USDA scientists have devised a new analytical method for detecting and measuring concentrations of phytochemicals called polyphenols in plant materials. Also referred to as phenolics, this class of health-promoting compounds is found in certain foods and beverages. At the Agricultural Research Service Eastern Regional Research Center in Wyndmoor, Pennsylvania, scientists first used the new test on a variety of samples of beverages, grains and flaxseed. They used the new laboratory method to measure the amount of phenolics in various food samples by mixing them with Fast Blue BB diazonium salt. Under alkaline conditions, diazonium salt specifically couples with phenolics to form stable complexes that can be directly measured. The team then compared the new Fast Blue BB method to results using a traditional assay called Folin-Ciocalteu (FC). The results suggested that FC does not assess all phenolics present during tests and inadvertently measures other compounds besides phenolics.
(Source: ars.usda.gov)
