ABSTRACT
Honey contains a wide range of inorganic substances. Their content can be influenced, i.e., by the type of soil on which the bee pasture is located. As part of this study, the mineral profile of 32 samples of honey from hobby beekeepers from the Czech Republic wasevaluated and then compared with soil types in the vicinity of the beehive location. Pearson's correlation coefficient was used to express the relationship between mineral substances and soil type. There was a high correlation between antroposol and Zn (R = 0.98), Pb (R = 0.96), then between ranker and Mn (0.95), then regosol and Al (R = 0.97) (p < 0.05). A high negative correlation was found between regosol and Mg (R = -0.97), Cr (R = -0.98) and between redzinas and Al (R = -0.97) (p < 0.05). Both positive and negative high correlations were confirmed for phaeozem. The CART method subsequently proved that the characteristic elements for individual soil types are B, Ca, Mg, Ni, and Mn. The soil types of cambisol, fluvisol, gleysol, anthrosol, and kastanozem had the closest relationship with the elements mentioned, and it can therefore be assumed that their occurrence indicates the presence of these soil types within the range of beehive location.
ABSTRACT
The aim of this study was to determine the effect of various methods of processing, such as natural, washed, honey, anaerobic fermentation, and carbonic maceration, on the contents of heavy metals in green and roasted specialty coffees from various countries of origin (Ethiopia, Kenya, Rwanda, Burundi, Guatemala, Nicaragua, and Peru). The heavy metals aluminium (Al), nickel (Ni), chromium (Cr), cadmium (Cd), copper (Cu), and lead (Pb) were identified by a multi-element technique using inductively coupled plasma mass spectrometry. Mercury (Hg) content was determined by atomic absorption spectrometry. The processing method affected the contents of Hg, Al, Ni, Cr, Cd, and Pb in the green and roasted coffees (p < 0.001). Hg content varied in the green coffees processed by fermentation methods vs natural or washed methods (i.e. Rwandan and Guatemalan coffees). Cd content was highest in Guatemalan green coffee processed using carbonic maceration (0.062 mg/kg). Pb content differed between the Ethiopian and Rwandan roasted coffees, with the highest content in the washed method (0.252 mg/kg). The correlations between the contents of Cu and Al, Ni and Cr, and Pb and Cr were significant for both the roasted and green beans. In conclusion, the method of processing can affect the contents of heavy metals in green and roasted specialty coffees. Monitoring heavy metals when processing coffee with new methods, even though further processing such as roasting can substantially reduce their content in some cases, is therefore important.
ABSTRACT
The aim of this study was to determine the effect of roasting on the contents of polyphenols (PPH), acrylamide (AA), and caffeine (CAF) and to analyze heavy metals in specialty coffee beans from Colombia (COL) and Nicaragua (NIC). Samples of NIC were naturally processed and COL was fermented anaerobically. Green beans from COL (COL-GR) and NIC (NIC-GR) were roasted at two levels, light roasting (COL-LIGHT and NIC-LIGHT) and darker roasting (COL-DARK and NIC-DARK), at final temperatures of 210 °C (10 min) and 215 °C (12 min), respectively. Quantitative analyses of PPH identified caffeoylquinic acids (CQA), feruloylquinic acids, and dicaffeoylquinic acids. Isomer 5-CQA was present at the highest levels and reached 60.8 and 57.7% in COL-GR and NIC-GR, 23.4 and 29.3% in COL-LIGHT and NIC-LIGHT, and 18 and 24.2% in COL-DARK and NIC-DARK, respectively, of the total PPH. The total PPH contents were highest in COL-GR (59.76 mg/g dry matter, DM). Roasting affected the contents of PPH, CAF, and AA (p < 0.001, p < 0.011 and p < 0.001, respectively). Nickel and cadmium contents were significantly higher in the COL-GR than in the NIC-GR beans. Darker roasting decreased AA content, but light roasting maintained similar amounts of CAF and total PPH.