Coffee chlorogenic acid content

Melo, M., Amorim, H. V., Chemistry of Brazilian green coffee and the quality of the beverage. VI, The uv and visible spectral analysis and chlorogenic acids content in TCA soluble buffer extracts, Turrialba, 25, 243, 1975. (CA84 57533q)... 

Ohiokpehai O. (1982) Chlorogenic acid content of green coffee beans. Thesis, University of Surrey. 

Ohiokpehai O., Brumen G. and Clifford M.N. (1983) The chlorogenic acids content of some peculiar green coffee beans and the implications for beverage quality. 10th. Int. Colloq. Chem. Coffee (Salvador, Bahia 11-14.10.82) (ASIC, 1983), 177-86. 

Spectrophotometric analysis Spectrophotometric determination of total chlorogenic acid content in green coffee extract is conducted by measuring the absorbance at 324 nm, as in the AO AC standard procedures. Modification of this method by purification and extraction of the sample has been applied to eliminate interferences in roasted coffee. The formation of colored complexes with borates, molybdates, and periodates enables more accurate determination of specific classes of chlorogenic acids. 

Cblford, M.N. and Jarvis, T. (1988) The chlorogenic acids content of green robusta coffee beans as a possible index of geographic origin. Food Chem., 9,291-298. 

Deshpande, S. N., Aguilar, A. A., Effects of roasting temperatures and gamma-irradiation on the content of chlorogenic acid, caffeic acid and soluble carbohydrates of coffee, Int. J. Appl. Radiat. Isot., 26, 656, 1975. (CA84 57527r)... 

Belyaya, K. J., Clifford, M. N., Individual chlorogenic acids and caffeine contents in commercial grades of wet and dry processed Indian green robusta coffee, J. Food Sc 1. Technol, 32(2),104, 1995. (CA123 197159w)... 

Smith (1963a) and Feldman et al. (1969) underlined the importance of non-volatile compounds to the flavor of coffee. The comparison between the composition of green and of roasted coffee showed an important decrease in the content of proteins, chlorogenic acid and sucrose on roasting. Fractionation and analysis of the aroma precursors in green coffee have also been studied by Russwurm (1970) who considers that the non-volatile constituents of green coffee that may be involved in flavor formation are carbohydrates, proteins, peptides and free amino acids, polyamines and tryptamines, lipids, phenolic acids, trigonelline and various non-volatile acids. 

Using partition chromatography on a silicic acid column, Mabrouk and Deatherage (1956) determined the organic acids in five coffee extracts. Such a column does not normally separate the volatile acids, nevertheless, acetic acid was found to represent 0.59% of the total acid content, far away from the predominant non-volatile acid, chlorogenic acid, which represents 66.7% of the total organic acids. Also present in higher proportions than acetic acid were the non-volatile citric acid (E.57), 7.7 %, malic acid (E.53), 7.2%, and tartaric acid (E.55), 6.2%. Oxalic acid (E.42) and pyruvic acid (E.38) were quantified. 

Analytical work on the acid content of raw and roasted coffees was published by von Werner and Kohley (1965a,b,c), but mainly on the chlorogenic acids. 

Clifford M.N. and Kazi T. (1987) The influence of coffee bean maturity on the content of chlorogenic acids, caffeine and trigonelline. Food Chem. 26, 59-69. 

Chlorogenic acids are the most abundant acids of coffee (Tables 21.2 and 21.3). The content of these acids drops on roasting as shown in Table 21.6. 

Flow signals obtained for chlorogenic acid are shown in Figure 36.4. The response was linear between 5.0 x 10 and 3.0 x 10 M [5,15]. The FIA-ECD method was examined in detail for determining the acid content in coffee. In the test solution preparation, 250 mL of hot water was poured onto 20 g coffee powder on a filter paper, and the filtrate was diluted with an ethanol solution containing 3 mM VKj and 38 mM LiC104 [5,15]. 

---