The short version of Degree of hydrolysis fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-08-24 and is reviewed periodically as new material appears.
Enzyme choice influences the peptide size distribution and the resulting functional properties. Some proteases cut at specific amino acid residues, while others act more broadly, so two hydrolysates with the same degree of hydrolysis can differ in peptide sequences. Short peptides are generally more water-soluble and less likely to form gels under heat, although bitterness can increase when hydrophobic residues become exposed. The relationship between peptide length, taste, and bioactivity is an active area of study, and not all proposed effects are established in human trials.
Composition tables often report protein content on a dry basis, ash, moisture, fat, and lactose. Because hydrolysis adds water to peptide bonds, the total mass yield can appear slightly higher than the original protein if residual salts and water are counted. Some products are further processed by ultrafiltration, spray drying, or decolorization, which alters mineral content and flavor. Product labels may distinguish partially hydrolyzed from extensively hydrolyzed whey, but these terms are not always defined by a single numerical threshold across regions.
Whey protein hydrolysate is a dairy ingredient made by treating whey protein with proteases that cleave peptide bonds. The starting material is typically whey protein concentrate or isolate, which contains beta-lactoglobulin, alpha-lactalbumin, and smaller amounts of bovine serum albumin and immunoglobulins. Hydrolysis shortens protein chains into peptides and free amino acids, changing solubility, viscosity, and flavor compared with intact whey protein. The extent of cleavage is commonly described by degree of hydrolysis, a percentage of broken peptide bonds relative to total bonds.
Stability and storage practices affect measured quality over time. Hydrolysate powders are hygroscopic and can absorb moisture, leading to caking, Maillard browning, and reduced solubility. Cool, dry storage in sealed containers limits these changes, while high humidity and warm temperatures accelerate them. Microbiological testing for total aerobic counts, yeasts, molds, and specified pathogens is typical for food ingredients. Regulatory status varies by country; in many jurisdictions hydrolyzed whey protein is regulated as a food ingredient rather than a drug, and claims about reduced allergenicity require specific substantiation.
Quality control for whey protein hydrolysate begins with verifying protein content, moisture, ash, and fat using standard food analysis methods. Total nitrogen by Kjeldahl or Dumas combustion gives an estimate of protein, often calculated with a dairy-specific conversion factor. Amino acid analysis after acid hydrolysis quantifies individual residues but destroys tryptophan and may convert glutamine and asparagine. The extent of peptide bond cleavage is usually estimated by measuring free amino groups, soluble nitrogen, or trichloroacetic acid-soluble peptides. These tests are operationally defined and can give different results across laboratories.
Peptide size distribution is central to product characterization because biological and functional effects often depend on molecular weight. Size-exclusion chromatography, reversed-phase high-performance liquid chromatography, and capillary electrophoresis can separate peptides by size or hydrophobicity. Mass spectrometry provides sequence-level information and can detect marker peptides, though it is less common for routine lot release. For allergen control, enzyme-linked immunosorbent assays estimate residual intact protein or specific milk proteins, but results depend on antibody recognition and may not detect small peptides. No single method captures the full composition.
| Property | Value | Notes |
|---|---|---|
| Appearance | Off-white to pale yellow powder | Color varies with hydrolysis and drying |
| Solubility class | Highly soluble in water | Short peptides often dissolve more readily than intact protein |
| Typical protein content | 70-90% dry basis | Depends on starting material and purification |
| Degree of hydrolysis | 2-30% commonly reported | Method and calculation vary |
| Common synonyms | Hydrolyzed whey protein; whey protein hydrolysate | Labels may use either order |
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.
Bitterness often increases with hydrolysis because hydrophobic peptides are exposed. Processing strategies therefore include selecting enzymes that cleave at specific sites, using exopeptidases to remove terminal hydrophobic residues, or blending hydrolysates with other ingredients. Allergenicity is another consideration: extensive hydrolysis can reduce IgE-binding epitopes, but it does not guarantee absence of allergenic potential. Regulatory frameworks vary in how they classify hydrolyzed whey for infant formula or sports products. Claims about reduced allergenicity or faster absorption depend on the specific product and study design, and are not uniform across all hydrolysates.
Testing hydrolysate powders typically begins with proximate analysis for moisture, ash, fat, and total nitrogen. Protein content is calculated from nitrogen using a conversion factor, most often Kjeldahl or Dumas combustion. Peptide size distribution is assessed by size-exclusion chromatography, reversed-phase HPLC, or mass spectrometry. Sodium dodecyl sulfate polyacrylamide gel electrophoresis can show residual intact protein bands. Free amino groups may be quantified by colorimetric assays to estimate cleavage extent, though different methods and laboratories are not always directly comparable.
Dry hydrolysate powders are generally stable when kept cool, dry, and sealed, while moisture uptake can cause caking, Maillard browning, and loss of solubility. Higher temperatures accelerate these changes and may alter flavor. Recommended storage conditions often fall between 15 and 25 degrees Celsius with relative humidity below 60 percent. Once reconstituted, liquid hydrolysate solutions support microbial growth and may develop bitterness or haze over time. Packaging in moisture-barrier containers with desiccants helps maintain quality during transport and warehouse storage.
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.
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.
Bupropion (bis 2000 unter dem Internationalen Freinamen Amfebutamon bekannt, in Medikamenten als Bupropionhydrochlorid verwendet) ist ein Arzneistoff zur Behandlung von Depressionen, zur Raucherentwöhnung sowie zur Appetitzüglung. Der Wirkstoff gehört zur Gruppe der substituierten Cathinone, eine Untergruppe der Amphetamine, und ist daher zum Beispiel mit dem Anoretikum Amfepramon und dem Stimulanz Cathinon verwandt. Bupropion wird vorrangig als selektiver Wiederaufnahmehemmer von Dopamin und Noradrenalin (SNDRI – Selektive Noradrenalin/Dopamin Reuptake Inhibitor) eingestuft. Die klinische Relevanz seiner dopaminergen Wirkung wird jedoch zunehmend angezweifelt. Neuere Forschungsergebnisse zeigen, dass Bupropion direkt eine Dopamin- und Noradrenalin-Ausschüttung bewirkt (siehe Wirkungsweise). Bupropion wurde 2021 in die Liste der unentbehrlichen Arzneimittel der Weltgesundheitsorganisation in der Gruppe der Psychopharmaka als „Medikament bei Suchterkrankungen“ aufgenommen.
=== Depression === Bupropion ist seit 2007 in Deutschland unter dem Handelsnamen Elontril (Bupropionhydrochlorid) zur Behandlung von Depression zugelassen. In den USA wird Bupropion seit 1984 als Antidepressivum eingesetzt. In mehreren Studien konnte gezeigt werden, dass die Wirksamkeit von Bupropion mit der Wirksamkeit der Antidepressiva aus der Klasse der sogenannten selektiven Serotonin-Wiederaufnahmehemmer (SSRI) vergleichbar ist. Bezogen auf Response und Remission wirkt es im Vergleich schlechter als Venlafaxin. Die unter der Behandlung mit vielen SSRI häufig auftretende sexuelle Dysfunktion (Post-SSRI Sexual Dysfunction – PSSD) kommt unter Bupropion seltener vor. Bupropion wirkt in der Zweitlinientherapie nach Therapieversagen von Citalopram ähnlich gut wie Buspiron, Venlafaxin und Sertralin und führt bei etwa einem Viertel der Patienten zu einer Remission. In einer Veröffentlichung im New England Journal of Medicine wurde darauf hingewiesen, dass die US-Zulassung der SR-Retardformulierung von Bupropion (Wellbutrin SR) als Antidepressivum sich auf drei Wirksamkeitsstudien stützte, von denen die US-amerikanische Zulassungsbehörde für Arzneimittel (FDA) zwei als negativ beurteilte.
=== Kombinationstherapie === Die Kombination von Bupropion mit anderen Antidepressiva (außer Citalopram und Desipramin), Benzodiazepinen (außer Diazepam) und Neuroleptika wurde nicht systematisch untersucht. Lediglich im Rahmen von Untersuchungen zur Wirkung von Bupropion auf von SSRI ausgelöste sexuelle Dysfunktionen wurden Kombinationen von Bupropion mit verschiedenen SSRI durchgeführt. Die Idee, eine sexuelle Dysfunktion aufgrund der Einnahme anderer Antidepressiva durch zusätzliche Gabe von Bupropion zu bessern, ist umstritten. Es wurde jedoch in einigen klinischen Studien eine deutliche Verbesserung von durch SSRI hervorgerufenen sexuellen Dysfunktion beobachtet. In Kombination mit anderen Antidepressiva soll Bupropion einige Nebenwirkungen dieser Stoffe ausgleichen. Unerwünschter Müdigkeit, die durch sedierende Antidepressiva (z. B. Mianserin und Mirtazapin) entsteht, kann gegebenenfalls durch die stimulierende Wirkung von Bupropion entgegengewirkt werden. Zur Besserung von Müdigkeitserscheinungen wird Bupropion am Beginn, das ermüdende Antidepressivum am Ende des Tages genommen. Schlaffördernde oder sexuell dämpfende Antidepressiva wiederum können den durch Bupropion ausgelösten Schlafstörungen oder dem Priapismus entgegenwirken. Das Beheben von Nebenwirkungen anderer Antidepressiva ist keine zugelassene Indikation von Bupropion.
=== Raucherentwöhnung === Die Substanz ist zur Raucherentwöhnung zugelassen und in Deutschland unter dem Namen Zyban erhältlich. In einer Metaanalyse von 31 Studien zeigte sich, dass unter der Behandlung mit Bupropion der Anteil von Patienten, die nach der Behandlung mindestens sechs Monate lang nicht rauchten, mit 19 % fast doppelt so hoch war, wie der von 10,3 % unter einer Placebo-Behandlung. Bupropion ist im direkten Vergleich ebenso wirksam wie Nikotinpflaster. Nikotinpflaster zusätzlich zu Bupropion verbesserten die Abstinenzrate nicht. Es gibt Hinweise darauf, dass Bupropion dem Vareniclin unterlegen ist. Die Therapie ist nur bei Trägern einer bestimmten, bei europäischstämmigen Menschen allerdings weit verbreiteten, Genvariante im Cytochrom-P450-System erfolgversprechend: Ungefähr 45 % aller Menschen europäischer Herkunft haben den Genotyp CYP2B6*6. 33 % der Träger dieser Genvariante konnten durch Bupropion mit dem Rauchen aufhören (bei den Probanden, die ein Placebo erhielten, waren es nur 14 %). Die Träger einer anderen Genvariante (Genotyp CYP2B6*1) hatten jedoch keinen Nutzen durch Bupropion.
Sources: de.wikipedia.org
Hydrolysate has undergone enzymatic cleavage of peptide bonds, while isolate is largely intact protein. Both can originate from the same whey stream, but hydrolysis changes peptide size, solubility, taste, and allergenicity testing outcomes. The two ingredients are not interchangeable in every formulation.
No. A higher degree of hydrolysis means more peptide bonds have been broken, which can increase solubility and reduce viscosity but also raise bitterness and processing cost. The best degree depends on the intended use, such as a beverage, bar, or culture medium.
No. They differ by starting whey material, enzyme type, hydrolysis conditions, and downstream purification. These variables produce different peptide profiles, mineral contents, and functional properties. Two products with the same label category may therefore behave differently.
Hydrolysis extent is commonly estimated by quantifying free amino groups or soluble nitrogen after protein cleavage. The result is expressed as a percentage of cleaved peptide bonds. Different assays use different definitions and may not agree exactly.