Demand for Greek yoghurt has grown considerably, reaching 36% of US yogurt demand in 2014 from just 1–2% in 2004. Unfortunately, Greek yogurt production yields 2–3 kg of acid whey waste for every kilogram of yogurt; in 2015, approximately 771,000 metric tons of Greek yoghurt were produced.
Projects aimed at consuming this rapidly accumulating waste product include converting it into animal feed or industrial-grade ethanol. Some companies are also evaluating anaerobic digestion of the acid whey to produce methane, which can then be used to generate electricity.
Acid whey is also rich in lactose, galactose, calcium phosphate, and lactic acid, all of which have potential applications in food, Dean Sommer, a food and cheese technologist at the Center for Dairy Research at the University of Wisconsin, Madison, tells Chemical & Engineering News. “Our goal was to take acid whey, which is mostly considered a waste product, and use modern dairy processing equipment and techniques to fractionate potentially valuable products,” Sommer says.