Unlocking Spinach Polyphenols: Novel Extraction, Impact of Processing, Value-Addition and Therapeutic Potentials

Spinach (Spinacia oleracea L.) is globally recognized as a functional food due to its diverse composition, which includes minerals, vitamins, and polyphenols – compounds with various therapeutic properties that extend beyond its essential nutritional value. However, despite their health-promoting potential, Spinach Polyphenols (SP) remain underutilized due to challenges in efficient extraction, limited understanding of bioavailability, and scattered research findings. This review examines several innovative and green extraction methods to recover polyphenol concentration levels and their bio-accessibility. Thermal and non-thermal processing of spinach is known to exert measurable effects on bioactive compounds. Adding SP to nutrient-enriched food products improves micro- and macronutrients, antioxidants, and sensorial and techno-functional properties. The bioavailability of bioactive compounds, crucial for achieving their therapeutic properties, such as antioxidant, anti-inflammatory, antimicrobial, antidiabetic, anticancer, anti-obesity, and cardiovascular prevention effects, highlights the key factors affecting bioavailability throughout metabolism. Recent advances have expanded the application of spinach's biological compounds in the food, pharma and health sectors. It has encouraged the researchers to conduct further studies to address limitations and current research gaps.