Impact of carrier oil on interfacial properties, CBD partition and stability of emulsions formulated by whey protein or whey protein-maltodextrin conjugate

Abstract

Oil phase composition may affect properties of the oil-water interface and the characteristics of fabricated emulsions. This study aims to investigate the impacts of varying oil phase composition of medium-chain triglyceride (MCT) and long-chain triglyceride (LCT) at volume ratios ranging from 0/100 to 100/0 on biomechanical properties of cannabidiol (CBD)-loaded emulsions stabilized by whey protein (WP) or whey protein-maltodextrin (WP-MD) conjugate. Interfacial tension, surface protein load, droplet size and zeta potential of emulsions significantly increased with increased LCT ratio (p < 0.05). Partition analysis indicated that CBD was mainly located in the oil phase, and its presence was enhanced from 90% to 96% by increasing the LCT proportion. Increased LCT ratio was not beneficial for the physical or oxidation stability of emulsions, but it did increase CBD retention during an accelerated 16-day storage test (55 °C). At all oil compositions, WP-MD stabilized emulsions showed higher surface protein load, smaller particle size, narrower size distribution, lower zeta potential, better protection towards CBD, and improved oxidation stability in comparison with those emulsified with WP alone. These results provide insight into the influences of carrier oil on emulsion characteristics and offer guidance for the rational selection of suitable oil phases for emulsion-based delivery systems.