Process optimization and characteristics of enzymatically cross-linked and ultrafiltrated whey

Abstract

Whey, a byproduct of cheese production, is valued for its high-quality proteins. Ultrafiltration concentrates these proteins but faces challenges such as membrane fouling. This study investigates the use of transglutaminase to improve ultrafiltration efficiency by reducing fouling and optimizing protein recovery. Whey was divided into samples of whey in natura (WIN) and whey partially demineralized (WPD). Both were treated with different concentrations of transglutaminase (0, 0.5, 1.5, and 2.5% relative to protein mass) and ultrafiltered using polyethersulfone membranes at 4 bar. Effectiveness was evaluated by permeate flux and protein concentration, as well as physicochemical and structural characterizations such as FTIR, TGA, and molecular weight analysis. Transglutaminase reduced membrane fouling, increasing permeate flux. The 2.5% enzyme concentration was most efficient for WIN, while 1.5% was ideal for WPD. Enzymatic treatment increased protein concentration and thermal stability of the concentrates. FTIR analysis indicated the formation of cross-links between proteins. Molecular weight analysis revealed larger and more stable protein aggregates, improving ultrafiltration performance. This study suggests that transglutaminase is promising for optimizing whey ultrafiltration, improving protein recovery and process efficiency, with potential large-scale application in the food industry.