engleski

Antioxidant activity of protein/glucosyl-hesperidin complexes

Glucosyl-hesperidin (GH) is a water-soluble derivate of hesperidin, well known for its antioxidant potential. The purpose of this work was preparation of dry complexes of proteins and GH. Two types of proteins were used, milk proteins (80% of caseins) and brown rice proteins, both at different percentage levels (2, 5, 10 and 15%). Milk proteins showed a higher affinity for GH, but in both cases adsorption of GH onto proteins decreased with increased content of proteins. Antioxidant activity was evaluated by DPPH, ABTS, FRAP and CUPRAC methods. Antioxidant activity evaluated with DPPH and ABTS methods, showed a slight increase with increased protein content, while there was no significant difference between the two proteins. On the contrary, FRAP and CUPARC methods showed a higher antioxidant potential of milk protein complexes. Additionally, both methods of analysis indicated a decrease of antioxidant activity with increasing protein content. Structural changes of proteins upon adsorption of GH were evaluated by FTIR and DSC analyses. FTIR spectra of loaded proteins differed from the pure protein spectra, confirming that upon formation of complexes structural changes occurred. DSC analysis showed that protein/glucosyl-hesperidin complexes had a slightly lower temperature of denaturation. Obtained complexes can be used in preparation of functional food ingredients since they can enrich foods with GH and proteins.

glucosyl-hesperidin ; milk proteins ; brown rice proteins ; antioxidant activity

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