Extraction, purification, food applications, and recent advances for enhancing the bioavailability of 6-gingerol from ginger – A review

6-Gingerol is the major pharmacologically active component of ginger (Zingiber officinale) rhizome widely used in the food, cosmetics, and pharmaceutical industries. Various extraction and purification methods have been developed to obtain highly purified 6-gingerol. 6-Gingerol can be extracted using conventional and nonconventional extraction techniques. Hydroalcoholic solutions and liquid CO₂ are the most suitable solvents for the extraction of 6-gingerol, while microwave-assisted extraction is the best extraction method. High-speed counter-current chromatography is the purification technique resulting in the highest purity of 6-gingerol. Despite the various biological properties of 6-gingerol, the low bioavailability of 6-gingerol is the main challenge that limits its application. Novel encapsulation and solubilization techniques, including nano-emulsion, complexation, micelles, and solid dispersion methods, have been introduced to enhance the bioavailability of 6-gingerol, overcoming its limitations. 6-Gingerol showed potential applications as a natural antioxidant, preservative, and flavor enhancer as well as demonstrated a synergistic effect with different ingredients for maintaining the quality and shelf-life of the food products. The current work provides a comprehensive review of the prevailing techniques applied for extraction and purification of 6-gingerol from the rhizome of ginger, current research on the application of 6-gingerol in the food industry, and novel advances for increasing its bioavailability.