Total phenols assay Folin-Ciocalteu

Total Phenols Assay (Folin-Ciocalteu Reagent)... 

The Folin-Ciocalteu assay is the most widely used method to determine the total content of food phenolics (Fleck and others 2008). Folin-Ciocalteu reagent is not specific and detects all phenolic groups found in extracts, including those found in extractable proteins. A disadvantage of this assay is the interference of reducing substances, such as ascorbic acid (Singleton and others 1999). The content of phenolics is expressed as gallic acid or catechin equivalents. 

Methods used for the detection of PAs in cmde or partially purified extracts can also be adapted for post-column analysis after fractionation (see below). Direct quantitative analysis of PAs in crude grape phenolic extracts is often impossible due to the complex sample matrix. Thus, fractionation or purification is often necessary before analysis. The Folin-Ciocalteu and Pmssian Blue assays are widely used for the quantification of total polyphenols in plants [27,28]. These methods are not specific for PAs due to the reaction of other phenolic compounds with these reagents. 

Table 5.6 shows the total phenolic content (determined using the Folin-Ciocalteu assay) and antioxidant activity (ABTS radical scavenging capacity) of extracts from morama bean seed coat and cotyledon prepared with acidified mefhanol. If is clear fhaf morama bean seed coat and cotyledon have appreciable levels of fofal phenolics and antioxidant activity. These phenolics are concentrated in the seed coat. It has been reported that the morama bean cotyledon contains high levels of the amino acid tyrosine (Maruatona et ah, 2010) which is phenolic in nature and can therefore confribufe fo fhe fofal phenolic content of the cotyledon as determined with the Folin-Ciocalteu assay. 

Colorimetric Indirect Method based on the typical reaction of polyphenols with formaldehyde, Singleton " proposed an assay for the quantification of phenolic material condensable with formaldehyde. He described a colorimetric procedure, instead of the gravimetric method, combining the Folin-Ciocalteu assay wifii the method of Stiasny (Fig 2). First, the total phenol content of the extract was measured before the precipitation reaction by the Folin-Ciocalteu method following the... 

Leamsomrong, K., M. Suttajit, and P. Chantiratikul. 2009. Flow injection analysis system for the determination of total phenolic compounds by using Folin-Ciocalteu assay. Asian J. Appl. Sci. 2(2) 184-190. 

The content of total polyphenols was determined by colorimetric assay with Folin-Ciocalteu s phenol reagent, according to Singleton and Rossi 14). 

Fig. 2 SEC elution profile of apple procyanidins using a Toyopearl HW-40 F column. Experimental conditions the column size was 950 x 25 mm inner diameter mobile phase solvent was acetone-8 M urea (pH 2) (6 4) flow rate was 1.0 mL/min the eluent was fractionated into 3 ml fractions each the total phenolics content (i.e., the value corresponding to the absorbance at 760 nm) in each fraction was estimated by modified Folin-Ciocalteu assay filled circle= chromatogram of apple procyanidins (10 mg/0.5 ml of mobile phase) open c// c/e=chromatogram of a mixture of standard oligomers from monomer to trimer (each 2 mg/0.5 ml of mobile phase) (reproduced from ref. [24] with permission from Elsevier)...

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