Preparation and Extraction of Pectin from Robusta Coffee (Coffea canephora) Peel Waste as a Sustainable Agriculture Biomass

Department of Agricultural and Biosystems Engineering, Faculty of Agricultural Technology, Universitas Gadjah Mada Jl. Flora No. 1, Bulaksumur, Yogyakarta, 55281, Indonesia

Abstract

Indonesia is one of the top global coffee producers. In 2023, Indonesia produced high coffee productivity up to 760.2 thousand tons, primarily dominated by robusta coffee (Coffea canephora). However, this situation may raise significant environmental concerns regarding the disposal of coffee peel waste. About 0.18 tons of coffee peel waste is estimated to be generated per 1 ton of processed coffee beans, which needs proper waste management. Meanwhile, the coffee peel contains a valuable component of pectin that can be used in various applications to support circular economy and environmental sustainability. This study aimed to investigate the composition and characteristics of pectin extract from robusta coffee peel waste. Coffee peel sample was collected from Sambak Village, Magelang Regency, Central Java, Indonesia. The acid extraction method was applied to obtain pectin extract using a solvent of HCl (1 M) and alcoholic precipitation with ethanol (96%). About 6.23 ± 2.43 % of pectin yield on average was extracted per 100 g of dried coffee peel waste. FTIR test results confirmed the presence of functional groups of pectin characteristics at the peak points of 3320.46; 1731.69; and 164.92 cm^-1. These findings showed that the extracted pectin from coffee peel waste is one of the promising and sustainable ways to utilize agricultural biomass.