Potential of prodendronic polyamines with modulated segmental charge density as novel coating for fast and efficient analysis of peptides and basic proteins by CE and CE-MS.

In this work, the suitability of a new polymer family has been investigated as capillary coatings for the analysis of peptides and basic proteins by CE. This polymer family has been designed to minimize or completely prevent protein-capillary wall interactions and to modify the EOF. These coating materials are linear polymeric chains bearing as side cationizable moiety a dentronic triamine derived from N,N,N',N'-tetraethyldiethylenetriamine (TEDETA), which is linked to the backbone through a spacer (unit labeled as TEDETAMA). Four different polymers have been prepared and evaluated: a homopolymer which comprised only of those cationizable repetitive units of TEDETAMA, and three copolymers that randomly incorporate TEDETAMA together with neutral hydrosoluble units of N-(2-hydroxypropyl) methacrylamide (HPMA) at different molar percentages (25:75, 50:50 and 75:25). It has been demonstrated that the composition of the copolymers influences the EOF and therefore the separation of the investigated biopolymers. Among the novel polymers studied, poly-(TEDETAMA-co-HPMA) 50:50 copolymer was successfully applied as coating material of the inner capillary surface in CE-UV and CE-MS, providing EOF reversing together with fast and efficient baseline separation of peptides and basic proteins. Finally, the feasibility of the polymer-coated capillary was shown through the analysis of lysozyme in a cheese sample.

Bioaccessibility of pistachio polyphenols, xanthophylls, and tocopherols during simulated human digestion.

OBJECTIVE: The bioaccessibility of bioactives from pistachios has not been previously evaluated. In the present study we quantified the release of polyphenols, xanthophylls (lutein), and tocopherols from pistachios (raw pistachios, roasted salted pistachios, and muffins made with raw pistachios) during simulated human digestion. METHODS: A dynamic gastric model of digestion that provides a realistic and predictive simulation of the physical and chemical processing and accurately mimics the residence time and the luminal environment within the human stomach was used for the digestion studies. RESULTS: More than 90% of the polyphenols were released in the gastric compartment, with virtually total release in the duodenal phase. No significant differences were observed between raw shelled and roasted salted pistachio. The presence of a food matrix (muffin) decreased the bioaccessibility of protocatechuic acid (78%) and luteolin (36%). Almost 100% bioaccessibility of lutein and tocopherols was found after duodenal digestion, with no difference among the three samples. CONCLUSION: The rapid release of the assayed bioactives in the stomach maximizes the potential for absorption in the duodenum and contributes to the beneficial relation between pistachio consumption and health-related outcomes.

Multidimensional liquid chromatography for the determination of chiral coumarins and furocoumarins in Citrus essential oils.

In this work the enantiomeric distribution of chiral coumarins (meranzin and epoxyaurapten), and furocoumarins (oxypeucedanin, byakangelicol, and epoxybergamottin) in different Citrus essential oils (lemon, lime, grapefruit, and bitter orange) was determined by means of a heart-cutting multidimensional-liquid chromatography (MD-LC) system, equipped with a microsilica column in the first dimension in a combination to a cellulosic-based chiral column used in the second dimension. The normal phase-liquid chromatography-liquid chromatography (NP-LC-LC) instrumentation was equipped with a photodiode array detector and a multiport valve as interface. For method optimization and the determination of absolute configuration, natural compounds were isolated and racemic mixture was synthesized. The NP-LC-LC/PDA (where PDA is photodiode array) method provided a good baseline separation of chiral coumarins (meranzin and epoxyaurapten) and furocoumarins (epoxybergamottin and byakangelicol) present in cold-pressed Citrus essential oils without any sample pretreatment. Results obtained showed that for all the chiral compounds present in Citrus essential oils analyzed, there is always a clear prevalence of one of the two enantiomers, and do not appear influenced by the different geographical origin of the oils.