As more shoppers demand natural and sustainable cosmetics, researchers in Poland have assessed the feasibility of incorporating spent coffee grounds into cosmetic scrubs and examined the effectiveness of natural emulsifiers apricot kernel oil, soya lecithin, and olive oil to stabilise the emulsion.
Coffee is a widely used product in the food and drink industry. Yet, according to the study’s authors, only about 30% of the coffee bean’s mass is utilised to transform into a coffee drink. This means that a large fraction of the bean ends up as spent coffee grounds, which are mainly disposed of as waste.
The study, which aimed to investigate the physical characteristics, stability, and consumer sensory perceptions of the emulsions and scrubs, came to the conclusion that spent coffee grounds are a good option for cosmetic applications, with gentle abrasive properties and a naturally pleasant aroma.
The study
For the research, the spent coffee grounds were dried and sieved to achieve the optimal particle size for use in scrubs, which was between 150 and 300 micrometres.
Among the three tested emulsifiers, apricot kernel oil showed the most consistent stability and superior performance compared to soya lecithin and olive oil.
The emulsions made with the apricot kernel oil emulsifier remained stable throughout the study period and effectively incorporated additional ingredients like glycerine and castor oil.
In contrast, the soya lecithin emulsions were incompatible with other components and delaminated within a week.
The results also indicated that the choice of emulsifier directly affected the cosmetic scrub’s physical properties, including viscosity and texture.
The researchers concluded that the spent coffee grounds with an apricot kernel oil emulsifier in scrub formulations was the optimum choice for a stable product to meet consumer preferences for natural and eco-friendly ingredients.
Overall the emulsions had a creamy texture and a pleasant coffee aroma. There were no significant changes in colour or odour and the samples stayed sterile over the observation period, indicating good preservative efficacy and formulation safety.
Source: Cosmetics
https://www.mdpi.com/2079-9284/12/1/31
“Preparation of Cosmetic Scrub Bases from Coffee Waste and Eco-Friendly Emulsifiers”
Waldemar Szaferski and Marcin Janczarek
First published 19 February 2025