The effect of roasting temperature on ferulic acid levels of robusta coffee bean with thin layer chromatography (TLC)-densitometry

The purpose of this study was to quantitatively analyze ferulic acid levels of Robusta coffee bean extracts from two samples from different regions (Argopuro and Kaliwining, Jember District), with different roasting temperatures (180 °C and 200 °C for 10 minutes) using Thin Layer Chromatography (TLC)-Densitometry method. The analytical method used was the TLC-Densitometry, which utilized methanol solvent p.a; stationary phase: Merck silica Gel 60 F254 plate; chloroform mobile phase: methanol: formic acid (v/v/v) = (85:15:1) in a saturated chromatographic chamber; the test concentration of 50 ppm and the plates were analyzed with the Densitometry winCATS Camag scanner using a UV-Vis detector at 254 nm wavelength and blue fluorescence at 366 nm wavelength. The results showed that the standard correlation coefficient (R) of ferulic acid was 0.9947. Quantitative analysis of ferulic acid levels obtained on the average results of Argupuro coffee bean extract at roasting temperatures 180 °C and 200 °C amounted to 1.935598±0.020671 mg/g and 1.419963±0.051633 mg/g, while Robusta Kaliwining coffee bean extract at 180°C and 200°C roasting temperature were 3.18087±0.06738 mg/g and 2.420237±0.1989 mg/g. Statistical analysis with One-Way Anova obtained p value <0.005. Least Significant Different Test (LSD) obtained p value <0.005 in each group. Based on the statistical analysis it was concluded that there was an effect of roasting temperature on ferulic acid levels in Robusta coffee bean extract, with the highest ferulic acid content obtained in Robusta Kaliwining coffee bean extract in Jember Regency at roasting temperature of 180 °C was 3.180875±0.020671 mg/g.