Coffee pectin production: An alternative way for agricultural waste management in coffee farms
Sunita Chamyuang, Amorn Owatworakit, Uraiwan Intatha, Sitthi Duangphet
Abstract
Chiang Rai Province is home to the largest Arabica coffee plantation, accounting for 16% of coffee plantation in Thailand. During the green bean production from coffee cherries, 45% of the coffee pulp is treated as agricultural waste. This study aimed to increase the value of the coffee cherry pulp by using it as an alternative source of pectin. A double extraction process was used to extract pectin: in the first extraction, acid was used to extract the coffee pulp, followed by the second extraction with base. Both acid and base solutions yielded from the extractions were combined prior to the pectin precipitation step. The pectin yield from this double extraction method was 2-fold higher than that yielded from previous methods. Furthermore, to reduce toxicity during the extraction method, we use citric acid to replace hydrochloric and nitric acids. Among three heating conditions during extraction: boiling, autoclave, and microwave, the boiling method gave the highest pectin yield at 15.9%. Unlike the high methoxyl pectin (HMP) yield from citrus, the coffee pectin from the boiling and microwave-assisted methods was categorized as the low methoxyl pectin (LMP). The LMP from coffee cherry can be used as prebiotic supplement or in wound dressing film production. Importantly, producing LMP not only has the potential to reduce post-harvest agricultural waste by 3800 tons per year in Chiang Rai Province but also provides value to agricultural waste and additional income to coffee growers.