Research Trends on Valorisation of Agricultural Waste Discharged from Production of Distilled Beverages and Their Implications for a “Three-Level Valorisation System”

The circular economy, driven by waste elimination, material circulation and nature regeneration, is crucial for business, people, and the environment. With the increasing demand for distilled beverages, managing agricultural waste like spent grains is paramount. While previous studies focused on individual beverages, investigating technologies across different types of beverages has been overlooked. This paper provides a systematic review of agricultural waste valorisation over the past five years, focusing on four representative distilled beverages: whisk(e)y, tequila, baijiu and shochu. Research efforts have primarily focused on bioenergy production from whisk(e)y and tequila waste, whereas extracting functional substances is common for baijiu and shochu. Through integrating different technologies, a “Three-level Valorisation System” was proposed to enhance the translation of agricultural waste into value-added products like proteins. This system is directly relevant to the distilled beverage industry globally and applicable to associated industries such as biofuel and food production.