Study On The Red Pigment Extracted From Carmine Radish

Edible pigments are widely used in many fields. Compared with synthetic pigments, natural edible pigments gain their advantages for the characteristics of edibleness and free of side effects.In this study, four varieties of carmine radish provided by Cruciferae Vegetable Institute, College of Horticulture and Landscape, Southwest University were used as experiment material, the extraction method was studied and the carmine radish pigment content in different growth periods were measured. In the experiment, we studied the effects of various extraction agents and found out the optimal extraction method for carmine radish pigment. Then the stability of extracted pigments was comparatively studied with several influencing factors, including light, heat, pH value, metal ions, food additives (oxidant, reduction agent, preservative, sugar agent and NaCl),and the composition and recipe of optimal stabilizing agent is ascertained. Furthermore, we undertook a conscientious study on physical and chemical properties on the extracted carmine radish pigment.The result showed that the content of carmine radish pigment increased with the growing of the radish, and it reached 3% when the radish flowered, which was the highest content.The result showed that 50% ethanol was feasible to extract carmine radish pigment. The detailed extraction protocol was as the follows: Raw material→cleaned→cut into slices→immersed in 50% ethanol for 10 hours→filtered by fabric filter→concentrated in vacuum→dry under 60℃→purple red powder→seal at once. The highest content was 3%.The selected composition of stability agents was 0. 04% vitamin C and 0. 08% citric acid, and when the stable agent was added, the stability and color of pigment could be improved greatly. Further studies showed that the survival rate reached 95.51%, while the control was 85.13%. The pigment was soluble in acid solvents and insoluble in non - polar organic solvents. It was stabile in acid condition (pH≤3 is optimal). The major metal ions had no influence on pigment stability, only Fe³⁺,Fe²⁺,Sn²⁺,Pb²⁺,Al³⁺,Cu²⁺ had a little influence. It has good resistance to heat and light , but it is unstable to oxidant and reducing agent. Oxidant could destruct pigment stability completely. Preservative and sugar agent had no obvious effect on stability.