Valorization of spent coffee grounds as the specialty material for dullness and aging of skin treatments

Abstract

Abstract Background Coffee beans contain oil with health benefits from fatty acids. The unprocessed and processed coffee beans are mostly identical in coffee oil quality and are substantively supplied for certain industries. However, the cost-effective valorization of specialty ingredients from spent coffee grounds for cosmetics is sparely presented. Linoleic acid-rich spent coffee oil, as a specialty material for skin lightening and antiaging cosmetics, is objectively to be presented. Results Spent coffee oils were prepared by different methods. The most cost-effective material with a high extraction yield, linoleic acid content and unsaturated/saturated fatty acid (UFA/SFA) ratio (13.21 ± 0.25, 32.09% and 0.97) was modified. The modified oil was boosted in linoleic acid (77.20% or 140.57% improvement) and the UFA/SFA ratio (33.12). The physicochemical properties of the oil were applicable for cosmetics as per its safety profiles in B16F10 melanoma and normal human skin fibroblast cells. The oil significantly better inhibited cellular melanogenesis than kojic and linoleic acids (p < 0.01), with prominent tyrosinase and TRP-2 inhibitions. The cellular antioxidant activity of the oil was comparable to those of ascorbic and linoleic acids. The collagen stimulating efficacy of the oil was significantly better than that of ascorbic but comparable to that of linoleic acid as indicated by the MMP-2 inhibitory activities (p < 0.01 and p < 0.001, respectively). Conclusions The oil is a specialty material for skin brightening and skin wrinkle reduction/skin elasticity improvement products. A successive circular bioeconomy of spent coffee ground waste in a more profitable cosmetic industry is indicated. Graphic abstract

Keywords

• Spent coffee grounds
• Fatty acids
• Cosmetics
• Cellular biological activity
• Specialty material
• Biological residues