Caffeine Content of Retail Market Coffee in Portugal

Abstract

How much caffeine does one ingest when drinking a simple cup of coffee in Portugal? The study presented herein tried to answer this question through the assessment of caffeine content of commercially available espresso coffee samples, both caffeinated and decaffeinated, using a high-performance liquid chromatography assay. Caffeine was rapidly separated from the sample matrix using a RP-18 column (250×4 mm i.d., 5 μm). The flow rate was 1.0 mL/min and the mobile phase consisted of water acidified with 5% of orthophosphoric acid/methanol (35:65, v/v). Caffeine was detected directly at 273 nm. The assay was validated for linearity, lower limit of quantification and limit of detection, precision, accuracy, and stability. Seventeen different brands of caffeinated coffee and six of decaffeinated coffee were analyzed. As for capsule coffee, eight caffeinated and two decaffeinated blends were analyzed. The caffeine content of caffeinated coffee varied from 53.8 ± 5.9 to 141.3 ± 5.3 mg/cup, whereas for caffeinated capsule coffee caffeine concentrations ranged from 45.0±5.3 to 60.8±6.2 mg/cup. As for decaffeinated coffee, caffeine concentrations ranged from 0.96 ± 0.04 to 3.9 ± 0.1 mg/cup and for decaffeinated capsule coffee from 0.93±0.04 to 1.2±0.1 mg/cup.

An examination of consumer exposure to caffeine from commercial coffee and coffee-flavoured milk

“…The expanded caffeine analysis conducted on commercial espresso coffee confirms that the mean caffeine content (107 mg/ serving) is higher than earlier international reports of 78, 35, 85 and 62 mg/serving, respectively by Barone and Roberts (1996), Harland (2000), Knight et al (2004) and Mandel (2002). These Australian values are in agreement with values found in retail coffees from the United Kingdom (105 mg/serving) (Food Standards Agency, 2004) and on home-prepared retail market coffee in Portugal (98 mg/serving) (Candeias et al, 2009). Consequently, any individual or population-based quantification of caffeine intake involving persons, who purchase retail coffee or use ground coffee varieties at home is prone to potential errors.…”

Investigation of extraction phenomena in continuous circulation coffee brewing and comparison with other brewing methods

“…Despite the growing interest and economic relevance of single‐serve brewing methods, there are relatively few scientific studies surrounding the topic. A majority of these studies examined the composition of drip and espresso brews produced with commercially available capsules and brewing systems (Albanese et al, 2009; Angelino et al, 2018; Bartel et al, 2015; Candeias et al, 2009; Gloess et al, 2013; Lopes et al, 2016; Parenti et al, 2014; Rahn & Yeretzian, 2019). Studies by Eiermann et al (2020) and Wang et al (2016) were the only existing literature to examine the extraction dynamics of single‐serve brewing as they relate to the properties of the packed bed and the physicochemical quality of the resultant brew.…”

Use of Multivariate Analysis Techniques for Evaluation of Analytical Data—Determination of the Mineral Composition of Cabbage (Brassica oleracea)

“…The determination of organic and inorganic nutrients in some cases may reveal the nutritional potential of new plants, as well as contribute to the formulation of food composition tables, which are used by nutritionists and doctors (Candeias et al 2009;Borah et al 2009). This way, many studies involving determination and evaluation of food composition have been performed with this objective (Uluozlu et al 2007;Divrikli et al 2003;Richert and Sneddon 2008).…”