Betacyanins and Betaxanthins in Cultivated Varieties of Beta vulgaris L. Compared to Weed Beets.

Milan Skalicky,Pavla Vachova,Vaclav Hejnak,Hajihashemi Shokoofeh,Jan Kubes,Md Tahjib-Ul-Arif

doi:10.3390/molecules25225395

Milan Skalicky, Pavla Vachova + Show 4 more

Open Access

https://doi.org/10.3390/molecules25225395

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Abstract

There are 11 different varieties of Beta vulgaris L. that are used in the food industry, including sugar beets, beetroots, Swiss chard, and fodder beets. The typical red coloration of their tissues is caused by the indole-derived glycosides known as betalains that were analyzed in hypocotyl extracts by UV/Vis spectrophotometry to determine the content of betacyanins (betanin) and of betaxanthins (vulgaxanthin I) as constituents of the total betalain content. Fields of beet crops use to be also infested by wild beets, hybrids related to B. vulgaris subsp. maritima or B. macrocarpa Guss., which significantly decrease the quality and quantity of sugar beet yield; additionally, these plants produce betalains at an early stage. All tested B. vulgaris varieties could be distinguished from weed beets according to betacyanins, betaxanthins or total betalain content. The highest values of betacyanins were found in beetroots ‘Monorubra’ (9.69 mg/100 mL) and ‘Libero’ (8.42 mg/100 mL). Other beet varieties contained less betacyanins: Sugar beet ‘Labonita’ 0.11 mg/100 mL; Swiss chard ‘Lucullus,’ 0.09 mg/100 mL; fodder beet ‘Monro’ 0.15 mg/100 mL. In contrast with weed beets and beetroots, these varieties have a ratio of betacyanins to betaxanthins under 1.0, but the betaxanthin content was higher in beetcrops than in wild beet and can be used as an alternative to non-red varieties. Stability tests of selected varieties showed that storage at 22 °C for 6 h, or at 7 °C for 24 h, did not significantly reduce the betalain content in the samples.

Highlights

The EU is the world’s leading producer of sugar beets, with a cultivation area of 1.74 million hectares (2018)—approximately 50% of the global production
Betalains were present at greater levels in samples of MFB (Figure 2C); there was no significant difference in the content of these metabolites between ESB/LSC/LSB
In order to better identify weed beet infestation of beet crops, an improvement on the methods described in the literature that focused on the typical colorants in beetroots was used, in which total betalain content was determined in hypocotyl extracts

Summary

Introduction

The EU is the world’s leading producer of sugar beets, with a cultivation area of 1.74 million hectares (2018)—approximately 50% of the global production. The cultivation area was 157 thousand hectares in 1980, 50 thousand hectares in 2008, and 65 thousand hectares nowadays with a yield of 71.2 t/ha [1]. Other beet crops, such as fodder beets, Swiss chard, and beetroots, are produced, but are of lesser importance. Swiss chard is the exception, because it is the leaves rather than the roots that are harvested and they have a high content of vitamins and antioxidant phenolic compounds [2]

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