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Title:Vsebnost kofeina v kavnih zrnih in kavnih napitkih : diplomsko delo
Authors:ID Zajšek, Nika (Author)
ID Kristl, Janja (Mentor) More about this mentor... New window
ID Ivanuš, Anja (Comentor)
Files:.pdf VS_Zajsek_Nika_2025.pdf (1,54 MB)
MD5: AFAB6E0B43676C331B509639A56DC7E1
 
Language:Slovenian
Work type:Bachelor thesis/paper
Typology:2.11 - Undergraduate Thesis
Organization:FKBV - Faculty of Agriculture and Life Sciences
Abstract:Kofein je naravni alkaloid iz skupine metilksantinov in sodi med najpogosteje zaužite psihoaktivne spojine na svetu. V diplomskem delu je določena vsebnost kofeina v 30 vzorcih kave, od tega je 28 vzorcev sorte Coffea arabica, en vzorec Coffea canephora (robusta) in en vzorec mešanice obeh vrst. Ekstrakcija kofeina iz zmletih vzorcev je izvedena z dodatkom 40 ml vode na 45 mg mlete kave in z vrenjem 30 min. Iz mlete kave sta pripravljena napitka espreso in turška kava. Koncentracija kofeina je določena s tekočinsko kromatografijo (LC). Rezultati pokažejo, da espreso vsebuje več kofeina na napitek (56,7 ± 1,2 mg/napitek) kot turška kava (40,5 ± 0,8 mg/napitek), medtem ko je izkoristek ekstrakcije višji pri turški kavi (75,7 ± 0,7 %) kot pri espresu (60,3 ± 1,0 %). Svetlo praženi vzorci vsebujejo več kofeina (14,4 ± 0,4 mg/g) kot srednje praženi (12,2 ± 0,4 mg/g). Vpliv metode predelave ni enoznačen, saj sta koncentraciji suhe in mokre metode različni glede na način priprave napitka. Interakcija med metodo predelave in stopnjo praženja ni statistično značilna, pri turški kavi pa se pokaže kot mejno značilna (p = 0,080). Za potrditev interakcije bi bilo potrebno dodatno preverjanje z večjim številom vzorcev.
Keywords:kava (Coffea spp.), kofein, kavni napitki, ekstrakcija kofeina, HPLC
Place of publishing:Maribor
Place of performance:Maribor
Publisher:N. Zajšek
Year of publishing:2025
Number of pages:1 spletni vir (1 datoteka PDF (VI, 45, [2] str.))
PID:20.500.12556/DKUM-94878 New window
UDC:663.93:543(043.2)=163.6
COBISS.SI-ID:253069059 New window
Publication date in DKUM:14.10.2025
Views:192
Downloads:58
Metadata:XML DC-XML DC-RDF
Categories:FKBV
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Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:28.08.2025

Secondary language

Language:English
Title:Caffeine in Coffee Beans and Coffee Beverages
Abstract:Caffeine is a natural alkaloid from the methylxanthine group and one of the most widely consumed psychoactive substances in the world. In this work, the caffeine content was determined in 30 coffee samples, including 28 samples of Coffea arabica, one sample of Coffea canephora (Robusta), and one sample of a mixture of both species. Caffeine was extracted from ground coffee by adding 40 ml of water to 45 mg of coffee and boiling the mixture for 30 minutes. Two beverages were prepared: Espresso and Turkish coffee. The caffeine concentration was determined using liquid chromatography (LC). The results show that espresso contained more caffeine per serving (56.7 ± 1.2 mg/serving), while the extraction yield of Turkish coffee (75.7 ± 0.7 %) was higher than that of espresso (60.3 ± 1.0 %). Light roasted samples contained more caffeine (14.4 ± 0.4 mg/g) than medium roasted samples (12.2 ± 0.4 mg/g). The effect of the processing method was not uniform, as the differences between dry and wet processing varied depending on the brewing method. The interaction between processing method and roast level was not statistically significant; however, it was borderline significant for Turkish coffee (p = 0,080). Further studies with a larger number of samples would be required to confirm this interaction.
Keywords:coffee (Coffea spp.), caffeine, coffe beverages, caffeine extraction, HPLC


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