Green Enzymatic Decaffeination of Robusta Coffee Using Bromelain from Pineapple Peel for Sustainable Processing
Robusta coffee contains relatively high levels of caffeine, so consumption should be limited due to potential health risks if consumed excessively. This condition drives the development of effective, safe, and sustainable decaffeination technologies. Enzymatic decaffeination using a crude bromelain extract from pineapple peel offers a green chemistry approach that uses natural biocatalysts and agricultural waste. This study aimed to determine the optimal concentration of crude bromelain extract to reduce caffeine content in Robusta coffee beans and to evaluate its effects on moisture content, ash content, pH, and color brightness. A completely randomized design with one factor and six bromelain concentrations (0–50%) with three replications was applied. Data were analyzed using analysis of variance followed by Duncan’s multiple range test at a significance level of 0.05. The results showed that increasing bromelain concentration consistently reduced caffeine content from 2.74% to approximately 0.21% at 5% concentration. The pH and color brightness decreased as the enzyme concentration increased. The moisture content increased but remained below the national quality standard, whereas the ash content decreased, indicating mineral leaching during the enzymatic process. A crude bromelain concentration of 50% was considered practically optimal, achieving significant caffeine reduction with manageable physicochemical changes. These findings highlight the potential of scalable, efficient green decaffeination to support a sustainable, low-caffeine Robusta coffee industry.