Characterization and evaluation of emulsifying properties of high pressure microfluidized and pH shifted corn gluten meal

Ozturk, Oguz Kaan
Mert, Behiç
This study presents a potential application for adding value to corn gluten meal, which is often used as animal feed and underutilized in food industry. This study is aimed to improve water holding ability of zein-rich by product corn gluten and investigate possibility of using it as an emulsifier. The potential use of microfluidization (500-1250 bar and 25 degrees C) and pH shifting (to pH6, 8, and 10) as a modification process for corn gluten meal and their effects on emulsifying properties were investigated. The formulations used for CGM(g):corn oil (mL) mixtures were 5:15, 5:30, 5:50, 10:15, 10:30, 10:50, 15:15, 15:30, and 15:50. Microfluidization and pH modification decreased the particle size of emulsions, resulting in the formation of tissues and micropores, and a consequent increase in surface area and water-holding capacity. pH shifting in dispersions around neutrality (pH6 and pH8) provided improvements in emulsion properties; however, excessive shifting (pH10) caused protein denaturation. Herschel-Bulkley model was well-fitted to explain flow behaviors. Flow and viscoelastic measurements showed that all formulations exhibited shear thinning and elastic gel-like behavior. The sedimentation rate, measured using LUMiSizer, was decreased by microfluidization and pH modifications. This study showed that these treatments can be used to convert an underutilized material into a valuable one in food industry.