Effect of screening and subculture on the production of betaxanthins in Beta vulgaris L. var. ‘Dark Detroit’ callus culture

Plant cell culture is an innovative technology to produce a variety of substances including natural dyes. Betaxanthins are considered food-safe nutraceutics pigments because exhibit antiradical and antioxidant activity. An important obstacle for developing large-scale production systems based in plant cells has been the instability of metabolite accumulation. In this work, a protocol was established to obtain yellow callus of B. vulgaris var. ‘Dark Detroit’. Homogeneous and heterogeneous pigmented callus were obtained with yellow, red, orange and colorless phenotype. Particular attention was done to isolate and establish a yellow line. After continuous screening of the more intense yellow callus it was possible to increase the betaxanthins production 1.8-fold after 48 subcultures. Spectrophotometric and chromatographic analysis of the pigments, confirmed the presence of betaxanthins. HPLC analysis indicated two mainly distinct betaxanthins, vulgaxanthin I and II. B. vulgaris yellow callus line did not loose pigment production ability as a result of long-term subculture.