On the Path to Sustainable Cosmetics: Development of a Value-Added Formulation of Solid Shampoo Incorporating Mango Peel Extract

The excessive use of water and plastic packaging in the cosmetic industry imposes the need to develop sustainable alternatives. Moreover, agricultural by-products are reported in the literature to be rich in bioactive properties, namely high antioxidant capacity, suggesting their potential use in cosmetic formulations as substitutes for commercial additives. The aim of this work was the development of a sustainable formulation of solid shampoo, incorporating extracts from mango peel as antioxidants. The characterization of the extracts revealed the presence of several phenolic compounds and a strong antioxidant capacity. Six formulations of solid shampoo were produced by varying the quantity of the additives: tocopherol and butylated hydroxytoluene, used as positive controls, and mango peel (MP) extract. The antioxidant capacity assays demonstrated that the MP extract increased the antioxidant activity of the shampoos, in comparison to the positive controls and the stability tests revealed that the MP extract is a stable ingredient. Hence, it was concluded that the MP extract is a strong source of antioxidants with the potential to replace commercial antioxidants in cosmetics. Thus, it was possible to develop a value-added formulation of solid shampoo, eliminating the use of water and plastic for the packaging, and reusing waste from the food sector.