Propylene Glycol and its Effects on Reducing Hydration and Increasing Color Stability of Red Cabbage Anthocyanins
Hello! My name is Kelly and I am a Food Science and Technology major and a Human Nutrition minor here at OSU. I am a third year, although I transferred from a different university after my freshman year, so technically this is my second year at OSU.
This summer I had the opportunity to research in Dr. Giusti’s lab in the food science department. She specializes in anthocyanins, which are essentially the chemical compounds that make up the colors in fruits and veggies. Because consumer trends have been preferencing natural foods, many companies in the food industry are looking for ways to replace the artificial colors that they use with natural food colors. Anthocyanins have been a promising method for replacement for not only are there many different pigments that can be isolated, those pigments can react in different pHs to produce even more colors. One of the few downfalls of anthocyanins however, are that they are highly reactive with water and can actually lose their color.
My project was focused on the preservation of anthocyanin pigments that had been extracted from red cabbage. I used propylene glycol, a common additive used in the food industry, as a method to reduce the water activity buffer solutions. Theoretically, the propylene glycol would have bound the free water in the solutions, preventing the water from interacting with the anthocyanins and promoting color retention. In reality, the exact opposite happened (as the amount of propylene glycol increased, color loss also increased) although I am still not quite sure why.
Even though I did not get the results I was hoping for, I’m glad to have done this experiment because it indicates that more research should be done to evaluate the effects of water and sugar on pigment retention. I am also extremely grateful to Dr. Giusti, her post-doc student Gregory Sigurdson, as well as the FOODsure program which provided funding for this opportunity. Hopefully, with future exploration, better preservation methods can develop and assist food companies in their transition to natural colorants.