Effects of annealing temperature and time on the structural and physicochemical properties of sweet potato flour hydrogels

Ziwen Zhang; Mengshan Shang; David Julian McClements; Chao Qiu; Na Ji; Lei Dai; Yang Qin; Liu Xiong; Qingjie Sun

doi:10.1016/j.fochx.2023.100674

Effects of annealing temperature and time on the structural and physicochemical properties of sweet potato flour hydrogels

Food Chem X. 2023 Apr 5:18:100674. doi: 10.1016/j.fochx.2023.100674. eCollection 2023 Jun 30.

Authors

Ziwen Zhang^{1

2}, Mengshan Shang³, David Julian McClements⁴, Chao Qiu³, Na Ji^{1

2}, Lei Dai^{1

2}, Yang Qin^{1

2}, Liu Xiong^{1

2}, Qingjie Sun^{1

2}

Affiliations

¹ College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province 266109, China.
² Qingdao Special Food Research Institute, Qingdao 266109, China.
³ State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
⁴ Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA.

Abstract

The physicochemical properties of sweet potato flour (SPF) can be modified by annealing. Native SPF was annealed in deionized water at a flour-to-water ratio of 1:3 (w/v) and temperatures of 50, 55, 60, or 65 °C for either 12 or 24 h. Annealed SPF maintained the A-type crystalline region and displayed increased relative crystallinity, increased pasting temperature, and decreased breakdown. SPF gels showed enhanced hardness together with better springiness when SPF was annealed at low temperature/long time or high temperature/short time. Annealed SPF hydrogel sheets contained larger, more uniform, and smoother pores than native ones. Noticeably, hydrogel sheets made of SPF annealed at 50 °C for 24 h exhibited advanced fracture strain from 93% to 176%. Overall, this work showed that annealing could modulate the characteristics of SPR hydrogels, which may widen the extent of applications in food industries. However, the annealing conditions need to be optimized.

Keywords: Annealing; Flour; Hydrogels; Stretchability; Sweet potato.