Study examines avocado seeds as color source
Nov. 16, 2011
by Jeff Gelski
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UNIVERSITY PARK, PA. — Avocado seeds are potential sources of new colorants for use in foods, according to a study in the November/December issue of the Journal of Food Science published by the Institute of Food Technologists. Researchers at The Pennsylvania State University said avocado seeds potentially may be used as alternatives to synthetic colors. Examples of current alternatives are extracts of turmeric, paprika and beets.
Avocado growers typically view the seeds as waste. The researchers found the seeds developed an orange color when they were crushed with water. Heat treatment of the seed prevented color development. The addition of exogenous polyphenol oxidase (PPO) restored color development but peroxidase did not.
Color formation resulted in a decrease in the concentration of polyphenols, which indicated utilization for color formation. The orange color intensified as the pH was adjusted from 2.0 to 11.0. The changes were partially reversible when pH was adjusted from 7.5 to 11 in the presence of oxygen and completely reversible when the pH was changed in the absence of oxygen. The color was stable in solution at minus 18 degrees Celsius (0 degrees Fahrenheit) for two months.