Perbandingan Asam Fenolat dan Total Fenolik Kopi Arabika Bogor dari Pengolahan Pascapanen dan Tingkat Sangrai Berbeda

Abstract

Kopi mengandung senyawa fenolik, yang dapat dianalisis dari kandungan total fenolik atau senyawa fenolik tertentu. Komposisi dan konsentrasi fenolik dalam kopi dipengaruhi oleh proses pascapanen dan tingkat penyangraiant. Penelitian ini bertujuan untuk membandingkan rasio asam fenolat (diukur sebagai asam klorogenat) terhadap total kandungan fenolik dalam kopi arabika Bogor, dengan mempertimbangkan perlakuan pascapanen dan tingkat penyangraian yang berbeda. Sampel kopi diberikan perlakuan pascapanen (kering, basah, dan madu) dan penyangraian (ringan dan gelap). Proses penyangraian melibatkan pemanasan kopi pada suhu antara 147,9°C hingga 178,8°C untuk penyangraian ringan, dan 190,2°C hingga 200°C untuk penyangraian gelap (masing-masing selama 10 menit). Biji kopi hijau digunakan sebagai kontrol. Warna biji kopi, konsentrasi asam fenolik dalam ekstrak kopi, dan konsentrasi fenolik total dalam ekstrak kopi dianalisis dengan colorimeter, HPLC, dan spektrofotometer secara berturut-turut. Hasil penelitian menunjukkan bahwa penyangraian secara signifikan memperkuat warna gelap kopi arabika Bogor. Di antara asam fenolat, isomer 5-CQA muncul sebagai yang paling dominan dan juga paling rentan terhadap degradasi selama penyangraian. Seiring dengan peningkatan tingkat penyangraian, konsentrasi asam fenolat secara konsisten menurun. Kandungan total fenolik pada awalnya meningkat pada kopi ringan namun kembali menurun pada kopi gelap. Biji kopi hijau memiliki proporsi asam fenolat tertinggi (83%), sedangkan kopi gelap memiliki proporsi terendah (19%). Meskipun kopi ringan memiliki kandungan total fenolik tertinggi, konsentrasi asam fenolat menurun secara signifikan dibandingkan dengan biji kopi hijau.

Coffee contains abundant phenolic compounds, which can be evaluated either collectively as total phenolics or individually as specific phenolic components. The presence and amount of phenolics in coffee are influenced by various factors, including postharvest treatments and the roasting process. This study aimed to compare the ratio of phenolic acid, specifically chlorogenic acid, to the total phenolic content in Bogor arabica coffee, considering different postharvest treatments and roasting levels. The coffee samples underwent different postharvest treatments (dry, wet, and honey) and were subjected to two types of roasting processes (light and dark). Green coffee beans were used as the control. The roasting procedure involved heating the coffee within the temperature range of 147.9°C to 178.8°C for light roasting and 190.2°C to 200°C for dark roasting (each for 10 minutes). The color of the coffee beans, the concentration of phenolic acid in the coffee extract, and the total phenolic content in the coffee extract were analyzed using a colorimeter, high-performance liquid chromatography (HPLC), and spectrophotometer, respectively. The findings revealed that roasting significantly intensified the dark color of Bogor arabica coffee. Among the phenolic acids, the 5-CQA isomer emerged as the most dominant and was also the most susceptible to degradation during the roasting process. As the roasting level increased, the concentration of phenolic acid consistently decreased. Interestingly, the total phenolic content initially increased in light-roasted coffee but decreased in dark-roasted coffee. Green coffee beans exhibited the highest proportion of phenolic acid (83%), whereas dark-roasted coffee had the lowest proportion (19%). Although light-roasted coffee had the highest total phenolic content, its phenolic acid concentration decreased significantly compared to green coffee beans.