Food Science and Quality Management www.iiste.org ISSN 2224-6088 (Paper) ISSN 2225-0557 (Online) Vol.46, 2015 19 Sensory Attributes of Coffee under Different Shade Regimes and Levels of Management Danstan Odeny 1 George Chemining'wa 2 Solomon Shibairo 2 Cecilia Kathurima 1 1.Coffee Research Institute, P.O. Box 4-00232, Ruiru 2.Department of Plant Science and Crop Protection, University of Nairobi, P.O. Box 29053-00625, Nairobi Abstract Despite coffee bean physical and beverage quality attributes being inherent factors, the environment, which includes crop management factors, can play a major role in determining their expression. This study was conducted to evaluate the effect of management and shade levels on beverage quality of coffee. The study was carried out at the Kenya Agricultural and Livestock Research Organization, Coffee Research Institute (KALRO- CRI) farm in Bungoma County, Kenya. The coffee management levels were categorized depending on field operations and application of inputs. The different shade levels were based on the distances from the trunk of shade tree and shading levels were estimated by measuring the Photosynthetic Photon Flux Density (PPFD) in µmol m-2 s-1 using a Line Quantum Sensor. The sensory characteristics fragrance/aroma, flavor, aftertaste, acidity, body, balance and overall were assessed by a panel of seven trained judges. The beverage quality, except for acidity and balance, were largely unaffected by management or shade levels, however trends showed that most of the variables, on average, had higher scores in shade than in full sun. Shade was positively correlated with all sensory variables while management was negatively correlated with all. This suggested that use of shade, under low management, could offset the limited application of external inputs to some extent. Keywords: Coffea arabica, shade, management levels and quality 1. Introduction Coffee beverage quality, which is intimately related to its taste and aroma, is an important attribute of coffee that generates consumer satisfaction (Muschler 2001; Petracco 2001; Agwanda et al. 2003; Chalfoun et al. 2013). It is also often referred to as cup or liquor quality and is used as a measure for price determination (Gichimu et al. 2012). The beverage quality is based on the characterization of numerous factors such as fragrance and aroma, flavour, aftertaste, acidity, body, balance, overall and total score (Kathurima et al. 2009). Coffee beverage quality is assessed organoleptically (organoleptic relates to attributes perceptible by the senses) by trained coffee tasters (van der Vossen 1985; Agwanda 1999). There has been an emergence of a market for quality coffee which explains the increasing interest in research on environmental factors and local production systems that affect quality (Avelino et al. 2007). The international markets are also increasingly indicating demand for quality– differentiated coffee (Oberthur et al. 2011). The market success of the international specialty coffee industry, including rapidly increasing numbers of small to medium roasters of high quality coffee beans and several chains of upmarket coffee houses provide evidence that consumers are more discerning about beverage quality and are willing to pay for it (Pendergrast 1999). A coffee tree in good growing conditions tends to produce larger beans with better flavour (Wintgens 2004). Climate, altitude, and shade have a strong influence on flowering, bean expansion, and ripening through their effect on temperature, availability of light and water (Carr 2001; Decazy et al. 2003). Shade, or conditions that provide lower air temperatures such as higher elevations slow down the ripening process of coffee berries allowing more time for complete bean filling (Vaast et al. 2006) resulting in bigger beans that are denser and far more intense in flavour than those grown under lower altitudes or under full sunlight. The slower maturation process, therefore, plays a central role in ensuring high cup quality, possibly by guaranteeing the full manifestation of all biochemical steps required for the development of the beverage quality (Silva et al. 2005). Other authors (Muschler 2004; Geromel et al. 2008; Bote & Struik 2011; Somporn et al. 2012) have reported similar positive effects of shade on coffee bean size and beverage quality. Kathurima et al. (2012) recognized the significant contribution of the shade to the increased premium grades, AA and AB, which are highly valued in the coffee trade in Kenya but found no clear gain on the sensory quality parameters. Studies have also shown that different shade tree species affect the sensory quality differently. Shade also reportedly reduces the portion of rejects which include diseased, mummified or dried berries. In Costa Rica, Muschler (1998) reported that rejects accounted for up to 10% in the un-shaded samples and less than 1% under shade. Excessive use of nitrogen, while it increases production, has been reported to reduce bean density and quality. In South America, Dessalegn (2005) reported that coffee grown with heavy application of nitrogen fertilizer had poorer, lighter and thinner body than that from unfertilized fields. A high concentration of calcium and potassium in beans has been associated with a bitter and “hard” taste while no correlation has been reported between phosphorus and the physical and organoleptic quality of the bean (Northmore 1965). A study by Foote (1963) showed that nutrient deficiencies may decrease cup flavour. On the other hand, Pochet (1990)