Low-cost fat recovery from industrial ice cream waste: Separation mechanisms, process modeling, and techno-economic feasibility

Ice cream waste (ICW) is an emerging high-volume dairy byproduct that is largely discarded despite containing recoverable fats suited for high-value applications. This study evaluated proteolytic hydrolysis and pH-shift treatments as strategies to alter ICW emulsions and enhance fat separation. The techno-economic analysis (TEA) was conducted for feasibility of an industrial fat-recovery process. Authentic industrial ICW from four production batches (1.8–10.3% fat) was treated with pepsin, trypsin, or bromelain, respectively, at 37 °C or 60 °C for up to 24 h, or exposed to pH 2, 4, or 11 for 5 h, followed by centrifugation. Fat recovery, fat purity, and top-layer composition were quantified and analyzed, multivariate statistics, and regression, and were used to parameterize an Aspen Plus process model and TEA. Short-time proteolytic hydrolysis (1–2 h) at moderate temperatures improved fat recovery. The control without proteases achieved high fat recovery (∼95%) and increased fat purity relative to the untreated baseline, whereas proteolysis and high-temperature treatments did not significantly increase total recoverable fat and reduced fat purity. The pH-shift experiments showed that alkaline treatment (pH 11) favored fat separation compared with acidic conditions. The model estimated a minimum selling price of $0.40 kg -1 (±7%) for the recovered fat product, with variations driven primarily by differences in the initial fat content of the ICW. Increasing the processing scale can further improve profitability. These results demonstrate a simple, economically viable route to recover fat from ICW, supporting the transition toward a circular bioeconomy.