Development of corn fiber gum-soybean protein isolate double network hydrogels through synergistic gelation

Authors: YAN, WENJIA - China Agricultural University; YIN, LIJUN - China Agricultural University; LI, JINLONG - China Agricultural University; Yadav, Madhav; JIA, XIN - China Agricultural University

Submitted to: Food and Bioprocess Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/2020
Publication Date: 2/15/2020
Citation: Yan, W., Yin, L., Li, J., Yadav, M.P., Jia, X. 2020. Development of corn fiber gum-soybean protein isolate double network hydrogels through synergistic gelation. Food and Bioprocess Technology. https://doi.org/10.1007/s11947-020-02412-1.
DOI: https://doi.org/10.1007/s11947-020-02412-1

Interpretive Summary: Corn fiber gum (CFG) is carbohydrate polymer that is present in the cell wall of corn kernels. CFG can be extracted from corn fiber, which is a low valued by-product of the dry or wet milling of corn kernels. In addition to its major carbohydrate components, CFG also contains a small amount of phenolic compounds. Many studies have reported that CFGs can be connected to each other through phenolic groups to form hydrogels when treated with an enzyme called “laccase”. However, the hydrogels formed by simple enzyme treatment may not be strong enough to encapsulate drugs or bioactive compounds and act as their delivery vehicle in the human body. To solve this problem, we have prepared double network hydrogels by using a mixture of CFG and soy protein isolate (SPI). The hydrogel formation of CFG and SPI were initiated by adding laccase and gluconic acid lactone in the same mixture. During such hydrogel formation, the CFG and SPI hydrogels become intertwined with each other and form a double network hydrogel. The mechanical properties, flow behaviors, water holding capacity and microscopic analysis of these hydrogels were compared. These studies indicated that these new hydrogels have uniform and dense inner structure with a smooth surface. They are also stronger than the hydrogel prepared with either CFG or WPI alone. Thus, this technique of double network hydrogel formation can be useful for making stronger hydrogels with more uniform structure. These findings will help to increase the utilization of CFG and WPI polymers in food and pharmaceutical applications and may benefit US corn and soybean growers. The utilization of these products may improve the markets for corn and soybean processing by-products. The production of novel hydrogel products may also benefit the U.S. consumers, food and pharmaceutical industries and ultimately the U.S. economy.

Technical Abstract: Corn fiber gum (CFG)-soybean protein isolate (SPI) cold-set hydrogels were formed under the action of laccase and D-(+) -gluconic acid d-lactone (GDL), leading to the gelation of CFG and SPI. The storage modulus (G’) and elasticity modulus (G’’) of CFG-SPI double network (DN) hydrogels were superior to those gels prepared with either SPI or CFG alone. Uniaxial compression testing and texture profile analysis (TPA) indicated that the CFG-SPI DN hydrogels combined some of the mechanical characteristics of the individual CFG and SPI hydrogels. Scanning electron microscopy (SEM) showed that CFG-SPI DN hydrogels had the most uniform and most dense structure. CFG-SPI DN hydrogels had the highest water-holding capacity compared with single network hydrogels. CFG-SPI DN hydrogels with various mechanical properties and microstructures were prepared by controlling the composition ratios of CFG to SPI.