Fatty acid composition and sensory properties as descriptors of differentiation of specialty coffees based on spontaneous and induced processing methods

Abstract

The composition of fatty acids (FA) and sensory properties of specialty coffees from Guatemala, Nicaragua, Peru, Ethiopia, Kenya, Burundi, and Rwanda processed by spontaneous methods (i.e., natural, washed, and honey) and induced methods (i.e., anaerobic fermentation and carbonic maceration) were determined. Palmitic, stearic, oleic, linoleic, linolenic, and arachidic acids and 10 important attributes of the coffee such as fragrance/aroma, flavour, aftertaste, acidity, body, balance, overall, uniformity, clean cup, sweetness, and total score were evaluated. The FA composition and sensory scores following the Specialty Coffee American Association protocols were used to differentiate 19 coffee samples based on the processing method. Principal component analysis (PCA) effectively differentiated coffees processed by spontaneous methods from those processed by induced methods. Notably, Peruvian coffee processed by carbonic maceration exhibited the highest linoleic acid content, while the same coffee processed naturally showed the highest palmitic acid content. All coffee samples scored 10 points for uniformity, clean cup, and sweetness. The highest total scores for the spontaneous processing methods were 88.75 (washed Kenyan) and 87.75 (washed Ethiopian) but ranged from 82.75 to 85.00 for the other coffees. For the best specialty coffees processed by induced methods, scores ranged from 87.25 to 88.00 in seven out of nine coffees. Coffees from different geographical areas processed with innovative methods, such as anaerobic fermentation, carbonic maceration, and high-scoring spontaneously processed coffees, were among the highest qualities.