Valorisation of olive processing waste for the development of value-added products

In our study, olive leaves derived from oil mills waste, were used as a source of valuable bioactive compounds with great anti-aging and antioxidant activities. More specifically, spray drying under optimized conditions was used for the encapsulation of an enzymatically modified olive leaf extract in order to preserve its quality for further valorisation. Morphology, particle size distribution, identification of the type of interaction between core and wall materials, thermal stability and encapsulation efficiency (EE) were studied for the produced encapsulation system. Subsequently, the microparticles were incorporated in a cosmetic formulation which was subjected to oscillatory, heat stability and microbiological tests and to a food supplement that was subjected to an in-vitro dissolution test. The physicochemical characterization of the encapsulation product showed generally spherical particles, physically entrapped in the polymeric matrix with satisfactory thermal properties, sensitivity to high humidity conditions and an EE of 81.34%. Regarding the cream formulation, it passed successfully the 6-months microbiological test and showed great heat stability after placed for 1, 2, 3 and 6 months in four temperatures (from 5 to 45 °C) with little or no differences in pH, appearance and microscopic structure. Finally, concerning the supplement, the dissolution test showed that the main release of the extract occurred in the small intestine, indicating that this, for the most part, oil mills waste, can be transformed into a great source for the development of value-added products with nutritional, health and antioxidant benefits.