Simultaneous Determination of Some Biochemical Contents of Coffee Arabica (Coffea arabica L.) Varieties and Correlation with Organoleptic Cup Quality in Contrasting Altitudes in Southwest Ethiopia

Abstract

Coffee is one of the most important agricultural commodities. The objective of this study was to simultaneously determination the biochemical constituents (caffeine, chlorogenic and nicotinic acids) and correlation with organoleptic cup quality of commonly grown coffee Arabica varieties in contrasting altitude of Southwest Ethiopia. A rapid and validated HPLC Diode Array Detector method was used for the simultaneous determination of targeted analytse in green and roasted coffee beans. The moisture content and pH were recorded from 10.13±0.04 to 12.49±0.08 and 5.36±0.04 to 5.81±0.04 respectively. The results of the chemical analysis showed that caffeine content in green coffee varieties was ranged from 12.34±0.08 mg/g (high altitude) to 19.89±0.28 mg/g (low altitude), chlorogenic content was also recorded 27.17±0.38 mg/g (high altitude) to 39.18±0.24 mg/g (low altitude) and nicotinic acid was ranged from 7.13±0.52 mg/g (low altitude) to 10.16±0.75 mg/g (high altitude). The caffeine content in roasted coffee varieties was ranged from 13.93±0.29 (high altitude) to 20.88±0.14 mg/g (low altitude) and chlorogenic content was recorded 8.56±0.02 (high altitude) to 16.21±0.10 mg/g (low altitude) and nicotinic acid ranged from 8.76 ±0.11 mg/g (high altitude) to 6.34±0.031 mg/g (low altitude). A highly significant decrement was observed in chlorogenic acid content after roasting, as altitude increases the caffeine and chlorogenic acid decreased. In contrary, nicotinic acid increase as altitude increase in green coffee varieties. As can be concluded from the result, as altitude increases caffeine and chlorogenic acid decreases but nicotinic acid increase. The caffeine content in green beans was lower as compared to roasted beans; significant degradation of chlorogenic acid was observed after roasting beans of the same variety. There was a significant interaction between altitude and coffee varieties on chemical constituents of coffee. These chemical contents could be used for coffee discriminators of coffee varieties and different altitudes. A highly significant correlation was also observed between biochemical contents and cup quality evaluation with altitude.

Keywords: key word Altitude, Coffee, Varieties’

DOI: 10.7176/FSQM/93-03

Publication date: January 31^st 2020