Carotenoid profiles of red- and yellow-colored arils of cultivars of Taxus baccata L. and Taxus × media Rehder.

The botanical delimitation of Taxus species and cultivars may be facilitated by characterizing the pigment profiles of their red- and yellow-fleshed arils. Therefore, we determined genuine carotenoid profiles of differently colored arils of seven defined cultivars of Taxus baccata L. and Taxus × media Rehder. In-depth HPLC-DAD-ESI/APCI-MSn analyses revealed the presence of 43 carotenoids. Exceptional retro-carotenoids dominated the profiles of all samples assessed. Rhodoxanthin (E/Z)-isomers were predominant in the red-colored arils, resulting in a rather unusual abundance of carotenoid isomers as expressed by ratios of up to 1.3:2.0:0.9 between (all-E)-, (6Z)-, and (6Z,6'Z)-rhodoxanthin, respectively. By contrast, the uncommon yellow arils of Taxus baccata L. 'Lutea' mainly contained eschscholtzxanthin (E/Z)-isomers and esters. Total carotenoid concentrations ranged from 17.00 to 58.78 µg/g fresh weight across all samples assessed. Highest total rhodoxanthin concentrations of 51.33 ± 0.46 µg/g fresh weight were obtained from the red arils of Taxus × media Rehder 'Hicksii'. Overall, Taxus arils represent a promising source of carotenoids and, in particular, of retro-carotenoids with exceptional molecular structures and extraordinary absorption properties.

Addition of either gastric lipase or cholesterol esterase to improve both ß-cryptoxanthin ester hydrolysis and micellarization during in vitro digestion of fruit pulps.

Using the INFOGEST in vitro digestion protocol adapted to carotenoids, the impact of additional rabbit gastric lipase (RGL) on the hydrolysis extent of ß-cryptoxanthin esters was evaluated for the first time, and compared with the addition of porcine cholesterol esterase (CEL). Both the modifications increased the hydrolysis of (all-E)-ß-cryptoxanthin esters from mandarin and peach pulps, although the outcomes were different. Addition of RGL consistently increased the average hydrolysis extent from 55.2% to 59.5% in mandarin pulp and from 22.7% to 48.8% in peach pulp (p < 0.05). The addition of CEL produced lower hydrolysis extents, i.e., 58.5% in mandarin (not statistically significant) and 28.4% in peach (p < 0.05), compared to those obtained with RGL. The hydrolysis extent positively correlated with the carotenoid ester concentration in both matrices. Bioaccessibility values were higher in mandarin pulp (range 32-34%) compared to those in peach pulp (range 16-21%), and were associated with the hydrolysis extent of the carotenoid esters during digestion. Addition of RGL and CEL produced no significant (p < 0.05) effect on the overall carotenoid bioaccessibility values of mandarin, while positively affected those in peach. Altogether these results corroborate that the hydrolysis extent of xanthophyll esters limits bioaccessibility. Additionally, hydrophobicity of the carotenoid inversely correlates with micellarization, as free (all-E)-xanthophylls micellarized in a higher extent compared to (all-E)-ß-carotene and xanthophyll esters. The new information of our results is that the addition of rabbit gastric lipase substantially contributes to the hydrolysis of ß-cryptoxanthin esters from fruit pulps, and consequently, to increase carotenoid bioaccessibility, being even more effective than CEL.

Carotenoid esters in foods - A review and practical directions on analysis and occurrence.

Carotenoids are naturally found in both free form and esterified with fatty acids in most fruits and some vegetables; however, up to now the great majority of studies presents data on carotenoid composition only after saponification. The reasons for this approach are that a single xanthophyll can be esterified with several different fatty acids, generating a great number of different compounds with similar chemical and structural characteristics, thus, increasing the complexity of analysis compared to the respective saponified extract. This means that since UV/Vis spectrum does not change due to esterification, differentiation between free and acylated xanthophylls is dependent at least on elution order and mass spectrometry (MS) features. The presence of interfering compounds, especially triacylglycerides (TAGs), in the non-saponified extract of carotenoids can also impair carotenoid ester analyses by MS due to high background noise and ionization suppression since TAGs can be present in much higher concentrations than the carotenoid esters. This leads to the need of development of new and effective clean-up procedures to remove the potential interferents. In addition, only few standards of xanthophyll esters are commercially available, making identification and quantification of such compounds even more difficult. Xanthophyll esterification may also alter some properties of these compounds, including solubility, thermostability and bioavailability. Considering that commonly consumed foods are dietary sources of xanthophyll esters and that it is the actual form of ingestion of such compounds, an increasing interest on the native carotenoid composition of foods is observed nowadays. This review presents a compilation of the current available information about xanthophyll ester analyses and occurrence and a practical guide for extraction, pre-chromatographic procedures, separation and identification by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Determination of free and esterified carotenoid composition in rose hip fruit by HPLC-DAD-APCI(+)-MS.

Rose hip fruit, which contains high concentration of carotenoids is commonly used for different food products in Europe and it is considered to have medical properties. In this study, a simple, rapid and efficient HPLC-DAD-APCI(+)-MS method was developed and applied to identify and quantify the carotenoids in rose hip fruit of four rose species, including both unsaponified and saponified extract. In the unsaponified extract 23 carotenoid esters were detected, in which either rubixanthin ester or violaxanthin ester was the dominant component of the ester composition. In the saponified extract 21 carotenoids, including 11 xanthophylls and 10 carotenes were detected. This is the first time the total carotenoid composition, including the carotenoid esters in rose hip fruit were identified and quantified. This work reveals the potential of rose hip fruit to be utilized as a healthy dietary material and give chemical information for the possible future development in the pharmacology field.