Phenolics flavonoids anthocyanins and antioxidant contents of baked white and purple waxy corn products

Abstract

Phytochemical compounds are naturally occurring pigments with claimed benefits. However, these pigments are sensitive to degradation by high pH, light and temperature. Waxy corn (maize) contains high phytochemical compounds. Corn snacks are popular snacks, and possibly functional foods with high antioxidant capacities. Therefore, the objective of this study was to investigate the TPN, TFN, ACN, DPPH-RSA, ABTS-RSA and FCA of white and purple waxy corn processed into baked corn products. Dough acidification treatment with fumaric acid was assessed as a means to reduce phytochemical compounds and antioxidant losses. Purple waxy corn contained higher DPPH-RSA, ABTS-RSA and FCA [2.3, 6.9 mg Trolox equivalents (TE)/g, and 77 μg EDTA/g] than those of white waxy corn (2.0, 6.2 mg TE/g, and 36 μg EDTA/g); however, it had lower TPN and TFN levels (1.9 mg GE/g and 1.6 mg QE/g) than those of white waxy corn (2.1 mg GE/g and 1.8 mg QE/g). White waxy corn did not have a detectable amount of ACN, while purple waxy corn kernels contained 270 μg CE/g. Lime cooking had the greatest negative impact on the stability of TPN, TFN, ACN, DPPH-RSA, ABTS-RSA and FCA. However, dough acidification of white and purple waxy corn reduced TPN (5 and 9%), TFN (4 and 4%), DPPH-RSA (5 and 2%), ABTS-RSA (5 and 6%), and FCA (6 and 12%) losses. Similarly, ACN losses were observed for purple waxy corn kernels when processed into dough (16%) and baked waxy corn products (13%). Acidified treatment of baked waxy corn products also significantly reduced microbial growth. Acidified baked purple waxy corn products contained lower amounts of TPC and TFC (1,030 and 25 CFU/g) than those of acidified baked white waxy corn products (3,100 and 26 CFU/g). This study compared phytochemical compounds and antioxidant contents among corn genotypes and confirmed that dough acidification could reduce TPN, TFN, ACN, DPPH-RSA, ABTS-RSA and FCA losses.