Total and High-Molecular-Weight Phenolics

According to Joslyn and Goldstein (1964), the Folin-Denis method, published in 1912, was first intended for the measurement of tannins in wine and whiskey, and then used for the assay of tannins in fruits (Swain and Hillis 1959 Craft 1961). Various methods for phenolic compound analysis have been reported (Joslyn and Goldstein 1964 Hartley 1987 Karchesy 1989 Hagerman 1989), but the Folin-Denis method is still very useful for the measurement of phenolic compounds in fruits. 

975 25, v/v) is added, followed by 1 g of kaolin. The mixture is stirred vigorously with a glass rod and left until a precipitate forms. The supernatant is filtered with paper, and the absorbance of the filtrate is measured by the Folin-Denis method as described above. The value obtained is subtracted from the total phenolic content and designated as the HMWF of the phenoHc compounds. 

---