Perbandingan Aktivitas Antioksidan dan Kadar Asam Klorogenat Kopi Arabika Brazil dengan Kopi Arabika Indonesia

Abstract

Kandungan antioksidan dalam kopi dapat dipengaruhi oleh jenis, tingkat sangrai, dan asal kopi. Meta-analisis sebelumnya menunjukkan bahwa kopi Arabika dari Brazil yang disangrai pada tingkat light (ringan) dan medium memiliki aktivitas antioksidan tertinggi. Namun, hasil tersebut perlu dilakukan verifikasi melalui uji antioksidan in-vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic (ABTS), dan ferric ion reducing antioxidant power (FRAP). Kopi Arabika Brazil dibandingkan dengan lima kopi Indonesia yang berasal dari daerah penghasil kopi Arabika terbesar tahun 2020, yaitu Sumatera Utara, Aceh, Sulawesi Selatan, Jawa Barat, dan Jawa Timur yang mempunyai kopi Arabika khas masing-masing, Mandailing, Gayo, Toraja, Java Preanger, dan Java Ijen-Raung. Penelitian ini bertujuan memverifikasi hasil meta-analisis penelitian sebelumnya, mengidentifikasi biji kopi Indonesia yang berpotensi memiliki aktivitas antioksidan yang tinggi atau setara dengan kopi Brazil serta kandungan senyawa total fenol dan asam klorogenatnya, dan mengidentifikasi hubungan kandungan asam klorogenat dengan aktivitas antioksidannya. Penelitian dilakukan dilakukan melalui tiga tahapan, yaitu persiapan sampel, verifikasi hasil meta-analisis, serta analisis asam klorogenat dan total fenol sampel kopi. Sampel biji kopi hijau (Brazil dan Indonesia) dibeli dari distributor Indonesia. Kopi disangrai pada tingkat medium yang lebih banyak dikonsumsi dibanding tingkat sangrai light. Kopi digiling, diseduh, dan hasil seduhan digunakan untuk analisis antioksidan, total fenol, dan asam klorogenat. Pengukuran sifat fisik meliputi warna, dimensi, densitas, dan massa 100 biji kopi. Nilai L* kopi sangrai berada di rentang 29,84–32,68 yang tidak berbeda nyata menunjukkan keenam kopi mengalami proses penyangraian yang sama. Kopi yang telah disangrai juga mengalami pertambahan ukuran panjang, lebar, tinggi, dan volume namun densitas dan massa 100 biji kopi menjadi lebih kecil. Rerata nilai total padatan terlarut (TPT) adalah 2,09 g/100 mL. Hasil pengujian antioksidan menunjukkan bahwa kopi Brazil memiliki aktivitas antioksidan DPPH IC50 tertinggi (4,38 mg TPT/mL) dan sesuai dengan hasil meta-analisis, sedangkan pada uji ABTS IC50 dan FRAP menunjukkan hasil yang berbeda. Keenam kopi memiliki aktivitas antioksidan ABTS IC50 yang tidak berbeda, sedangkan kopi Gayo memiliki aktivitas antioksidan FRAP terbesar (82,47 g TEAC/100 g TPT). Kopi Gayo memiliki potensi untuk dipilih sebagai kopi dengan aktivitas antioksidan yang dapat lebih tinggi atau setara kopi Brazil berdasarkan nilai FRAP. Kopi Toraja memiliki total fenol dan kadar asam klorogenat terbesar. Namun besarnya nilai total fenol dan asam klorogenat tidak membuat kopi Toraja memiliki aktivitas antioksidan terbesar. Kondisi ini disebabkan karena asam klorogenat mengalami degradasi menjadi senyawa fenolik lain selama penyangraian sehingga asam klorogenat tidak menjadi senyawa antioksidan utama dalam sampel kopi sangrai medium. Pemetaan biji kopi dilakukan melalui Principal Component Analysis (PCA) menegaskan bahwa kopi Gayo mempunyai potensi yang setara sebagai sumber antoksidan dengan kopi Brazil, meskipun dengan mekanisme yang berbeda.

The antioxidant content in coffee was influenced by the type, roast level, and origin of coffee. A previous meta-analysis indicated that Arabica coffee from Brazil that was roasted to light and medium levels had the highest antioxidant activity. However, these results needed to be verified through in-vitro antioxidant tests, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic (ABTS), and ferric ion reducing antioxidant power (FRAP) tests. Brazilian Arabica coffee was compared to five Indonesian coffees from major Arabica coffee-producing regions in 2020, namely North Sumatra, Aceh, South Sulawesi, West Java, and East Java, each with their distinct Arabica coffee varieties, namely Mandailing, Gayo, Toraja, Java Preanger, and Java Ijen-Raung. This research aimed to verify the results of the previous meta-analysis, identify Indonesian coffee beans with the potential for high or equivalent antioxidant activity to Brazilian coffee, as well as their total phenol and chlorogenic acid content, and identify the relationship between chlorogenic acid content and their antioxidant activity. The research was conducted in three stages, including sample preparation, verification of the meta-analysis results, and the analysis of chlorogenic acid and total phenol in the coffee samples. Green coffee bean samples (from Brazil and Indonesia) were purchased from an Indonesian distributor. The coffee was roasted to a medium level, which is more commonly consumed compared to light roast levels. The coffee was ground, brewed, and the brew was used for antioxidant, total phenol, and chlorogenic acid analysis. Physical properties, including color, dimensions, density, and the mass of 100 coffee beans, were measured. The L* values of the roasted coffee were in the range of 29.84–32.68, which did not significantly differ, indicating that all six coffees underwent the same roasting process. The roasted coffee also experienced an increase in length, width, height, and volume, but a decrease in density and mass of 100 coffee beans. The mean value of total soluble solids (TSS) was 2.09 g/100 mL. The antioxidant test results showed that Brazilian coffee had the highest DPPH IC50 antioxidant activity (4.28 mg TSS/mL), consistent with the meta-analysis results, while the ABTS IC50 and FRAP tests showed different results. All six coffees had similar ABTS IC50 antioxidant activities, whereas Gayo coffee had the highest FRAP antioxidant activity (82.47 g TEAC/100 g TSS). Gayo coffee had the potential to be selected as coffee with higher or equivalent antioxidant activity compared to Brazilian coffee based on the FRAP value. Toraja coffee had the highest total phenol and chlorogenic acid content. However, the high total phenol and chlorogenic acid content did not make Toraja coffee have the highest antioxidant activity. This was because chlorogenic acid degraded into other phenolic compounds during roasting, making chlorogenic acid not the main antioxidant compound in medium-roasted coffee samples. Coffee bean mapping through Principal Component Analysis (PCA) confirmed that Gayo coffee had the potential to be an antioxidant source equivalent to Brazilian coffee, albeit with different mechanisms.