Utilization of coffee pulp for the production of sustainable cellulosic composite and plant-based hydrogel as a potential human wound dressing

Abstract

In this study, coffee pulp cellulose (CPC) was recovered from the coffee pulp biomass generated during wet processing of Arabica coffee using the following sequential extractions. As for screening, the Microarray Polymer Profiling (MAPP) was used to characterize the gylco The alcohol-insoluble fraction (AIF) was obtained from dried coffee pulp following by dichloromethane and ethanol to remove fat-soluble components. Ammonium oxalate extraction yielded insoluble dietary fiber, and lignin was removed from the pectin-free fraction using hydrogen peroxide and sodium borohydride. The resulting coffee pulp cellulose (CPC) was obtained after drying. Pectin was not detected in the cellulose fraction, indicating that the extraction was only partially successful in purifying the soluble and non-soluble polysaccharides. Structural damage and the presence of lignin and hemicellulose were also observed in the cellulose, as evidenced by its shredded morphology and Fourier Transform Infrared spectra. Cellulosic coffee pulp-based hydrogels were fabricated with of CPC ranging from 0.25 to 1.00 g with alginate and pectin as hydrophilic polymers and cross-linked by calcium chloride. The hydrogel with the lowest CPC concentration demonstrated a porous structure that allowed water molecules to diffuse into the material, causing it to swell or increase in size. The hydrogel with 0.38 g CPC had the highest maximum swelling degree (MSD), while incorporating CPC at 0.50 g resulted in the longest durability, as determined by the integrity value. The study found that all formulations of the hydrogel exhibited no toxicity towards HaCaT cells. This suggests the possibility of the industrial recovery of cellulose from underutilized materials, providing a sustainable solution to supply chain challenges.