Ganesan Narsimhan

Bio: Ganesan Narsimhan is an academic researcher from Purdue University. The author has contributed to research in topics: Adsorption & Emulsion. The author has an hindex of 34, co-authored 140 publications receiving 3465 citations. Previous affiliations of Ganesan Narsimhan include Monash University, Clayton campus & Monash University.

Solubility of Globular Proteins in Polysaccharide Solutions

Abstract: A statistical thermodynamic model based on the lattice model proposed by Baskir et al. (1987) was employed to predict the solubilities of globular proteins such as ovalbumin and lysozyme at their isoelectric points in dextran solutions of different molecular weights. The model accounted for protein-polysaccharide and polysaccharide-solvent interactions as well as entropy of mixing, and it employed simplifying assumptions such as a linear homogeneous polysaccharide molecule and a spherical globular protein molecule of uniform surface properties. The protein-polysaccharide interaction parameter χs, obtained by fitting the model to experimental data for one molecular weight of dextran, was found to be 0.132 and 0.115 for ovalbumin and lysozyme, respectively. Solubilities of ovalbumin and lysozyme in dextran solutions of different molecular weights exhibited a shallow maximum at intermediate dextran concentrations and compared well with model predictions. Protein solubility was found to be very sensitive to protein-polysaccharide interactions and increase with more favorable protein-polysaccharide interactions (larger χs), less favorable polysaccharide-solvent interactions (larger χ), smaller size protein molecule, and lower molecular weight polysaccharide.

Analysis of dispersed-phase systems: Fresh perspective

Abstract: Dispersed-phase systems are analyzed with a fresh perspective where the volume fraction of the dispersed phase is emphasized, not particle numbers as in population balance. Such volume fraction balances are more pertinent to engineering because they deal with the amount of the dispersed phase relative to that of the continuous phase. Although it is easy to make detailed volume fraction balances directly or from population balance, many interesting features are identified here with balance equations in terms of volume fraction, which simply characterize the dispersion process and structure the resulting equation. They lead to equivalent “single-particle” (comprising the entire dispersed phase) processes which can be simulated with great simplicity allowing rapid calculation of quantities associated with the dispersed phase and dispersion. The techniques can solve an inverse problem for mass-transfer coefficients of individual droplets from (simulated) measurements of the bivariate distribution of drop size and concentration of a transferring solute. Such inverse problem method is important in developing experimental techniques techniques to measure multivariate population distributions such as those of Bae and Tavlarides (1989) and of flow cytometry.

Analysis of creaming and formation of foam layer in aerated liquid.

Abstract: A model for creaming and formation of a foam layer in an aerated system consisting of Newtonian liquid is proposed. The variation of air volume fraction in the dispersion layer is described by hindered creaming which is coupled to syneresis in the top foam layer that is described by flow of liquid through a network of Plateau borders due to gravitational and capillary forces. The present analysis accounts for the compressibility of foam layer by coupling creaming analysis with syneresis in the foam layer. The behavior of the system is described by three parameters: (a) characteristic time scale of creaming of an isolated bubble, (b) hydrodynamic interaction factor, and (c) capillary number, ratio of capillary and gravitational forces in the foam layer. System behavior is shown to be different for four different regions of initial air volume fractions for which the phase diagram and evolution of the profile of air volume fraction for batch dispersion are presented.

Effect of thermal behavior of β-lactoglobulin on the oxidative stability of menhaden oil-in-water emulsions.

Abstract: This study reports how emulsion oxidative stability was affected by the interfacial structure of β-lactoglobulin due to different heat treatments. Four percent (v/v) menhaden oil-in-water emulsions, stabilized by 1% (w/v) β-lactoglobulin at pH 7, were prepared by homogenization under different thermal conditions. Oxidative stability was monitored by the ferric thiocyanate peroxide value assay. Higher oxidative stability was attained by β-lactoglobulin in the molten globule state than in the native or denatured state. From atomic force microscopy of β-lactoglobulin adsorbed onto highly ordered pyrolytic graphite in buffer, native β-lactoglobulin formed a relatively smooth interfacial layer of 1.2 GPa in Young's modulus, whereas additional aggregates of similar stiffness were found when β-lactoglobulin was preheated to the molten globule state. For denatured β-lactoglobulin, although aggregates were also observed, they were larger and softer (Young's modulus = 0.45 GPa), suggesting increased porosity and thus an offset in the advantage of increased layer coverage on oxidative stability.

Applications of nanotechnology in food packaging and food safety: Barrier materials, antimicrobials and sensors

Abstract: In this article, several applications of nanomaterials in food packaging and food safety are reviewed, including: polymer/clay nanocomposites as high barrier packaging materials, silver nanoparticles as potent antimicrobial agents, and nanosensors and nanomaterial-based assays for the detection of food-relevant analytes (gasses, small organic molecules and food-borne pathogens). In addition to covering the technical aspects of these topics, the current commercial status and understanding of health implications of these technologies are also discussed. These applications were chosen because they do not involve direct addition of nanoparticles to consumed foods, and thus are more likely to be marketed to the public in the short term.

Population Balances: Theory and Applications to Particulate Systems in Engineering

Abstract: Foreword. Preface. Introduction. The Framework of Population Balances. Birth and Death Functions. The Solution of Population Balance Equations. Similarity Behavior of Population Balance Equations. Inverse Problems in Population Balances. The Statistical Foundation of Population Balances. Index.