8 research outputs found
Characterization of hydroxytyrosol-ÎČ-cyclodextrin complexes in solution and in the solid state, a potential bioactive ingredient
This study focused for the first time on characterizing the inclusion complexes between ÎČ-cyclodextrin (ÎČ-CD) and hydroxytyrosol (HT) in the solid state. In solution, HT and ÎČ-CD are able to form a 1:1 inclusion complex with an association constant of 33.2âŻÂ±âŻ3.7âŻM-1. In the solid state, the inclusion complexes prepared by freeze-drying and spray-drying of an equimolar mixture of both partners were characterized and compared by 13C NMR and SEM. After dissolution, their free radical-scavenging ability was also determined by UVâvisible spectroscopy. The results show that ÎČ-CD and drying processes have no effect on the efficiency of HT to reduce the DPPH radical. The solid state 13C NMR data provided information on the spatial proximity between ÎČ-CD and HT and suggest the formation of inclusion complexes for both drying processes compared to the physical mix. However, the morphology of the solids obtained was significantly different, as spherical particles were formed by spray-drying while freeze-drying only provided irregular shapes
Development of new products with nutraceutical aims from olive mill coproducts
Avec les problĂ©matiques environnementales actuelles associĂ©es aux effluents industriels, lâintĂ©rĂȘt de nouveaux moyens de management des dĂ©chets grandit continuellement. Le grignon dâolive deux-phase aussi appelé« alperujo », est un des principaux polluants industriels du bassin MĂ©diterranĂ©en, liĂ© Ă la production dâhuile dâolive.La premiĂšre partie de cette thĂšse a soulignĂ© le haut potentiel des grignons dâolive comme source riche en composĂ©s phĂ©noliques. ÎČ-CD a Ă©tĂ© choisi pour extraire les biophĂ©nols prĂ©sents des grignons. Le comportement de la ÎČ-CDavec les phĂ©nols de lâolive a Ă©tĂ© tout dâabord Ă©tudiĂ© avec des biophĂ©nols modĂšles, le tyrosol et lâhydroxytyrosol, par des procĂ©dĂ©s classiques, que sont lâatomisation et la lyophilisation. La capacitĂ© de la ÎČ-CD Ă former des complexes avec les biophĂ©nols modĂšles a Ă©tĂ© confirmĂ©e par des analyses UV spectroscopique et de RMN 13C CP/MAS.Lâutilisation de la ÎČ-CD native Ă lâĂ©tat solide comme agent dâextraction des phĂ©nols a Ă©tĂ© Ă©valuĂ©e. Plus de 60% etde 20% des composĂ©s phĂ©noliques ont Ă©tĂ© extraits par la ÎČ-CD solide Ă partir de solutions de biophĂ©nols modĂšles et du jus dâalperujo respectivement. Cette procĂ©dure en une Ă©tape a conduit Ă lâenlĂšvement concomitant phĂ©nols de lâolive dâeaux usĂ©es et Ă la rĂ©cupĂ©ration de poudres riches en biophĂ©nols et de qualitĂ© alimentaire. A la suite, des Ă©tudes de biodisponibilitĂ©s in vitro ont rĂ©vĂ©lĂ© lâeffet nĂ©gatif de consommer les biophĂ©nols avec des aliments tandis que la ÎČ-CD a permis dâaugmenter lâabsorption intestinale de certains composĂ©s, comme le tyrosol et lâacidep-coumarique. Ainsi, il a Ă©tĂ© montrĂ© dans cette Ă©tude que les grignons dâolive constituent une source riche en composĂ©s phĂ©noliques, abondante et Ă©conomique, et que la ÎČ-CD native Ă lâĂ©tat solide pourrait ĂȘtre reconnue comme agent dâextraction efficace, Ă©cologique et sain, conduisant Ă la rĂ©cupĂ©ration de produits Ă hautes valeurs ajoutĂ©es par une simple procĂ©dure en une Ă©tape.In relation to the current environmental issues of industrial effluents, the interest of new managementpathways of by-products is still growing. Two-phase olive pomace also called âalperujoâ is one of the main industrialpollutants in the Mediterranean basin, associated with the olive oil production.The first part of this thesis highlighted the high potential of alperujo to be considered as a phenolic-rich source.Then, ÎČ-CD has been chosen to extract olive biophenols from alperujo. The behaviour of ÎČ-CD with olive phenolshas been firstly studied with biophenol models, i.e. tyrosol and hydroxytyrosol by usual spray- and freeze-dryingprocesses. The ability of ÎČ-CD to form complexes in the solid state has been revealed by UV spectroscopy and13C CP/MAS NMR analyses. The use of ÎČ-CD in the solid state as phenol-extracting agent was evaluated. Over 60%and 20% of phenolic compounds were extracted from biophenol model solutions and alperujo juice respectively.This one-step procedure led to the concomitant removal of olive phenols from wastewaters and to recover foodgradebiophenol-rich powders. Successively, in vitro bioavailability studies revealed the downside of combiningfood with biophenols whereas ÎČ-CD allowed to increase the intestinal absorption of some phenols, such as tyrosoland p-coumaric acid. Therefore, it has been shown in this work that alperujo is a phenolic-rich source and that nativeÎČ-CD in the solid state could be recognized as an efficient, green and safe-grade extraction agent leading to therecovery of high values added products by a simple one-step procedure
Direct and Rapid Profiling of Biophenols in Olive Pomace by UHPLC-DAD-MS
A correction to this article is available online at https://doi.org/10.1007/s12161-017-1107-8.Olive mill by-products are effluents generated during olive oil production process. The two-phase centrifugation system produces a semi-solid olive pomace called âalperujo.â This by-product is a combination of liquid and solid wastes derived from the three-phase manufacturing process. A direct and fast analytical method by ultra-high-performance liquid chromatography-DAD coupled with ESI/MS-MS has been developed for the profiling of phenolic compounds. Thirty-five metabolites belonging to phenyl alcohols, secoiridoids, flavonoids, and iridoids were identified as the main constituents of alperujo in 12 min, including p-coumaroyl aldarate and a verbascoside derivative found for the first time in alperujo and a new ligstroside derivative. Six quantitatively significant components were determined at concentrations ranging from 17.7 mg/L for p-coumaric acid to 370.7 mg/L for hydroxytyrosol. Our data confirm that alperujo is an interesting source of phenolic compounds that could be extracted for use as nutraceuticals
One-Step Extraction of Olive Phenols from Aqueous Solution Using ÎČ-Cyclodextrin in the Solid State, a Simple Eco-Friendly Method Providing Photochemical Stability to the Extracts
International audienceThe extraction of phenolic compounds from olive mill wastes is important, not only to avoid environmental damages, but also because of the intrinsic value of those biophenols, wellknown for their high antioxidant potential and health benefits. This study focuses on tyrosol (Tyr) and hydroxytyrosol (HT), two of the main phenolic compounds found in olive mill wastes. A new, simple, and eco-friendly extraction process for the removal of phenolic compounds from aqueous solutions using native ÎČ-cyclodextrin (ÎČ-CD) in the solid state has been developed. Several ÎČ- CD/biophenol molar ratios and biophenol concentrations were investigated, in order to maintain ÎČ-CD mostly in the solid state while optimizing the extraction yield and the loading capacity of the sorbent. The extraction efficiencies of Tyr and HT were up to 61%, with a total solid recovery higher than 90% using an initial concentration of 100 mM biophenol and 10 molar equivalents of ÎČ-CD. The photochemical stability of the complexes thus obtained was estimated from DE*ab curve vs. illumination time. The results obtained showed that the phenols encapsulated into solid ÎČ-CD are protected against photodegradation. The powder obtained could be directly developed as a safe-grade food supplement. This simple eco-friendly process could be used for extracting valuable biophenols from olive mill wastewater
Beta-Cyclodextrin Does not Alter the Bioaccessibility and the Uptake by Caco-2 Cells of Olive By-Product Phenolic Compounds
Alperujo-a two-phase olive mill waste that is composed of olive vegetation water and solid skin, pulp, and seed fragments - is a highly valuable olive by-product due to its high content in phenolic compounds. In this study, we assessed whether beta-cyclodextrin (beta-CD), which is used to extract and protect alpejuro phenolic compounds (hydroxytyrosol-O-glucoside, tyrosol, caffeic, and p-coumaric acids) could impact on their bioaccessibility (i.e., the percentage of molecule found in the aqueous phase of the digesta) and uptake by intestinal cells, by using an in vitro digestionmodel and Caco-2 TC7 cells in culture, respectively. Our results showed that beta-CD did not change the bioaccessibility of the selected phenols. Hydroxytyrosol-O-glucoside and caffeic did not cross Caco-2 cell monolayers. Conversely ferulic acid, identified as the main caffeic acid intestinal metabolite, was absorbed through intestinal cell monolayers (similar to 20%). Interestingly, beta-CD moderately but significantly improved the local absorption of tyrosol and p-coumaric acid (2.3 +/- 1.4% and 8.5 +/- 4.2%, respectively, p < 0.05), even if their final bioavailability (expressed as bioaccessibility x absorption by Caco-2 cells) was notmodified (16.2 +/- 0.6% vs. 16.8 +/- 0.5% for tyrosol and 32.0 +/- 3.2% vs. 37.2 +/- 3.2% for p-coumaric acid, from pure alperujo and alperujo complexed with beta-CD, respectively). Overall, our results show that beta-CD is an interesting extraction and storage agent for phenolic compounds that does not alter their in vitro bioavailability
Effect of Foods and ÎČ-Cyclodextrin on the Bioaccessibility and the Uptake by Caco-2 Cells of Hydroxytyrosol from Either a Pure Standard or Alperujo
International audienceHydroxytyrosol bioaccessibility and absorption by the intestinal cells have been studied using an in vitro digestion model and Caco-2 TC7 monolayers cells in culture, in the presence or absence of ÎČ-cyclodextrin and foods. Hydroxytyrosol was either provided as a pure standard or in an alperujo powder. The presence of foods significantly decreased hydroxytyrosol bioaccessibility and absorption (-20% and -10%, respectively), while ÎČ-cyclodextrin had no effect. Moreover, the presence of other compounds from alperujo in the intestine compartment reduced hydroxytyrosol absorption by Caco-2 cells compared to pure standard (-60%). The final bioavailability of hydroxytyrosol, defined as its quantity at the basolateral side of cultured cell monolayers compared to the initial amount in the test meal, was 6.9±0.4%, 31.1±1.1% and 40.9±1.5% when hydroxytyrosol was from al perujo, or a standard administered with or without food, respectively.Our results show that conversely to foods, ÎČ-cyclodextrin does not alter hydroxytyrosolbioavailability