The moisture migration behavior of wheat starch/gluten blended powders and extrudates

Abstract

Water migration plays an important role in the wheat-based products manufacture and is not only related to starch and gluten content, but also to the structure formed by gluten. Various gluten structure samples were constructed in powder and extrudate form. Density, moisture sorption isotherms, water migration rate, water binding energy of powders and extrudates were investigated. The average density of extrudates increased from 856 to 1321 kg m⁻³, which existed a linear relationship with starch content. The shrinkage of the starch displayed higher than that of gluten when the water activity change from 0.35 to 0.11. The monolayer moisture content (M₀) of the starch was higher than that of gluten. Starch powder had a higher desorption rate and lower sorption rate than gluten, however, starch extrudate had higher sorption and desorption rates than gluten, for the extruded gluten has formed a network structure. The binding energy of the starch was higher than that of gluten, and which of all samples was close to zero when moisture content was greater than 20%. Those information on moisture migration behavior may guide to optimize the drying processing with balance of noodle quality, noodle yield, and energy consumption.

Keywords:

• Starch
• gluten
• monolayer moisture content
• water migration rate
• water binding energy

Disclosure statement

We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled.

Additional information

Funding

The authors would like to acknowledge the financial support from the China Agriculture Research System (CARS-03) and the National Natural Science Foundation of China (31771927). We are also grateful to Mr. Ren Chuanshun for preparing raw gluten and starch, and to METER Group, Inc. and Mr. Zhang Jungang for MSI analysis assistance.