EVALUATION OF SELECTED QUALITATIVE PARAMETERS OF SWEET POTATO IN DEPENDENCY ON ITS CULTIVAR IN SLOVAKIA

Year 2018, Volume: 2 Issue: 2, 62 - 65, 08.12.2018

Miroslav šlosár , Alžbeta Hegedűsová İvana Mezeyová , Mária Tımoracká Ondrej Hegedűs

Abstract

In this study, selected qualitative parameters
(total carotenoids, vitamin C, total polyphenols) of sweet potatoes (Ipomoea
batatas L.) grown in Slovakia were evaluated. The field experiment was
established in the area of the Slovak University of Agriculture in Nitra in 2017.
In experiment, registered cultivar 'Beauregard' was used as a comparable
cultivar. Other three cultivars ('Dubaian', 'Višnjica white', Višnjica purple')
were marked according to the market place from which tubers for seedling
production were bought.  The sweet
potatoes were grown by hillock system and plants were mulched by black
non-woven textile. The seedlings were planted on the 1st June 2017. The tuber
harvest were realised on the 13th September 2017 and qualitative parameters
were analysed immediately after harvest. The carotenoid and polyphenol content
was determined spectrophotometrically (polyphenols in lyophilised sample;
expressed in mg of gallic acid equivalent.kg^-1 of dry weight) and
vitamin C content chromatographically (HPLC). The statistically significant
differences of parameter content were found among tested sweet potato
cultivars. The highest total carotenoid content (TCC) was found in cultivar
'Dubaian' (107.04 mg.kg^-1 fresh weight). Generally, significant
differences of TCC were detected between cultivars with orange flesh colour
(64.87 mg.kg^-1 f. w.;107.04 mg.kg^-1 f. w.) and cultivars
with purple and white flesh colour (3.02 mg.kg^-1 f. w.; 8.00 mg.kg^-1
f. w.). The highest content of total polyphenols was found in cultivar with
purple flesh of tubers - 'Višnjica purple' (5398.77 mg GAE.kg^-1 dry
weight). Other cultivars were characterized by expressively lower values of
total polyphenol content (1557.02-2412.91 mg GAE.kg^-1 d. w.). The
highest vitamin C content was determined in cultivar 'Dubaian' (436.83 f. w.),
following by cultivars 'Beauregard' (309.37 f. w.), 'Višnjica purple' (233.27
f. w.) and 'Višnjica white' (205.73 f. w.). Results of this study showed
significant variability of polyphenol and carotenoid content in different-coloured
sweet potatoes.

Keywords

sweet potato, cultivar, carotenoids, polyphenols, vitamin C

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