Primary metabolites and betanin: their interplay in the roots of Table Beet (Beta vulgaris L.)

Abstract

Relevance. The main source of the natural pigment betanin is table beet, known for its medicinal and antioxidant properties, earliness and long shelf life, rich in bioactive compounds, minerals and vitamins. This research was induced by the lack of information required by breeders to increase betanin content in beet. Metabolite profiling is an effective way to assess the interplay between individual metabolites and betanin content in table beet.Materials and methods. The material was selected from the the N.I. Vavilov Institute of plant industry (VIR) collection. Biochemical analysis was based on VIR’s guidelines, and metabolite profiling on gas chromatography, coupled with mass spectrometry.Results. 17 free amino acids were found in the beet root extract. The greatest number of positive correlations with other amino acids (r˃0.72) was found in tyrosine, alanine and phenylalanine. A significant (r = –0.66) negative correlation was observed between betanin and succinic acid, credibly associated with betalamic acid. Sucrose predominated among carbohydrates (95%). Sucrose and maltose showed a weak positive correlation with betanin. Unsaturated oleic and saturated palmitic acids dominated among fatty acids (52% and 20% of total fatty acids, respectively). Earlier-ripening and cold-resistant table beet accessions showed a predominance of unsaturated fatty acids and lower betanin content. The disclosed interactions are important for betanin-rich red beet breeding.

Keywords

• red beet
• betalains
• betanin
• free amino acids
• organic acids
• carbohydrates
• fatty acids