Dairy and whey ingredients glossary

Whey from acid-coagulated products (e.g. Greek yoghurt, cottage cheese, casein), with a lower pH and higher mineral and lactic-acid content. Historically hard to process and often under-valued, but with the right route it can become a useful raw material rather than a disposal cost.

The main protein family in milk, forming micelles that are important for cheese making, texture and nutrition. Casein behaves differently from whey protein, especially in response to pH and heat.

A soluble form of casein made by treating acid or rennet casein with alkali. Caseinates are used for their emulsification, water-binding and texture-building properties.

A whey protein engineered to dissolve into a transparent, juice-like drink rather than a milky shake. It demands very tight control of pH, fat, minerals and protein denaturation, because clarity exposes every imperfection. The fastest-growing premium format in sports and wellness nutrition.

A mineral-rich ingredient recovered from milk, whey or permeate streams. These products are often positioned around calcium, phosphate and broader dairy mineral nutrition.

Demineralised whey is whey from which minerals have been partially removed, graded by demineralisation level (e.g. D90 ≈ 90% removed). Used heavily in infant formula; the degree of demineralisation drives both cost and application suitability.

Glycomacropeptide (GMP, also written CMP) is a casein-derived peptide released during rennet cheese making. It is present in sweet whey and can be relevant to specialist nutrition, whey composition and ingredient fractionation.

The fat-rich stream separated from whey during microfiltration, when producing whey protein isolate. A by-product whose value can make or break the economics of a WPI route, depending on whether a market outlet exists for it. Also known as WPPC (Whey Protein Phospholipid Concentrate).

Antibody proteins naturally present in milk and especially colostrum. They are relevant to bioactive dairy ingredients and immune-positioned products.

An iron-binding dairy protein found in small amounts in milk and whey. It is a high-value bioactive fraction often associated with immune, antimicrobial and specialist nutrition applications.

Milk sugar; the largest solids fraction of whey after water. Recovered and refined as a product in its own right (food, pharmaceutical carrier, infant formula) and a key variable in protein purity, flavour and clarity.

Whey in which lactose has been broken down into glucose and galactose by lactase. This can affect sweetness, digestibility, browning behaviour and formulation performance.

A dairy protein ingredient enriched in casein micelles, usually produced by microfiltration of milk. It is valued for slow digestion, heat behaviour, opacity and texture-building properties.

Milk protein concentrate (MPC) is a dairy protein ingredient made by concentrating skim milk proteins, usually by membrane filtration. MPC contains both casein and whey proteins in approximately the same ratio as milk.

Milk protein isolate (MPI) is a high-protein dairy ingredient, typically containing at least 90% protein on a dry basis. MPI contains both casein and whey proteins and is used in high-protein foods and beverages.

Whey protein obtained directly from milk, usually by microfiltration, rather than from cheese whey. It is often positioned as less processed and may have different flavour and functionality from cheese-derived whey protein.

The stream that passes through a membrane during filtration; for whey, mainly lactose, minerals and water. Once a waste stream, permeate is now a traded ingredient, used to standardise dairy products or as a lactose source.

Whey protein that has been enzymatically broken into smaller peptides. Hydrolysis can affect digestibility, bitterness, solubility, heat stability and application suitability.

Whey with part of the lactose removed. It differs from WPC because the mineral level may remain relatively high, making the composition and application fit different.

The stream retained by a membrane during filtration: the concentrated, protein-rich fraction that goes on to become WPC or WPI. The complement of permeate.

Whey from rennet-coagulated cheese (e.g. cheddar, mozzarella), with a near-neutral pH. Its higher lactose and lower mineral content generally make it the preferred feedstock for premium protein ingredients.

The liquid fraction left after milk is coagulated and the curd removed in cheese or casein manufacture. Once treated as a low-value by-product, whey is now the feedstock for a high-value protein industry, and its composition (protein, lactose, fat, minerals) determines what can profitably be made from it.

Whey protein concentrate (WPC) is whey concentrated by membrane filtration to raise its protein content, typically anywhere from 35% to 80% on a dry basis, while retaining some lactose and fat. The workhorse of the protein ingredients market, used across sports nutrition, bakery, beverages and infant formula.

Whey protein hydrolysate (WPH) is whey protein partly broken down into smaller peptides by enzymatic hydrolysis, used in sports recovery and clinical nutrition. Hydrolysis can introduce bitterness, so the degree of hydrolysis is balanced against taste.

Whey protein isolate (WPI) is whey protein concentrated to 90%+ protein with most fat and lactose removed, usually by microfiltration or ion exchange. Commands a premium and suits low-lactose, high-purity applications, but the extra purification means lower overall protein recovery from the same whey.

Whey protein phospholipid concentrate (WPPC) is a co-product generated during some whey protein isolate or low-fat WPC processes. It contains whey proteins, phospholipids and residual fat fractions, and may offer value beyond standard side-stream use.

The milk proteins that remain in liquid whey after casein has been separated during cheese or casein manufacture. They are valued for their nutritional quality and functional properties.

Whey Protein Concentrate standardised to around 80% protein. The most widely traded high-protein whey ingredient: it recovers more protein per tonne of whey than WPI, but carries more fat and lactose, which affect clarity, flavour and behaviour in application. Often the more economic route when a premium WPI price isn't assured.

A minor but high-value whey protein, prized for its amino-acid profile (rich in tryptophan) and used in infant and clinical nutrition. It is harder to isolate than the dominant β-lactoglobulin, and membrane fractionation conditions strongly affect both how much can be recovered and its sensory profile.

The most abundant protein in bovine whey and the main driver of its gelation, foaming and heat-related behaviour. Its thermal denaturation underpins many of whey protein's functional and sensory properties, including mouthdrying.

Concentration factor (CF) is the ratio between the starting feed volume and the final retentate volume in a concentration process. It helps describe how much a stream has been concentrated during membrane processing or evaporation.

A membrane operating mode where liquid flows across the membrane surface rather than directly through it. Crossflow helps limit cake build-up and supports continuous separation.

The difference between inlet and outlet pressure across a membrane housing or process section. Rising pressure drop can indicate fouling, blockage or flow limitations.

Diafiltration (DF) is the washing of a retentate with water during filtration to flush out more lactose and minerals, raising protein purity toward isolate levels. More diafiltration means higher purity but greater water and energy use, a cost-versus-spec trade-off.

The rate at which permeate passes through a membrane. In practice, flux is a key indicator of membrane productivity and can decline when fouling, viscosity or operating conditions limit performance.

The build-up of material on a membrane surface or within membrane pores. Fouling can reduce flux, change separation behaviour and increase cleaning requirements.

Ion exchange (IEX) is a method that binds and releases whey proteins by electrical charge to reach very high purity, used to make some WPIs. Delivers high protein content but alters the protein profile and adds cost and complexity versus membrane routes.

An accounting of where every component (protein, fat, lactose, ash, solids) goes as whey moves through a process. The essential tool for comparing production routes (e.g. WPC80 vs WPI) on yield, recovery, side-stream value and economics before any capital is committed.

The replaceable membrane unit installed in a membrane housing. Element design and condition influence capacity, selectivity, pressure drop and cleaning performance.

Separating whey into individual protein fractions (e.g. enriching α-lactalbumin or removing lactoferrin) using membranes of specific pore size and operating conditions. The route to higher-value, single-protein ingredients, and highly sensitive to parameters such as pressure, pH and membrane type.

Microfiltration (MF) is a membrane process with a larger pore size than UF, used to remove larger components such as fat globules and bacteria and, increasingly, to fractionate individual whey proteins. Central to producing whey protein isolate and native protein.

Molecular weight cut-off (MWCO) is a membrane characteristic that describes the approximate molecular size at which components are retained. It helps compare membrane selectivity, especially in ultrafiltration and protein fractionation.

Nanofiltration (NF) is a membrane process that removes water and some small ions while retaining larger components such as lactose and proteins. In dairy and whey processing, NF is often used for partial demineralisation or concentration.

The approximate size of openings in a membrane, especially relevant to microfiltration. Pore size helps determine which components are retained and which can pass into the permeate.

Describes how much of the protein entering a process is retained in the intended product. It is usually expressed as a percentage and is used to understand yield, process efficiency and where valuable protein may be lost.

A measure of how well a membrane retains a specific component, such as protein, fat or lactose. It is useful for understanding separation performance and where valuable components may be lost.

Reverse osmosis (RO) is a membrane process that mainly removes water from a dairy stream while retaining most dissolved solids. It is often used to concentrate milk, whey or permeate before further processing.

A common membrane format where flat membrane sheets are wrapped around a central permeate tube. It is widely used in dairy UF, NF and RO systems.

Total solids (TS) is the proportion of a stream that is not water. A foundational figure in any mass balance and process calculation, and a key control point in concentration and drying.

Ultrafiltration (UF) is a membrane process that concentrates whey protein by letting water, lactose and minerals pass while retaining protein. The foundation of WPC manufacture; the concentration factor sets the finished protein content.

A powder processing step that joins fine particles into larger, more open structures. Agglomeration can improve powder wetting, dispersibility and reconstitution.

A non-crystalline form of lactose that can be unstable and hygroscopic. It is important in dairy powders because it can contribute to stickiness, caking and changes during storage.

How much a powder weighs per unit volume (including the air between particles) and how freely it moves through hoppers, bags and dosing systems. These affect packaging, transport cost, dosing and line performance: practical factors behind cost-in-use.

The formation of crystals from dissolved material, such as lactose in concentrated whey or permeate. Good crystallisation control is important for drying, powder stability and texture.

Removing water by boiling under vacuum to concentrate whey or retentate before drying. A major energy cost in the plant, and a step where heat exposure can begin to affect protein functionality.

Treating a powder, often by agglomeration and/or lecithination, so it wets and disperses quickly without lumping when stirred into liquid. Critical to consumer experience in shaker- and spoon-prepared products.

Coating powder particles with lecithin to improve wetting and dispersion. The lecithin source (soya, sunflower, rapeseed) can affect not only instantising performance but flavour, oxidative stability and shelf-life.

Discoloured powder particles caused by overheating or drying deposits. They are a visible quality defect and may indicate drying or cleaning issues.

A liquid containing suspended solids, such as crystallised lactose in concentrated permeate. Slurry behaviour affects pumping, crystallisation control and drying performance.

Atomising concentrated liquid into a hot air stream to produce a stable powder. The final, defining step for most whey ingredients; drying conditions influence solubility, particle structure, density and shelf-life.

The tendency of powders to soften or become sticky at elevated temperatures. It is relevant to drying performance, powder storage and caking risk.

The mineral fraction of a dairy ingredient. Ash level is a common specification limit, particularly for acid whey and high-purity isolates, and influences taste, clarity and application performance.

Measures related to mass per unit volume and comparison with water. These are useful for process calculations, standardisation and liquid handling.

Free fatty acids (FFAs) are fatty acids released from triglycerides, often through lipase activity or fat damage. FFAs can contribute to flavour defects such as rancid or soapy notes.

The isoelectric point (pI) is the pH at which a protein has no net electrical charge. Around this point, proteins are often less soluble and more likely to aggregate or precipitate.

A traditional analytical method used to estimate protein content by measuring nitrogen. It is widely used in dairy ingredient specifications, although it measures total nitrogen rather than only intact protein.

An analytical measure often used to estimate moisture by measuring weight loss during drying. It is important for powder specifications, stability and shelf life.

A non-enzymatic reaction between reducing sugars, such as lactose, and amino groups from proteins or amino acids. It can cause browning, flavour changes and nutritional loss during heating or storage.

The mineral and salt system naturally present in milk. Milk salts influence buffering, protein stability, heat behaviour and mineral balance.

The size distribution of powder particles or protein aggregates. It affects wetting, dispersion, appearance and, as research links it to mouthfeel, sensory perception in the final drink.

A measure of acidity or alkalinity. In dairy systems, pH strongly affects protein solubility, heat stability, microbial control, flavour and processing behaviour.

Protein on dry basis (PDB) is the amount of protein expressed as a percentage of the product dry matter. It is commonly used in powders because moisture levels can vary.

Solids-not-fat (SNF) is the non-fat solids in a dairy product, including protein, lactose and minerals. SNF is useful for understanding composition, nutrition and processing behaviour.

Titratable acidity (TA) is a measure of total acid content rather than only free hydrogen ions. It is useful in fermented dairy, acid whey and products where buffering capacity affects how acidity is perceived and controlled.

The whey protein nitrogen index (WPNI) is an analytical indicator of the amount of undenatured whey protein remaining after heat treatment. A higher WPNI usually indicates less heat damage and more native whey protein structure.

A measure of the electrical charge on protein particles in suspension, indicating colloidal stability and how proteins interact with one another and with saliva. A useful predictor of behaviour such as aggregation, stability and mouthfeel.

A puckering, drying mouthfeel (familiar from strong tea) caused by interactions that reduce oral lubrication. In whey it is linked to acidity and protein–saliva interactions, and is closely related to mouthdrying.

The ability of a system to resist pH change when acid or alkali is added. Dairy systems are often strongly buffered, which affects acidification, flavour and process control.

The lowest concentration at which an attribute can be reliably perceived. Establishing thresholds (e.g. for mouthdrying at a given protein level) tells formulators how far they can push protein content before sensory penalties set in.

An ingredient that helps stabilise an emulsion by reducing tension between oil and water phases. Emulsifiers are important in beverages, powders, sauces and fat-containing systems.

A system where droplets of one liquid are dispersed within another liquid that does not naturally mix with it. Milk is an emulsion of fat droplets in a water-based phase.

How long a foam remains stable before collapsing or draining. It is relevant to dairy desserts, beverages, bakery systems and aerated products.

The ability of an ingredient or formulation to create foam. Whey proteins can have strong foam-forming properties depending on pH, heat treatment, salts and formulation conditions.

The ability of whey protein to form a gel when heated or otherwise triggered, valuable in some applications (texture, water-holding) and a defect in others. Gelation behaviour is also why certain whey streams cause problems when blended.

The ability of a product or ingredient to remain physically stable during heating. In dairy and protein systems, it is especially important because heat can cause proteins to unfold, interact and form aggregates, which may affect appearance, texture, solubility and process performance.

Terms describing whether a molecule or surface tends to avoid water or interact with water. These properties influence protein behaviour, wetting, emulsification and solubility.

A residual film left on the mouth surfaces after consumption. A key mouthfeel attribute in protein beverages that builds with repeated sips and contributes to liking or disliking.

A sensory sensation where the mouth feels dry, rough or less lubricated after consumption. In protein-rich products, it can be linked to ingredient type, protein concentration, minerals, acidity, heat treatment, flavour system or interactions with saliva.

The physical sensations a food or drink produces in the mouth (smoothness, thickness, coating, drying, slipperiness), as distinct from taste and aroma. Often the deciding factor in whether a protein product is enjoyed and re-purchased.

The tendency of proteins to stick to the mucous surfaces of the mouth. Mucoadhesion of whey, increased by thermal denaturation, is one of the mechanisms thought to drive mouthdrying.

A term relating to sensory properties such as taste, aroma, texture and appearance, often expressed as “sensory properties” for clarity.

The unfolding of a protein's structure, usually by heat, which changes how it behaves: its solubility, gelation, clarity and mouthfeel. Controlling thermal denaturation is central to whey processing; over-exposure to heat can increase mouthdrying and reduce performance.

How readily a protein dissolves in water. A core quality attribute: poor solubility shows up as sediment, lumping and inconsistent dosing, especially in clear and ready-to-mix formats.

The release of liquid from a gel or structured food system. In dairy, it is commonly seen as whey separation in yoghurt, cheese or protein gels.

A group of assessors calibrated to measure specific product attributes objectively and reproducibly, using a defined vocabulary. The backbone of credible sensory work, turning “it tastes a bit off” into measurable, comparable data for development and quality.

The study of friction and lubrication between surfaces, applied in food science to how a product behaves between tongue and palate. It explains mouthfeel attributes such as smoothness and slipperiness, and is used to engineer protein drinks that feel better to drink.

How a liquid flows and deforms. Viscosity affects mouthfeel, processability and stability; rheological measurement is used to understand and engineer the texture of protein beverages.

How easily a powder takes up water (wettability) and spreads through it without clumps (dispersibility). Together they define the consumer's reconstitution experience and are the main targets of instantisation.

A spore-forming bacterium that can be relevant in dairy powders and cooked foods. Its spores can survive some heat treatments and later grow if conditions allow.

A layer of microorganisms attached to a surface, often protected by organic material. Biofilms can be difficult to remove and may become a source of recurring contamination.

Clean-in-place (CIP) is an automated cleaning method used to clean the internal surfaces of tanks, pipes and processing equipment without dismantling them. CIP is central to dairy hygiene and operational control.

Clean-out-of-place (COP) is a cleaning method where removable parts are taken apart and cleaned separately, often in dedicated wash tanks. COP is used for items such as fittings, hoses and utensils.

A group of bacteria often used as hygiene indicators. Their presence can suggest poor sanitation, environmental contamination or process control issues.

A food component, often a protein, that can trigger an immune reaction in sensitive individuals. Allergen control includes identification, segregation, cleaning, labelling and verification.

The shared values, behaviours and habits that influence how people manage food safety in practice. A strong food safety culture helps ensure that systems are followed even when no one is watching.

Good manufacturing practices (GMPs) are the basic practices and controls needed to produce food safely and consistently. GMPs cover people, equipment, premises, cleaning, operations and documentation.

A foodborne pathogen that can grow at refrigeration temperatures. It is especially important in ready-to-eat foods and dairy environments where post-process contamination is possible.

The number and type of microorganisms present in a product, ingredient or environment. Managing microbial load is central to shelf life, safety and process hygiene.

A controlled heat treatment designed to destroy relevant pathogens and improve product safety. Pasteurisation conditions depend on product type, target organisms and process design.

A microorganism that can cause illness. In food safety, pathogens must be controlled through raw material management, processing, hygiene, storage and verification.

A microbiological test that estimates the number of viable bacteria in a sample under defined test conditions. It is used as a general quality and hygiene indicator.

A milder heat treatment than pasteurisation. It can reduce microbial load but is not equivalent to pasteurisation for food safety purposes.

Evidence that a control measure or process is capable of achieving the intended food safety outcome. Validation asks whether the control can work.

Activities used to confirm that controls are being applied as intended and remain effective. Verification asks whether the system is working in practice.