The objective of this work was to produce a gluten-containing food matrix (pasta) rich in dietary fiber (DF), polyphenols, and antioxidant activity, through partial substitution with a dry flour from decocted Hibiscus sabdariffa L. calyces. The food matrix was made by mixing semolina (75%) and decocted calyces flour (25%) (S75–HF25), and its proximate composition, polyphenols content, antioxidant capacity, and starch hydrolysis rate were evaluated. The dietary fiber (DF) content (18.7 g/100g, dry basis, db) in the S75–HF25 pasta was markedly higher than in semolina control pasta (5.0 g/100g, db). Cooking the S75–HF25 pasta decreased the extractable polyphenols content and antioxidant capacity measured with DPPH, while enhancing the ABTS + antioxidant value. The cooked pasta showed an “as eaten” DF content of 34.7 g/100g, which was higher than in semolina pasta (6.7 g/100g). The starch hydrolysis rate of the composite pasta was reduced compared to the semolina pasta. The resistant starch content in the composite pasta was around 60% higher than the semolina pasta. The high DF content in the decocted calyces of Hibiscus sabdariffa L. helps to retain the polyphenol content and antioxidant capacity in the cooked pasta food matrix.
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