If you have been reading about Degree of hydrolysis and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-07-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
Whey protein hydrolysate is made by cleaving peptide bonds in whey proteins. The starting material is usually whey protein concentrate or isolate obtained during cheese or casein production. Proteolytic enzymes, acid, or heat can drive hydrolysis, although commercial processes favor controlled enzymatic treatment. The degree of hydrolysis describes the proportion of peptide bonds broken and separates partial from extensive hydrolysates. The resulting powder contains short peptides, free amino acids, residual intact protein, minerals, lactose, and fat in proportions that depend on the starting whey and downstream filtration.
Molecular weight distribution is a central compositional feature, and hydrolysis shifts the population toward lower-mass peptides, often below ten kilodaltons in extensively treated products. Enzyme choice, reaction time, temperature, pH, and enzyme-to-substrate ratio influence the peptide profile. Ultrafiltration or diafiltration may remove enzymes, salts, and smaller molecules. Because peptide size affects solubility, taste, foaming, and digestibility, manufacturers specify molecular weight ranges. However, two hydrolysates with similar average molecular weight can differ in peptide sequence and functional behavior.
Industrial production begins with whey protein concentrate or isolate dispersed in water. Selected proteases, such as trypsin, pepsin, or microbial enzymes, are added under controlled pH and temperature. Hydrolysis continues until a target hydrolysis level is reached, after which heat or pH adjustment inactivates the enzyme. Ultrafiltration, diafiltration, and ion exchange may remove larger peptides, salts, or residual lactose. The liquid is then concentrated and spray-dried into powder. Processing choices influence peptide size, bitterness, mineral content, and microbial quality.
Analytical control focuses on protein content, hydrolysis extent, molecular weight distribution, and residual intact protein. Kjeldahl or Dumas methods measure total nitrogen, while size-exclusion chromatography or mass spectrometry estimates peptide profiles. Sodium dodecyl sulfate polyacrylamide gel electrophoresis can show remaining intact proteins, though small peptides may not resolve. Enzyme-linked immunosorbent assays are used to assess residual allergenic proteins in some contexts. Because no single method captures all relevant features, manufacturers combine several assays and report values against internal specifications.
| Property | Value | Notes |
|---|---|---|
| Appearance | Off-white to cream powder | Color varies with starting whey and drying |
| Solubility | Dispersible in water | Solubility depends on peptide size and pH |
| Typical protein content | 70–90% dry basis | Varies by filtration and hydrolysis degree |
| Typical storage temperature | 15–25 °C | Keep dry and away from heat |
| Common analytical method | Size-exclusion chromatography | Used for molecular weight distribution |
Whey protein hydrolysate is a dairy ingredient made by treating whey protein with proteolytic enzymes. The starting material is whey, the liquid remaining after cheese or casein production, and its main proteins include beta-lactoglobulin, alpha-lactalbumin, and bovine serum albumin. Enzyme action breaks peptide bonds, producing shorter peptides and some free amino acids. The result is not a single uniform substance; composition depends on whey source, enzyme type, hydrolysis conditions, and downstream filtration. Hydrolysates are often described by average peptide length or degree of hydrolysis rather than by one fixed molecular weight.
Compared with whey protein concentrate or isolate, hydrolysate has a smaller average peptide size and a higher proportion of low-molecular-weight fractions. This change can affect solubility, viscosity, osmolality, taste, and foam formation. Some hydrolysates are bitter because hydrophobic peptides are exposed during cleavage. The term hydrolysate does not indicate a guaranteed peptide profile; two products with the same reported hydrolysis value can differ in peptide sequence and residual intact protein. Commercial specifications usually state protein content, moisture, ash, fat, and microbiology, while peptide distribution may be reported as a range.
Quality control for hydrolyzed whey protein focuses on composition, peptide size, and batch consistency. Protein content is commonly measured by Kjeldahl or combustion analysis, while moisture and ash are determined by gravimetric methods. Peptide molecular weight distribution is often assessed by size exclusion chromatography or mass spectrometry. The extent of hydrolysis can be estimated by titration, trinitrobenzenesulfonic acid assays, or formol titration. Because hydrolysis produces a complex mixture, no single test captures every relevant property, and laboratories often combine several methods.
Allergen testing is relevant because whey is a milk-derived ingredient. Immunoassays can detect residual milk proteins, but hydrolysis may alter or destroy antibody-binding sites, leading to false negatives or underestimation. Liquid chromatography with tandem mass spectrometry can identify specific peptide markers and is less dependent on intact protein epitopes. Regulatory labeling rules for milk allergens vary by country, and a product described as hydrolyzed is not automatically exempt from allergen declaration. For infants, specialized formulas require strict control of protein molecular weight and sterility, which adds testing beyond routine composition.
=== Bleaching === About 60% of the world's production of hydrogen peroxide is used for pulp- and paper-bleaching. The second major industrial application is the manufacture of sodium percarbonate and sodium perborate, which are used as mild bleaches in laundry detergents. A representative conversion is:
Wine Chemistry and Biochemistry, by M. Victoria Moreno-Arribas, Carmen Polo and María Carmen Polo, on Google books Mass Spectrometry in Grape and Wine Chemistry, by Riccardo Flamini and Pietro Traldi, on Google books Antoine de Saporta La Chimie des vins: les vins naturels, les vins manipulés et falsifiés (1889). Google Books
== Organisation structure == The ARL is governed by a board of directors, referred to as a “commission”. The board was previously composed of representatives of member clubs and state leagues but was reconstituted with directors independent of the member clubs and leagues and renamed as a “commission”. It is headquartered in Sydney at “Rugby League Central”, Moore Park, New South Wales. All 17 National Rugby League clubs and the New South Wales Rugby League and the Queensland Rugby League are members of the commission. This means that the commission has 19 shareholder members in total.
Sources: en.wikipedia.org
Individual transmembrane adenylyl cyclase isoforms have been linked to numerous physiological functions. Soluble adenylyl cyclase (sAC, AC10) has a critical role in sperm motility. Adenylyl cyclase has been implicated in memory formation, functioning as a coincidence detector. AC-IV was first reported in the bacterium Aeromonas hydrophila, and the structure of the AC-IV from Yersinia pestis has been reported. These are the smallest of the AC enzyme classes; the AC-IV (CyaB) from Yersinia is a dimer of 19 kDa subunits with no known regulatory components (PDB: 2FJT). AC-IV forms a superfamily with mammalian thiamine-triphosphatase called CYTH (CyaB, thiamine triphosphatase). These forms of AC have been reported in specific bacteria (Prevotella ruminicola O68902 and Rhizobium etli Q8KY20, respectively) and have not been extensively characterized. There are a few extra members (~400 in Pfam) known to be in class VI. Class VI enzymes possess a catalytic core similar to the one in Class III.
=== 1989 Kramatorsk, Ukraine === The 1989 Kramatorsk incident happened in 1989 when a small capsule 8 by 4 millimetres (0.3 by 0.2 inches) in size of caesium-137 was found inside the concrete wall of an apartment building in Kramatorsk, Ukrainian SSR. It is believed that the capsule, originally a part of a measurement device, was lost in the late 1970s and ended up mixed with gravel used to construct the building in 1980. Over 9 years, two families had lived in the apartment. By the time the capsule was discovered, 6 residents of the building had died, 4 from leukemia and 17 more receiving varying doses of radiation.
== Further reading == Kim ES, Deeks ED (September 2015). "Empagliflozin/Linagliptin: A Review in Type 2 Diabetes". Drugs. 75 (13): 1547–57. doi:10.1007/s40265-015-0457-z. PMID 26323340. S2CID 27675087.
Sources: en.wikipedia.org
Both derive from whey, but hydrolysate has been treated to break peptide bonds, producing shorter peptides. Isolate is filtered to high protein content with much of its original protein structure intact. The two differ in peptide size, taste, and functional properties.
Hydrolysis targets proteins rather than lactose, so residual lactose depends on the starting whey and filtration steps. Lactose-free or low-lactose hydrolysates require additional processing.
No. Extensive hydrolysis can reduce some allergenic epitopes, but residual peptides may still bind IgE in sensitive individuals. Product-specific testing and clinical guidance determine suitability.
Hydrolysis extent is often estimated by measuring the increase in soluble nitrogen or free amino groups relative to total nitrogen. The o-phthaldialdehyde method and trinitrobenzenesulfonic acid assay are common laboratory approaches. Values are method-dependent, so comparisons require the same assay and calculation.