ARS | Publication request: Comparing phenolic concentration using folin-ciocalteu and fast blue BB diazonium salt

Submitted to: Mississippi Academy of Sciences Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 7, 2012
Publication Date: February 10, 2012
Citation: Ratcliff, T., Marshall, D.A., Sassenrath, G.F., Steele, M. 2012. Comparing phenolic concentration using folin-ciocalteu and fast blue BB diazonium salt. Mississippi Academy of Sciences Proceedings. 57(1):88.

Technical Abstract: Polyphenolics contribute to antioxidant properties of food, juices, and beverages, and are essential to the human diet. These phytochemicals have various preventive and disease fighting properties. The polyphenolics contribute to antioxidant properties and these compounds include flavonoids, flavonols, flavonolols, flavonones, isoflavones, flavones, anthocyanidins, flavanalols, chalcones, anthocyanins, chlorogenic acid isomers, cinnamic and benzoic acid families, stilbenes, lignins, lignans, tannins, tocopherols and tocotrienols. Folin–Ciocalteu method is commonly used to measure total phenolic content of fruit samples. Folin-Ciocalteu uses 2N Folin to reduce chemical compounds. The problem with this method is that it will also react with non-phenolic antioxidants as well as reducing substances (ascorbic acid, glucose, fructose, sulphites) that are common food additives, or that are naturally present in juices, fruits and vegetables. In addition, amino acids (tyrosine, tryptophan) and proteins containing these amino acids will react as phenol compounds because of their phenolic ring. Fast Blue BB method uses a diazonium salt, which reacts with the phenol group only, making Fast Blue BB more reliable to measure total phenolics. However, the Fast Blue BB method requires the production of a standard solution (background) that is measured after each test. Both reagents work by oxidization/reduction of phenol compounds within plant samples. The main goal was to determine which method would produce readings that are more precise and reproducible. Of the two methods, Folin–Ciocalteu and Fast Blue BB, Fast Blue BB read the highest total phenolics and reproducibility. Of the different variations of Fast Blue BB tested, the process that produced the highest concentration was the NaOH base samples in acetone extraction solvent at 120 min in the dark. These findings will provide for more accurate measurements of total phenolic concentration.