The Value Chain Transformation of Madhuca longifolia Deoiled Cake: A Critical Assessment of Saponin Valorization and Its Implications in Different Industries

Abstract:

Madhuca longifolia (Mahua), a multipurpose tree of the Sapotaceae family, produces large amounts of deoiled seed cake as a byproduct of oil extraction. This cake contains 4-8% saponins along with proteins, fibres, and minerals. This review examines how it can be transformed into a valuable resource through saponin valorization, covering extraction methods, industrial uses, and sustainability. We discuss conventional and biotechnological methods, including solvent, supercritical fluid, ultrasound-assisted, microwave-assisted, and enzyme-assisted extraction. Saponins find applications in pharmaceutical, nutraceutical, cosmetic, detergent, biopesticide, and food sectors. The review also considers technical challenges in extraction and purification, economic concerns around processing costs versus market value, and the environmental benefits of waste valorization and circular economy integration. Special attention is given to Chhattisgarh, where Mahua is an important minor forest produce supporting tribal livelihoods, with a single tree capable of earning Rs. 40,000-50,000 a year. The review identifies gaps in biorefinery integration, standardized protocols, life cycle assessments, and region-specific value chains, and offers a roadmap for turning Mahua deoiled cake from an underused waste stream into a high-value bioactive resource supporting sustainable rural development and the circular bioeconomy.