Carbonized Beverages

New Gushing Mechanism Proposed by Applying Particle Size Analysis and Several Surfactants

Abstract
The complex phenomenon of gushing occurring in carbonized beverages has been investigated in order to better understand the mechanism and to give input for further research to introduce preventive measures for the industry. The knowledge that microbubbles are stabilized through surface active substances, and in this form can induce gushing, was used to examine a selection of representative surfactants. For the analysis, a particle size distribution method was used which enabled to detect particles at nanometer level, starting from 0.8 nm onwards. The experiments using pure aliphatic surfactants (DTAC, TTAC, CTAC, ODTABr, CPC, SDS, and Tween 20) revealed that only CTAC, solved in CO₂ containing table water at 2 g/l (above the critical micellar concentration), induced gushing. CTAC therefore was characterized as gushing typical by its structure (length of hydrophobic part and kind of head group). Gushing caused by CTAC was not only observed through shaking of the bottles, but also without any shaking at all. The latter observed fact was not explainable by the mechanical incorporation of CO₂ bubbles stabilized by CTAC monomers, but generally through stabilized microbubbles formed by a mechanism that is yet unknown. The particle size analysis revealed that particles grow, starting from ca. 10 nm to reach several 100 nm, if sufficient amounts of CO₂ molecules are present. The growth was accelerated by a mild shaking of the bottles. The results pointed out that CTAC micelles grow by diffusion of CO₂ molecules into the hydrophobic core. Thereby, microbubbles are formed and stabilized through CTAC monomers at the interface gas/liquid, and can grow to gushing-relevant sizes of several 100 nm. ©2009 BrewingScience

Keywords gushing, particle size distribution, surfactant, hexadecyltrimethylammonium chloride (CTAC), micelle growth, carbon dioxide diffusion, stabilized microbubbles

Source: BrewingScience – Monatsschrift für Brauwissenschaft, 62 (July/August 2009), pp. 100-107
M. Christian, V. Ilberg, A. A. Aydin, J. Titze, A. Friess, F. Jacob and H. Parlar
Research Center Weihenstephan for Brewing and Food Quality, Techinical University of Munich, Germany
Department of Chemical Engineering, Istanbul Technical University, Turkey
Deloitte Cunsulting GmbH, Germany

Cereal Chemistry

Optimizing Grinder Type and Methods of Expressing Wheat MEAL Particle Size for Wheat Texture (hardness or Softness) Measurement and Near-Infrafed Reflectance Spectroscopy

Abstract
The grinding characteristics of three wheat grinders (LabConco, Falling Number KT-33-3, and Udy cyclone) were compared by measuring the particle size of meals produced, using four sieving technigues and five Microtrac laser light-scattering optical measurements. Seven wheat samples used in the evaluation represented a wide range of texture (hardness or softness). The LabConco-ground meals were coarser than the others, and samples were best differentiated by sieving the meals to determine particle size distribution on means as an assessment of wheat textrue. Meals produced by the Falling Number grinder were of generally intermediate particle size distribution, and samples were best differentiated by analyzing meal particle size with the Microtrac instrument. The Udy cyclone produced meals having much finer mean particle size, more narrow particle size distributions, and overall the best differentiation among wheat samples (using the Microtrac). Therefore, the Udy / Microtrac combination was the best procedure for evaluating the texture of wheat samples with equal, if not better, statistical power than a (more coarse) grinder and sieving combination commonly used for particle size index testing. 1987 American Association of Cereal Chemists

Charles S. Gaines, Raymond E. Miller, John R. Donelson, and Maura M. Bean - USDA

Effects of Particle Size on Flour Functionality

This study by the USDA explores the effects of extraction rate, particle size, and chlorination extent on flour functionality by SRC, DSC, RVA and cake baking. Effects of chlorination on flour are listed as to modify amylose-associated phospholipid, enhance amylose pasting, decrease gluten strength, and decrease flour pH. The study concluded that of the three factors explored by milling extraction rate and chlorination extent showed dramatic effects, but additional milling to reduce particle size was a less significant factor. ©2007 USDA

Meera Kweon, USDA, ARS, Soft Wheat Quality Lab, Wooster, OH 44691

Applications & Industries