Spent coffee grounds: A review on current research and future prospects

• Most of the polysaccharides remain as insoluble material bound to the SCW.
• The essential amino acids comprise almost half (∼49%) of the total SCW amino acid.
• Caffeine obtained from SCW is equivalent up to 48% of those extracted from coffee beans.
• Lipids (90.2%) mainly remained in SCW.
• Innovative ideas are needed to use this low cost SCW and exploit its full potential.

Spent coffee ground (SCG) contains large amounts of organic compounds (i.e. fatty acids, amino acids, polyphenols, minerals and polysaccharides) that justify its valorization. Earlier innovation explored the extraction of specific components such as oil, flavor, terpenes, and alcohols as value-added products. However, by-products of coffee fruit and bean processing can also be considered as potential functional ingredients for the food industry. There is an urgent need for practical and innovative ideas to use this low cost SCG and exploit its full potential increasing the overall sustainability of the coffee agro-industry.