Bioaccessibility and cellular uptake by Caco-2 cells of carotenoids and chlorophylls from orange peels: A comparison between conventional and ionic liquid mediated extractions.

Native extracts from orange peels were obtained by a conventional method using acetone and, an alternative method using ionic liquid (1-butyl-3-methylimidazolium chloride ([C4mim]Cl)). The bioaccessibilities and cellular uptakes of carotenoids, esters and chlorophylls were evaluated, since the influence of esterification on bioaccessibility and bioavailability is not well established. For this, the extracts were emulsified, submitted to in vitro simulated digestion model according to the INFOGEST protocol, followed by uptake by Caco-2 cells. Compounds were separated, identified and quantified by HPLC-PDA-MS/MS. After digestion, 22.0% and 26.2% of the total carotenoids and 45.9% and 68.7% of the chlorophylls were bioaccessible from the acetone and [C4mim]Cl extracts, respectively. The bioaccessibilities of xanthophylls and carotenes were significantly higher than those of the mono- and diesters. The uptake by Caco-2 cells varied from 130.2 to 131.9 ng/mg cell protein for total carotenoids and from 243.8 to 234.2 ng/mg cell protein for chlorophylls in the acetone and [C4mim]Cl extracts, respectively. In general, xanthophylls and esters were better absorbed than carotenes.

Green Extraction Approaches for Carotenoids and Esters: Characterization of Native Composition from Orange Peel.

Orange peel is a by-product produced in large amounts that acts as a source of natural pigments such as carotenoids. Xanthophylls, the main carotenoid class found in citrus fruit, can be present in its free form or esterified with fatty acids, forming esters. This esterification modifies the compound's chemical properties, affecting their bioavailability in the human body, and making it important to characterize the native carotenoid composition of food matrices. We aimed to evaluate the non-saponified carotenoid extracts of orange peel (cv. Pera) obtained using alternative green approaches: extraction with ionic liquid (IL), analyzed by high performance liquid chromatography coupled to a diode array detector with atmospheric pressure chemical ionization and mass spectrometry HPLC-DAD-APCI-MS, and supercritical fluid extraction (SFE), followed by supercritical fluid chromatography with atmospheric pressure chemical ionization and triple quadrupole mass spectrometry detection (SFC-APCI/QqQ/MS) in an online system. Both alternative green methods were successfully applied, allowing the total identification of five free carotenoids, one apocarotenoid, seven monoesters, and 11 diesters in the extract obtained with IL and analyzed by HPLC-DAD-APCI-MS, and nine free carotenoids, six carotenoids esters, 19 apocarotenoids, and eight apo-esters with the SFE-SFC-APCI/QqQ/MS approach, including several free apocarotenoids and apocarotenoid esters identified for the first time in oranges, and particularly in the Pera variety, which could be used as a fruit authenticity parameter.

Ionic liquid associated with ultrasonic-assisted extraction: A new approach to obtain carotenoids from orange peel.

The aim of this study was to develop a new method for carotenoid extraction from orange peel, using ionic liquid (IL) to replace conventional organic solvents, assisted by ultrasound. Four different IL were tested: 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), 1-n-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), and 1-hexyl-3-methylimidazolium chloride ([HMIM][Cl]). Response surface methodology was applied in order to optimize the carotenoid extraction conditions, and Amberlite XAD-7HP resin was used to separate the carotenoids from the IL, allowing their recovery. Determination of carotenoids was carried out by high-performance liquid chromatography coupled to photodiode array and mass spectrometry detectors (HPLC-DAD-MSn). Thermal stability at different temperatures (60 °C and 90 °C) and peroxyl radical scavenging activity of the carotenoid extracts obtained with acetone and IL were evaluated. [BMIM][Cl] was the most effective IL, leading to a total carotenoid content of 32.08 ±â€¯2.05 µg/g, while 7.88 ±â€¯0.59 µg/g of dry matter was obtained by acetone extraction. IL and carotenoid recoveries using XAD-7HP resin were in the range of 59.5-63.8% and 52.2-58.7%, respectively. A carotenoid extract was successfully obtained with IL, finally isolated just by using ethanol, besides being more stable and presenting higher antioxidant activity than that obtained with acetone.