Evaluation of the digestibility and antioxidant activity of protein and lipid after mixing nuts based on in vitro and in vivo models

[Display omitted] •Co-digestion enhanced the protein and lipid digestibility of nuts.•Co-digestion improved the antioxidant activity of nuts both in vitro and in vivo.•The amino acid and fatty acid content in the mice increased after the mixed nuts diet.•Amino acid and fatty acid contents show positive correlation to antioxidant activity. This study aimed to evaluate the change of digestibility and antioxidant activity of protein and lipid after mixing walnuts, cashews, and pistachios using in vitro and in vivo models. The results showed that mixed nuts significantly reduced the digested particle size and the degree of hydrolysis of protein and triacylglycerol compared to single nuts in vitro. As a consequence of co-digestion, bioaccessibility and antioxidant activity for amino acids and fatty acids were increased by 1.12–1.87 fold and 1.62–3.81 fold, respectively. In vivo studies, the mixed nuts diet increased the concentration of amino acids and fatty acids in the small intestine by 27.69%–158.26% and 18.13%–152.09%, respectively, and enhanced levels of antioxidant enzymes in the liver and serum, all without causing weight gain. These findings highlight the positive interaction between single and mixed nuts, where mixed nuts enhanced the digestibility and antioxidant activity of single nuts both in vitro and in vivo.