Whey: generation, recovery, and use of a relevant by-product

Whey is a by-product formed during the milk coagulation process in the manufacture of cheese, casein, or similar dairy products. Its composition, rich in water, lactose, protein, and minerals, shows nutritional quality and high potential for use as an input for both the food and bioprocessing industries, in the preparation of dairy products, ethanol and biogas manufacture, and other products. However, the generation of excessive volume of whey in the dairy manufacturing processes and its rapid perishing can set challenges in the use of this by-product, requiring investments in refrigeration, processing, and transportation. Such difficulties lead to less useful uses of this input, such as supplementation of animal feed and soil irrigation, and even its disposal as waste, causing economic and environmental disadvantages. Thus the valorization of whey, as well as investment in research and technology, are fundamental advances for the expansion of activities of the global dairy industry. This chapter presents an overview of the characteristics of whey, its main destinations, and processing to obtain it, aiming to valorize this by-product of the cheese industry.