Greek-style yoghurt industry byproduct utilization

Acid whey is the main byproduct of strained yoghurt production. In the production of strained yoghurt, for each kg of milk used initially, 2/3 discharged as whey (producing acid serum). Acid serum or whey byproduct has appeared as a global problem in recent years, due largely to the rapid growth of the market demand for Greek-style yogurt (3 times increase from 2007 to 2016 in US, Canada and Europe; FAO 2016). Despite the profits generated from the production of these dairy products, the industry has been struggling to find cost-effective solutions for the utilization or disposal of acid whey. The huge amounts of acid whey are difficult to manage, while bearing components (e.g., lactose) in particularly high concentrations which are difficult to degrade. The acid whey has also a very low pH value. The direct discharge to the environment would mean simultaneous consumption of vast amounts of oxygen, resulting in the destruction of aquatic life in large areas. Thus, acid whey utilization is a new research field of great importance for Greek or Greek-style yoghurt industry. In this context, it has been suggested several ways, which include both the isolation and purification of constituents of the acidic serum at high concentrations, such as lactose, and the use of these ingredients to produce high value products (e.g. pure lactose, lactulose, galacto-oligosaccharides, serum proteins).