The Recovery of Potentially High-Value Compounds from Milk By-Products and the Development of Functional Foods, Case of Whey: A Review

The dairy industry is one of the most important sectors in food processing, contributing to the production of daily-needed products. Milk processing also results in the formation of by-products that can worsen the environment if not utilised properly. In this context, several efforts have been undertaken to mitigate their impacts by incorporating them into a novel production process/cycle. Milk by-products can serve as a natural source of high-value, high-impact inputs when introduced into such a process. Milk by-products can be a natural source of high-value-added compounds and a cost-effective substrate for microbial growth and metabolites production. The current review focuses on cheese whey as a key milk by-product, due to its significant production volume and environmental impacts. In fact, from ten litres of milk utilised in cheese production, eight to nine litres of whey are formed, and untreated whey can cause severe pollution due to its high biochemical oxygen demand and chemical oxygen demand. Recently, cheese whey has been widely utilised as a primary material for microbial fermentation and enzymatic processes to produce a diverse range of chemicals and products with applications in the pharmaceutical, food, and biotechnology industries. This review contributes to defining a framework for valorising whey through the application of bioprocesses in designing foods with enhanced qualities and the generation of biomaterials.