Jurnal Rekayasa Proses
Vol 20 No 1 (2026): Volume 20, Number 1, 2026

Characterization of caffeine crystals obtained from the extraction process of green robusta coffee beans

Tri Hariyadi (Politeknik Negeri Bandung)
Ayu Ratna Permanasari (Politeknik Negeri Bandung)
Iwan Ridwan (Politeknik Negeri Bandung)
Bambang Soeswanto (Politeknik Negeri Bandung)
Teguh Taufiqurohim (Politeknik Negeri Bandung)
Unung Leoanggraini (Politeknik Negeri Bandung)
Fania Hidayati (Politeknik Negeri Bandung)
Renata Naomi Cinta Sedjati (Politeknik Negeri Bandung)
Mentik Hulupi (Politeknik Negeri Bandung)



Article Info

Publish Date
09 Jun 2026

Abstract

Robusta coffee contains a higher caffeine content, ranging from 1.6–2.4%, nearly twice as much as Arabica coffee, which contains only 0.9–1.2%. Caffeine content is widely utilized in various fields, such as pharmaceuticals and the food and beverage industry. This study aims to analyze the effect of temperature and time on the solid–liquid extraction process of green coffee beans, as well as to evaluate the effectiveness of two different solvents in the liquid–liquid extraction process for obtaining caffeine crystals. Solid–liquid extraction was carried out at temperature variations of 70°C, 80°C, 90°C, and 97°C, with durations of 30 minutes, 45 minutes, 60 minutes, 75 minutes, and 90 minutes. Liquid–liquid extraction was performed using two types of organic solvents, namely chloroform and dichloromethane. The results were analyzed by measuring caffeine purity using a melting point apparatus and high-performance liquid chromatography (HPLC) based on retention time parameters, as well as determining caffeine concentration using a UV–Vis spectrophotometer. The optimum temperature and time for solid–liquid extraction were found to be 97°C for 60 minutes. Liquid–liquid extraction yielded a caffeine content of 2.18 mg/g using chloroform, and 1.38 mg/g using dichloromethane. Based on melting point and HPLC retention time testing, the caffeine crystals obtained from liquid–liquid extraction with dichloromethane showed higher purity, with a melting point of 236°C and a retention time of 2.06 minutes. These values are close to those of pure caffeine, which has a melting point of 236°C and a retention time of 2.01 minutes, compared to the caffeine crystals obtained using chloroform.

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Journal Info

Abbrev

jrekpros

Publisher

Subject

Chemical Engineering, Chemistry & Bioengineering

Description

Jurnal Rekayasa Proses is an open-access journal published by Chemical Engineering Department, Faculty of Engineering, Universitas Gadjah Mada as scientific journal to accommodate current topics related to chemical and biochemical process exploration and optimization which covers multi scale ...