Effects of sprouting and salt stress on polyphenol composition and antiradical activity of einkorn, emmer and durum wheat

Abstract

Germination is related with improvements of nutritional value of seeds, since it promotes accumulation of health-promoting phytochemicals. However, only few studies have investigated on phytochemicals accumulation during sprouting under sub-optimal conditions. Thus, we investigated the effect of salinity during germination of an einkorn (TMoM), an emmer (TDiZ) and a durum wheat (TDuC) genotype on the total polyphenols (TPC), free- and bound-phenolic acids [PAs; i.e. caffeic acid, syringic acid, Pcoumaric acid, trans-ferulic acid, and salicylic acid] contents and antiradical activity (Trolox equivalent antioxidant capacity; TEAC) of sprouts and wheatgrass. The following NaCl treatments were applied: 0 (control), 25, 50 and 100 mM NaCl concentration throughout the whole experiment, or 50 and 100 mM NaCl until sprout stage and then 0 mM until wheatgrass stage (recovery treatments). TMoM showed higher total bound-PAs both in sprouts and wheatgrass with respect to the other Triticum genotypes (+25% and 24%, respectively) as well as of total bound-PAs and bound-SA in the recovery treatments. Moderate salt stress significantly increased all the investigated variables in TDiZ. Salt stress induced higher TPC and TEAC as well as total free-PAs values till 50 mM NaCl in TDuC, whilst significantly lowered total bound-PAs due to the negative variation of both P-CA (-84%) and trans-FA (-81%) acids. Results indicate that salinity during germination could be efficiently modulated to improve the nutritional quality of sprouts, wheatgrass and cereal-based products.