Chlorogenic green coffee

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)... 

Clifford MN, Knight S, Surucu B and Kuhnert N. 2006a. Characterization by LC-MS(n) of four new classes of chlorogenic acids in green coffee beans dimethoxycinnamoylquinic acids, diferuloylquinic acids, caffeoyl-dimethoxycinnamoylquinic acids, and feruloyl-dimethoxycinnamoylquinic acids. J Agric Food Chem 54(6) 1957-1969. 

The ubiquitous plant compound chlorogenic acid (isolated from green coffee beans) is formed by transesterification with the glycoside cinnamoyl-glucose.187 Coumaroyl-CoA is converted into monomeric and dimeric amides with agmatine, which provides barley plants with resistance to mildew.188 Similar compounds with various polyamines and derived from p-coumaric, caffeic, ferulic, or sinapic acid appear to... 

Green coffee beans (Coffea arabica) are one of the richest dietary sources of chlorogenic acids. 5-O-Caffeoylquinic acid is the dominant chlorogenic acid accounting for 50% of the total. This is followed by 3-0- and 4-O-caffeoyl-quinic acid, the three analogous feruloylquinic acids and 3,4-0-, 3,5-0- and 4,5-O-dicaffeoylquinic acids (Fig. 1.32) [Clifford, 1999]. Levels decline ca. 80% during the roasting of coffee beans, but sizable amounts with substantial antioxidant activity are still found in the typical cup of coffee. 

O-Dicaffeoylquinic acid Figure 1.32 Main chlorogenic acids in green coffee beans. 

As an example, Urakova et al. compared the analysis of chlorogenic acid in green coffee bean extracts by thin layer chromatography on silica (i.e. normal-phase liquid chromatography) and by reversed-phase HPLC The validation data (LOD, LOQ, repeatability, and various precision parameters), the recoveries and the quantitative results were totally comparable. It can be assumed that both methods find the true value. Either method can be used, depending on the preference or instrumentation of a laboratory. 

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. 

De Maria et al. (1995, 1996c) have described a simultaneous determination of total chlorogenic acids, trigonelline and caffeine in green coffee by high-performance gel filtration chromatography. They also... 

Non-volatile multifunctional acids present in green coffee are not mentioned here. Their contribution to the flavor and taste qualities essentially concerns the roasted coffee beverage. Their structures and properties are partly discussed in Section 5.E. Similarly, free acid-phenols present in small amounts, mainly decomposition products of chlorogenic acids and depsides, will be discussed in Section 5.H. 

The y-quinide G.15, the lactone of the main quinic acid (E.52) formed during roasting was identified in roasted coffee (chlorogenic lactones have been found in green coffee, see Section 2.1.4). The identification of isomers of this lactone was described by Maier s group (Scholz and Maier, 1990 Scholz-Bottcher et al., 1991 Scholz-Bottcher and Maier, 1992). The formation of the main lactone reached a maximum with a medium roast, whereas the minor isomers increased regularly. 

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. 

TABLE 2 Chlorogenic Acids Identified in Green Coffee Beans (Robusta and Arabica) by Liquid Chromatography Tandem Mass Spectrometry ... 

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. 

Seven chlorogenic and hydroxycinnamic acids (caffeic, p- and o-coumeric, ferulic, 4-methoxy-, 3,4-dimethoxy-, 3,4,5-trimethoxycinnamic) were extracted from green coffee and baseline resolved on a Cjg colunm (A = 320 nm) using a complex 47-min 15/85 - 80/20 methanol/water (1% acetic acid) gradient [374]. Peak shapes were excellent. Linear ranges of 4—400 pg/mL with detection limits of 0.1 pg/mL were reported. 

Moreover, green coffee beans contain a number of chlorogenic acids such as derivatives of caffeoylquinic acid, dicaffeoylquinic acid, and feruloylquinic acid [428], whose amount and distribution in the coffee beans depend on the bean type and degree of ripeness. During the roasting process, a significant... 

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