Detection of the Electrical Conductivity and Acidity of Honey from Different Areas of Tepi
Honey is the ingredient of most industrial products for sweetening and improving its food composition. The study is therefore based on the determination of physical parameters such as electrical conductivity and acidity. The instrumentation and apparatuses used in the work are conductometry and titration apparatuses. Honey samples obtained from different areas with respect to Tepi town have been analyzed and the result obtained is on the basis of conductometry and acidity measurement. Hence 20g of each anhydrous honey sample was weighed and dissolved in 100mL of deionized water in order to prepare 20 %( w/v) solution to measure conductivity. The acidity is detected after 10g of each honey sample is dissolved in 75mL of deionized water. The conductivity in summer honey determined to be 0.097mS/cm, 0.153mS/cm 0.117mS/cm and 0.337mS/cm in Korcha, Mexi, Sheko and Gobito respectively. Acidity is found to be 17, 28.67, 29 and 25miliequi/Kg. The conductivity in winter honey is detected to be 0.123, 0.186, 0.103 and 0.246mS/cm. The acidity in winter honey is 3.36-4.26 and 18.3-25.3meq/Kg from pH meter and titration respectively. The conductivity of darker honey is slightly greater than lighter honey, which indicated that the darker honey has more mineral content; and acidity of three honey samples is almost similar. The honey products are safe and fit the international honey commission standard and probably both darker and lighter honey are nutritionally important.
Honey and its physical parameters
e aim of this study was to find how close relations exist between the results of microscopic analysis, optical rotation and electrical conductivity in 55 honey samples from the Czech Republic. e obtained results were to be interpreted in relation to the classification of honey samples according to their origin (honey groups: blossom, honeydew and compound honey). e relations were positive, very close (r > 0.80) and very highly significant (P < 0.001). Several analysed samples would have been inserted into honey groups wrongly if only conductivity had been measured. is fact and high correlation coefficients evidence that exact classification of honey must be car - ried out not only by measuring the conductivity but also on the basis of optical rotation and microscopic analysis - namely in transition intervals of conductivity between the particular honey groups.
Development of new analytical methods for the determination of caffeine content in aqueous solution of green coffee beans
BackgroundThis study was conducted to develop fast and cost effective methods for the determination of caffeine in green coffee beans. In the present work direct determination of caffeine in aqueous solution of green coffee bean was performed using FT-IR-ATR and fluorescence spectrophotometry. Caffeine was also directly determined in dimethylformamide solution using NIR spectroscopy with univariate calibration technique.ResultsThe percentage of caffeine for the same sample of green coffee beans was determined using the three newly developed methods. The caffeine content of the green coffee beans was found to be 1.52 ± 0.09 (% w/w) using FT-IR-ATR, 1.50 ± 0.14 (% w/w) using NIR and 1.50 ± 0.05 (% w/w) using fluorescence spectroscopy. The means of the three methods were compared by applying one way analysis of variance and at p = 0.05 significance level the means were not significantly different. The percentage of caffeine in the same sample of green coffee bean was also determined by using the literature reported UV/Vis spectrophotometric method for comparison and found to be 1.40 ± 0.02 (% w/w).ConclusionNew simple, rapid and inexpensive methods were developed for direct determination of caffeine content in aqueous solution of green coffee beans using FT-IR-ATR and fluorescence spectrophotometries. NIR spectrophotometry can also be used as alternative choice of caffeine determination using reduced amount of organic solvent (dimethylformamide) and univariate calibration technique. These analytical methods may therefore, be recommended for the rapid, simple, safe and cost effective determination of caffeine in green coffee beans.