The impact of dual-frequency power ultrasound (DPU) on the molecular weight distribution (MWD) of corn gluten meal (CGM) hydrolysates and its mechanism were investigated in the present study. The mechanism was studied from aspects of structural and nano-mechanical characteristics of the major protein fractions of CGM, viz. zein and glutelin. The results of molecular weight distribution indicated that DPU pretreatment of CGM was beneficial to the preparation of peptides with molecular weights of 200-1000Da. Moreover, FTIR spectral analysis and atomic force microscopy characterization showed that the DPU pretreatment changed the contents of secondary structure of proteins, decreased the particle height and surface roughness of glutelin, reduced the Young's modulus and stiffness of zein while increased its adhesion force. In conclusion, DPU pretreatment of proteins before proteolysis is an efficient alternative method to produce short-chain peptides because of its positive effects originating from acoustic cavitation on the molecular conformation, nano-structures and nano-mechanical properties of proteins as well.

The double T‐junction microchannel is a classical microstructured chemical device used to generate gas/liquid/liquid three‐phase microflows. An experimental study that focused on the three‐phase flow phenomena and bubble/droplet generation rules in a double T‐junction microchannel was introduced. Based on the published knowledge of gas/liquid and liquid/liquid two‐phase microflows, new flow patterns were carefully defined: bubble cutting flow, spontaneous break‐up and bubble cutting coupling flow, and bubble/droplet alternate break‐up flow. According to the classical correlations of bubble and droplet volumes and their generation frequency ratio, the operating criteria for creating different three‐phase flow patterns were established and a model for the dimensionless average bubble and droplet volumes in the three‐phase microflows was developed. These various three‐phase microflows have great application potential in material science and flow chemistry synthesis. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1722–1734, 2015

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