Conventional and emerging methods for cereal by-product valorisation

Cereal processing yields significant volumes of by-products such as bran, germ, husks, and distillers’ grains, which are rich in nutrients and bioactives yet remain underexploited in human food systems. This review synthesises current evidence on their compositional and functional attributes, including proteins, dietary fibres, resistant starches, lipids, polyphenols, and phytosterols. Comparative analysis shows that conventional processing methods including fermentation, enzymatic hydrolysis, extrusion, and micronisation reduce antinutritional factors, improve mineral bioavailability, and enhance sensory attributes in bran- and germ-enriched foods. Recent studies demonstrate that emerging non-thermal technologies such as high-pressure processing, ultrasonication, steam explosion, pulsed electric fields, and cold plasma can further increase soluble dietary fibre, enhance protein solubility, release bound phenolics, and improve antioxidant activity, while preserving heat-sensitive nutrients. Applications in bakery, dairy, beverage, and nutraceutical sectors confirm the feasibility of cereal by-product valorisation, though challenges remain with off-flavours, coarse textures, spoilage risks, and limited solubility. The review concludes that optimised, scalable, and energy-efficient processing strategies can transform cereal by-products into high-value functional ingredients, supporting zero-waste production, clean-label innovation, and circular bioeconomy goals in sustainable food systems. • This review introduces emerging green technologies to valorise cereal processing waste. • Novel strategies are evaluated to enhance nutritional value and functionality of cereal waste. • Integrated processing approaches are discussed to overcome sensory and technical challenges. • The paper supports circular bioeconomy goals through sustainable food innovation.