Dry powder formulations from olive oil wastewater with high nutraceutical properties

Objectives The olive oil extraction process leads to a high amount of olive oil waste water (OW), a rich source of polyphenolic compounds that can exert a wide range of beneficial effects on human health, most of them due to polyphenolic compounds antioxidant properties [1, 2]. In order to minimize the impact to the environment and to valorize the sustainable development of several local products, a concentrated solution from OW was obtained and, starting from this solution, we developed a stable dry powder formulation which maintains its high nutraceutical properties. Methods On the concentrated olive oil wastewater, here called HP30, a preformulation study was performed in order to select the appropriate excipients in terms of solubility, viscosity and dispersibility of the systems. In particular, we tested four different excipients, here called E1 (polysaccharide), E2 (polysaccharide), E3 (oligosaccharide) and E4 (desiccant) and after the above mentioned studies we selected the three giving better results, i.e. E1 E3 and E4. Different amounts of the selected excipient were used to obtain the formulations from HP30, called F1 (5% E1, 10% E3), F3 (5% E1, 30% E3), F1b (5% E1, 10% E3, 2% E4) and F3b (5% E1, 30% E3, 2% E4), respectively. DSC studies were carried out to evaluate the thermal properties of the prepared formulations and to optimize the freeze-drying process. All obtained formulations were characterized by the Folin assay to analyze the polyphenols content with respect to the HP30 and by stability studies. Results The HP30, a concentrated solution from the OW was treated to obtain stable solid formulations with high nutraceutical properties. After preliminary studies we selected three excipients and we prepared four different formulation called F1, F3, F1b and F3b. All formulations were obtained by an optimized freeze-drying process. From a macroscopic point of view all powders showed a light brown colour, they had good flow properties with respect to the sticking HP30 powder and they resulted stable up to five months storage under normal conditions of humidity and temperature. The Folin assay, carried out on the formulations, did not show significant differences in term of polyphenolic amount with respect to the HP30 for the formulations F1 and F1b, while a reduction of 20 % w/w was evidenced on F3 and F3b powders. So, we can assume that the freeze-dryied process is an useful method to obtain solid formulations from the OW not significantly modifying the composition of the principal components and that F1 and F1b are promising nutraceutical product obtained from olive oil wastewater. References: [1] Casamenti F. & Stefani M. “Olive polyphenols: new promising agents to combat aging-associated neurodegeneration” Expert Review of Neurotherapeutics, 2016 [2] Cornwell D, “Nutritional benefit of olive oil: the biological effects of hydroxytyrosol and its arylatingquinone adducts” Journal of agricultural and food chemistry, 2008