Development of a green extraction technique to obtain natural bioactive compounds from Alperujo, an agro-industrial by-product

MARAULO, GASTÓN EZEQUIEL; LIONELLO, MELINA; DOS SANTOS FERREIRA, CRISTINA; MAZZOBRE, M. FLORENCIA

Viena

Conferencia; ISEKI e-conference series: Food Quality and Texture in Sustainable Production and Healthy Consumption; 2020

There is a growing consumer demand for foods formulated with natural bioactive compounds to replace synthetic additives or provide nutraceutical value. Vegetables and agro-industrial wastes are promising sources of these compounds, but their extraction is generally associated with time-consuming techniques or to the use of organic solvents that cause damage to the environment. Argentina has been increasing olive oil production in the last years. Alperujo (ALP), a waste product of the olive oil process, is obtained in massive quantities each year by this seasonable and geographic concentrated production. Due to the oil extraction process, many of the phenolic compounds present in the fruit remain in the alperujo. It also has high levels of organic and mineral matter, critical acidity and salinity; therefore, its disposal is difficult and could affect the ecosystem. Sometimes ALP is treated with organic solvents to extract their bioactive compounds, but it may also result in environmental pollution. Cyclodextrins (CD), oligosaccharides with a cone truncated spatial geometry, can encapsulate bioactive compounds. The use of CD solutions for extraction processes is currently being studied to promote the obtention of both hydrophilic and hydrophobic compounds in a single stage, with the advantage of being a safe and non-polluting method. Compared to organic solvents extraction, the CD-assisted water-based method is environmentally sustainable, being safe, green, and economical. In this sense, our research aims to optimize green extraction techniques to obtain bioactive compounds from different vegetable sources studying the solvent potential of aqueous CD solutions. Particularly, we optimized the ultrasound-assisted extraction of bioactive compounds from alperujo using β-cyclodextrin (BCD) aqueous solutions. The extraction efficiency was evaluated measuring the total phenolic compounds by the Folin-Ciocalteu assay and the antioxidant activity with DPPH method. The optimal extraction conditions which maximize the antioxidant activity and the phenolic content of the extracts were: solution of BCD 15 mM, ultrasonication time of 10 min, and stirring time of 21 h at 60 °C. The extracts were freeze-dried, and the physicochemical, thermal, and sensorial stability of the powders was studied. The BCD presence in the freeze-dried extract decreased the lightness, hygroscopicity and stabilized the color. This optimized method avoids using organic solvents, reduces processing times, and could generate added value to an industrial waste of difficult disposal. Although basic valorization strategies are mostly accepted worldwide, the effectiveness of creating value from waste remains quite limited. The presented results can positively impact the three pillars of sustainability of olive oil production. Green and sustainable methods can effectively recover bioactive compounds from agroindustrial wastes to formulate healthy and innovative food products.