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Trigonelline in coffee
Phytockmistry, Vol. 30, No. 7, pp. 2309 -2310, 1991 Printed in Great B&am.
0
TRIGONELLINE
0031-9422/91 $3.00+0.00 1991 Pergamon Prms plc
IN COFFEE
PAULO MAZZAFERA Institute of Biology, Unicamp CP6109, Campinas (SP), 13081, Brasil (Received in revisedform 30 November 1990) Key Word Index-Co&q
Rubiaceae; coffee; analysis; trigonelline.
Abstract-Seeds of ripened fruits of twenty-eight plants of Co&a, one of Psilunthus and two inter-specific hybrids of Cofia were analysed for trigonelline content in order to investigate the genetic variability.
~ODU~ON
Trigonelline, ~-methyl~taine of py~dine-3-car~xylic acid, is found in coffee seeds and its content depends on the coffee species Cl]. The importance of trigonelline in coffee is connected to nutritional aspects, as roasting causes its conversion to nicotinic acid (niacin) [2]. The nicotinic acid content of green coffee varies from I.6 to 4.4 mg per lOOg, increasing almost 10 times with roasting [l]. According to Tepley and Prier [3] the daily consumption of 3.5 cups of coffee can supply one-third of the minimum daily requirement of this vitamin, deficiency of which causes the disease pellagra. As to the quality of coffee beverage, Viani and Horman 12, 41 observed that among the products formed from trigonelline during roasting nine of them could be found in the flavour. However, little is known about the variability of the trigonelline content in seeds of coffee species. Yeransian et al. [5] showed that arabica green coffee contained ca lo!, robusta 0.7% and liberica 0.25% of t~gone~ine. From a compilation of the literature Macrae [l] found similar values. We present results of an analysis of seeds of ripened fruits of twenty-eight coffee trees comprising nine species of CoJka, one of Psilanthus and two inter-specific hybrids of Co@a. RESULTS AI’ll) DISCUSSION
Part of the trigonelline found in coffee seeds is transformed into nicotinic acid during roasting [2, 41. The previous knowledge of trigonelline content in coffee beans should permit the estimatation of the potential of nicotinic acid in the roasted coffee. The results in the Table 1 show that among the species studied, C. canepkora cv Guarini had the highest trigonelline content and the cultivars of C. dewevrei, a well defined group, the lowest values. Excluding cultivars Laurina and Semperflorens, all other coffee trees of C. arabica contained t~gonelline around 2%. It is interesting to note that C. arabica cv Laurina, which has low caffeine and oil content [6] was the one that had least trigonelline in the arabicas analysed. However, as the coffee trees Mokka ‘LrLr’ and Mokka ‘I&, that differ from laurina alelles, showed the same level of trigonelline, the influence of this genetic factor on the level of the substance could not be shown. In addition to PRY
30:7-o
arabica trees, the values found for the other species showed a genera1 variability in trigonelline content. Data on trigoneiiine in green coffee are scarce in the literature. Kogan et al. [7] determined trigonelline by paper chromatography. More recently, Ferreira et al. [g] Table 1. Trigonelline content in seeds of coffee species Trigonelline* C. orabica cv Abramulosa 2 Bourbon Red Caripe Catuai Red Caturra Red Cioiccie Gliiucia Ibati Laurina Maragogipe Mokka ‘LrLr’ Mokka ‘lrlr’ Mundo Novo Red National SemperlIorens Sumatra Hibrido de Timor C. libericavar. Dewevrei C. dewevreicv Abeokutae Dibowskii Excelsa C. canephoru cv Guariui C. stenophylla C. salvatrix C. liberica C. racemosa C. brevipes Psil~~h~ trav~c~e~~~ C. arabicax C. libericu var. Dewevrei C. racemosax C. augenioides
2.31 2.06 2.30 2.48 2.23 2.11 2.40 1.97 1.52 2.06 2.19 2.24 2.13 1.81 2.90 2.37 2.39 1.37 0.88 0.84 0.77 3.08 1.89 1.21 1.01 2.31 2.23 1.33 1.72 1.92
*Results are average determinations in duplicate (g per 100g dry wt). tIncUed because Psilanthus was previously classified as Coffea section Paracofflka.
P. MAZZAFERA
2310
analysed this substance in arabicas and robustas by the iodometric method. The values found by these authors are lower than those we found, being no more than 1%. The extraction of trigonelline from coffee beans does not seem to be difficult because of its high solubility in hot water, and the recovery of trlgonelline from Sep-Pak cartridges was 100%. For chromatography, isocratic running was best performed with buffer alone. In this running condition it was seen that nicotinic acid, that could interfere, eluted from the column in 7 min and trigonelline in 3.6 min. We believed that the differences among previous papers and our results arise from the methods used to determine trigonelline. Trugo et a!. [9] used HPLC to investigate trigonelline in instant coffee, concluding that the method was simple and reliable. According to Poulton [lo] during seed germination and early growth of several plants, trigonelline declines and pyridine nucleotides appear in the tissue, suggesting an involvement in the process as a precursor of NAD. We did not find any relation between seed size and trigonelline content in the seeds of the species analysed here. EXPERIMENTAL
The seeds used in this study were kindly supplied from the germplasm bank of the Institute AgronBmico at Campmas. Dry seeds finely groud were extracted with hot H,O (95”, 250mg per IOOml) for 10 min. After cooling, the vol. was adjusted and samples were run m Sep-pak Cl8 cartridges (Waters Associates) and eluted with NaOAc 0.5%, pH 5.0.
Determinations of trigonelline was done by HPLC using a ODS-Hypersil 5 pm column (4.6 mm x 25 cm). with NaOAc 5% pH.5 as isocratic solvents (flow rate 1 ml min- ‘) and UV monitor 272 nm. The areas obtained m an integrator-recorder were compared
with those of standard
solns of trigonelhne
REFERENCES 1. Macrae, R. (1985) m Coffee Vol. 1. pp. 115-152. Elsevier. 2. Viani, R. and Horman, I. (1974) .I. Food SCL 39, 1216. 3. Tepley, L. J. and Prier, R. F. (1957) Publication No. 24. The Coffee Brewing Institute, New York. 4. Viani, R. and Horman, I. (1975) in Colloquium International sur la Chimie du Cafp (ASIC), VIII, pp. 273-278. Hambourg. 5. Yeransian, J. A., Kadin, H. and Berker, E. (1963) Assoc. Anal. Chem. 46, 3 15. 6. Tango, J. S. and Carvalho, A. (1963) Bragantw (Brasil) 22, 793. 7. Kogan, L., Dicarlo, F. J. and Maynard, W. E. (1957) Anal. Chem. 25, 1118. 8. Ferreira, L. A. B., Villar, H., Fragoso, M. A. C., Agmar, M. C., Cruz, M. J. R. and Gorqalves, M. N. (1971) in Colloquium International SW la Chimie du Cafe (ASIC), V, pp. 128-147 Lisbonne. 9. Trugo, L. C., Macrae, R. and Dick, J. (1983) J. Sci. Food Agrrc. 34, 300. 10. Poulton, J. E. (1981) in The Biochemistry ofPlants Vol. 7. Secondary Plant Products, pp. 668-723. Academic Press.
0
TRIGONELLINE
0031-9422/91 $3.00+0.00 1991 Pergamon Prms plc
IN COFFEE
PAULO MAZZAFERA Institute of Biology, Unicamp CP6109, Campinas (SP), 13081, Brasil (Received in revisedform 30 November 1990) Key Word Index-Co&q
Rubiaceae; coffee; analysis; trigonelline.
Abstract-Seeds of ripened fruits of twenty-eight plants of Co&a, one of Psilunthus and two inter-specific hybrids of Cofia were analysed for trigonelline content in order to investigate the genetic variability.
~ODU~ON
Trigonelline, ~-methyl~taine of py~dine-3-car~xylic acid, is found in coffee seeds and its content depends on the coffee species Cl]. The importance of trigonelline in coffee is connected to nutritional aspects, as roasting causes its conversion to nicotinic acid (niacin) [2]. The nicotinic acid content of green coffee varies from I.6 to 4.4 mg per lOOg, increasing almost 10 times with roasting [l]. According to Tepley and Prier [3] the daily consumption of 3.5 cups of coffee can supply one-third of the minimum daily requirement of this vitamin, deficiency of which causes the disease pellagra. As to the quality of coffee beverage, Viani and Horman 12, 41 observed that among the products formed from trigonelline during roasting nine of them could be found in the flavour. However, little is known about the variability of the trigonelline content in seeds of coffee species. Yeransian et al. [5] showed that arabica green coffee contained ca lo!, robusta 0.7% and liberica 0.25% of t~gone~ine. From a compilation of the literature Macrae [l] found similar values. We present results of an analysis of seeds of ripened fruits of twenty-eight coffee trees comprising nine species of CoJka, one of Psilanthus and two inter-specific hybrids of Co@a. RESULTS AI’ll) DISCUSSION
Part of the trigonelline found in coffee seeds is transformed into nicotinic acid during roasting [2, 41. The previous knowledge of trigonelline content in coffee beans should permit the estimatation of the potential of nicotinic acid in the roasted coffee. The results in the Table 1 show that among the species studied, C. canepkora cv Guarini had the highest trigonelline content and the cultivars of C. dewevrei, a well defined group, the lowest values. Excluding cultivars Laurina and Semperflorens, all other coffee trees of C. arabica contained t~gonelline around 2%. It is interesting to note that C. arabica cv Laurina, which has low caffeine and oil content [6] was the one that had least trigonelline in the arabicas analysed. However, as the coffee trees Mokka ‘LrLr’ and Mokka ‘I&, that differ from laurina alelles, showed the same level of trigonelline, the influence of this genetic factor on the level of the substance could not be shown. In addition to PRY
30:7-o
arabica trees, the values found for the other species showed a genera1 variability in trigonelline content. Data on trigoneiiine in green coffee are scarce in the literature. Kogan et al. [7] determined trigonelline by paper chromatography. More recently, Ferreira et al. [g] Table 1. Trigonelline content in seeds of coffee species Trigonelline* C. orabica cv Abramulosa 2 Bourbon Red Caripe Catuai Red Caturra Red Cioiccie Gliiucia Ibati Laurina Maragogipe Mokka ‘LrLr’ Mokka ‘lrlr’ Mundo Novo Red National SemperlIorens Sumatra Hibrido de Timor C. libericavar. Dewevrei C. dewevreicv Abeokutae Dibowskii Excelsa C. canephoru cv Guariui C. stenophylla C. salvatrix C. liberica C. racemosa C. brevipes Psil~~h~ trav~c~e~~~ C. arabicax C. libericu var. Dewevrei C. racemosax C. augenioides
2.31 2.06 2.30 2.48 2.23 2.11 2.40 1.97 1.52 2.06 2.19 2.24 2.13 1.81 2.90 2.37 2.39 1.37 0.88 0.84 0.77 3.08 1.89 1.21 1.01 2.31 2.23 1.33 1.72 1.92
*Results are average determinations in duplicate (g per 100g dry wt). tIncUed because Psilanthus was previously classified as Coffea section Paracofflka.
P. MAZZAFERA
2310
analysed this substance in arabicas and robustas by the iodometric method. The values found by these authors are lower than those we found, being no more than 1%. The extraction of trigonelline from coffee beans does not seem to be difficult because of its high solubility in hot water, and the recovery of trlgonelline from Sep-Pak cartridges was 100%. For chromatography, isocratic running was best performed with buffer alone. In this running condition it was seen that nicotinic acid, that could interfere, eluted from the column in 7 min and trigonelline in 3.6 min. We believed that the differences among previous papers and our results arise from the methods used to determine trigonelline. Trugo et a!. [9] used HPLC to investigate trigonelline in instant coffee, concluding that the method was simple and reliable. According to Poulton [lo] during seed germination and early growth of several plants, trigonelline declines and pyridine nucleotides appear in the tissue, suggesting an involvement in the process as a precursor of NAD. We did not find any relation between seed size and trigonelline content in the seeds of the species analysed here. EXPERIMENTAL
The seeds used in this study were kindly supplied from the germplasm bank of the Institute AgronBmico at Campmas. Dry seeds finely groud were extracted with hot H,O (95”, 250mg per IOOml) for 10 min. After cooling, the vol. was adjusted and samples were run m Sep-pak Cl8 cartridges (Waters Associates) and eluted with NaOAc 0.5%, pH 5.0.
Determinations of trigonelline was done by HPLC using a ODS-Hypersil 5 pm column (4.6 mm x 25 cm). with NaOAc 5% pH.5 as isocratic solvents (flow rate 1 ml min- ‘) and UV monitor 272 nm. The areas obtained m an integrator-recorder were compared
with those of standard
solns of trigonelhne
REFERENCES 1. Macrae, R. (1985) m Coffee Vol. 1. pp. 115-152. Elsevier. 2. Viani, R. and Horman, I. (1974) .I. Food SCL 39, 1216. 3. Tepley, L. J. and Prier, R. F. (1957) Publication No. 24. The Coffee Brewing Institute, New York. 4. Viani, R. and Horman, I. (1975) in Colloquium International sur la Chimie du Cafp (ASIC), VIII, pp. 273-278. Hambourg. 5. Yeransian, J. A., Kadin, H. and Berker, E. (1963) Assoc. Anal. Chem. 46, 3 15. 6. Tango, J. S. and Carvalho, A. (1963) Bragantw (Brasil) 22, 793. 7. Kogan, L., Dicarlo, F. J. and Maynard, W. E. (1957) Anal. Chem. 25, 1118. 8. Ferreira, L. A. B., Villar, H., Fragoso, M. A. C., Agmar, M. C., Cruz, M. J. R. and Gorqalves, M. N. (1971) in Colloquium International SW la Chimie du Cafe (ASIC), V, pp. 128-147 Lisbonne. 9. Trugo, L. C., Macrae, R. and Dick, J. (1983) J. Sci. Food Agrrc. 34, 300. 10. Poulton, J. E. (1981) in The Biochemistry ofPlants Vol. 7. Secondary Plant Products, pp. 668-723. Academic Press.