Potential Utilization of Unavoidable Food Supply Chain Wastes–Valorization of Pea Vine Wastes

Combating food waste is a vital 21st century global challenge befitting of green and sustainable chemistry. Prevention is the first and foremost route for reduction of food waste, but inevitably, there are unavoidable food losses as a result of primary and secondary processing that represents an interesting green and sustainable chemistry valorization opportunity. Herein, pea vine waste (Pisum sativum) as an unavoidable food supply chain waste is explored as the source for (bio)­renewable chemicals and materials and as a potential bioenergy source. Through a cascade approach simulating a potential biorefinery, pea vine waste was subjected to pseudosubcritical water extraction as a green extraction methodology technique to extract potential platform molecules: 5-hydroxy furfural (HMF); ethanoic acid; sugars (levoglucosenone, rhamnose, xylose, fructose, glucose and sucrose); and a precipitated biopolymer showing pectinaceous and starch-like characteristics as evidenced by infrared spectroscopy, solid-state ¹³C NMR, and thermogravimetric analysis. The postextraction residues of pea vine waste were further subjected to microwave pyrolysis to produce a bio-oil and a biochar. The bio-oil is rich in phenolic compounds while the biochar has a gross calorific value of 26.6 MJ kg^–1 and thus may be used as a potential source of bioenergy. While peas alone have been explored previously, the work within represents the first study of valorization of pea vine wastes, a real as-received industrial problematic waste source, using a cascade approach of pseudo-sub-critical water and microwave pyrolysis simulating a potential biorefinery