Total polyphenol, flavonoid and other bioactive materials in different asparagus cultivars

Abstract

The favourable active ingredient composition of numerous vegetables is published frequently; however its value is often influenced by the variety and the given production year. In the current experiment the main aim was to determinate the bioactive materials (total polyphenol, flavonoid, vitamin C, sulphate-S, protein, nitrate-ion) of blanched (white) asparagus for three widely known varieties ('Cumulus', 'Vitalin', 'Grolim'), grown on mouldy brown sandy soil, in 3 consecutive years (2012- 2014). A significant difference has been found among the varieties in the average of the observed data. 'Vitalin' was prominent with its high total polyphenol (35.16 mg/100 g), vitamin C (59.34 mg/100 g) and flavonoid (0.52 mg/100 g) content. High sulphate-S content-which is characteristic for asparagus-has been measured in the case of 'Cumulus' (287.77 mg/100 g), together with the highest protein content (2.23%). The vitamin C content of the spears is significantly influenced by the production year, therefore higher temperature fluctuations had a negative effect on it, which resulted in its value reducing to one-tenth of the best years in some cases (89.06 mg/100 g). Additionally, it has been found that white asparagus develops under etiolated circumstances, it is not inclined to nitrate accumulation, which is well represented by the values under 20 mg/kg. Selecting the proper cultivar is important for raw asparagus extract production, which can be produced only of raw materials rich in bioactive materials (including high sulphur content). In this regard 'Vitalin' and 'Cumulus' seemed to be the most advantageous choices.