The coffee mineral profile during extraction

The aim of the study is to research the profile of mineral elements in coffee grounds formed during double extraction of coffee. The objects of the study are samples of ground roasted Arabica and Robusta coffee, 7 g of which were extracted with 100 ml of artesian bottled drinking water Aqua Balt. The resulting coffee grounds KG1 were subjected to the second extraction under the same conditions, obtaining coffee grounds KG2. Coffee, KG1 and KG2 were ashed to a constant weight, then the profile of mineral elements in them was determined by the X-ray spectral method on an EDX-7000P X-ray fluorescence spectrometer, SHIMADZU. Arabica and Robusta coffee differed in the mass fraction of ash by 1.23 times, in which 10 mineral elements were identified. The profile of mineral elements included: K > P > Ca > S > Mg > Fe > Mn > Cu > Rb > Zn. In the coffee grounds obtained after the first extraction (KG1), the mass fraction of ash increased for Arabica by 7.7 %; robusta – by 7.3 %, in which the amount of K and Rb decreased, and the amount of other elements increased. The profile of mineral elements of KG1 changed – the amount of Ca began to prevail over the amount of P. The second extraction resulted in a decrease in the mass fraction of ash in the coffee grounds KG2 compared to KG1, but it prevailed compared to coffee, and the profile of mineral elements had a form identical to KG1, in which K prevailed, amounting to 49.86 and 56.59 %, re-spectively, for Arabica and Robusta, despite a decrease in its amount by 47.4 % compared to coffee and by 19.1 % compared to KG1 Arabica and by 28.9 and 11.9 %, respectively, for Robusta. The use of dry coffee grounds KG1 and KG2 in the amount of 10 % in the production of flour confectionery products will enrich them with macroelements (K, P, Ca, Mg) up to 4 %, microelements (Fe, Mn, Cu) – by 6–36 %.