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Taro (Colocasia esculenta (L.) Schott) je ena najpomembnejših tropskih gomoljevk. Prilagojen je na toplo in vlažno okolje. Namen diplomske naloge je bil določiti vsebnost vodotopnih in celokupnih oksalatov v kormih nekaterih kultivarjev tara iz Vanuata. Vodotopne oksalate smo ekstrahirali z vodo, za ekstrakcijo celokupnih oksalatov pa smo uporabili 0,2 M HCl. V ekstraktih vzorcev smo koncentracije oksalatov določili s tekočinsko kromatografijo. Najnižjo vrednost 52 mg/100 g pri vodotopnih oksalatih smo izmerili v kormu kultivarja VU 1819, ki je bil pobran v 8. mesecu po sajenju (MPS). Z vidika prehrane je najpomembnejše, da je vsebnost netopnih oksalatov v rastlini čim manjša, saj povzročajo ledvične kamne. V kormu kultivarja VU 396 smo izračunali najnižjo vrednosti netopnih oksalatov, in sicer 7 mg/100 g. Med vegetacijsko dobo se vrednosti oksalatov spreminjajo. Zaradi velikih razlik v vsebnosti oksalatov med kultivarji statističnih razlik med posameznimi meseci izkopavanja kormov ni bilo. Z vidika vsebnosti oksalatov je najprimernejši čas izkopavanja v 8.MPS. Taro (Colocasia esculenta (L.) Schott) is one of the most important tropical root crops. It is adapted to hot and wet environment. The main objective of the presented study was to determine the water-soluble and total oxalate content in corms of taro cultivars from Vanuatu. Water-soluble and total oxalates were extracted with water and 0,2 M HCl, respectively. In the sample extracts, the concentration of oxalate was determined by liquid chromatography. The lowest content of water-soluble oxalates (52 mg/100 g) was determined in a corm sample of the cultivar VU 1819 harvested 8 month after planting (MAP). From the nutritional point of view, it is important that the levels of insoluble oxalates in plants are low because they can be a cause of kidney stones formation. The lowest insoluble oxalate content was recorded in a corm sample of the cultivar VU 396 (7 mg/100 g). The contents of oxalate changed throughout the vegetation period. No significant differences in the contents of oxalate were observed during the growth period and this was mainly due to the big differences among cultivars. Regarding the oxalate content in corms, it could be recommended that corms should be harvested 8 MAP. |
