Mechanistic insights into solubilization of rice protein isolates by freeze-milling combined with alkali pretreatment

Tao Wang; Hao Zhang; Li Wang; Ren Wang; Zhengxing Chen

doi:10.1016/j.foodchem.2015.01.057

Mechanistic insights into solubilization of rice protein isolates by freeze-milling combined with alkali pretreatment

Food Chem. 2015 Jul 1:178:82-8. doi: 10.1016/j.foodchem.2015.01.057. Epub 2015 Jan 21.

Authors

Tao Wang¹, Hao Zhang¹, Li Wang¹, Ren Wang², Zhengxing Chen³

Affiliations

¹ State Key Laboratory of Food Science and Technology, National Engineering Laboratory for Cereal Fermentation Technology, and School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
² State Key Laboratory of Food Science and Technology, National Engineering Laboratory for Cereal Fermentation Technology, and School of Food Science and Technology, Jiangnan University, Wuxi 214122, China. Electronic address: nedved_wr@jiangnan.edu.cn.
³ State Key Laboratory of Food Science and Technology, National Engineering Laboratory for Cereal Fermentation Technology, and School of Food Science and Technology, Jiangnan University, Wuxi 214122, China. Electronic address: zxchen_2008@126.com.

PMID: 25704687
DOI: 10.1016/j.foodchem.2015.01.057

Abstract

The solubilization of rice protein isolates (RPIs) has been regarded as one of the critical and challenging processes affecting commercial availability. Simultaneous treatment with freezing and milling (freeze-milling) combined with alkali pretreatment can remarkably increase the maximum achievable amounts of soluble RPIs by up to 42 times. This study investigates the mechanism of solubilization of RPIs by freeze-milling (RPI(fm)). Structural analyses reveal that milling causes proteins to unfold with ice crystals formed inside protein bodies. Fluorescent and Fourier transform infrared spectra show that RPI(fm) possesses disrupted hydrophobic surface and exposed hydrophilic inner groups. Size exclusion chromatography results reveal that RPI(fm) exhibits disaggregation and strong water-protein interactions. These results indicate that freeze-milling may be a promising manufacturing technique in food industry.

Keywords: Freezing; Milling; Rice protein isolate; Solubilization.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Alkalies
Freezing
Hydrophobic and Hydrophilic Interactions
Molecular Weight
Oryza / chemistry*
Plant Proteins / chemistry
Plant Proteins / isolation & purification*
Protein Conformation
Protein Folding
Solubility

Substances

Alkalies
Plant Proteins