Introduction
The food processing of fruit and vegetables, and especially of the Prunus genus, generates millions of tons of waste each year. Thus, the valorization of these fruit stones has become an emerging trend for obtaining bioactive compounds. Particularly, fatty acids and tocopherols, which exhibit antioxidant properties and can prevent and mitigate certain diseases, can be extracted from Prunus seeds and be used for potential applications in the food and cosmetics industries.
Methods
A novel method based on ultrasound-assisted extraction (UAE) using the green solvents tert-butanol and ethanol has been designed and optimized to obtain oil from Prunus spinosa L. seed residues generated before maceration and after maceration in alcohol for 6 months to produce liquor. The obtained oils were characterized by both fatty acid and tocopherol profiles using GC-MS and HPLC-DAD, respectively. Their bioactive potential was evaluated in terms of oxidative stability and antimicrobial activity against several bacteria.
Results
The obtained oils were rich in unsaturated fatty acids, mainly oleic (61-73%), linoleic (18-30%) and palmitic acid (5-7%), together with β+γ-tocopherols (84-100 mg/kg). The processing to which sloe stones are subjected has a significant impact on the oil chemical composition. Overall, the oils obtained after maceration had the highest variety and content of unsaturated fatty acids, the highest total tocopherol content and the best oxidative stability. In addition, these oils showed the most varied antimicrobial capacity against Gram-positive (S. aureus) and Gram-negative (E. coli and P. aeruginosa) ubiquitous bacteria.
Conclusions
A simple, fast, economical and environmentally friendly extraction method has been developed as an efficient alternative methodology to the traditional Soxhlet method with n-hexane for the extraction of oil from sloe seed residues.
Specifically, the sloe seed oil obtained after maceration showed the greatest potential for its feasible use in the cosmetics and food industries.
