Physicochemical, Nutritional, and Antioxidant Properties in Seven Sweet Potato Flours

Lin Zhang; Yan Gao; Bowen Deng; Weidong Ru; Chuan Tong; Jinsong Bao

doi:10.3389/fnut.2022.923257

Physicochemical, Nutritional, and Antioxidant Properties in Seven Sweet Potato Flours

Front Nutr. 2022 Jun 15:9:923257. doi: 10.3389/fnut.2022.923257. eCollection 2022.

Authors

Lin Zhang^{1

2}, Yan Gao^{1

2}, Bowen Deng^{1

2}, Weidong Ru², Chuan Tong³, Jinsong Bao^{1

2}

Affiliations

¹ Hainan Institute, Zhejiang University, Yazhou Bay Science and Technology City, Sanya, China.
² Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Zhejiang Province, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
³ College of Food Science and Technology, Zhejiang University of Technology, Hangzhou, China.

Abstract

Sweet potato flour is a key ingredient for the production of new food products worldwide, which imparts desired properties, nutritional value, antioxidants, and natural color to processed foods. However, little information regarding the functional properties of the sweet potato flour is available. In this study, the genetic diversity in the physiochemical, nutritional, and antioxidant properties of wholemeal flour from seven sweet potato varieties was investigated. The total phenolic content (TPC) of the free and bound fractions ranged from 13.85 to 90.74 mg gallic acid equivalent (GAE)/100 g and from 5.07 to 24.29 mg GAE/100 g, respectively. The average protein content of sweet potato was 5.41 g/100 g ranging from 3.40 to 8.60 g/100 g DW. The total amino acid content averaged 45.13 mg/g DW. The average contents of 12 mineral elements were in the order of K > P > Ca > Mg > Mn > Fe > Zn > Cu > Ni > Se > Cr > Cd. K and P contents were the highest among all accessions, which were positively correlated with most of the other minerals. The average starch content of sweet potato was 53.90 g/100 g DW, ranging from 31.68 to 64.90%. The peak viscosity (PV), hot paste viscosity (HPV), and cold paste viscosity (CPV) were in the range of 90.7-318.8 Rapid Visco Unit (RVU), 77.3-208.3 RVU, and 102.6-272.7 RVU, respectively. The hardness values and cohesiveness (Coh) varied among different sweet potatoes, with a range of 8.20-18.48 g and 0.22-0.68, respectively. The gelatinization onset, peak, conclusion temperatures, and enthalpy were in the ranges of 59.39-71.91°C, 70.19-88.40°C, 78.98-95.79°C, 1.85-5.65 J/g, respectively.

Keywords: nutritional properties; phenolics; physicochemical properties; sweet potato; wholemeal flour.