engleski

Chromatography Separation of Essential Ions in Stevia

Stevia (Stevia rebaudiana Bertoni) belongs to the family Asteracae and the intensive sweet taste of its leaves provided the name „new age sugar“. Stevia is cultivated for the sweet taste leaves, which are, after drying and grinding, used as a substitute for artificial sweeteners. The Stevia products are widespread as food additives and a natural calorie free sweetener. An intensive sweetness originates from glycosides, i.e. termostable chemical compounds well tolerated the low pH values. The subject of the whole interdisciplinary study was to determine the effect of fertilizer doses and the soil type (pH) on the fresh leaves yield. Furthermore, content of glycosides (stevioside and steviol) and mineral composition of Stevia leaves were determined. Plants were grown in a 5 L pots on the two types of acid soil (pH 4.0 and 5.0), which were different according to their supply with major nutrients. Five doses (from 0 up to 1.6 g per plant) of Multi-Comp Base mineral fertilizer 14:13:20+2MgO+ME were applied. After harvest, leaves were dried at 70°C for 72 h, ground, sieved and homogenized. The concentrations of 7 anions (F-, Cl-, NO2-, Br-, NO3-, SO42-, H2PO4-) and 6 cations (Li+, Na+, NH4+, K+, Ca2+, Mg2+) was simultaneously determined by suppressed ion chromatography (two Dionex 1000 systems) using an IonPac AS 17 and IonPac CS 16 separation columns fitted with an IonPac AG 17 and IonPac CG 16 guard columns, the eluent solutions were KOH and MSA, respectively. Detection was done after 2h hot (at 90°C) ultra-pure water extraction at 1:1000 (w/v) ratio. Simultaneous analysis was enabled by a splitter, installed on autosamplerAS40, which split the sample in two pipelines, one for anion and other for cation system. Slightly overshadowed by all other nutrient, sodium and chlorine, as mineral components, play the very important role in Stevia. In this paper content of Na+ and Cl- as essential micronutrients in Stevia is shown and discussed.

sodium; chlorine; pH; soil; yield

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