CD Tesis
Deteksi Kafein Pada Kopi Berbasis Biosensor Amperometris dan Principal Component Analysis
The demand for biosensor devices has increased in various commercial sectors and especially in research, particularly sensors capable of fast and reliable measurements. The detection of caffeine in coffee has been the subject of extensive research due to the increased consumption of food, beverages, and medications. Coffee consumption has become a lifestyle trend in society, often without consideration for the caffeine content, which can have implications for health. Caffeine levels produce varied side effects for each individual, but the recommended consumption levels for coffee range from low (~40 mg or ~0.5 mg/kg) to moderate (~300 mg or 4 mg/kg). Excessive caffeine intake can lead to high blood pressure, cardiovascular issues, and disruptions in the nervous system due to sustained consumption. Therefore, quantifying caffeine in beverages is essential for pharmaceutical, food, clinical tests, and requires reliable and accurate analytical methods.
In this study, caffeine was detected in three types of coffee varieties: Arabica, Robusta, and Liberika from Temanggung, using an amperometric biosensor with Saccharomyces cerevisiae yeast as the bioreceptor, based on the level of dissolved oxygen (DO) resulting from yeast cell metabolism. The solution concentrations were prepared in a ratio of 1:20 g/mL. Caffeine detection data in coffee were combined with the multivariate principal component analysis (PCA) method for accuracy and data visualization and validated using High-Performance Liquid Chromatography (HPLC) method.
The experimental results showed that when yeast was added with caffeine, there was a decrease in voltage values for each concentration of 400, 800, 1200, 1600, and 2000 mg/L by 0.63%, 2.01%, 2.80%, 4.18%, and 6.29%, respectively. The biosensor responses resulted in concentration conversions of 759.04 mg/L for Arabica, 588.96 mg/L for Liberika, and 1235.84 mg/L for Robusta. These biosensor data were compared with the HPLC method, showing very small difference with an error rate < 2%. Clustering and visualizing caffeine measurement data using PCA resulted in a total variance of 92.1% for PC1 and PC2, with PC1 contributing 72.1% and PC2 contributing 20.1%.
Based on the conducted experiments, the amperometric biosensor can be used for caffeine level measurements in various coffee samples, demonstrating good biosensor characteristics
Kata kunci : Amperometric biosensor, Saccharomyces cerevisiae, caffeine, Temanggung coffee, principal component analysis
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