Monomers, Materials and Energy from Coffee By-Products: A Review

Abstract

In recent years, the circular economy and sustainability have gained attention in the food industry aimed at recycling food industrial waste and residues. For example, several plant-based materials are nowadays used in packaging and biofuel production. Among them, by-products and waste from coffee processing constitute a largely available, low cost, good quality resource. Coffee production includes many steps, in which by-products are generated including coffee pulp, coffee husks, silver skin and spent coffee. This review aims to analyze the reasons why coffee waste can be considered as a valuable source in recycling strategies for the sustainable production of bio-based chemicals, materials and fuels. It addresses the most recent advances in monomer, polymer and plastic filler productions and applications based on the development of viable biorefinery technologies. The exploration of strategies to unlock the potential of this biomass for fuel productions is also revised. Coffee by-products valorization is a clear example of waste biorefinery. Future applications in areas such as biomedicine, food packaging and material technology should be taken into consideration. However, further efforts in techno-economic analysis and the assessment of the feasibility of valorization processes on an industrial scale are needed.

Potential Uses of Spent Coffee Grounds in the Food Industry

“…Recent reports and reviews on the use of SCG and other coffee processing by-products are available [ 85 ], including applications in the fabrication of construction materials [ 86 ], cosmetics [ 87 ], recovery of bioactive substances [ 88 ], biopolymers and biocatalysts [ 89 , 90 ], food packaging [ 91 ], materials and energy [ 92 ], as well as multiple uses considering a biorefinery approach [ 5 , 93 , 94 , 95 , 96 , 97 , 98 , 99 ]. In the next sections, we will comment on the latest findings on applications of SCG that are of particular interest for the food industry.…”

“…Recent comprehensive reviews are available in the scientific literature on the topic of composite materials produced with spent coffee grounds and other coffee by-products that could be used for food applications [ 91 , 92 , 143 ].…”

Estímulos e barreiras para a economia circular no setor alimentício

“…Um exemplo são as biorrefinarias (BOROWSKI, 2021), agentes relevantes na recuperação de energia limpa e renovável (OVERTURF et al, 2020;WEBER;TRIERWEILER;TRIERWEILER, 2020). É possível, mais especificamente, a utilização de sobras de grãos de café para produzir biodiesel, bioetanol, óleo, carvão ou biogás (SISTI et al, 2021).…”

Durability of biopolymeric composites formulated with fillers from a by‐product of coffee roasting

“…Coffee is the most widely cultivated product in the world and consequently it deserves a large interest. [ 21–23 ] Antioxidants and other valuable chemicals [ 24,25 ] have been obtained from coffee wastes, and coffee grounds have been used as fillers in composites based on poly(butylene adipate‐ co ‐terephthalate) (PBAT), [ 26 ] polypropylene, [ 27 ] cellulose, [ 28 ] PLA, [ 29 ] polyhydroxybutyrate (PHB). [ 30 ]…”

“…Those bioactive compounds can be extracted and further used for food, cosmetic and nutraceutical purposes. [ 23,32,33 ] SSK is also reported as feedstock for biofuel production, adsorbent material to remove potential toxic metal in water, for composting and soil fertilization. [ 32,33 ] Some recent studies have been made to promote SSK recycling as reinforcement in sustainable composites.…”