in homemade jam — naturally present in fruits like apple and citrus peel, or added as a powder when a fruit's own pectin is too low.
See also: Degree of esterification, Syneresis
A test for lactoperoxidase, used to confirm that milk has not been over-heated.
Used to check whether blanched frozen vegetables were heated for long enough — a positive result means the enzyme survived and the vegetable may spoil in storage.
See also: Phosphatase test, Pasteurisation
Milliequivalents of peroxide oxygen per kilogram of fat, measuring primary oxidation products (hydroperoxides).
What a quality lab checks on stored cooking oil or fried snacks to catch rancidity before it's noticeable by smell or taste.
See also: Rancidity, Antioxidant
A test for the enzyme alkaline phosphatase, used to confirm adequate milk pasteurisation.
The quick lab check that confirms milk was actually pasteurised properly, used routinely by dairies and food inspectors.
See also: Pasteurisation, Peroxidase test
A copper-containing enzyme responsible for enzymatic browning in cut fruit and vegetables. Optimum pH is around 6–7 and it is largely inactivated above about 80 °C.
The enzyme responsible for cut apples, bananas and potatoes turning brown — the same reaction as enzymatic browning, named for the enzyme that drives it.
See also: Enzymatic browning, Blanching
The basic hygiene and operational conditions — GMP, sanitation, pest control, personnel hygiene — that must be in place before HACCP can work.
The basic hygiene systems — pest control, cleaning schedules, staff hygiene — a food business needs in place before a HACCP or FSSAI licence audit can even proceed.
A substance that prevents or retards microbial spoilage. Class I preservatives are traditional substances such as salt, sugar and vinegar; Class II are chemical preservatives such as benzoates and sorbates.
Listed on food labels as INS numbers, like INS 211 or INS 282; the reason bread, sauces and pickles last weeks instead of days.
See also: Hurdle technology, Water activity
Live microorganisms which, administered in adequate amounts, confer a health benefit on the host.
The “live cultures” claim on yoghurt and probiotic-drink packaging, backed by a specific bacterial count and strain the product has to maintain until its expiry date.
See also: Lactic acid bacteria, Dietary fibre
The aggregation of denatured protein molecules into an insoluble network, following denaturation and driven by newly exposed hydrophobic groups.
Why beating and heating egg whites turns a runny liquid into a firm meringue or omelette.
See also: Denaturation, Isoelectric point, Casein
Weight gain in grams per gram of protein consumed, measured in growing rats.
An older method still referenced in nutrition labelling and animal-feed formulation to compare how well different protein sources support growth.
See also: Biological value, Limiting amino acid
A chart relating dry bulb temperature, wet bulb temperature, humidity ratio, relative humidity and enthalpy of moist air.
Used by engineers designing food dryers, cold stores and bakeries to control humidity and prevent condensation or over-drying.
See also: Wet bulb temperature, Relative humidity
The factor by which a reaction rate changes for a 10 °C rise in temperature.
Explains why food spoils roughly twice as fast for every 10°C rise in storage temperature — the basis for shelf-life predictions and cold-chain rules.
See also: Accelerated shelf life testing, z-value
Deterioration of fats producing off-flavours. Hydrolytic rancidity releases free fatty acids by lipase or water; oxidative rancidity is a free-radical chain reaction with oxygen at unsaturated bonds.
The “off” smell and taste in old cooking oil, stale namkeen or biscuits made with old ghee — caused by fat breaking down over time.
See also: Peroxide value, Antioxidant, Free fatty acid
A sugar with a free aldehyde or ketone group that can act as a reducing agent — glucose, fructose, lactose and maltose are reducing sugars. Sucrose is not, because both anomeric carbons are involved in the glycosidic bond.
Involved in the Maillard browning of bread crust and biscuits, and the basis of the test strips used to check sugar levels in some quality labs.
See also: Maillard reaction, Invert sugar
The ratio of the partial pressure of water vapour in air to its saturation pressure at the same temperature, as a percentage.
What a food warehouse or spice storage room controls to stop products absorbing moisture and clumping or growing mould.
See also: Water activity, Psychrometric chart
The rate at which harvested produce consumes oxygen and releases carbon dioxide, heat and water.
Why some vegetables like spinach wilt and spoil within a day at room temperature while others like potatoes last for months.
See also: Climacteric fruit, Controlled atmosphere storage, Q10
A pressure vessel used to sterilise food after sealing in its container, allowing temperatures above 100 °C.
The industrial pressure cooker used to sterilise canned foods and retort pouches, like packaged ready-to-eat curries.
See also: Cold spot, Commercial sterility, Aseptic packaging
The re-association of gelatinised starch chains, mainly amylose, into an ordered crystalline structure during cooling and storage, expelling water (syneresis).
Why rice and bread go hard and stale in the fridge faster than at room temperature — the starch re-crystallises as it cools.
See also: Starch gelatinisation, Syneresis, Amylose
The dimensionless ratio of inertial to viscous forces, Re = ρvD/μ.
Used by process engineers to predict whether fluid moving through a pipe in a dairy or juice plant will flow smoothly or turbulently, which affects mixing and cleaning.
See also: Laminar flow, Holding tube
The study of deformation and flow. Newtonian fluids have constant viscosity; non-Newtonian fluids do not.
The science behind why ketchup stays thick until you shake or squeeze it, and why ice cream should feel creamy, not icy, in the mouth.
See also: Newtonian fluid, Thixotropy
Milligrams of KOH needed to saponify one gram of fat.
Used in soap-making and oil-quality testing to judge the average size of fatty acid chains in a fat or oil.
See also: Iodine value
The measurement of food attributes through the human senses under controlled conditions. Discriminative tests detect difference, descriptive tests characterise it, affective tests measure liking.
The formal tasting panels food companies run before launching a new product, deciding things like whether a new biscuit is “too sweet.”
See also: Triangle test, Hedonic scale
The period during which a food remains safe and retains its intended sensory, chemical, physical and microbiological characteristics under stated storage conditions.
The date printed on every packaged food label, based on real storage testing rather than a guess.
See also: Accelerated shelf life testing, Water activity
The mechanical energy delivered to unit mass of material in an extruder, in J/kg.
Used by snack-food engineers to control how puffed or dense an extruded product, like a corn puff or pasta shape, turns out.
See also: Extrusion
Atomising a liquid feed into a hot air stream so droplets dry almost instantly into powder.
How milk powder, instant coffee and infant formula are made — liquid sprayed into hot air, drying to powder almost instantly.
See also: Freeze drying, Wet bulb temperature
The irreversible swelling of starch granules when heated in water above a characteristic temperature, in which the crystalline structure is lost, amylose leaches out and viscosity rises sharply.
Why raw rice and raw atta dough have to be cooked with water and heat before becoming soft rice or roti — the starch granules swell and burst.
See also: Retrogradation, Amylose, Amylopectin
A heat process severe enough to destroy all microorganisms including spores, typically above 100 °C under pressure.
Ensures canned and UHT foods are completely free of microorganisms, unlike pasteurised products which still need refrigeration.
See also: Commercial sterility, Pasteurisation, UHT
The relation giving the settling velocity of a sphere in a fluid, proportional to the square of particle diameter and the density difference, and inversely proportional to viscosity.
Explains why cream rises to the top of unhomogenised milk over time, and is used to design the centrifugal separators dairies run.
See also: Homogenisation, Emulsion
The direct transition of a solid to vapour without passing through the liquid phase, occurring below the triple point of water — 0.0098 °C and 611 Pa.
The physics behind freeze-dried coffee and camping food — ice turns straight to vapour without melting, leaving the food's structure intact.
See also: Freeze drying, Glass transition temperature
The spontaneous expulsion of liquid from a gel as its network contracts.
The watery liquid that separates on top of curd, paneer or an old jar of jam — a texture defect food manufacturers try to prevent.
See also: Retrogradation, Pectin
A time-dependent decrease in viscosity under constant shear, with recovery on standing.
Why tomato ketchup flows more easily after shaking or stirring but thickens again once left standing.
See also: Rheology, Newtonian fluid
Unsaturated fatty acids with at least one double bond in the trans configuration, formed industrially by partial hydrogenation or naturally by rumen bacteria.
The reason vanaspati, some margarines and bakery shortenings carry FSSAI-mandated limits and warning labels — linked to heart disease risk.
See also: Hydrogenation, FSSAI
A discriminative sensory test in which a panellist receives three samples, two identical, and identifies the odd one.
The blind taste test food companies run to check if consumers can actually tell the difference when a recipe or ingredient changes, like a sugar or salt reduction.
See also: Sensory evaluation, Hedonic scale
Heating to roughly 135–150 °C for 2–5 seconds followed by aseptic packaging, giving a shelf-stable product without refrigeration.
What makes Tetra Pak milk shelf-stable for months without refrigeration until opened, unlike pasteurised milk which needs the fridge.
See also: Pasteurisation, Aseptic packaging, z-value, HTST principle
The ratio of the vapour pressure of water in a food to the vapour pressure of pure water at the same temperature. It measures how much water is available for microbial growth and chemical reactions — not how much water is present.
Why honey and jam don't need refrigeration despite containing a lot of water, while fresh bread does — bacteria and mould need “available” water, not just any water.
See also: Moisture content, Hurdle technology, Water sorption isotherm
A curve relating equilibrium moisture content to water activity at constant temperature, typically sigmoidal.
Used to decide the right packaging material and shelf-life claim for dry products like biscuits, namkeen and spice mixes.
See also: Water activity, Moisture content
The temperature reached by a wetted surface in a moving air stream at steady state, where evaporative cooling balances heat gain from the air.
Used in food drying and cold storage design to understand how effectively air can cool or dry a product through evaporation.
See also: Psychrometric chart, Spray drying, Constant rate period
The soluble milk proteins remaining after casein removal — chiefly β-lactoglobulin and α-lactalbumin. Heat-labile but acid-stable.
The liquid left over from making paneer or cheese, now sold separately as a popular protein supplement powder in gyms and nutrition stores.
See also: Casein, Denaturation
The temperature increase required to reduce the D-value by a factor of ten — the slope of the thermal death time curve.
Used alongside D-value by canning engineers to predict how a sterilisation process needs to change if the processing temperature is adjusted.
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