Improved Normal-Phase High-Performance Liquid Chromatography Procedure for the Determination of Carotenoids in Cereals

Abstract

Besides the health benefits associated with whole-grain consumption, cereals are recognized sources of health-enhancing bioactive components such as carotenoids, which are a group of yellow pigments involved in the prevention of many degenerative diseases and which have been used for a long time as indicators of the color quality of durum wheat and pasta products. This work reports a fast, sensitive, and selective procedure for the extraction and determination of carotenoids from cereals and cereal byproducts. The method involves sample saponification and extraction followed by normal-phase high-performance liquid chromatography, allowing the separation of the main carotenoids pigments of cereals, especially lutein and zeaxanthin. An application of the established method to various species of cereals and cereal byproducts is also shown. The highest carotenoid levels were found in maize (approximately 11.14 mg/kg of dry weight), which contains high amounts of beta-cryptoxanthin (2.40 mg/kg of dry weight), and, among the cereals considered, has the highest content of zeaxanthin (6.43 mg/kg of dry weight) and alpha+beta-carotene (1.44 mg/kg of dry weight). With the exception of maize, lutein is the main compound found (from 0.23 to 2.65 mg/kg of dry weight in oat and durum wheat, respectively). Moreover, whereas alpha+beta-carotene and zeaxanthin are principally localized in the germ, lutein is equally distributed along the kernel.

Agronomic, nutritional and nutraceutical aspects of durum wheat (Triticum durum Desf.) cultivars under low input agricultural management

“…Lutein accounted for approximately half of the total carotenoid amount and ranged from 1.50 µg/g (Solex) to 3.23 µg/g (Svevo) ( Table 4). The observed pigment contents were in general agreement with those previously reported for old and modern durum wheat varieties (Hung et al, 2011;Digesù et al, 2009;Panfili et al, 2004).…”

The colours of durum wheat: a review

“…Some of these solvents have also been used in aqueous solution for anthocyanin extraction, including ethanol, methanol and acetone (Castañeda-Ovando et al 2009) and, as most widely used in wheat, acidified methanol (Abdel-Aal et al 2006;Hosseinian et al 2008).The most sensitive, although expensive, technique used for the identification and quantification of the carotenoids is based on high-performance liquid chromatography (HPLC) with a photodiode array detector system. The chromatographic separation is achieved using either normal or reverse-phase HPLC (Panfili et al 2004;Burkhardt and Böhm 2007;Digesù et al 2009;Van Hung and Hatcher 2011).…”

“…The degree of yellowness in durum wheat grain and its end products is affected not only by carotenoid biosynthesis in the grain (Hentschel et al 2002;Panfili et al 2004), but also by carotenoid degradation during processing. This degradation has been mainly ascribed to oxidative enzymes that are responsible for the discoloration and darkening processes that can occur during pasta making (Borrelli et al 1999;Trono et al 1999;Dexter and Marchylo 2000;Feillet et al 2000;Hessler et al 2002).…”

“…a-carotene, b-carotene, b-cryptoxanthin), these are present in very low amounts that range from 3% to 5% (Panfili et al 2004;Fratianni et al 2005;Abdel-Aal et al 2007;Digesù et al 2009).…”

Hulless Barley – A Rediscovered Source for Functional Foods Phytochemical Profile and Soluble Dietary Fibre Content in Naked Barley Varieties and Their Antioxidant Properties

“…Lutein and zeaxanthin are the two main carotenoids identified in barley (Goupy et al, 1999;Panfili et al, 2004). The electron rich chain makes them effective radical scavengers (Cooke et al, 2002) and inhibit free radical propagation reactions such as lipid peroxidation.…”