Study on the stability of red pigments produced by a seedborne endnophytic fungus from Tartary Buckwheat

The ferment characterization and its red pigment stability of Tartary Buckwheat seed-borne endophytic fungi TBSBEF-9 were studied. The results showed that the pigment harbored in the extracellular of isolate TBSBEF-9 could be detected after 3 days ferment and reached its highest level at the sixth day. The whole wavelength scan showed that the maximal absorbtion was 510 nm. The pigment was soluble in water, ethanol and other polar solvents. And it showed pink under acidic conditions, orange under alkaline conditions. The pigment displayed a remarkable thermal (< 100益) stability. Metal ions such as Ca2+, Ba2+, K+, A13+, Mg2+ had no significant effect on the pigment colour, the oxidants such as KMnO4, H2O2, FeCl3 would hence the red colour, while the reducing agent Vc made the pigment color lighter. Salt, sugar had no obvious effect on the colour change and under the citric acid it would fade. Therefore, the physicochemical properties of the pigment of Tartary Buckwheat were stable. The result also implied that the pigment was an ideal and natural color additive.