Coffee Science - v.14, n.4, 2019
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/12725
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Item Application of coffee peel waste as raw material for xylooligosaccharide production(Editora UFLA, 2019-10) Ratnadewi, Anak Agung Istri; Masruroh, Handariatul; Suwardiyanto; Santoso, Agung BudiCoffee is the second most common trade commodity in the world after petroleum. The coffee industry generates large amounts of waste in the form of coffee peels. Coffee peel waste consist of lignocellulose containing hemicelluloses and other chemical compounds. The objective of this research was to extract xylan, the main component of hemicelluloses from coffee waste, and to utilize the xylan in the production of xylooligosaccharide (XOS). Xylan was extracted from coffee waste using NaOH solution and neutralized by HCl 6 M. Afterward, xylan was precipitated using ethanol. Various NaOH concentrations (4, 8, 12 and 16 % w/v) were used to obtain the xylan. NaOH solution with a concentration of 12 % results 43 % extraction of xylan from coffee waste. Xylan obtained from the extraction was hydrolyzed using endo-β-1,4-xylanase from Bacillus sp. to produce XOS. The incubation time of enzyme-substrate was observed at 40 oC, pH 5 and enzyme dose of 23.6 U. Thin layer chromatography results showed that the hydrolyzed products of xylan are XOS with composition xylobiose (X2), xylotriose (X3), xylotetraose (X4) and xylopentaose (X5). LC-MS studies revealed that X2 is the dominant product with the concentration of 6.00 ppm. This research demonstrates the potential to utilizate coffee peel waste as a source of xylan for the production of XOS.Item Coffee waste biochars: characterization and zinc adsorption from aqueous solution(Editora UFLA, 2019-10) Sertoli, Lindiamara; Carnier, Ruan; Abreu, Cleide Aparecida de; Coscione, Aline Renée; Melo, Leônidas Carrijo AzevedoThe final disposal of organic wastes has become a major challenge with increasing industrialization and population growth. Coffee wastes can be converted into biochar and provide economic and environmental benefits, such as heavy metal remediation in different media. We produced biochars at 700 °C from spent coffee grounds and coffee parchment, characterized them physically and chemically and evaluated their Zn adsorption capacity from aqueous solution. Batch adsorption experiments were performed with six Zn concentrations using four replicates. The desorption process was performed sequentially with a pH 4.9 buffer acetic acid solution. Langmuir and Freundlich isotherms were fitted to the adsorption data using non-linear models. Results show that both biochars are alkaline and have high values of point of zero charge (PZC) (9.2 and 7.7 for coffee parchment and spent coffee grounds biochar). These characteristics indicate precipitation as the main mechanism of Zn immobilization and may have contributed to the low adsorption capacity obtained (0.056 and 0.792 mg g-1 for spent coffee ground and coffee parchment biochar, respectively). Although the biochars have shown low adsorption capacity, they bound Zn strongly and the adsorption process is not easily reversed.