Characterization of Components in Whey Permeate to Assess Upcycling Potential

The increasing demand for dairy products like cheese and Greek yogurt has led to a surge in whey permeate by-product. The most common outlet for dairy process by-products is low value fertilizer and animal feed. The aim of the current study was to characterize the energy content and component composition of sweet whey and acid whey to explore their potential for conversion to energy or upcycle into higher-value food or feedstock. Whey permeate, whether acid whey or sweet whey, is nutrient-rich, and we hypothesize that it can be converted into a feedstock for bio-oil production by hydrothermal liquification. Here we present bomb calorimetry data obtained to assess energy content, and high-performance liquid chromatography (HPLC) data that was used to measure lactose content. Results indicated energy densities of 14.2 ± 0.4 kcal/g and 15.2 ± 0.6 kcal/g for sweet whey and acid whey, respectively. Lactose levels were measured at 41.1 ± 0.5 mg/mL in sweet whey and 18.78 ± 1.2 mg/mL in acid whey. These findings indicate the potential for whey permeate to be used for on-site bioenergy production that may contribute to more sustainable dairy industry operations.