This is a working overview of Kjeldahl method, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-03-03 and is reviewed periodically as new material appears.
Whey protein hydrolysate is a dairy ingredient produced when whey proteins are treated with proteolytic enzymes or, less commonly, acid or heat under controlled conditions. The treatment cleaves peptide bonds and yields shorter peptide chains than those found in intact whey protein. The starting material is usually sweet whey or acid whey from cheese manufacture, concentrated by membrane filtration before hydrolysis. The resulting ingredient retains many amino acids from the original protein but differs in molecular size, solubility, and taste profile.
The parent whey proteins include beta-lactoglobulin, alpha-lactalbumin, serum albumin, immunoglobulins, and glycomacropeptide, depending on the whey source. Hydrolysis does not remove these sequences; it fragments them into peptides of varying length. The peptide distribution depends on the enzyme specificity, reaction time, temperature, pH, and enzyme-to-substrate ratio. Because the mixture is heterogeneous, a single molecular weight cannot describe the product. Instead, laboratories report a distribution, often spanning from a few hundred to several thousand daltons.
Whey protein hydrolysate appears in foods and supplements where rapid digestion, low viscosity, or reduced intact-protein content is desired. It is distinct from whey protein isolate and concentrate, which contain largely intact proteins, though hydrolysates can be made from either. In infant formula, extensively hydrolyzed whey is used in some specialty products, while partially hydrolyzed forms appear in other formulations. Human health effects depend on the specific peptide mixture and are not uniform across all hydrolysates.
Storage stability depends on moisture, temperature, oxygen, and packaging, and hydrolysates are hygroscopic and can cake when exposed to humid air. Maillard reactions between peptides and residual lactose can cause browning and flavor changes during warm storage, while lipid oxidation may develop if residual fat is present. Cool, dry conditions and sealed containers slow these reactions. Shelf-life studies typically monitor moisture, color, solubility, molecular weight profile, and microbial counts over time. Accelerated tests estimate stability, but real-time data remain the reference for shelf-life assignment.
Regulatory status differs by country and intended use. In many jurisdictions, whey protein hydrolysate is regulated as a food ingredient, while specific infant formula or medical food uses may require additional review. Labeling rules govern protein content claims, allergen statements, and terms such as partially hydrolyzed or extensively hydrolyzed. Analytical methods for degree of hydrolysis are not fully standardized, so values can depend on the assay. This variability makes direct comparison between products difficult unless the method and reference material are stated.
Quality control for whey protein hydrolysate begins with specification of protein, moisture, ash, fat, lactose, and degree of hydrolysis, while molecular weight distribution is measured by size-exclusion chromatography or electrophoresis. Free amino acid content can be quantified by amino acid analysis. Microbial limits, heavy metals, and residual enzyme activity are also monitored. Because hydrolysis conditions influence batch consistency, manufacturers validate processes and test each lot against release criteria. Sampling plans and reference standards help compare results across laboratories.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Whey hydrolysate; hydrolyzed whey protein | Abbreviations such as WPH appear in ingredient lists |
| Appearance | Off-white to light cream powder | Color can vary with starting whey and drying method |
| Solubility class | Highly soluble in water | Short peptides often dissolve more readily than intact whey protein |
| Typical storage temperature | 15–25 °C | Cool, dry conditions limit moisture uptake and browning reactions |
| Typical analytical method | Size-exclusion chromatography | Used to estimate molecular weight distribution of peptides |
Composition reflects both the original whey and the hydrolysis process. Products contain protein-derived peptides, variable ash, moisture, and residual lactose or fat depending on filtration. Some free amino acids increase during hydrolysis, and bitterness often rises with higher degrees of hydrolysis due to exposed hydrophobic residues. Mineral profiles vary with the whey source and any neutralization step. Allergenicity may be reduced in extensively hydrolyzed products, but the extent depends on residual intact protein and peptide size, and this remains a subject of ongoing study.
Whey protein hydrolysate is a dairy-derived ingredient made by treating whey protein with enzymes or acid to break peptide bonds. The starting material is typically sweet whey or acid whey from cheese manufacture, which contains beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin, and immunoglobulins. Hydrolysis shortens protein chains into peptides and free amino acids, changing solubility, viscosity, and taste. The extent of breakdown is described by degree of hydrolysis, a percentage of cleaved peptide bonds. This value influences functional and sensory properties but does not by itself define a specific molecular profile.
Commercial production usually begins with whey protein concentrate or isolate, not raw whey, to reduce fat and lactose. Food-grade proteases from bacterial or plant sources are added under controlled temperature and pH, then inactivated by heat or pH adjustment. The resulting liquid may be clarified, filtered, concentrated, and spray-dried into powder. Enzyme choice, reaction time, and pretreatment conditions create products with different peptide size distributions. Because these variables are proprietary and not standardized, two hydrolysates with the same degree of hydrolysis can differ in peptide sequences and mineral content.
Storage stability depends on moisture, temperature, and packaging. Dry powders with low water activity resist microbial growth, but they can still absorb water, develop off-colors through Maillard reactions, or oxidize residual lipids. Sealed containers kept in a cool, dry place are standard. Stability studies typically monitor moisture, solubility, color, peptide size, and microbial counts over months. Established practice favors low humidity and moderate temperatures. How brief excursions above recommended conditions affect peptide profiles and sensory qualities is less predictable and may depend on the specific product matrix.
Laboratories characterize hydrolyzed whey protein with several complementary assays. Total nitrogen methods, such as Kjeldahl or Dumas, estimate protein content using a dairy conversion factor. Free amino group assays, including TNBS and OPA, track the extent of peptide-bond cleavage. Size-exclusion chromatography and reversed-phase HPLC reveal peptide size distributions and hydrophobicity. Mass spectrometry can identify specific peptides, while amino acid analysis quantifies individual residues. No single test captures every relevant property, so results are usually interpreted together with process records and specification limits.
== Uses == Trap baits containing dimethyl trisulfide have been used to capture Calliphora loewi and other blowflies. Dimethyl trisulfide has been found to be an effective cyanide antidote in a rodent model for cyanide poisoning both against subcutaneous potassium cyanide and inhaled hydrogen cyanide, converting cyanide to much less toxic thiocyanate. It is suggested that dimethyl trisulfide can be used in a mass casualty cyanide exposure setting. In conjunction with these studies, the LD50 of dimethyl trisulfide in CD-1 mice was found to be 598.5 mg/kg, which may be compared to the LD50 of potassium cyanide of 8.0 mg/kg.
Induction of apoptosis by 2-meOE2 may be p53 dependent or independent. 2-meOE2 has also been found to inhibit aromatase activity, thereby lowering the in situ synthesis of E2 in cancer tissue. 2-meOE2 has a higher binding affinity for sex hormone-binding globulin (SHBG) than E2 and 2-OH-E2 and has no affinity for the estrogen receptor. 2-meOE2 is also a potent inhibitor of angiogenesis in tumor tissues. Administration of this estradiol metabolite prevents vascular smooth muscle growth. This inhibition of angiogenesis is eliminated by co-administration with cytochrome P450 and COMT inhibitors, thereby confirming the involvement of cytochrome P450 enzymes in the blockade of tumor blood supply. Further antitumor activity of 2-meOE2 has been identified through immunomodulation. The cytokines IL-6 and TNFα, as well the prostaglandin PGE2, are capable of stimulating aromatase activity. Since macrophages and lymphocytes are present in breast tissue, this provides a concerning means of upregulating in situ estradiol biosynthesis. 2-meOE2 appeared to be able to halve the basal aromatase activity in mammary fibroblasts, possibly through destabilisation of the microtubules that mediate translocation of the cytokine receptors to the plasma membrane. Inhibition of cytokine receptor synthesis and blockade of the autocrine and paracrine actions of cytokines and PGE2 were also observed.
The Boston keratoprosthesis is the most widely used synthetic cornea to date with over 900 procedures performed worldwide in 2008. The Boston KPro was developed at the Massachusetts Eye and Ear Infirmary under the leadership of Claes Dohlman.
Aerotolerant anaerobes use fermentation to produce ATP. They do not use oxygen, but they can protect themselves from reactive oxygen molecules. In contrast, obligate anaerobes can be harmed by reactive oxygen molecules. There are three categories of anaerobes. Where obligate aerobes require oxygen to grow, obligate anaerobes are damaged by oxygen, aerotolerant organisms cannot use oxygen but tolerate its presence, and facultative anaerobes use oxygen if it is present but can grow without it. Most aerotolerant anaerobes have superoxide dismutase and (non-catalase) peroxidase but do not have catalase. More specifically, they may use a NADH oxidase/NADH peroxidase (NOX/NPR) system or a glutathione peroxidase system. An example of an aerotolerant anaerobe is Cutibacterium acnes.
Sources: en.wikipedia.org
=== Treatment of type 2 diabetes === They are widely used as antidiabetic drugs in the management of diabetes mellitus type 2. They act by increasing secretion of insulin from the beta cells in the pancreas. Sulfonylureas are ineffective where there is absolute deficiency of insulin production such as in type 1 diabetes or post-pancreatectomy. Sulfonylureas can be used to treat some types of neonatal diabetes. Historically, people with hyperglycemia and low blood insulin levels were diagnosed with type 1 diabetes by default, but it has been found that patients who receive this diagnosis before 6 months of age are often candidates for receiving sulfonylureas rather than insulin throughout life. A 2011 Cochrane systematic review evaluated the effects on treatment of Latent Autoimmune Diabetes in Adults (LADA) and found that Sulfonylureas did not improve metabolic control of glucose at 3 and 12 months, even worsening HbA1c levels in some cases, when compared to insulin. The same review did not find improvement of fasting C-peptide following treatment with sulfonylurea. Still, it is important to highlight that the studies available to be included in this review presented considerable flaws in quality and design. While prior sulfonylureas were associated with worse outcomes, newer agents do not appear to increase the risk of death, heart attacks, or strokes.
== History == Cambrex was founded in 1979, when the Ennis Family acquired the castor oil and derivatives product lines from NL Industries. In 1987, CasChem was renamed Cambrex Corporation and became listed on NASDAQ. In 1990, Cambrex was listed on the NYSE. Cambrex entered the pharmaceutical market in 1994 with the acquisition of Nobel Pharma Chemistry business, now known as Cambrex Karlskoga AB and Cambrex Profarmaco. Through multiple acquisitions during the late 1990s, the firm entered the bioscience and the chiral enzymatic catalyst markets. Cambrex acquired two contract biopharmaceutical manufacturing facilities in 2001, to bulk manufacture biologics and pharmaceutical ingredients from clinical to commercial scales. In 2007, the firm decided to focus on its core competencies and sold the biologics business to Lonza Group. In 2008, Prosyntest (now Cambrex Tallinn) was acquired, and Steve Klosk was appointed CEO, while remaining President. To broaden their biocatalysis platform, Cambrex acquired IEP in 2010, now known as Cambrex IEP. In 2019, Cambrex acquired Avista Pharma Solutions for $252m to become a fully integrated CDMO. In late 2019, Cambrex was acquired by an affiliate of the Permira funds. In 2020, Cambrex completed a major expansion at its Edinburgh, UK facility known for solid form screening alongside a biopharmaceutical expansion at its Durham, NC facility. Thomas Loewald was appointed CEO of Cambrex in September 2020. In 2022, Cambrex acquired Q1 Scientific, based out of Waterford, Ireland.
=== Pro-101-2 (diabetic foot ulcers) === Pro-101-2 is a topical PDGF-BB gel candidate for the treatment of DFUs. The company received IND approval from NMPA in July 2021 and completed Phase I clinical trials in October 2021. The Phase II clinical trial was initiated in February 2022, with the first patient enrolled in December 2024. As of 31 December 2025, the Phase II trial was ongoing in China.
== Publications == Collier was a co-editor of the eighth edition and editor-in-chief of the five-volume ninth edition of the "microbiologist’s bible", Topley and Wilson's Principles of Bacteriology and Immunity (now Topley and Wilson's Microbiology and Microbial Infections), which won the Society of Authors' 1998 award in the advanced edited book category.He was also joint editor of Developments in Antiviral Chemotherapy (1980).He was a co-author of Human Virology (1993).
She entrusts to scientists the task of continuing to investigate, so that satisfactory answers may be found to the questions connected with this Sheet." John Paul II showed himself to be deeply moved by the image of the Shroud and arranged for public showings in 1998 and 2000. In his address at Turin Cathedral on Sunday 24 May 1998 (the occasion of the 100th year of Secondo Pia's 28 May 1898 photograph), he said: "The Shroud is an image of God's love as well as of human sin... The imprint left by the tortured body of the Crucified One, which attests to the tremendous human capacity for causing pain and death to one's fellow man, stands as an icon of the suffering of the innocent in every age." On 30 March 2013, as part of the Easter celebrations, there was an exposition of the shroud in the Cathedral of Turin. Pope Francis recorded a video message for the occasion, in which he described the image on the shroud as "this Icon of a man", and stated that "the Man of the Shroud invites us to contemplate Jesus of Nazareth". In his carefully worded statement, Francis urged the faithful to contemplate the Shroud with awe, but "stopped firmly short of asserting its authenticity". Pope Francis went on a pilgrimage to Turin on 21 June 2015, to pray before and venerate the Holy Shroud and honour St. John Bosco on the bicentenary of his birth.
Sources: en.wikipedia.org
It is made from whey, a byproduct of cheese or casein production, or from whey protein concentrate or isolate. Enzymes break the intact whey proteins into shorter peptides. The final composition depends on the starting whey and the hydrolysis conditions.
No. Whey protein isolate is a purified intact protein, while hydrolysate has been enzymatically cleaved into smaller peptides, and hydrolysate can be produced from isolate or concentrate. The two ingredients differ in molecular size, taste, and functional behavior.
Hydrolysis cleaves proteins but does not necessarily remove lactose, which is a sugar. It can reduce the size of allergenic proteins, yet residual peptides may still trigger reactions in sensitive individuals. Allergen status depends on the extent of hydrolysis and must be assessed for each product.
Methods include trinitrobenzenesulfonic acid assay, o-phthaldialdehyde assay, formol titration, and nitrogen solubility. Values depend on calibration and assay conditions. Results should be interpreted with the stated method.