Quality characteristics and acrylamide content of commonly sold coffee brands in Kenyan markets

Abstract

Coffee, a globally cherished beverage, has diverse nutritional and health benefits. However, the composition of the beverage varies with each cup, influenced by factors such as bean type and the addition of ingredients. Acrylamides, known to be carcinogenic and genotoxic, are found in processed coffee beans, causing concern over its consumption. This study determined the levels of acrylamides found in the commonly sold coffee brands in Kenyan markets, alongside other quality characteristics. The study was conducted in Nairobi and Kiambu Counties, where different samples of local and imported coffee brands were purposefully obtained from each sub-county. The physicochemical characterization of coffee samples including moisture content, total ash, acid insoluble ash, water-soluble ash, alkalinity of soluble ash, water-soluble matter, petroleum ether extract, and the concentration of acrylamide, Fe, Zn, P, Ca, Mg, K, Na, and caffeine were analysed at the Department of Food Science and Technology, University of Nairobi. Obtained data was analysed using statistical software R. The results showed significant differences in acrylamide concentration (F (11, 156) = 4.86, p < 0.001), calcium content (F (11, 156) = 2.74, p = 0.003), magnesium content (F (11, 156) = 2.52, p = 0.006), and caffeine concentration (F (11, 156) = 4.47, p < 0.001) among the different coffee brands. However, no significant differences were observed for the other characteristics (p > 0.05). The means of moisture content was 5.8%, total ash 5.8%, acid insoluble ash 0.4%, water soluble ash 79.5%, alkalinity of soluble ash 3.4mg/L, water soluble matter 47.9%, petroleum ether extract 13.8%, and acrylamide concentration 0.071 µg/100g. The mean of Fe was 7.822, Zn 6.954, P 40.669, Ca 65.596, Mg 117.588, K 222.956, Na 4.663, and Caffeine content was 0.0832, all in mg/100g. Differences especially in the level of acrylamide across the brands is a major concern. The study highlights the need for quality control measures in the coffee industry to ensure consistent quality and safety for consumers. This can go a long way in empowering individuals with insights into their coffee's nutritional worth and potential effects on their wellbeing, safeguarding its quality and health benefits. Key words: Coffee, Quality characteristics, Acrylamides, Coffee brands, Nutritional worth, well-being