Impact of pectin or chitosan on bulk, interfacial and antioxidant properties of (+)-catechin and β-lactoglobulin ternary mixtures

• Pectin-(+)-catechin-β-lg formed small complexes.
• Chitosan-(+)-catechin-β-lg formed bigger complexes with reduced polydispersity.
• Oil/water interfacial elasticity was improved by pectin-(+)-catechin-β-LG.
• Free content of (+)-catechin and antioxidant capacity were not affected by interactions.

The interactions effect between (+)-catechin, β-lactoglobulin and two types of polysaccharides (pectin and chitosan) were studied at pH 4.Dynamic light scattering (DLS) revealed that pectin formed smaller complexes in the presence of (+)-catechin and β-lg, while chitosan presented a reduced number of populations with higher particle size. Dynamic interfacial data (obtained by a drop tensiometer) revealed that the complexes formed between pectin (+)-catechin and β-lg slowed down the β-lg migration to the oil/water interface; contrarily to the chitosan mixtures where protein migrated faster. The surface dilatational modulus of β-lg was ∼45 mN/m and increased to ∼60 mN/m when mixing with pectin and (+)-catechin, while the values of the surface dilatational modulus for the chitosan mixed interfacial films decreased to ∼35 mN/m. The free (+)-catechin content decreased 12% and 10% when interacting with pectin and chitosan, respectively, as compared to pure (+)-catechin. However, the (+)-catechin antioxidant activity were not affected by the interactions. Complexes formed between polyphenols, proteins and polysaccharides could be used as a good alternative to understand and consequently improve the phytochemicals stability in food matrices.

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