Life Sciences Commons^™

Microstructure Of Whey Protein/ Anhydrous Milkfat Emulsions, M. Rosenberg, S. L. Lee

Food Structure

Research has been undertaken in order to determine the microstructure of emulsions consisting of whey proteins and anhydrous milk fat. The results revealed that whey protein films were formed at oil/water interfaces. Scanning electron microscopy (SEM) analysis of chemically fixed specimens1 and cryo-SEM analysis of partially etched, fro zen specimens revealed that the ad sorbed protein layer (coating the fat droplets) had a granular, aggregated appearance. Emulsions with a high fat load prepared under high homogenization pressure exhibited a bimodal particle-size distribution. Clu!;tering of the protein-coated droplets, and sharing phenomena at the oil / protein interfaces were evident in these …

The Surface Coverage Of Fat On Food Powders Analyzed By Esca (Electron Spectroscopy For Chemical Analysis), Pia Faldt, Bjorn Bergenstahl, Gilbert Carlsson

Food Structure

ES.A (electron spectroscopy for chemical analysis) was used to estimate the fat coverage on different spray-dried food powder surfaces. The method presented here represents a new way of estimating the actual surface coverage of fat on a food powder. The ESCAmethod is illustrated with three different series of experimen ts. The results obtained with the ESCA-technique are combined with the results obtained from the conventional free fat extraction technique for different spray-dried powders.

In the first series , emulsion s containing different ratios of protein to fat were spray-dried. An increase in the amount of fat in the emulsion gives …

Structure And Rheology Of Dairy Products: A Compilation Of References With Subject And Author Indexes, David N. Holcomb

Food Structure

No abstract provided.

Structures And Properties Of Stabilized Vitamin And Carotenoid Dry Powders, Victor E. Colombo, Francoise Gerber

Food Structure

The development of special formulated forms of vitamin and carotenoid dry powders solved most of the technical problems encountered in handling the original pure crystalline or oily compounds. Various procedures to obtain stabilized products have been introduced on an industrial scale for feed , food and pharmaceutical purposes. Proven modes of manufacture of formulated dry powders includes the numerous spraying processes for emulsions, dispersions or solutions, and the production of adsorbates of fat-based products.

The objective of this paper is to provide an overview of stabilized vitamin and carotenoid dry powders. This contribution is intended to demonstrate the usefulness of …

Influence Of Emulsifier On The Competitive Adsorption Of Whey Proteins In Emulsions, Jean-Luc Courthaudon, Eric Dickinson, Yasuki Matsumura, Andrea Williams

Food Structure

The influence of Tween 20 (polyoxyethylene sorbitan monolaurate) on the composition of adsorbed protein films in hydrocarbon oil-in-water emulsions containing B-lactoglobulin and a-lactalbumin has been investigated at neutral pH. The kinetics of pol ymerization of adsorbed 13-lactoglobulin via sulphydryl-disulphide interchange is little affected by Tween 20. Add ing emulsifier after homogenization leads to slightly greater competitive d i splacement of protein from the interface for emul sions made with pure 8-lactoglobulin than for equivalent emulsions made with 0.-lactalbumin . For emulsions made with the two proteins in a 1 : 1 molar ratio, adding emulsifier after homogeniza t ion leads …

Functional And Microstructural Effects Of Fillers In Comminuted Meat Products, Frederick W. Comer, Paula Allan-Wojtas

Food Structure

Fillers are used in comminuted meat products such as wieners to increase yield, improve stability, and modify textural properties. Light microscopy, scanning electron microscopy and transmission electron microscopy show that comminutred meat products are mechanical mixtures in which the microstructural features of starch and insoluble protein ingredients are largely retained. The water absorption and gelation properties of these ingredients contribute to the stability and textural firmness. Soluble proteins may improve stability through emulsion formation but the role of emulsion formation i s clearly secondary to that of gelation. The characteristic springy gel structure of wieners is determined by the gelation …

Changes In The Ultrastructure Of Emulsions As A Result Of Electron Microscopy Preparation Procedures, M. Liboff, H. D. Goff, Z. Haque, W. K. Jordan, J. E. Kinsella

Food Structure

Various methods of preparing emulsions for electron microscopy were examined with peanut oil/protein and ice cream mix emulsions. For transmission electron microscopy {TEM) , fresh peanut oil/bovine serum albumin emulsions were mixed with 2% agar , fixed in phosphate-buffered (pH 7 . 0) 4% glutaraldehyde solution and postfixed in phosphate-buffered (pH ? . 0) 1% osmium tetroxide alternatively , the glutaraldehyde- fixed samples were briefly rinsed in acetone prior to postfixation . Both preparations yielded satisfactory fat globule preservation. Similar emulsions were prepared on loops and suspended over vapors of 25% gJ nt.RrBl r'lehyr'le Rnc'l 1% oRmi urn tetroxide . …

The Effects Of Polysorbate 80 On The Fat Emulsion In Ice Cream Mix: Evidence From Transmission Electron Microscopy Studies, H. D. Goff, M. Liboff, W. K. Jordan, J. E. Kinsella

Food Structure

Emulsifiers are used in ice cream to produce a dry, smooth textured product with desireable melting properties. They function by promoting a partial destabilization of the fat emulsion. Polyoxythylene sorbitan monooleate is used very commonly in the ice cream industry for this purpose. The objective of this research was to examine by transmission electron microscopy the differences in the fat globules in typical ice cream mix emulsions prepared with and without 0.08% polyoxyethylene sorbitan monooleate.

Ice cream mix was combined 3:1 with a 2% solultion of ultralow gelling temperature agarose at 20 degrees C, fixed with 4% glutaraldehyde, postfixed with …

Processing Effects On Meat Product Microstructure, Glenn R. Schmidt

Food Structure

Animal species, meat ingredient properties, comminution equipment, mechanical action, product composition, type and level of non-meat ingredients, and thermal processing greatly affect the structural and organoleptic properties of meat products. However, additional research in the area of restructured meat products, meat protein functionality and lipid properties in meat products remains to be done. The interaction of meat proteins with lipids, water and ions should be further investigated. Considerable control of raw materials, mechanical action and heat processing is essential to make research applicable to product and process development.