Carotenoids content and variability in einkorn (Triticum monococcum ssp monococcum L.)

Einkorn (Triticum monococcum ssp monococcum L.) is a diploid wheat (2n=2x=14) domesticated ca. 10000 years ago and widely grown for millenia in Europe, until the advent of free-threshing and higher yielding polyploid wheats curtailed its role. Today einkorn is a relic crop, only grown in small areas of the Mediterranean region (mainly Balkans and Morocco). Recent studies highlighted several positive traits available in einkorn genepool: resistance to diseases, pests and stresses, high protein content, good breadmaking and biscuit-making quality and relevant carotenoids content. Carotenoids are a group of plants-synthesized, fat soluble pigments; b-carotene and about 50-60 other similar compounds are known as vitamin–A precursors. Furthermore, carotenoids mediate cellular functions and behave as protective antioxidants: in this role, lycopene, zeaxanthin and lutein are more effective than b-carotene as scavengers of oxidative species. Carotenoids, mainly lutein, are about 2-4 ppm in bread wheat and 3-11 ppm in durum wheat. Objectives of our research were to study the variation for carotenoids content in einkorn and to assess the influence of location and planting season. To these ends, samples from einkorn accessions grown in agronomic trials in two locations (S. Angelo Lodigiano, Italy, and Cologne, Germany) during 1997 and 1998, and in S. Angelo Lodigiano in two planting seasons (autumn and spring) during 1999 and 2000 were analysed for carotenoid content. The carotenoids were extracted following the official AACC method and the absorption spectrum of three samples and two controls was determined with a spectrophotometre at wavelengths between 350 and 550 nm. Afterwards, carotenoid content was measured for all the samples at two different wavelengths (436 and 448 nm), corresponding to the maximum absorbances of b-carotene and lutein. The einkorn accessions had a carotenoid content ranging from 13.8 to 30.4 ppm at 448 nm, three to eight times higher than the bread wheat controls (Centauro and Salmone) and up to 2.5 times better than the durum wheat controls (Duilio and Simeto). Pigment content varied between locations (S. Angelo 23.1 ppm and Cologne 24.7 ppm) and between planting seasons (autumn 25.7 ppm and spring 24.5 ppm); however, no significant interaction among accessions and the other factors was detected. The einkorn accessions ID112, ID347 and ID559 were scarce in carotenoids (below 15 ppm) while ID190, ID209, ID259, ID279, ID529, ID1352, ID1387 and ID398 exibited contents above 27 ppm.