Thermal Stability of Betalains in By-Products of the Blanching and Cutting of Beta vulgaris L. Var conditiva

Abstract

The objective of this study was to evaluate the thermal stability (5°C, 25°C, and 45°C) of betalains present in by-products of the blanching and cutting of Beta vulgaris L. var conditiva, to evaluate the possibility of taking advantage of them as a source of natural colorants to be incorporated in food products. The identification of the betalain compounds present in these by-products was also performed. Blanching waters showed pigment degradation at all the temperatures evaluated. The remnant tissues were freeze dried rendering beetroot powders whose pigments only presented thermal degradation at 45°C. Sixteen betalain compounds were identified in powders by chromatography and it was concluded that a thermal treatment at 45ºC during six days affected the chemical stability of some of these compounds, producing a diversity of betalain degradation products. Results obtained allowed concluding that the red beetroot powder would have a better performance as a natural coloring additive than the blanching water at temperatures below 45°C. Probably, the low water activity of the powder and its lignin content ensured an effective protection of the pigments up to this temperature.