Reference
The 14 functionality groups
The top-level groups every measured property belongs to, with the unit rules of each.
Why properties are grouped
Every property the platform stores belongs to exactly one of 14 groups. The groups follow how functionality is studied. For example, steady-shear flow and oscillatory rheology are separate groups, because they come from different experiments with different conditions and their values should not be mixed.
There are 81 properties across the 14 groups. The tables on this page come from the vocabulary the platform itself uses (version 2.1.0), so they always match it.
The 14 functionality groups, in order, with what belongs in each
01
- Group
- Composition and purity
- Properties
- 8
- What belongs here
- How much protein the material contains and what that protein is made of: protein content, protein purity, the amino acid composition, and hydrophobic/hydrophilic amino acid fractions. These describe the MATERIAL, not its behaviour in a food system.
02
- Group
- Molecular and structural properties
- Properties
- 11
- What belongs here
- Properties of the protein molecule and its conformation: hydrolysis and denaturation extent, apparent molecular mass, surface hydrophobicity, free sulfhydryl and disulfide content, secondary-structure fractions, and the isoelectric point.
03
- Group
- Particle and colloidal properties
- Properties
- 5
- What belongs here
- Behaviour of the dispersed phase: particle or droplet size, electrokinetic charge, optical turbidity of the dispersion, and tension at the interface.
04
- Group
- Powder and bulk properties
- Properties
- 5
- What belongs here
- Handling behaviour of the dry powder: loose bulk density, tapped density, and the flowability metrics computed from or measured alongside them.
05
- Group
- Texture and mechanical properties
- Properties
- 12
- What belongs here
- Mechanical response of the formed gel or solid: hardness/firmness, gel strength, and the texture-profile-analysis parameters derived from a compression cycle.
06
- Group
- Water-interaction properties
- Properties
- 5
- What belongs here
- How much water the material holds, absorbs, binds or swells with, under the study’s own protocol.
07
- Group
- Oil- and fat-interaction properties
- Properties
- 4
- What belongs here
- How much oil or fat the material holds, absorbs or binds, under the study’s own protocol.
08
- Group
- Emulsifying properties
- Properties
- 6
- What belongs here
- Formation and persistence of an oil-in-water emulsion: emulsifying activity, the turbidimetric activity index, emulsifying capacity, emulsion stability, the turbidimetric stability index, and creaming.
09
- Group
- Foaming properties
- Properties
- 3
- What belongs here
- Formation and persistence of a protein foam: foaming capacity/ability/expansion/overrun, and foam stability.
10
- Group
- Solubility and dispersibility
- Properties
- 3
- What belongs here
- How much protein goes into, and stays in, solution: protein solubility, the standardized NSI and PDI assays, soluble protein concentration, and solubility profiles across pH, ionic strength or temperature.
11
- Group
- Gelation properties
- Properties
- 3
- What belongs here
- Whether and at what concentration a gel forms: least/minimum gelation concentration, critical gel concentration, and qualitative gel-forming ability.
12
- Group
- Viscosity and flow behavior
- Properties
- 5
- What belongs here
- Steady-shear response: apparent/dynamic/shear viscosity, shear stress, yield stress, and the power-law parameters fitted to a flow curve.
13
- Group
- Rheological and viscoelastic properties
- Properties
- 5
- What belongs here
- Oscillatory response: storage modulus G′, loss modulus G″, complex modulus G*, loss tangent tan δ, and complex viscosity η*.
14
- Group
- Thermal properties
- Properties
- 6
- What belongs here
- Thermal transitions and thermal robustness: denaturation onset/peak/endset temperatures, glass transition temperature, transition enthalpy, and thermal stability.
The unit rules of each group
The rules state which conversions a group allows and, more importantly, which it does not. Many reporting mistakes in this literature are conversions that were correct arithmetic and wrong science, such as comparing a protein content on a dry basis with one as-is.
Where the literature has no agreed definition for a property, the reported unit and basis are kept and not converted: 26 of the 81 properties are handled this way, and the glossary marks each one.
Unit policy by group
Composition and purity
- Unit policy
- Dry vs as-is basis and the nitrogen-to-protein conversion factor (N×6.25, N×5.7, N×5.5 …) are part of the number, are carried as structured basis qualifiers on the row, and are recorded with the method; two protein contents — or two protein purities — on different bases or with different nitrogen factors are never equated, and an unstated basis never matches a stated one. Amino acid results carry their denominator (per g protein vs per g sample vs per mole of residues): mg/g, g/100 g and mol% are different quantities and never interconvert. A bare % is never rewritten as % w/w, % w/v or % v/v.
Molecular and structural properties
- Unit policy
- SDS-PAGE reports an APPARENT molecular mass (kDa/Da is a molar mass, never a gram mass). Surface hydrophobicity is probe- and instrument-relative and is given NO universal unit: it is comparable only within one study. Free -SH and -S-S- are separate measurements in µmol/g WITH their denominator basis, and neither is derived from the other. Secondary-structure fractions are percentages of the stated deconvolution method. pI is dimensionless.
Particle and colloidal properties
- Unit policy
- A particle size is meaningless without WHICH measure it is (D10/D50/D90, d[3,2], d[4,3], Z-average, hydrodynamic diameter); those are different numbers from one sample and never interconvert. Zeta potential keeps its SIGN. Turbidity is NOT one universal quantity: an absorbance/OD at a stated wavelength and path length and a nephelometric NTU reading are different measurements and are held in different dimensions so neither can convert into the other.
Powder and bulk properties
- Unit policy
- Densities interconvert deterministically (kg/m³, g/mL, g/cm³) and never touch a solution concentration (g/L, mg/mL), which is a different dimension. Flowability is NOT a universal number but a family: angle of repose (degrees), Carr index (%) and Hausner ratio (dimensionless) are three separate quantities, and whichever the source reported is the one that is stored.
Texture and mechanical properties
- Unit policy
- FORCE (N, mN, gf, kgf) and STRESS (Pa, kPa, MPa) are kept strictly distinct and NEVER converted into one another — that conversion needs the probe geometry, which is not in the unit. Method, probe geometry, sample dimensions, compression %, crosshead speed, cycle count and temperature decide whether two synonym-looking terms are the same measurable; they are not merged blindly. Springiness is a recovered DISTANCE or a RATIO depending on the instrument definition and the two do not convert; adhesiveness is a work (force×time/energy); resilience is a ratio or a percentage, preserving the definition. The original value and unit are always retained even where a safe normalization exists.
Water-interaction properties
- Unit policy
- g water/g SAMPLE and g water/g PROTEIN differ by the protein content and are never merged; mL/g is a volume per mass and never becomes g/g without the liquid density (an assumption, not arithmetic); a bare % is protocol-defined. Holding, absorption, binding, swelling and hydration are separate protocols and are NOT automatically interchangeable — a study that defines two of them identically says so in the method.
Oil- and fat-interaction properties
- Unit policy
- The same denominator rules as the water family, plus: the OIL TYPE (soybean, corn, sunflower, rendered fat …), the sample basis and the centrifugation conditions are part of the method and are preserved. Oil holding, oil absorption, oil binding and fat absorption are separate protocol families and are not merged by default.
Emulsifying properties
- Unit policy
- Activity, EAI, capacity and stability are FOUR different quantities and are never treated as identical. EAI is an interfacial area per mass (m²/g). Emulsifying capacity is source-defined (often mL oil/g protein, or a percentage) and carries no universal unit. ESI is a time (min or the stated unit) from turbidity decay and a percent emulsion stability never becomes an ESI. Creaming index is a percentage of total height at a stated standing time.
Foaming properties
- Unit policy
- Capacity, ability, expansion and overrun are candidate aliases ONLY after the source’s FORMULA has been checked — whether the initial liquid volume is subtracted changes the number — so those names resolve with an ontology-review flag rather than silently. Foam stability is meaningless without its OBSERVATION TIME: it is stored as a percentage of remaining foam at a stated time, or as a time to collapse/half-life, and the two never convert.
Solubility and dispersibility
- Unit policy
- A percent solubility is a percent of the STUDY’S OWN definition (soluble/total) and is never rewritten as % w/w. A soluble protein CONCENTRATION (mg/mL, g/L) is a different quantity and is never converted to a percentage — the total protein is not part of the unit. NSI and PDI are standardized protocols and are not interchangeable with each other or with a generic solubility. A solubility PROFILE is a series: every point is its own row carrying its pH, ionic strength and temperature as part of the row identity, never a scalar.
Gelation properties
- Unit policy
- A gelation concentration is reported on the author’s own basis (% w/v, g/100 mL or another stated basis) and the author’s terminology and method are preserved: least, minimum and critical gelation concentration are closely related but are not silently unified. Gel-forming ability and gelling capacity stay QUALITATIVE categorical observations unless the study defines a quantitative measure, in which case that measure is stored as its own property with its own unit.
Viscosity and flow behavior
- Unit policy
- Viscosity is Pa·s, mPa·s or cP. The consistency coefficient K is Pa·sⁿ — its own dimension, because the exponent depends on the flow index n, so K never converts to a viscosity. The flow behavior index n is dimensionless. Temperature, the shear rate (s⁻¹) or shear-rate range, the model, the fitting range and WHICH viscosity was reported are all retained; the shear rate is part of the ROW IDENTITY for a flow curve, so a curve is many rows, never an average.
Rheological and viscoelastic properties
- Unit policy
- Moduli are Pa/kPa/MPa; tan δ is dimensionless; η* is a viscosity (Pa·s) and is NOT the steady-shear viscosity. The frequency (Hz) or angular frequency (rad/s), the strain or stress amplitude, whether the measurement sat inside the linear viscoelastic region, the temperature, the sweep type and the time are all part of the measurement; a frequency sweep, a strain sweep and a time sweep are separate series and are never pooled.
Thermal properties
- Unit policy
- Temperatures are °C or K (an affine conversion, never a scaling). Enthalpy is J/g SAMPLE, J/g PROTEIN or another explicitly stated basis, and the basis travels with the number. MULTIPLE THERMAL TRANSITIONS STAY SEPARATE ROWS and are never averaged into one Td. Thermal stability keeps the actual quantitative method where one exists, and is preserved as a qualitative conclusion where it does not.
Properties outside the 14 groups
A functionality group describes what a protein does in a food. Some stored properties describe something else, such as nutrition or process yield. They are kept on separate lists and are never counted among the functionality groups.
For example, in vitro protein digestibility and degree of hydrolysis both involve enzymes breaking peptide bonds, but they mean different things. They are kept apart, and no conversion between them exists.
Properties stored outside these groups
Nutritional and protein-quality properties
- Group
- Protein quality and digestibility
- Properties
- 1
- Which
- In vitro protein digestibility
Process yield and recovery
- Group
- Extraction yield and protein recovery
- Properties
- 2
- Which
- Extraction yield, Protein recovery
Related
The property glossary
Where to find the definition, other names, accepted units and comparison rules for each of the 81 properties, and how to read an entry.
Units and standardisation
How units are standardised: the reported value is kept beside the converted one, and unsafe conversions are refused.
Data dictionary
Every field in the FoodProt AI export, listed in the order it is written.
Reviewing the vocabulary (ontology)
Shared terms, project terms and synonyms, and why outside identifiers are never made up.