Antioxidant- and dietary fiber-enriched crackers using cashew nut skin powder

The consumption of dietary fiber is recommended to modulate the gut microbiota and promote overall human health. Meanwhile, the inclusion of antioxidants into foods is considered an effective way to reduce their oxidation, such as lipid and protein oxidation, and to bring many health benefits. Utilizing the food byproducts to produce antioxidant- and dietary fiber-enriched products is an attractive approach to reduce food waste and enhance dietary fiber and antioxidant intake. In this study, the cashew nut skin (CNS), a by-product of cashew nut production, was incorporated into a cracker formula at different levels to produce antioxidant- and dietary fiber-enriched crackers. Compared to the control cracker, which did not contain CNS, the cracker incorporated with 10% CNS powder showed an increase of approximately 3.5 times and 11 times in dietary fiber and total phenolic content, respectively. Notably, the total tannin and flavonoid content of the incorporated cracker at 10% was 7.21 mg GAE/ g dw and 6.24 mg QE/ g dw, respectively, while they are undetectable in the control cracker. However, the addition of CNS resulted in reductions in the dimensions, hardness and overall acceptability of the cracker. Specifically, compared to the control cracker, the diameter and thickness of the cracker incorporated with 10% CNS powder were 3 and 7% lower, respectively while the hardness dropped by 47%. The addition of 2.5% CNS did not significantly change the overall acceptability of the product but the addition of 5 to 10% CNS led to a significant decline in acceptability. Transglutaminase treatment of the blended dough at enzyme dose of 1.0 U/g protein and incubation time within 12–24 min was successfully applied to restore the detrimental effects of CNS incorporation on the textural properties and the overall acceptability of the cracker products.