Black locust flowers as a natural source of antioxidants: Sustainable production of high-quality oil from plum by-product and its incorporation in the moisturizing cream

Abstract

This study presents a challenge in terms of the development of cleaner technologies and sustainable development. The main effort was invested in the improvement of oxidative stability of plum seed oil using an eco-friendly and easy-to-use procedure (maceration). The fixed oil of plum seeds is composed of unsaturated fatty acids that are very sensitive to oxidative processes, but the addition of antioxidants can solve this problem. Since the obtained oil was further applied for the preparation of topical formulation, the aim was to avoid the use of toxic solvents and the process of their evaporation during the extraction of antioxidants from plant material. The way to overcome this problem was to directly use oil for the extraction of non-polar antioxidants from black locust flowers. The reason of use this plant material was due to its pleasant odor and high content of antioxidants. The maceration was carried out at the different temperatures (25, 40, and 60 °C) and the liquid-to-solid ratio of 10 mL/g for 48 h. After the extraction, the reducing capacity of the fixed oils was determined using a standard spectrophotometric method with Folin-Ciocalteu reagent. The extraction process was described using two kinetic models, Ponomaryov and non-stationary diffusion models. The optimal extraction time and temperature were 16 h and 60 °C, respectively, for the extraction of antioxidants. Thus obtained oil with improved stability was incorporated in the moisturizing cream to develop an innovative topical formulation that can be used against the harmful effects of the environmental factors. During the oil stabilization, the addition of synthetic antioxidants was omitted so that the application of natural antioxidants was favored. This was acceptable from an ecological point of view because in this way the planting of black locust trees will be intensified and thus the carbon dioxide emissions will be reduced. • The fixed oil of plum seeds was obtained from the industrial by-product. • The plum seed oil was enriched with antioxidants from black locust flowers. • A sustainable procedure was proposed for the improvement of oil stability. • The innovative moisturizing cream with fixed oil of plum seeds was designed.