A practical reference on Size exclusion chromatography: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-07-29. Anything still debated is marked as such rather than presented as settled.
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.
Whey protein hydrolysate is derived from whey, the liquid byproduct of cheese-making or casein coagulation. It consists of peptides and free amino acids produced when peptide bonds are cleaved by enzymes or acid. Hydrolysis lowers the average molecular weight and can change solubility, viscosity, and bitterness. The degree of hydrolysis indicates the proportion of peptide bonds broken and distinguishes partial from extensive hydrolysates. Commercial ingredients vary widely in peptide size, mineral content, and lactose level.
Production usually starts with whey protein concentrate or isolate. The material is dissolved, pasteurized, and adjusted to conditions that favor a chosen protease, such as trypsin, pepsin, or papain. Enzyme choice, pH, temperature, and reaction time determine peptide length, terminal residues, and functional behavior. After hydrolysis, the enzyme is inactivated by heat or pH change, and the liquid is clarified, filtered, concentrated, and dried. Membrane filtration can further fractionate peptides and remove some minerals or lactose. The final powder is typically spray-dried.
| Property | Value | Notes |
|---|---|---|
| Moisture content | Typically 3-7% | Higher moisture increases caking and browning risk |
| Water activity | Usually below 0.6 | Low water activity limits microbial growth |
| Storage temperature | 15-25 °C, dry conditions | Cool, dry storage slows quality loss |
| Peptide size method | Size exclusion chromatography | Calibration standards affect reported molecular weight |
| Allergen labeling | Milk declaration often required | Rules vary by jurisdiction and product type |
Quality control checks identity, composition, and contaminants. Moisture, ash, fat, and carbohydrate are measured by standard methods, and microbiological limits are set for total counts, coliforms, and specific pathogens. Heavy metals and pesticide residues may be monitored depending on market requirements. Adulteration with intact whey protein or individual amino acids is possible, so peptide fingerprints and free amino acid profiles can help verify authenticity. Regulatory frameworks vary: some countries treat hydrolyzed whey as a conventional dairy ingredient, while infant formula uses face additional compositional rules. Which marker peptides best confirm source and processing remains an open analytical question.
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.
Whey protein hydrolysate appears in infant formula, sports nutrition, and clinical nutrition. In infant formula, extensively hydrolyzed products are used when a reduced allergenicity is desired, though not all hydrolysates are hypoallergenic. In sports products, the ingredient is marketed for rapid amino acid delivery, but the practical advantage over intact whey protein remains debated. Research often compares hydrolysate with isolate or concentrate for absorption kinetics, muscle protein synthesis, and gastrointestinal tolerance. Regulatory categories differ by country, and label terms such as partially hydrolyzed or extensively hydrolyzed are defined in some jurisdictions but not others.
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.
=== Pyrimidines === Uridine phosphorylase or pyrimidine-nucleoside phosphorylase substitutes the anomeric-carbon-bonded phosphate of ribose 1-phosphate for the free base uracil, forming the nucleoside uridine. Uridine kinase (aka uridine–cytidine kinase) can then phosphorylate the 5’-carbon of this nucleoside into uridine monophosphate (UMP). UMP/CMP kinase (EC 2.7.4.14) can phosphorylate UMP into uridine diphosphate, which nucleoside diphosphate kinase can phosphorylate into uridine triphosphate. Thymidine phosphorylase or pyrimidine-nucleoside phosphorylase adds 2-deoxy-alpha-D-ribose 1-phosphate to thymine, with thymine bonding at the anomeric carbon of the deoxyribose, forming the deoxynucleoside thymidine. Thymidine kinase can then phosphorylate the 5’-carbon of this compound into thymidine monophosphate (TMP). Thymidylate kinase can phosphorylate TMP into thymidine diphosphate, which nucleoside diphosphate kinase can phosphorylate into thymidine triphosphate. The nucleosides cytidine and deoxycytidine can be salvaged along the uracil pathway by cytidine deaminase, which converts them to uridine and deoxyuridine, respectively. Alternatively, uridine–cytidine kinase can phosphorylate them into cytidine monophosphate (CMP) or deoxycytidine monophosphate (dCMP). UMP/CMP kinase can phosphorylate (d)CMP into cytidine diphosphate or deoxycytidine diphosphate, which nucleoside diphosphate kinase can phosphorylate into cytidine triphosphate or deoxycytidine triphosphate.
They present covalent cross-linkages between the polypeptide chains. These bonds are the strongest because they're covalent bonds, making them stronger than intermolecular forces. Glycosylation is another way to improve the thermostability of proteins. Stereoelectronic effects in stabilizing interactions between carbohydrate and protein can lead to the thermostabilization of the glycosylated protein. Cyclizing enzymes by covalently linking the N-terminus to the C-terminus has been applied to increase the thermostability of many enzymes. Intein cyclization and SpyTag/SpyCatcher cyclization have often been employed.
A protein called divalent metal transporter 1 (DMT1), which can transport several divalent metals across the plasma membrane, then transports iron across the enterocyte's cell membrane into the cell. If the iron is bound to heme it is instead transported across the apical membrane by heme carrier protein 1 (HCP1). These intestinal lining cells can then either store the iron as ferritin, which is accomplished by Fe2+ binding to apoferritin (in which case the iron will leave the body when the cell dies and is sloughed off into feces), or the cell can release it into the body via the only known iron exporter in mammals, ferroportin. Hephaestin, a ferroxidase that can oxidize Fe2+ to Fe3+ and is found mainly in the small intestine, helps ferroportin transfer iron across the basolateral end of the intestine cells. In contrast, ferroportin is post-translationally repressed by hepcidin, a 25-amino acid peptide hormone. The body regulates iron levels by regulating each of these steps. For instance, enterocytes synthesize more Dcytb, DMT1 and ferroportin in response to iron deficiency anemia. Iron absorption from diet is enhanced in the presence of vitamin C and diminished by excess calcium, zinc, or manganese. The human body's rate of iron absorption appears to respond to a variety of interdependent factors, including total iron stores, the extent to which the bone marrow is producing new red blood cells, the concentration of hemoglobin in the blood, and the oxygen content of the blood.
Sources: en.wikipedia.org
In January 2017, Palatin and AMAG Pharmaceuticals agreed that AMAG exclusively would complete development and market bremelanotide in North America and the two would work together to license it in other territories; AMAG agreed to pay $60 million upfront, up to $80 million in regulatory milestones, up to $300 million in sales milestones, and tiered royalties ranging from high single-digit to low double-digit percentages. A New Drug Application of bremelanotide for female sexual dysfunction was accepted by the US Food and Drug Administration (FDA) in June 2018, with a Prescription Drug User Fee Act (PDUFA) goal date set for 23 March 2019. It was approved for use in the United States in June 2019. At release, it was designated by the US Food and Drug Administration (FDA) as a first-in-class medication, which means that its mechanism was novel and different from previously approved medications.
== Awards == Phillips has been honored by Paul Newman and by John F. Kennedy Jr. as one of America's most generous business leaders when EAS was honored in 1999 with a Newman's Own/George Award. The United States Junior Chamber of Commerce honored Phillips in January 2000 as one of the Ten Outstanding Young Americans. Phillips was also chosen to help carry the Olympic torch on its relay across the United States for the 2002 Winter Olympics in Salt Lake City. Bill Phillips has donated over $5 million to the Make-A-Wish Foundation. Over the past 20 years Bill Phillips has granted over 600 wishes to kids facing life-threatening medical conditions through the Make-A-Wish Foundation. All the proceeds that would have gone to Phillips from the sale of his book Body-for-LIFE were donated to the Make-A-Wish Foundation. Phillips was awarded with The Ernst & Young Entrepreneur of the Year Award in 1997. On June 24, 2014, Bill Phillips was inducted into the Fitness Hall of Fame along with Jack LaLanne, Arnold Schwarzenegger, and Jillian Michaels.
Pluralism and regulation of the media, such as through 'the licensing of broadcasting, television or cinema enterprises', have long been seen as essential to protect freedom of opinion and expression, to ensure that citizens have a more equal voice, and ultimately to support the universal 'right to take part in the government'. In almost all member states there is a well funded public, and independent broadcaster for TV and radio, and there are common standards for all TV and radio, which are designed to support open, fact-based discussion and deliberative democracy. However, the same standards have not yet been applied to equivalent internet television, radio or "social media" such as the platforms controlled by YouTube (owned by Alphabet), Facebook or Instagram (owned by Meta), or Twitter (owned by Elon Musk), all of which have spread conspiracy theories, discrimination, far-right, extremist, terrorist, and hostile military content.
Following the re-election of Donald Trump in November 2024, Lula congratuled Trump on X (formerly Twitter) and again, after his inauguration, in January 2025, when Lula also highlighted Brazil-United States historical friendship. After Trump first threatened to impose tariffs on steel and aluminium in February 2025, and fulfilled that in March, Lula warned the United States economy could self-inflict damage, and promised to open a complaint against the 25% tariffs imposed on Brazilian steel and aluminum exports bound to US at the World Trade Organization. He also said he would not hesitate to call Trump to disscuss such tariffs, and hoped he answered his call.
Sources: en.wikipedia.org
In 1974, the Toronto Zoo was moved from its original downtown location to its current location in the Rouge River valley. The new location enabled the zoo to increase its overall area from 3 hectares (7.4 acres) to over 300 hectares (740 acres). The zoo was transformed at that time from a 19th-century style zoo with a few animals cramped behind iron bars into a zoo where space was provided to animals and the setting attempted to duplicate the animals' natural environments. There are a large number of golf courses in the district, with a mix of public and private courses. Dentonia Park is a public course established in 1967 and is situated in the Taylor-Massey Creek ravine beside the Victoria Park subway station. Formerly a private club, the Tam O'Shanter Golf Course was established in 1973 as a public course and is located alongside Highland Creek. Private clubs include the Toronto Hunt Club which was the first golf course in Scarborough, established in 1895 alongside Lake Ontario. and the Scarboro Golf and Country Club was established in 1912. The Cedarbrae Golf & Country Club was established in 1922 and moved to its current Rouge River Valley location at Steeles Ave East in 1954. On May 17, 2006, the Nike Malvern Sports Complex was opened in the Malvern neighbourhood. Nike Canada donated CA$500,000 to build the complex, which includes a basketball court, a practice soccer pitch, and a running track. The track was constructed from 50,000 used running shoes. The complex was built on the grounds of the St. Mother Teresa Catholic Academy and is open to the public.
Dextran hydrogels and dextran conjugate hydrogels are heavily cross-linked polymeric networks that have a strong affinity for water. These gels have soft, elastic physical properties and are biocompatible and biodegradable. Dextran hydrogels have also been shown to be stable and safe in vivo. Glucose-based polymeric gels have the advantage of being able to be chemically or physically modified to improve targeted drug delivery. Swelling is one mechanism by which drugs are released from the dextran hydrogels. Swelling can be reduced by increasing the molecular weight of dextran, leading to a slower drug diffusion rate out of the hydrogel. Swelling can also be lessened by increasing the amount of the conjugated species and introducing ethanol during the cross-linking reaction. Degradation of chemical linkages in the dextran hydrogels is another mechanism by which drugs are released from the polymeric matrices. An increase in degradation of the dextran hydrogel leads to an increase in drug release rate. Degradation of dextran hydrogels specifically is caused by dextranases, which are microbial enzymes mostly located in the colon.
Trauma to the region Inflammation (bug bites, acne) Varicose veins Infections Tumors (malignant or benign) Diseases of connective tissue Hypercalcemia Hyperphosphatemia Calcinosis cutis is associated with systemic sclerosis.
== Career and research == Her first position was at the Allan Memorial Institute of Psychiatry (associated with McGill University). In 1952, she joined the staff of the National Institute for Medical Research (NIMR) where she served as head of the division of Immunology from 1976 to 1988. During that time, she worked extensively with fellow immunologist John H. Humphrey to establish the immunology divisions. Askonas focused on B cells and determined their role in producing antibodies as part of the immune response. At the NIMR she began researching the biosynthesis of polypeptides in milk proteins discovering that the peptides were synthesised from amino acids rapidly in one piece. From 1955 to 1959 she studied the sites of antibody formation using radioactivity to develop our understanding of antibody molecules and the cells of the immune system. From 1959 to 1961 she studied plasma cell tumors as models for antibody formation. She went on to investigate macrophages and their role in antigen presentation (1962–1968). From 1963 to 1966 she studied the fate of antigen in relation to antibody formation and later continued her study of B cells from 1965 to 1970. She wrote several biographies of high-profile scientists, including Niels Kaj Jerne, César Milstein and John Herbert Humphrey. Askonas conducted a filmed interview with Stanley Peart as a segment of what became the Medical Sciences Video Archive housed in the special collections of the library at Oxford Brookes University.
=== Epidemiological and medical === Bogden JD, Kemp FW, Buse M, et al. (January 1981). "Composition of tobaccos from countries with high and low incidences of lung cancer. I. Selenium, polonium-210, Alternaria, tar, and nicotine". J. Natl. Cancer Inst. 66 (1): 27–31. doi:10.1093/jnci/66.1.27. PMID 6935462. Hecht SS (July 1999). "Tobacco smoke carcinogens and lung cancer". J. Natl. Cancer Inst. 91 (14): 1194–210. doi:10.1093/jnci/91.14.1194. PMID 10413421. Ernster, Virginia, et al. "Women and tobacco: moving from policy to action." Bulletin of the World Health Organization 78 (2000): 891–901. online Frieden, Thomas R. et al. The Health Consequences of Smoking: 50 Years of Progress: A Report of the Surgeon General (2014) online Kluger, Richard. Ashes to Ashes: America's Hundred-Year Cigarette War, the Public Health, and the Unabashed Triumph of Philip Morris (Vintage, 1997). excerpt Matuszko J (November 2006). "Tobacco Products Processing Detailed Study" (PDF). www.epa.gov. U.S. Environmental Protection Agency. Archived (PDF) from the original on October 9, 2022. Retrieved March 29, 2017. Oreskes, Naomi, and Erik M. Conway. Merchants of doubt: How a handful of scientists obscured the truth on issues from tobacco smoke to global warming (Bloomsbury Publishing USA, 2011). Slade, John. "The tobacco epidemic: lessons from history." Journal of psychoactive drugs 21.3 (1989): 281–291. online Warner, Kenneth E. 1986. Selling Smoke: Cigarette Advertising and Public Health (American Public Health Association, 1986). online
Sources: en.wikipedia.org
Size exclusion chromatography separates peptides by molecular size in solution, and mass spectrometry can provide more detailed mass information. Results are usually reported as a distribution rather than a single value. Method choice and calibration affect the reported range.
Many allergen tests rely on antibodies that bind intact milk proteins, and hydrolysis can remove or change those binding sites. A negative result may therefore reflect lost detection rather than absence of milk-derived material. Confirmatory methods and labeling rules are needed for reliable assessment.
Bitterness often comes from short peptides that contain hydrophobic amino acids. These peptides can interact with bitter taste receptors on the tongue. The intensity depends on the enzyme, degree of hydrolysis, and peptide profile.
Whey protein hydrolysate is whey protein that has been treated with enzymes or acid to break peptide bonds into smaller peptides. It is not a different protein source; it is a modified form of whey protein. Commercial products range from partially to extensively hydrolyzed.