Effects of Whole Purple Sweet Potato Flour Addition on the Characteristics of Mixed Flour Dough and Digestive Properties of Bread

Abstract:

On the basis of exploring the influence of addition of whole purple potato flour on the dough characteristics of whole purple potato flour-wheat flour mixed dough, the starch digestion characteristics, bioaccessibility of anthocyanosides and antioxidant activities of purple potato breads with different addition amounts of whole purple potato flour were compared. The results showed that the addition of purple sweet potato flour reduced the water absorption of mixed flour, shortened dough formation time, reduced dough’s stability, but delayed dough aging. With an increase in the addition amount of purple sweet potato flour, the resistant starch (RS) content in the starch of purple sweet potato bread increased, the glycemic index decreased, the antioxidant activity increased, and the bioavailability of total anthocyanins and anthocyanin monomers decreased. When the addition amount of purple sweet potato flour was 50%, the RS content in purple sweet potato bread’s starch was 39.60%, the glycemic index was 71.86, the total reducing capacity was 13.24 mg Vc/g, and the total anthocyanin bioavailability was only 2.64%. Ten anthocyanin monomers were detected. The bioaccessibility of delphinidin-3,5-diglucoside was the highest, followed by paeoniflorin 3-O-acyl glycoside monomer, with cyanidin 3-O-acyl glycoside monomer having the lowest bioaccessibility. The addition of whole purple sweet potato flour can prolong the shelf life of bread, delay starch digestion, improve its antioxidant activity, which meet consumers' demand for nutritious and healthy staple food products.