![]() ![]() Similarly, TRG is an alkaloid contributing to the aroma of the brew and is a precursor for the formation of different classes of volatile compounds during roasting ( Flament, 2001). During coffee roasting CAF is remained chemically stable except for minute reduction ( Hečimovič et al., 2011). , 2006).ĬAF is an alkaloid compound responsible for bitterness of the coffee brew ( Farah et al., 2006). Accordingly, correlations between coffee cup quality and some chemical attributes may be used as additional tools for evaluation of coffee quality ( Farah et al. These biochemical components of coffee are aroma precursors. Considerable variation of CAF, CGA, sucrose and TRG contents were observed in Arabica coffee ( Silvarolla et al., 2004). ![]() More than 950 compounds have been identified after roasting ( Yeretzian et al., 2003) the amount and types of compounds reported being dependent on location, roasting degree and analytical methods used.Ĭaffeine (CAF), chlorogenic acids (CGA), sucrose and trigonelline (TRG) are known biochemical compounds of coffee which have been used for characterization of coffee species ( Ky et al., 2001). Moreover, most compounds related to the aroma of coffee are produced by partial destruction of the green bean during roasting through the process of pyrolysis, degradation and Maillard reaction. Green coffee biochemical composition primarily depends on genetic variation and bean maturation ( Yigzaw et al., 2008). Though quality is an inherent factor, the interaction between environment and genetic diversity can play the major roles in determining the physical, organoleptic and biochemical compositions of coffee beans ( Mohammed et al., 2018).Ĭoffee is consumed for its stimulating and refreshing effects, which is influenced by a complex mixture of biochemical constituents. The genetic makeup of coffee and growing environmental conditions activate genes responsible for aroma precursors expressed during the roasting process ( Yigzaw et al., 2007). Overall, coffee quality attributes and biochemical composition vary with genetic variation, environmental gradients, agricultural practices and postharvest processing techniques ( Yigzaw et al., 2008). More importantly, quality determines the relative price of coffee as frequently observed in the current world market, where supply exceeds the demand. The country possesses a diverse genetic base and other natural factors that favor coffee productivity and quality.Ĭoffee quality is one of the key criteria that can help producers win global coffee market. Moreover, coffee production is a vital business and wealth creation opportunity that contributes to poverty reduction in major coffee producing areas of Ethiopia ( Abu, 2015). Coffee is still the leading export commodity, contributing about 25% of commodity export revenues (~5% GDP) of Ethiopia ( USDA-FAS, 2018). Arabica coffee is native to Southwestern Ethiopia and continues to serve as the main source of export earnings in the national economy, contributing decisively to the country's foreign exchange ( Taye et al., 2011). The global coffee production is dominated by Arabica coffee ( Coffea arabica L.) with a share of 64.5% ( ICO, 2017). Biochemical compositions can be used in predicting the quality of coffee and has special importance in determining the quality of coffee diversity in the BenchMaji and Sheka zones.Ĭoffee is one of the most economically important agricultural commodities worldwide ( Jeszka-Skowron et al., 2015). Correlations between cup quality and some chemical composition of coffee vividly showed that the biochemical content of beans can significantly influence coffee quality. Due to roasting, trigonelline, chlorogenic acids and antioxidant activity were lower in roasted coffee as compare to green coffee. Antioxidant activity of green and roasted coffee showed highly significant differences across districts. The result on dry matter basis range of trigonelline, chlorogenic acids and caffeine varied from 0.80 to 1.08 g/100g, 2.80–5.42 g/100g and 0.85–1.73 g/100g of green coffee, respectively. Significant variation in trigonelline, chlorogenic acids and caffeine content were observed among coffee samples. To determine biochemical compositions and antioxidant activity in green and roasted coffee and their correlation with cup quality samples were collected from nine districts of BenchMaji and Sheka zones. Coffee quality can be expressed by physical, organoleptic as well as biochemical compositions. Quality is a key criteria that can help producers win the global coffee market.
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