Search

Carotenoid esterification is a common mechanism for carotenoid sequestration, accumulation and storage in plants. Carotenoids are responsible for the bright yellow colour of pasta. Therefore, carotenoid retention during storage is of great importance in the durum wheat food chain. In this work, we investigated the role of carotenoid esterification on carotenoid retention in durum wheat using two consecutive storage experiments. Firstly, we compared two landraces and two durum wheat varieties as a preliminary work. We then compared individuals derived from the BGE047535×'Athoris' cross contrasting for esterification ability. Our results show that carotenoid esterification leads to a higher carotenoid retention during storage in durum wheat. Thus, the use of the carotenoid esterification would be useful as an extra strategy to ongoing efforts to improve carotenoid retention in the durum wheat food chain., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Liquid chromatography in conjunction with UV-visible spectroscopy and atmospheric pressure chemical ionisation (APCI) mass spectrometry has been used for the structural assignment of the lutein esters, including the regioisomeric forms, naturally occurring in the endosperm of tritordeum (×Tritordeum Ascherson et Graebner), a novel cereal. The distinctive mass spectrometry fragmentation pattern of lutein, characterized by a favored loss of the moieties at the position 3' of the ε-end ring, allowed an unambiguous structural identification of four monoesters (lutein 3'-O-linoleate, lutein 3-O-linoleate, lutein 3'-O-palmitate, lutein 3-O-palmitate) and four diesters (lutein dilinoleate, lutein 3'-O-linoleate-3-O-palmitate, lutein 3'-O-palmitate-3-O-linoleate, lutein dipalmitate). This is the first time that the regioisomers of carotenoid esters have been identified in a cereal. Evidences for a preferential xanthophyll acyltransferase activity regarding the position (3 or 3') and the acyl moiety are discussed. Further studies should be carried out in order to identify the acyltransferase enzymes and the acyl donor molecules involved in the xanthophyll esterification process., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Carotenoids are essential in human diet, so that the development of programs toward carotenoid enhancement has been promoted in several crops. The cereal tritordeum, the amphiploid derived from the cross between Hordeum chilense Roem. et Schulz. and durum wheat has a remarkable carotenoid content in the endosperm. Besides, a high proportion of these carotenoids are esterified with fatty acids. The identification of the gene(s) responsible for xanthophyll esterification would be useful for breeding as esterified carotenoids show an increased ability to accumulate within plant cells and have a higher stability during post-harvest storage. In this work, we analyzed five genes identified as candidates for coding the xanthophyll acyltransferase (XAT) enzyme responsible for lutein esterification in H. chilense genome. All these genes were expressed during grain development in tritordeum, but only HORCH7HG021460 was highly upregulated. Sequence analysis of HORCH7HG021460 revealed a G-to-T transversion, causing a Glycine to Cysteine substitution in the protein of H290 (the only accession not producing quantifiable amounts of lutein esters, hereinafter referred as zero-ester) of H. chilense compared to the esterifying genotypes. An allele-specific marker was designed for the SNP detection in the H. chilense diversity panel. From the 93 accessions, only H290 showed the T allele and the zero-ester phenotype. Furthermore, HORCH7HG021460 is the orthologue of XAT-7D, which encodes a XAT enzyme responsible for carotenoid esterification in wheat. Thus, HORCH7HG021460 (XAT-7Hch) is a strong candidate for lutein esterification in H. chilense and tritordeum, suggesting a common mechanism of carotenoid esterification in Triticeae species. The transference of XAT-7Hch to wheat may be useful for the enhancement of lutein esters in biofortification programs. [ABSTRACT FROM AUTHOR]

Carotenoids, especially β-cryptoxanthin, exert multiple biological activities in the organism. Various processing techniques can improve carotenoid bioavailability in relation to the food matrix. The study objective was to compare the bioavailability of carotenoids from orange juice (OJ) with that from a beverage obtained by alcoholic fermentation of orange juice (FOB). Seven volunteers were recruited for a randomized, controlled, and crossover study. Post-intake plasma carotenoid concentrations were measured by HPLC in the subjects at 0–8 h after their consumption of OJ or FOB. β-Cryptoxanthin and lutein absorption was significantly higher from FOB than from OJ, but no significant difference in zeaxanthin absorption was found. The mean baseline-corrected area under the concentration curve (AUC 0-8 h ) for β-cryptoxanthin, lutein and zeaxanthin was 24.6-, 1.3- and 4.65-fold larger, respectively, after FOB versus OJ consumption. This fermented orange beverage could be an abundant source of bioavailable carotenoids, and its regular consumption may exert healthy effects. [ABSTRACT FROM AUTHOR]

The effect of lutein esterification on the carotenoid distribution profile in the different fractions of tritordeum grains was studied. Durum wheat, a cereal lacking of lutein esters, was included for comparison in the study. Although carotenoid contents in endosperm and germ were significantly different for both cereals, the pigment distribution showed a marked dependence on the cereal's genetic background. Thus pigment content in durum wheat was 3 times higher in germ (2.52 μg/g fresh weight (fw)) than the endosperm (0.74 μg/g fw). In contrast, carotenoids in tritordeum were distributed more homogeneously (4.16 and 4.59 μg/g fw for germ and endosperm, respectively). Lutein esters were exclusively present in tritordeum fractions, with a 3-fold higher content in the endosperm, which suggests a preferential esterifying activity in this tissue. The fatty acid profile indicated that the presence of lutein esters could be limited by the existence of specific XAT (xanthophyll acyltransferase) enzymes and not by substrate availability. A positive impact of esterification on the even deposition pattern of pigments throughout the tritordeum grain was observed. These data could be useful for optimizing the retention of lutein through the food chain as well as to direct the breeding of crops enriched in lutein esters. [ABSTRACT FROM AUTHOR]

The outstanding high carotenoid content of the tritordeum (× Tritordeum Ascherson et Graebner) grains, a promising novel cereal derived from the crossing of durum wheat and the wild barley Hordeum chilense , has previously been assigned as a character derived from the genetic background of its wild parent. The carotenoid profile of H. chilense , especially the lutein esters presented in this study, provide biochemical evidences to confirm this affirmation, being the first time that the individual carotenoid profile of this cereal has been characterized. The total carotenoid content (6.14 ± 0.12 μg/g) and the individual carotenoid composition were very similar to the tritordeum grains, with lutein being the major carotenoid (88%; 5.38 ± 0.11 μg/g) and very low levels of β-carotene. In contrast to tritordeum, H. chilense presented a considerable amount of zeaxanthin (12%; 0.74 ± 0.01 μg/g). Up to 55% of lutein was esterified with palmitic (C16:0) and linoleic (C18:2) acids, presenting a characteristic acylation pattern, in agreement with the tritordeum one, and composed by four monoesters (lutein 3′- O -linoleate, lutein 3- O -linoleate, lutein 3′- O -palmitate and lutein 3- O -palmitate) and four diesters (lutein dilinoleate, lutein 3′- O -linoleate-3- O -palmitate, lutein 3′- O -palmitate-3- O -linoleate, lutein dipalmitate). These data may be useful in the field of carotenoid biofortification of cereals. [ABSTRACT FROM AUTHOR]

Preservation of lutein concentrations in wheat-based end-products during processing is important both for product quality and nutritional value. A key constituent involved in lutein degradation is endogenous lipoxygenase. Lutein and lutein ester concentrations were compared at intervals during storage of noodle sheets prepared from flour of wheat varieties representing a range in lipoxygenase activity, as well as in different mill streams and in different grain tissues. Higher lipoxygenase concentration was associated with an increased loss of free lutein and lutein mono-esters whereas lutein diesters appeared to be more resistant to degradation. Lutein degradation was reduced in the presence of a lipoxygenase inhibitor, when noodle sheets were heated to destroy enzyme activity or when pH was increased. In addition, three populations were used to investigate the genetic control of lipoxygenase. A previously reported mutation of Lpx-B1.1 was associated with a reduction in activity from high to intermediate whilst a new locus on chromosome 4D was associated with variation between intermediate and near-zero. The gene underlying the 4D locus is a putative lipoxygenase. Stability of lutein could be improved by deployment of the mutations at the 4B and 4D loci and/or by post-harvest storage of grain under conditions that promote esterification. [ABSTRACT FROM AUTHOR]

Carotenoids are essential in the human diet for their important functions in health. Besides, they are responsible for the yellow pigments desirable for industrial quality in durum wheat. The remarkable carotenoid content of durum wheat endosperm is mostly due to lutein. However, lutein esters have not been previously detected in durum wheat as in other cereals such as common wheat, tritordeum or Hordeum chilense. Esterification increases carotenoid stability and allows greater retention and accumulation through the food chain. Therefore, carotenoid esterification is revealed as a new key target in breeding. We characterized the carotenoid profile of 156 accessions of the Spanish durum wheat collection, searching for landraces with esterification ability. Interestingly, four accessions produced lutein monoesters and diesters. Also, traces of lutein monoesters were detected in eleven accessions. The identification of the first durum wheat accessions with esterification ability reported herein is a remarkable advance for carotenoid biofortification. Furthermore, variation for the relative content of zeaxanthin, α-carotene and β-carotene was also observed. This diversity for the β,ε and β,β branches of the carotenogenic pathway also represents a new opportunity for breeding for specific carotenoids in biofortification programs. [ABSTRACT FROM AUTHOR]