Zein/phenolic antioxidant nanoparticles stabilized Pickering emulsions: Effect of antioxidant hydrophobicity on lipid oxidation

Due to the presence of oils and fats, emulsions undergo lipid oxidation during storage, resulting in deterioration in sensory and nutritional qualities of emulsions. Phenolic antioxidants are widely used in inhibiting lipid oxidation. We found that phenolic antioxidants could form composite nanoparticles with zein and could be utilized to prepare Pickering emulsions with strong oxidative stability. Phenolic antioxidants with different hydrophobicity (octyl gallate, Propyl gallate and gallic acid) were fabricated into nanoparticles with zein (namely, Z/OG, Z/PG, Z/GA), and the oxidative stability of the as-prepared emulsions were much stronger than Tween 20 stabilized emulsions. And the Z/OG stabilized emulsions showed stronger oxidative stability than those stabilized by Z/PG and Z/GA. We also found that the antioxidative efficiency of octyl gallate was significantly higher than propyl gallate and gallic acid in Tween 20 stabilized emulsions. Compared with the Tween 20 stabilized emulsions, the difference in antioxidation efficiency between octyl gallate, propyl gallate and gallic acid was more obvious in the Pickering emulsions due to the combined effect of physical barrier and phenolic antioxidants. The results of this study help us to improve the antioxidant efficiency of phenolic antioxidants via the rational selection of antioxidant and a well-designed Pickering stabilization strategy.