α-amino acid and antioxidant activity of crackers, changes in α-amino acid (a), ABTS radical scavenging activity (b), and ferric reducing antioxidant power (c) of crackers during order in vitro gastric and intestinal conditions Data are expressed as mean ± standard deviation (n = 3). A,B different superscript capital letters denote significant differences between the formulation of crackers for the same sampling period of the in vitro assay (P < 0.05). a,b different lowercase superscript letters denote significant differences between different sampling periods of the in vitro assay for the same formulation of crackers (P < 0.05)