Co-preparation of pectin and cellulose from apple pomace by a sequential process

Abstract

Apple pomace contains a plentiful pectin and cellulose resource which coexist with lignin and hemicellulose by a complex chemical and physical association in the plant cell walls. To increase the value and promote the utilization of apple pomace, it was used to produce pectin and cellulose by chemical treatments. In the case of 110 min, 10% (w/w) acetic acid and 100 °C, extraction yield of pectin reached 19.6%. Response surface methodology was applied to determine the main factors affecting the lignin removal rate (LR). LR was optimal at 70 °C, pH 4.0 and 6.0% NaClO₂ concentration for 2 h in a 20% (w/v) ratio. These conditions removed 89.8% lignin from depectinated apple pomace followed by sodium hydroxide treatment for the cellulose. Cellulose was achieved more than 80.7%. Consequently, a large-scale experimental analysis showed that 196.0 g of pectin and 243.9 g of cellulose (90.4% purity) was collectively prepared from 1000 g of apple pomace.