Research on production of some natural food colorings

Tóm tắt

Stemming from the general trend of the world in the use of products from nature, three natural food colorings have been produced, namely the red from Momordica cochinchinensis fruits, the yellow from Gardenia jasminoides seeds, and the green from Boehmeria nivea (Ramie) leaves. Unlike industrial techniques using non-edible organic solvents, as well as traditional techniques using hot or cold water extraction, this study used ethanol 96% as a solvent for extraction. The results showed that the use of ethanol without adding water for extraction has obtained the colorings with the highest efficiency. The extraction parameters are as follows: 50 mL of ethanol, 1.0 g of dry materials, extraction temperature of 70 °C, extraction time of 60 minutes for the red and yellow colorings, and 90 minutes for the green coloring. All studied colorings were stable when heated to 90 °C for 60 minutes. The studied colorings were more stable at 4 °C in a refrigerator than at room temperature with the presence of light. They were also more stable when having been stored in ethanol than having been stored in water. After being stored for 6 days in ethanol, the weight of the red, yellow, and green colorings decreased by 2%, 0.4%, and 9.6%, respectively.