Green extraction of bioactive components from Phoenix dactylifera (L.) seeds using NADES: applications in functional food ingredients

Abstract

Date seeds, often considered agro-industrial waste, are a rich source of bioactive compounds such as polysaccharides, mono-oligosaccharides, phytosterols, carotenoids, and polyphenols, all possessing significant functional properties. This review explores the extraction of these compounds using Natural Deep Eutectic Solvents (NADES), a green, biodegradable, and cost-effective alternative to conventional solvents. The extraction efficiency is enhanced when NADES is combined with advanced techniques such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and heating-stirring-assisted extraction (HSAE). Optimal NADES formulations include choline chloride and lactic acid with UAE for polyphenols catechins, choline chloride and ethylene glycol with UAE for polysaccharides, menthol and eucalyptol with HSAE for phytosterols. Additionally, specific NADES combinations facilitate the extraction of carotenoids using Octanoic acid and L-proline with HSAE under controlled conditions. Extracts obtained using choline chloride and ethylene glycol with MAE exhibit promising applications in functional food systems, including food preservation. Notably, polyphenol-rich extracts have been shown to extend the shelf life of Oreochromis niloticus fillets stored at 4°C for up to 10 days. These findings underscore the potential of NADES-extracted date seed components as sustainable food ingredients, aligning with green chemistry principles and contemporary food technology trends.