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.

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

Bio-nanocomposites for food packaging applications

The structure

Fish gelatin: properties, challenges, and prospects as an alternative to mammalian gelatins

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.

Population Balances: Theory and Applications to Particulate Systems in Engineering

Structure, Drainage, and Coalescence of Foams and Concentrated Emulsions

A mechanistic model for baking of leavened aerated food

Flexible random-coil structure of polymer molecules and protein−polymer and polymer−solvent interactions were accounted for in the evaluation of the interaction potential between two globular prote...

Thermodynamics of Precipitation of Globular Proteins by Nonionic Polymers

To investigate the dispersibility of lipid coated particles in food suspensions, contact angle of lipid surface at different pH, salt concentration, protein concentration, surfactant type and concentration was measured. Contact angle decreased with an increase in the emulsifier conecentration when the concentration was low, and reached a fairly constant value at higher concentrations. Whey protein was more efficient compared to other emulsifiers and decreased the contact angle from 100° to 40° at a concentration of 0.5 g/L or higher in water. Tween 20 was more efficient than other tween emulsifiers and it decreased the contact angle from 100° to 67° at a concentration of 1 g/L. Surface pressure area isotherm of 150-80SV soybean oil coated particles at an air–water interface was obtained using Langmuir trough. Contact angle of the particles at the air–liquid interface, inferred from the critical surface pressure in the isotherm, agreed well with the contact angle of planar surface obtained using goniometer. Dispersibility of 150-80SV soybean oil coated particles in aqueous solution was characterized by measuring the bulk particle concentration upon suspension. At pH 2.5, 5 g/L whey protein in the presence of 0.5 mol/L NaCl in 50 g/L citrate buffer showed highest dispersibility.

Characterization of the effect of food emulsifiers on contact angle and dispersibility of lipid coated neutrally buoyant particles

Explicit solvent molecular dynamics (MD) simulation was carried out for the antimicrobial peptides (i) Cecropin P1 and C-terminus cysteine modified Cecropin P1 (Cecropin P1 C) in solution, (ii) Cecropin P1 and Cecropin P1 C adsorbed onto coesite −Si − O − and Si − O − H surfaces, and (iii) Cecropin P1 C tethered to coesite −Si − O − surface with either (PEO)3 or (PEO)6 linker. Low energy structures for Cecropin P1 and Cecropin P1 C in solution consists of two regions of high α helix probability with a sharp bend, consistent with the available structures of other antimicrobial peptides. The structure of Cecropin P1 C at low ionic strength of 0.02 M exhibits two regions of high α helix probability (residues AKKLEN and EGI) whereas at higher ionic strength of 0.12 M, the molecule was more compact and had three regions of higher α helix probability (residues TAKKLENSA, ISE, and AIQG) with an increase in α helical content from 15.6% to 18.7% as a result of shielding of electrostatic interactions. In the presence of Cecropin P1 C in the vicinity of −Si − O − surface, there is a shift in the location of two peaks in H − O − H density profile to larger distances (2.95 A and 7.38 A compared to 2.82 A and 4.88 A in the absence of peptide) with attenuated peak intensity. This attenuation is found to be more pronounced for the first peak. H-bond density profile in the vicinity of −Si − O − surface exhibited a single peak in the presence of Cecropin P1 C (at 2.9 A) which was only slightly different from the profile in the absence of polypeptide (2.82 A) thus indicating that Cecropin P1 C is not able to break the H-bond formed by the silica surface. The α helix probability for different residues of adsorbed Cecropin P1 C on −Si − O − surface is not significantly different from that of Cecropin P1 C in solution at low ionic strength of 0.02 M whereas there is a decrease in the probability in the second (residues ISE) and third (residues AIQG) α helical regions at higher ionic strength of 0.12 M. Though the total α helical content of adsorbed and tethered Cecropin P1 C was lower for hydrophilic Si − O − H surface compared to hydrophobic −Si − O −, hydrophobicity of the surface did not significantly affect the α helix probability of different residues. The conformation of Cecropin P1 C in solution is closer to that of tethered to −Si − O − with (PEO)6 than that tethered with (PEO)3 as a result of less surface interaction of tethered polypeptide with a longer linker. At low ionic strength of 0.02 M, tethered Cecropin P1 C to −Si − O − is found to exhibit lower α helix (13.0%) compared to adsorbed (15.6%) for (PEO)3 linker with this difference being insignificant for larger (PEO)6 linker molecule. Experimental values of % α helix inferred from circular dichroism spectra of Cecropin P1 in solution as well as in adsorbed state on silica surface compared well with the corresponding values obtained from MD simulation thereby validating the simulation procedure.

Ganesan Narsimhan

Papers

Structure, Drainage, and Coalescence of Foams and Concentrated Emulsions

A mechanistic model for baking of leavened aerated food

Thermodynamics of Precipitation of Globular Proteins by Nonionic Polymers

Characterization of the effect of food emulsifiers on contact angle and dispersibility of lipid coated neutrally buoyant particles

Effect of interaction with coesite silica on the conformation of Cecropin P1 using explicit solvent molecular dynamics simulation