Turning Waste into Value: Sustainable Bio-Emulsifiers from Agro-Food By-Products

Agro-food waste streams represent a significant environmental and economic burden due to their large volumes and elevated chemical oxygen demand (COD) and biological oxygen demand (BOD). Nevertheless, these residues constitute valuable reservoirs of bioactive and functional compounds, including polyphenols, carbohydrates, proteins, lipids, and fatty acids, thereby offering considerable potential as renewable feedstocks to produce value-added biobased materials [1,2]. This study investigates the synthesis, characterization, and performance evaluation of novel bio-based emulsifiers derived from agro-food byproducts, specifically cheese whey permeate (CWP) and soybean meal (SBM). CWP, a major byproduct of the dairy industry, was utilized as a substrate for the synthesis of sugar fatty acid esters (SFAEs), a class of nonionic surfactants recognized for their superior interfacial activity, biodegradability, and low ecotoxicity [3]. In parallel, SBM, a protein-rich residue generated during soybean oil extraction, was explored as an alternative renewable source for the development of high-performance emulsifying agents [4]. In both cases, a chemoenzymatic synthetic strategy was employed, and the reaction parameters were systematically optimized using chemometric methodologies. The synthesized bio-emulsifiers were comprehensively characterized and assessed for their surface-active properties, including their ability to reduce static and dynamic interfacial tension. Their emulsification performance was further evaluated through the preparation and stabilization of water-in-sunflower oil (W/O) emulsions, both in model systems and in more complex formulations, with stability monitored over extended storage periods. Furthermore, computational modeling and interfacial rheological analyses were conducted to elucidate the structural and mechanical properties of the oil–water interface and to predict long-term emulsion stability. The findings demonstrate the feasibility of valorizing agro-food waste as a sustainable source of bio-based emulsifiers, thereby contributing to the development of environmentally benign industrial formulations and supporting the implementation of circular economy and green chemistry principles.