Interactions of antinutrients mixtures with bovine serum albumin and its influence on in vitro protein digestibility

Abstract

Antinutrient mixtures are usually present in food formulations what can affect the protein digestibility. This work aimed to study the interactions of a mixture of antinutrients with bovine serum albumin and its effect on the in vitro protein digestion. Results showed that the phytic and tannic acid decrease the α-helix conformation of BSA and form insoluble complexes. The phytic acid and saponin increase the affinity between the tannic acid and the protein and change the nature of the forces involved in the binding as observed by isothermal titration calorimetry. The effect of each antinutrient on protein properties depends on the concentration and structure of the protein and the antinutrient. The tannic acid was the antinutrient that most decreased the protein digestion. The presence of both phytic acid and saponin changed the digestibility of protein containing tannin. The study of a mixture of substances is complex and involves several mechanisms of binding and molecules structure changes. This works shows that, despite the complexity of the system studied, the balance between the proportions of each component can determine its influence on the bioavailability of proteins and antinutrients. Thus, the results obtained in the present work may help in the understanding of reactions and protein behavior of complex mixtures such as food matrixes.