Exploring the phytochemical profile and sensory properties of green and roasted Coffea arabica L. beans from diverse geographic regions [Articol]

Abstract

The aim of study was to evaluate the phytochemical quality indicators (dry matter, ash, crude protein, antioxidant activity, total flavonoids, polyphenols and phenolic acids) of 100% Arabica (Coffea arabica L.) from Brazil, Colombia, Bolivia, Tanzania, El Salvador and Cuba. The samples were first analyzed as raw green coffee and then after the roasting process (medium roast 240 °C, 14 minutes). The same measurements were then performed on the roasted coffee as on the green coffee, to compare the samples and draw attention to the changes that occur during the roasting process. Finally, a sensory analysis (color, taste, aroma) was performed (the coffee was served using the French press method). The total dry matter content in green coffee was on average 93.05%, the crude protein content was 13.07% and the ash content was 2.94%. Using the DPPH method was determined the antioxidant activity, which was in the range of 7.32 – 21.55 mg TEAC/g (TEAC – Trolox equivalent antioxidant capacity) and the total content of polyphenols was on average 45.65 mg GAE/g (GAE – gallic acid equivalent). Subsequently, we determined the total content of flavonoids on average 31.91 mg QE/g (QE – quercetin equivalent) and the content of phenolic acids on average 13.14 mg CAE/g (CAE – caffeic acid equivalent). This was followed by roasting and repeating all measurements, with which was found an increase in dry matter by 5.93% and ash by 0.19%. When determining the total crude protein, only imperceptible changes occurred. The most significant decrease was observed in polyphenols and flavonoids, the total contents of which decreased during roasting, since these are relatively thermolabile substances. The content of total polyphenols after roasting in the tested samples ranged from 26.58 to 34.36 mg GAE/g, which is a decrease of more than 25%. As for flavonoids, the value ranged between 10.56 and 17.79 mg QE/g. The antioxidant activity did not change significantly, since various other bioactive substances participating in the antioxidant activity formed during roasting. The crude protein content also did not change significantly. The sensory evaluation took place without problems and all samples were evaluated relatively positively, the respondents evaluated the color, aroma, taste.