RT info:eu-repo/semantics/article T1 Production of molecular weight fractionated hemicelluloses hydrolyzates from spent coffee grounds combining hydrothermal extraction and a multistep ultrafiltration/diafiltration A1 Ramos Andrés, Marta A1 Andrés Iglesias, Cristina A1 García Serna, Juan K1 Coffee K1 Polysaccharide AB Spent coffee grounds are a huge residual stream from instant coffee makers. The production of spent coffee oil and molecular weight fractionated hemicellulose hydrolysates via supercritical CO2 and a hydrothermal treatment followed by concentration, separation, and purification through cascade ultrafiltration/diafiltration (30-10-5 kDa) was studied. Hemicelluloses extraction yield reached 3.49 g/100 g of dry defatted spent coffee after 40 min at 160 °C. The ultrafiltration system allowed concentrating up to 5-fold certain groups of hemicellulose, being most of them retained in the first membrane. Hemicellulose concentration and molecular weight of the feed exerted a great influence on the mass transfer through the membrane due to the formation of aggregates. However, purification through diafiltration allowed both to decrease by-products retentions from 45.6% to 8.7%, increasing the molecular weight of each fraction. Six hemicellulose products were obtained with purities between 83.7 and 97.8 wt% and weight-average molecular weights between 1641 and 49,733 Da. PB Elsevier SN 0960-8524 YR 2019 FD 2019 LK http://uvadoc.uva.es/handle/10324/43722 UL http://uvadoc.uva.es/handle/10324/43722 LA eng NO Bioresource Technology Volume 292, 2019, 121940 NO Producción Científica DS UVaDOC RD 24-nov-2024