Effects of polyphenols from Tasmannia lanceolata on structural, emulsifying, and antioxidant properties of pea protein

The effects of polyphenols from Tasmanian pepper ( Tasmannia Lanceolata ) leaf and berry on the functional properties of pea protein were investigated in flaxseed oil-in-water emulsions. Phenolic acids and flavonols in Tasmanian pepper leaf with smaller molecular weights led to stronger non-covalent interactions with pea protein, while anthocyanins from Tasmanian pepper berry induced protein aggregation under acidic condition and co-existed with proteins in neutral and alkaline conditions. The total phenolic content was significantly increased with incorporation of polyphenols from Tasmanian pepper leaf (334.94–445.92 μg/mL) and berry (72.89–153.03 μg/mL) to pea protein (4.19–15.59 μg/mL). The oxidative stability of emulsions at pH 3 and 7 was enhanced, reducing TBARS value from 1.54 to 2.68 mg MDA/kg in pea protein to 0.56–0.85 mg MDA/kg after 2 weeks storage. These findings illustrated the distinct interactions between pea protein and different polyphenols from Tasmanian pepper leaf and berry to enhance the antioxidant capacity of pea protein. • Tasmanian pepper leaf and berry contain significant amounts of polyphenols. • Phenolic acids and flavonols show higher binding affinity to pea protein than anthocyanins. • Protein aggregation by polyphenol reduces emulsion stability but prevents lipid oxidation.