This is a working overview of Spray drying, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-08 and is reviewed periodically as new material appears.
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.
Stability depends on moisture, temperature, oxygen, and packaging. Powdered hydrolysate generally requires cool, dry storage and protection from humidity because peptides can absorb water and undergo Maillard reactions with residual lactose. Higher temperatures can increase bitterness, discoloration, and loss of solubility over time, while liquid hydrolysate formats are more perishable and may need refrigeration or preservatives. Shelf-life studies typically monitor moisture, color, pH, protein solubility, and microbial counts. Exact stability limits vary by peptide profile, packaging, and water activity, so general rules should be treated as approximate.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Moisture content | ≤ 6% for powder | Lower moisture supports shelf stability |
| Water activity | Often below 0.3 | Higher values increase caking and browning |
| Typical storage temperature | 15–25 °C | Cool, dry, protected from humidity |
| Common analytical method | Size-exclusion chromatography | Estimates peptide molecular weight distribution |
| Bulk density | 0.3–0.6 g/mL | Depends on spray-drying and particle size |
Quality control focuses on degree of hydrolysis, molecular weight distribution, protein content, moisture, ash, and microbial limits. Degree of hydrolysis is commonly calculated from the number of cleaved peptide bonds relative to total peptide bonds. Size-exclusion chromatography and mass spectrometry can describe peptide size ranges, while amino acid analysis quantifies composition. Standard methods from dairy science organizations are often used, though no single method captures every functional property. Results are therefore reported alongside processing conditions.
Hydrolysates are generally stable as dry powders but can absorb moisture and undergo browning during warm storage. The bitter taste of some hydrolysates arises from hydrophobic peptides exposed by cleavage, and it varies with enzyme choice and degree of hydrolysis. Reduced allergenicity is sometimes claimed, but residual IgE-binding peptides may remain, especially in partial hydrolysates. Regulatory frameworks treat extensively hydrolyzed and partially hydrolyzed products differently, and labeling rules vary by country. More research is needed on how specific peptide profiles relate to clinical outcomes.
Commercial production begins with whey protein concentrate or isolate dissolved in water. A protease is added under controlled pH and temperature, and the reaction is stopped by heat or pH adjustment once a target degree of hydrolysis is reached. Membrane filtration, often ultrafiltration or diafiltration, removes enzymes and small solutes while retaining peptides. The liquid is then concentrated and spray-dried into a powder. Each step influences peptide length, mineral content, and flavor.
Quality control for hydrolysates often includes allergen and contaminant checks. Because whey is a milk-derived ingredient, milk protein residues may remain, and the extent to which hydrolysis reduces allergenic potential is product-specific and not fully predictable. Tests may screen for heavy metals, melamine, pesticides, and microbial indicators. Enzyme residues and processing aids are also monitored when regulations require it. Batch-to-batch consistency is assessed through peptide mapping or functional tests, since small process changes can alter taste, solubility, or nutritional performance.
Laboratories characterize whey protein hydrolysate by several complementary methods. Total nitrogen or Kjeldahl analysis estimates crude protein, while amino acid analysis gives a more detailed composition. Size-exclusion chromatography and mass spectrometry separate peptides by molecular weight and can reveal the distribution of chain lengths. Degree of hydrolysis is often calculated from free amino groups using trinitrobenzenesulfonic acid or o-phthaldialdehyde assays. No single measurement captures all relevant properties, so specifications usually combine protein content, peptide profile, moisture, ash, and microbial limits.
Storage stability depends on moisture, temperature, oxygen, and packaging. Dry hydrolysate powders are typically stable for months to years when kept cool and sealed, but they can absorb water and cake if exposed to humid air. Higher temperatures accelerate Maillard reactions between peptides and residual sugars, leading to browning and flavor changes. Lipid oxidation can occur if residual fat is present, producing off-odors. Once a powder is reconstituted, microbial growth becomes a concern, so liquid forms require refrigeration or other preservation steps.
== Montagnard influence == The working class was especially hurt by a hail storm which damaged grain crops in 1788, which caused bread prices to skyrocket. While the peasants of rural France could sustain themselves with their farms, and the wealthy aristocracy could still afford bread, the urban workers of France, the group that comprised the sans-culottes, suffered. In the city, the division grew between the sans-culottes and these wealthy aristocrats; the former had a particular hostility "towards those with large private incomes." The faction known as the Montagnards expressed concern for the working classes of France. When the National Convention met to discuss the fate of the former king Louis XVI in 1792, the sans-culottes vehemently opposed a proper trial, instead opting for an immediate execution. The moderate Girondin faction voted for a trial, but the radical Montagnards sided with the sans-culottes, deeming that a trial was not necessary, and won with a slim majority. Louis XVI was executed on January 21, 1793. The demands of the sans-culottes did not stop with the execution of the King, and the Montagnards worked hard to fulfil their mounting orders. This increased pressure from the radical masses exacerbated the ideological split between the Montagnards and the Girondins, and tensions began to grow within the convention. Eventually, by May 1793, the Montagnards worked with the National Guard—which was, at this time, mostly sans-culottes—to depose many of the Girondin deputies.
Evidence of the use of dye in pottery are found in most cases on the upper part of ceramic basins, on the inside surface, the areas in which the reduced dye-solution was exposed to air, and underwent oxidation that turned it purple. In the Late Bronze Age Hala Sultan Tekke on Cyprus was a major exporter of purple-dyed textiles with the dye coming from the mucus gland of the murex sea snail. The production of Murex purple for the Byzantine court came to an abrupt end with the sack of Constantinople in 1204, the critical episode of the Fourth Crusade. David Jacoby concludes that "no Byzantine emperor nor any Latin ruler in former Byzantine territories could muster the financial resources required for the pursuit of murex purple production. On the other hand, murex fishing and dyeing with genuine purple are attested for Egypt in the tenth to 13th centuries." By contrast, Jacoby finds that there are no mentions of purple fishing or dyeing, nor trade in the colorant in any Western source, even in the Frankish Levant. The European West turned instead to kermes dye provided by the insect Kermes vermilio, known as grana, or crimson. In 1909, Harvard anthropologist Zelia Nuttall compiled an intensive comparative study on the historical production of the purple dye produced from the carnivorous murex snail, source of the royal purple dye valued higher than gold in the ancient Near East and ancient Mexico.
=== Alcoholic beverages === In 2023, Monster launched the Monster Beast line of alcoholic beverages. The first release, The Beast Unleashed, featured flavors inspired by classic Monster Energy drinks but reformulated without sugar or caffeine, and brewed with alcohol at 6.0% alcohol by volume. The Beast Unleashed flavors include:
Sources: en.wikipedia.org
In the 1969 election, the SPD gained enough votes to form a coalition government with the FDP. SPD leader and Chancellor Willy Brandt remained head of government until May 1974, when he resigned after the Guillaume affair, in which a senior member of his staff was uncovered as a spy for the East German intelligence service, the Stasi. However, the affair is widely considered to have been merely a trigger for Brandt's resignation, not a fundamental cause. Instead, Brandt, dogged by scandal relating to alcohol and depression as well as the economic fallout of the 1973 oil crisis, almost seems simply to have had enough. As Brandt himself later said, "I was exhausted, for reasons which had nothing to do with the process going on at the time". Finance Minister Helmut Schmidt (SPD) then formed a government, continuing the SPD–FDP coalition. He served as Chancellor from 1974 to 1982. Hans-Dietrich Genscher, a leading FDP official, was Vice-Chancellor and Foreign Minister in the same years. Schmidt, a strong supporter of the European Community (EC) and the Atlantic alliance, emphasised his commitment to "the political unification of Europe in partnership with the USA". The goals of SPD and FDP drifted apart in the late 1970s and early 1980s. On 1 October 1982 the FDP joined forces with the CDU/CSU to elect CDU Chairman Helmut Kohl as Chancellor in a constructive vote of no confidence. Following national elections in March 1983, Kohl emerged in firm control of both the government and the CDU.
==== MeSH D12.776.835.700.350 – gtp phosphohydrolase-linked elongation factors ==== MeSH D12.776.835.700.350.200 – peptide elongation factor g MeSH D12.776.835.700.350.700 – peptide elongation factor tu MeSH D12.776.835.700.350.800 – peptide elongation factor 1 MeSH D12.776.835.700.350.850 – peptide elongation factor 2
=== Detection in biological fluids === Fentanyl may be measured in blood or urine to monitor for abuse, confirm a diagnosis of poisoning, or assist in a medicolegal death investigation. Commercially available immunoassays are often used as initial screening tests, but chromatographic techniques are generally used for confirmation and quantitation. The Marquis Color test may also be used to detect the presence of fentanyl. Using formaldehyde and sulfuric acid, the solution will turn purple when introduced to opium drugs. Blood or plasma fentanyl concentrations are expected to be in a range of 0.3–3.0 μg/L in persons using the medication therapeutically, 1–10 μg/L in intoxicated people, and 3–300 μg/L in victims of acute overdosage. Paper spray-mass spectrometry (PS-MS) may be useful for initial testing of samples.
== Astronomy == In astronomy, collisional excitation gives rise to spectral lines in the spectra of astronomical objects such as planetary nebulae and H II regions. In these objects, most atoms are ionised by photons from hot stars embedded within the nebular gas, stripping away electrons. The emitted electrons, (called photoelectrons), may collide with atoms or ions within the gas, and excite them. When these excited atoms or ions revert to their ground state, they will emit a photon. The spectral lines formed by these photons are called collisionally excited lines (often abbreviated to CELs). CELs are only seen in gases at very low densities (typically less than a few thousand particles per cm³) for forbidden transitions. For allowed transitions, the gas density can be substantially higher. At higher densities, the reverse process of collisional de-excitation suppresses the lines. Even the hardest vacuum produced on Earth is still too dense for CELs to be observed. For this reason, when CELs were first observed by William Huggins in the spectrum of the Cat's Eye Nebula, he did not know what they were, and attributed them to a hypothetical new element called nebulium. However, the lines he observed were later found to be emitted by extremely rarefied oxygen. CELs are very important in the study of gaseous nebulae, because they can be used to determine the density and temperature of the gas.
Sources: en.wikipedia.org
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.
Enzymatic cleavage can expose hydrophobic amino acid residues that interact with bitter taste receptors. The intensity depends on peptide sequence, hydrolysis extent, and further processing such as filtration or deamidation. Bitterness is not a reliable indicator of protein quality or allergenicity.
Moisture uptake, storage temperature, and packaging barrier properties are major factors. Residual lactose can participate in browning reactions when water activity and temperature rise. Shelf-life testing usually combines accelerated and real-time conditions to estimate change in color, solubility, and microbial stability.
Common laboratory methods measure free amino groups with TNBS or OPA reagents. The result is converted to a percentage using a reference standard and a defined protocol. Values are method-dependent, so comparisons require the same assay conditions.