Samples of common buckwheat (Fagopyrum esculentum Moench) and Tartary buckwheat (F. tataricum Gaertn.) were used in milling, sieving and analysing experiments. Rutin and quercetin were analysed in buckwheat samples, in milling and sieving fractions and after the contact of flour particles with water, to simulate conditions in dough. The concentration of rutin in Tartary buckwheat was 1.17–1.75% in dry matter, while it was only 0.003% in dry matter of common buckwheat. Thus it is in Tartary buckwheat in this case 400 times more rutin in comparison to common buckwheat. In buckwheat dough with the time after mixing flour and water, the concentration of rutin diminished, the time needed was different in common and Tartary buckwheat dough, and quercetin appeared instead. Immediately after the direct contact of flour particles of common and Tartary buckwheat with water the rutin concentration changed from 11.7 to 0.79 mg/100 g dry matter (DM), and quercetin appeared (5.7 mg/100 g DM), in comparison in initial flour the concentration of quercetin was only 0.6 mg/100 g DM. In common buckwheat dough the apparent concentration of rutin changed from initial 0.0258 mg/g to 0.0263 mg/g DM, and after one hour after the beginning of contact of flour with water rutin concentration changed to only 0.0005 mg/g DM).
Keywords: common buckwheat, Tartary buckwheat, flavonoids, rutin, quercetin, milling, dough
Izvleček
Raziskovali smo vzorce navadne ajde (Fagopyrum esculentum Moench) in tatarske ajde (F. tataricum Gaertn.). Vzorce smo mleli, presejavali, pripravljali testo (mešanica moke in vode) ter izmerili vsebnost rutina in kvercetina. Tatarska ajda ima bistveno višjo vsebnost rutina kot navadna ajda. Vsebnost rutina v raziskovani tatarski ajdi je 1,17–1,75 % v suhi snovi (SS), v navadni ajdi ´siva´ pa le 0,003 %. V tatarski ajdovi moki smo izmerili okoli 400x več rutina kot v navadni ajdovi moki. Pri neposrednem stiku ajdove moke z vodo težko najdemo vzporednice med tatarsko ajdo in navadno ajdo in dogajanji v povezavi z rutinom v testu. Koncentracija rutina v testu se po določenem času (različen čas pri navadni in tatarski ajdi – 5 minut do 2 uri) močno zniža, pojavi se kvercetin. Pri neposrednem stiku moke z vodo se vsebnost rutina v tatarski ajdovi moki močno zniža že po prvih 5 minutah delovanja (z 11,7 na 0,79 mg/100 g SS), pojavi pa se kvercetin (5,7 mg/100 g SS), v vzorcu moke ga je le 0,6 mg/100 g SS. Pri neposrednem stiku moke iz navadne ajde z vodo vsebnost rutina v moki (vzorec S) naraste v prvi uri z začetnih 0,0258 mg/g na 0,0263 mg/g SS (v začetnem času nekoliko manj enakomerno), v drugi uri stika moke in vode pa koncentracija rutina močno pade (na 0,0005 mg/g SS).
Ključne besede: navadna ajda, tatarska ajda, flavonoidi, rutin, kvercetin, mletje, testo
Flavonoid concentration in milling fractions of Tartary and common buckwheat
