Effect of dietary polyphenols on the in vitro starch digestibility of pigmented maize varieties under cooking conditions

• Published in: Food research international 2018-06, Vol.108, p.183-191
• Main Authors: Rocchetti, Gabriele, Giuberti, Gianluca, Gallo, Antonio, Bernardi, Jamila, Marocco, Adriano, Lucini, Luigi
• Format: Article
• Language: English
• Subjects: In vitro starch digestion; Metabolomics; Pigmented maize flours; Polyphenols; Resistant starch
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2018.03.049

Interest in using polyphenols as modulators of the activity of starch digestive enzymes is increasing. The main purpose of this study was to investigate the role of phenolic compounds characterising pigmented maize flours in the modulation of in vitro starch digestibility. Flours from three different pigmented maize varieties were evaluated under cooking conditions and compared to common yellow maize (YM). The untargeted metabolomics-based approach comprehensively annotated around 300 phenolic compounds, with a high distribution of anthocyanins and phenolic acids (in free and bound fractions of maize samples) and significant differences across genotypes. Following in vitro starch digestion, the cooked pigmented maize flours showed higher resistant starch content (from 5.1 to 6.9 g /100 g dry matter), as well as lower starch hydrolysis index (HI) when compared to YM flour, with the “Rostrato Rosso” maize having the lowest HI (i.e., 61). Coherently, multivariate statistics following metabolomics showed the discrimination potential of anthocyanins' profile after cooking, characterising the “Rostrato Rosso” during in vitro digestion. These findings might be related to the modulation of enzyme activity by phenolic compounds during in vitro digestion. Therefore, the use of pigmented maize flours might help in the formulation of gluten-free foods with slowly digestible starches by exploiting the wide phenolic composition of these matrices. [Display omitted] •Free and bound antioxidant profile in pigmented maize flours (PMFs) was described.•After cooking, PMFs had greater resistant starch content than yellow maize flour.•“Rostrato Rosso” had a different phenolic profile during in vitro starch digestion.•Anthocyanins were the best markers of the phenolic profile observed overtime.•The use of PMFs might be an effective strategy towards healthier food formulation.