Pre-blanching corn and pressurization effects on the physicochemical and microbiological qualities of corn milk

Abstract

© 2019 A corn milk was developed by pre-blanching corn with drinking water at either 70 or 80 °C, and the blanching water was used to extract the blanched corn seeds for corn milk BC70 or BC80, respectively. The corn milk extract was subsequently pressurized at 300–500 MPa for 10–30 min at 30 °C. Pressurized corn milk was then subjected to physicochemical and microbiological assessments for color, enzymatic activities, viscosity, microbial counts and flavor volatile components. The ΔE showed that pressure of 300 MPa–500 MPa had no effect on corn milk color, while heat induced marked change of ΔE which were visible. Moreover, pre-blanching corn and pressurization at 500 MPa increased inactivation of peroxidase, lipoxygenase and polyphenoloxidase >70–90% as well as the activity of trypsin inhibitor for >90%. Furthermore, BC80 following pressurization at 500 MPa/30 min led to more gelatinization of corn starch and increase viscosity. Additionally, BC80 following pressurization at 500 MPa for 20 and 30 min eliminated total microbes and bacilli. More volatile components from raw corn milk were retained in BC70 compared with BC80. Meanwhile, most volatiles present in BC80 were not associated with the raw corn milk, but were found with pre-blanching of the corn kernel.