Analysis of Pigment Distribution and Antibacterial Characteristics of Red Radish

To study the distribution,stability and antibacterial activity of natural pigment rich in red radish,the pigments of four kinds of red radish were extracted by ultrasonic assisted method,and the differences of pigment distribution were compared. The pigment extract was treated with different light,pH value,temperature and different concentrations of metal ions,oxidants,reducing agents and common food additives. The antibacterial properties of red radish pigment were verified by filter paper method. The results showed that the pigment distribution was different,and the pigment content of radish skin was the highest(0.039 mg/g). The pigment content in radish skin was significantly higher than that in other parts of radish. The pigment was more sensitive to light and high temperature(≥60 ℃),and it was the most stable when the pH was around 7. Fe³⁺ and Al³⁺ could reduce its stability. The resistance to reduction was stronger than the resistance to oxidation. Citric acid and vitamin C had color retention effect on pigments,while the sugar or salt had no significant effect on its stability. At the same time,the bacteriostatic test by filter paper method showed that the pigment had inhibitory effects on Escherichia coli and Staphylococcus aureus.