Extraction Technology and Stability of Red Radish Pigments from Raphnus sativus

Extraction technology and stability of red radish pigments from Raphnus sativus cv Xinlimei were studied.The results showed that red radish pigment yield was highest when it was extracted at 1∶2 rate of solid to solution and at(70 ℃) for 3 hours;among macroporous resins AB-8,NKA-9,S-8 and NKA-Ⅱ,AB-8 had the strongest sorption and the highest speed of adsorption.The stability of red radish pigments was affected by heat,light and pH.Heat degradation of red radish pigments based on first-order reaction kinetics was observed,half-life of the heat degradation was 73 days at(25 ℃),and residual rate after 5 hours indoors was 54.13 percentage points higher than that at the same time in sunshine.As pH increased,L value of red radish pigments decreased obviously,the color showed apart from red and close to bluish green.