Modern and ancient wheat (Triticum spp.) cultivars: comparison reveals interesting differences in phenolic compounds profiles

A project of a Germplasm Bank has been carried out at the Interdepartmental Research Centre for Agri- Food Biological Resources Improvement and Valorization (Biogest-Siteia, UNIMORE), aimed to wheat longterm conservation, valorization and exploitation. Nowadays, the Germplasm Bank keeps more than 150 accessions, including ten ancient cultivars, which have been all morphologically characterized, according to “Descriptor List for Wheat” (1). Identification of the secondary metabolites responsible for end-use quality of wheat may be considered a key-factor for all stake-holders, i.e. breeders, producers, grain handlers, millers, bakers and final consumers (2, 3, 4). Recent studies have focused on phenolic content of whole wheat, due to their antioxidant, antiinflammatory, anti-carcinogenic properties (3, 5, 6), highlighting furthermore that important differences in metabolic profile occur among cultivated varieties. The intense breeding programs developed since the 50s years of the last century, resulted in the selection of new wheat cultivars with high yield, less subjected to crop lodging and able to provide high strength flour, with a high aptitude to withstand mechanical processing. This resulted, in turn, in the replacement of local varieties and mostly in the decrease of the genetic variability. Notwithstanding, there has been recently a renewal of interest in the so-called “ancient grains”, cultivars with a distinct regional connotation, used in the last century or even earlier. In the present study, nine ancient varieties of wheat: Autonomia, Gentil rosso, Grano del miracolo, Inallettabile, Leone aristato, Mentana, Poulard di Ciano, Risciola, and Terminillo were compared with some modern cultivars. Extracts of whole meal flour were subjected to separation by LC-ESI-MS-TQ and phenolic compounds, i.e. hydroxycinnamic acids, hydroxybenzoic acids, flavones, and vanillin, were determined. Total phenolic content, expressed as gallic acid equivalents, of each sample was determined using the Folin–Ciocâlteu procedure. The ancient cultivars of wheat showed a phenolic content significantly higher in comparison with the modern cultivars. The ancient variety Poulard di Ciano (also known as Turgido Reggiano) was widely cultivated in the northern Italy and in Emilia Romagna region in the first years of XX century and can be considered the real autochthonous wheat of Reggio Emilia province. It showed the highest total phenolic content, followed by Risciola, Grano del Miracolo, Terminillo, and Leone Aristato (ranging between 0.95 and 0.70 mg/g, expressed as gallic acid equivalents). The lowest value was recorded for the modern cultivar Zanzibar (0.33 mg/g, as gallic acid equivalents). Many differences among cultivars emerged when quali-quantitative analysis were carried out. Terminillo showed statistically highest concentration of ferulic acid, followed by Risciola, Grano del Miracolo, Gentil Rosso, Poulard di Ciano, and Leone Aristato, while Blasco (taken as reference for modern cultivars) had the lowest concentration. Syringic acid presented the highest value for Risciola, Leone Aristato, and Mentana. Poulard di Ciano showed very high concentrations of sinapinic acid, while Blasco had the lowest content. Vanillin and vanillic acid, two biochemically correlated 4-hydroxy-3-methoxyphenyl- derivates, are very liked flavoring agents. They were found in Grano del Miracolo at the highest concentrations. Risciola, as well, showed high content of vanillin, followed by Inallettabile, while vanillic acid was present in high concentration in Gentil rosso, Terminillo, and Leone aristato. Blasco, also in this case, did not show high concentration of these metabolites. A complete comparison with all the cultivars stored in the Germplasm Bank is currently in progress. In the light of these first results the nutritional characteristics of the caryopsis, rich in micronutrients and compounds with nutraceutical activity, and the opportunity of increasing a more sustainable model of agriculture, make the ancient varieties of wheat an invaluable heritage to safeguard.