Proximate Composition, Antioxidant Activity, Mineral and Lipid Profiling of Spent Coffee Grounds Collected in Morocco Reveal a Great Potential of Valorization

Purpose Spent coffee grounds (SCGs) are a great pollution hazard towards the environment. However, SCGs may offer important opportunities of valorization. Here, we aimed at assessing SCGs valorization potential through physicochemical characterization. Methods Proximate composition and SCG oil physicochemical traits were determined using official analytical methods. Mineral profiling was performed using inductively coupled plasma optical emission spectrometry. Total phenolic (TPC) and flavonoid content (TFC) along with antioxidant activity were also determined. Results Proximate composition varied greatly among samples: Oil content (8.58 +/- 0.01-18.55 +/- 0.01%), protein content (13.87 +/- 1.12-16.12 +/- 1.30%), ash content (2.16 +/- 0.01-3.61 +/- 0.01%), and carbohydrates content (61.76 +/- 1.21-70.37 +/- 1.21%). Major elements were K (8323.23 +/- 974.00), Ca (6181.18 +/- 500.67), and Mg (2526.51 +/- 204.64 mg kg(-1)). SCGs oil was rich in linoleic acid (43.20 +/- 2.19%), palmitic acid (31.78 +/- 2.02%), and oleic acid (12.68 +/- 1.15%). Likewise, beta-sitosterol was the most abundant sterol (44.70 +/- 0.01%). SCGs contained important TFC (up to 32.18 + 0.41 mg QE g(-1)) and TPC (up to 57.48 +/- 0.10 mg GAE g(-1)) with great antioxidant activity as revealed by ABTS (up to 2.22 +/- 0.01 mmol TE g(-1)), DPPH (up to 92.12 +/- 0.22%) and FRAP (up to 93.94 +/- 6.19 mg TE g(-1)) as well as DPPH IC 50 (up to 53.73 +/- 1.03 mu g mL(-1)). Conclusion SCGs, given their investigated physicochemical properties, present promising valorization opportunities for environment, food industry, pharmaceutical fields and agricultural sector. [GRAPHICS] .