The chromatographic behavior of petanin, petunidin-3-O-[6-O-(4-O-(E)-para-coumaroyl-O-α-rhamnopyranosyl)-β-glucopyranoside]-5-O-β-glucopyranoside, is studied for the first time under conditions of reversed-phase high performance liquid chromatography in mobile phases with different pH values. The relationship between chromatographic behavior (retention time and peak efficiency) and transitions between different forms of anthocyanins is discussed. Analysis of the data obtained in the 2 to 6.5 range of mobile pH phases, the absorption spectra of petanin, and the results from studying the effect of adding tetrabutylammonium bromide to the mobile phase shows that increasing the pH results in the formation of uncharged and anionic forms, in addition to the pseudobase form.
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Reversed-phase HPLC with mass spectrometric and diode array detection as well as some literature data were used to reveal the individual types of solutes in anthocyanin complexes of tulip flower petals that are responsible for tulip flower petals coloration of the samples available in the local flower market. It has been found that the main components of the complexes are 3-rutinosides and their 2”’ and 3”’ acylated with acetic acid derivatives of the three anthocyanidins - delphinidin, cyanidin and pelargonidin in the color dependent ratios, though trace quantities of 3-glucosides were found in some cases. For the anthocyanin structure confirmation a correlation analysis of solute retentions of cyanidin or pelargonidin derivatives vs that of delphinidin was proposed based upon equivalence of structures alteration in the solute pairs for each series. The specificity of solutes retention modes was revealed by relative retention analysis, the trend parameters reflected particularities of chromatographic behavior as well as that of electron spectra of the solutes. The difference of acylated anthocyanins retentions was proposed to disclose the conformation states of solutes in the sorbent interface.
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The anthocyanin composition of five purple leaves cultivars of Ocimum basilicum L. was investigated by reversed-phase HPLC with mass-spectrometric detection by ESI mode with ion partial fragmentation as well as preparation of dried differently colored forms of anthocyanins encapsulated into maltodextrinmatrix. Analysis of the mass spectra revealed that according to the chromatographic profile the set of basil cultivar anthocyanins under investigation may be divided into two groups with the common feature being ahigh level of acylation with (mainly) p-coumaric, ferulic and malonic acids of the same base: cyanidin-3-dihexoside-5-hexoside. The presence of acylation with substituted cinnamic acids permits us to obtain solutions not only with a red color (the property of the flavylium form) but also with blue shades of coloration due to quinonoid and negatively charged quinonoid forms. All forms except that of flavylium are not stable in solution but stable enough to prepare dried encapsulated forms by lyophilization. Although the loss of anthocyaninswith drying is not negligible, the final product is characterized with high stability for storage in a refrigerator.
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In werkpakket A, Zeewierteelt, werd onderzocht wat het effect is van de nitraatconcentratie op de groei en eiwitgehalte van de zeewiersoorten Saccharina latissima en Ulva lactuca. Bij de laatste soort werd ook gekeken naar de aminozuursamenstelling. Hogere nitraatconcentraties zorgden bij beide zeewiersoorten voor een hogere groeisnelheid en een hogere eiwitgehalte. De totale aminozuurhoeveelheid van Ulva lactuca was hoger bij blootstelling aan een hogere nitraatconcentratie. Alle gemeten aminozuurgehaltes waren hoger, behalve die van methionine, die gelijk was ten opzichte van de Ulva lactuca die gekweekt werd onder lage nitraatconcentraties. Het is dus mogelijk om tijdens het groeiproces, de aminozuur- en eiwitgehalte van zeewier te verhogen. De toename in eiwitgehalte was zelfs zo snel, dat het mogelijk is om zeewier te verrijken door het twee weken voor de oogst onder verhoogde nitraatconcentraties te laten groeien.
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A novel synthetic approach to 2,6-bis(acrylamido)pyridine (BAAPy) has been developed, producing a dual-function monomer able to self-crosslink while providing functional binding sites through its amide and pyridine groups. The monomer's structure and purity were confirmed through NMR, FTIR, and HPLC analyses. Poly(BAAPy) was subsequently synthesized and employed in the purification of stilbenes, including t-resveratrol, t-ε-viniferin, and t-piceatannol, all extracted from grape canes. These stilbenes, widely recognized for their antioxidant, antifungal, and antimicrobial properties, are valuable phytochemicals. Grape canes, a by-product of grapevine pruning, serve as a natural and cost-effective source of these bioactive compounds. Using a single-step adsorption–desorption process with an ethanol–water solvent system, the method achieved a 13-fold enrichment of stilbenes with gravimetric purities over 37%. The dual functionality of BAAPy eliminates the need for external crosslinkers and enhances adsorption capacity.
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Exercise is one of the external factors associated with impairment of intestinal integrity, possibly leading to increased permeability and altered absorption. Here, we aimed to examine to what extent endurance exercise in the glycogen‐depleted state can affect intestinal permeability toward small molecules and protein‐derived peptides in relation to markers of intestinal function. Eleven well‐trained male volunteers (27 ± 4 years) ingested 40 g of casein protein and a lactulose/rhamnose (L/R) solution after an overnight fast in resting conditions (control) and after completing a dual – glycogen depletion and endurance – exercise protocol (first protocol execution). The entire procedure was repeated 1 week later (second protocol execution). Intestinal permeability was measured as L/R ratio in 5 h urine and 1 h plasma. Five‐hour urine excretion of betacasomorphin‐7 (BCM7), postprandial plasma amino acid levels, plasma fatty acid binding protein 2 (FABP‐2), serum pre‐haptoglobin 2 (preHP2), plasma glucagon‐like peptide 2 (GLP2), serum calprotectin, and dipeptidylpeptidase‐4 (DPP4) activity were studied as markers for excretion, intestinal functioning and recovery, inflammation, and BCM7 breakdown activity, respectively. BCM7 levels in urine were increased following the dual exercise protocol, in the first as well as the second protocol execution, whereas 1 h‐plasma L/R ratio was increased only following the first exercise protocol execution. FABP2, preHP2, and GLP2 were not changed after exercise, whereas calprotectin increased. Plasma citrulline levels following casein ingestion (iAUC) did not increase after exercise, as opposed to resting conditions. Endurance exercise in the glycogen depleted state resulted in a clear increase of BCM7 accumulation in urine, independent of DPP4 activity and intestinal permeability. Therefore, strenuous exercise could have an effect on the amount of food‐derived bioactive peptides crossing the epithelial barrier. The health consequence of increased passage needs more in depth studies.
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De eiwittransitie is de transitie van het gebruik van dierlijke eiwitten naar plantaardige eiwitten. Naast de groei van de wereldbevolking en de welvaart, zijn duurzaamheid en dierenwelzijn belangrijke drijfveren achter deze transitie. De bovengenoemde definitie van eiwittransitie geeft gelijk de grenzen van mijn lectoraat aan. Het gaat over de eiwittransitie van dierlijk naar plantaardig. Dit sluit het gebruik van insecten als alternatieve eiwitbron uit van het onderzoek binnen het lectoraat. Insecten zijn dieren, wel is waar met een gunstige voederconversie, maar als dierlijk eiwit draagt de consumptie van insecten niet bij aan de eiwittransitie. De tweede afbakening ligt in de toevoeging ‘in voeding’. Hiermee wordt de focus van mijn lectoraat aangegeven. Binnen mijn lectoraat richten wij ons op de toepassing van plantaardige eiwitten in humane voeding en niet op de toepassing van alternatieve of plantaardige eiwitten in diervoeder. Tot slot, richten wij ons op de eiwittransitie in de volle breedte van de voeding, dus op de vervanging van alle dierlijke eiwitten, zoals die uit melk, ei en vlees.
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Karapet’yants comparative analysis is applied to anthocyanin retention using the example of an extract of Adonis aestivalis petals. The attribution of anthocyanin peaks according to the comparative analysis is confirmed by the parameters of the mass spectra. A set of purple maize anthocyanins is used as a referencesample.
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Mycotoxins are small (MW approximately 700), toxic chemical products formed as secondary metabolites by a few fungal species that readily colonise crops and contaminate them with toxins in the field or after harvest. Ochratoxins and Aflatoxins are mycotoxins of major significance and hence there has been significant research on broad range of analytical and detection techniques that could be useful and practical. Due to the variety of structures of these toxins, it is impossible to use one standard technique for analysis and/or detection. Practical requirements for high-sensitivity analysis and the need for a specialist laboratory setting create challenges for routine analysis. Several existing analytical techniques, which offer flexible and broad-based methods of analysis and in some cases detection, have been discussed in this manuscript. There are a number of methods used, of which many are lab-based, but to our knowledge there seems to be no single technique that stands out above the rest, although analytical liquid chromatography, commonly linked with mass spectroscopy is likely to be popular. This review manuscript discusses (a) sample pre-treatment methods such as liquid-liquid extraction (LLE), supercritical fluid extraction (SFE), solid phase extraction (SPE), (b) separation methods such as (TLC), high performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE) and (c) others such as ELISA. Further currents trends, advantages and disadvantages and future prospects of these methods have been discussed.
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Penicillin acylase (PA) from Escherichia coli can catalyze the coupling of an acyl group to penicillin- and cephalosporin-derived beta-lactam nuclei, a conversion that can be used for the industrial synthesis of beta-lactam antibiotics. The modest synthetic properties of the wild-type enzyme make it desirable to engineer improved mutants. Analysis of the crystal structure of PA has shown that residues alphaR145 and alphaF146 undergo extensive repositioning upon binding of large ligands to the active site, suggesting that these residues may be good targets for mutagenesis aimed at improving the catalytic performance of PA. Therefore, site-saturation mutagenesis was performed on both positions and a complete set of all 38 variants was subjected to rapid HPLC screening for improved ampicillin synthesis. Not less than 33 mutants showed improved synthesis, indicating the importance of the mutated residues in PA-catalyzed acyl transfer kinetics. In several mutants at low substrate concentrations, the maximum level of ampicillin production was increased up to 1.5-fold, and the ratio of the synthetic rate over the hydrolytic rate was increased 5-15-fold. Moreover, due to increased tendency of the acyl-enzyme intermediate to react with beta-lactam nucleophile instead of water, mutants alphaR145G, alphaR145S and alphaR145L demonstrated an enhanced synthetic yield over wild-type PA at high substrate concentrations. This was accompanied by an increased conversion of 6-APA to ampicillin as well as a decreased undesirable hydrolysis of the acyl donor. Therefore, these mutants are interesting candidates for the enzymatic production of semi-synthetic beta-lactam antibiotics.
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