Citrus Pomace Biomass as a Source of Pectin and Lignocellulose Fibers: From Waste to Upgraded Biocomposites for Mulching Applications

Citrus pomace derived from the industrial processing of juice and essential oils mostly consists of pectin, cellulose, hemicellulose, and simple sugars. In this work, citrus pomace waste from an agricultural company in South Italy was used as source of pectin. The extraction conditions of the polysaccharide were optimized using a suitable combination of time and a concentration of a mild organic solvent, such as acetic acid; thus recovering high M-w pectin and bioactive molecules (flavonoids and polyphenols). The pectin was structurally (GPC, FTIR), morphologically (SEM), thermally (TGA/DTG), and mechanically characterized, while bioactive molecules were separated and the total phenolic content (TPC) and total flavonoids content (TFC) were evaluated. With the aim to develop novel biocomposite-based materials, the pectin extracted from citrus waste was reinforced with different amounts of lignocellulose fractions also recovered from citrus waste after polysaccharide extraction, according to a zero waste circular economy approach. The prepared biocomposites were morphologically and mechanically characterized to be used as biodegradable mulching systems for crop protection. Thus, the citrus waste biomass was recovered, fractionated into its main raw materials, and these were recombined to develop novel upgraded biocomposites for mulching applications, by means of a cost-effective and eco-sustainable approach.

Automated summary

In this study, citrus pomace waste was utilized to extract high M-w pectin and bioactive molecules for the development of biodegradable mulching systems. Through a zero waste circular economy approach, lignocellulose fractions were used to reinforce the pectin, resulting in novel upgraded biocomposites for mulching applications, demonstrating a cost-effective and eco-sustainable method for recycling citrus waste biomass.