Food Science Commons^™

High-Resolution Scanning Electron Microscopy Of Milk Products: A New Sample Preparation Procedure, William R. Mcmanus, Donald J. Mcmahon, Craig J. Oberg

Food Structure

A metal-impregnation technique (tannin-ferrocyanide- osmium tetroxide) and thin metal coating imparted excellent preservation , and electric and thermal properties to milk products for scanning electron microscopy, resulting in high- resolution images. Three nanometer resolution was obtained, with minimal edge effects, charging , thermal drift, and decoration. Samples were fixed in 2% gluta raldehyde, cryoprotected in 70% ethanol, and cryofractured, exposing internal structure. Fat was extracted with Freon 113 and the sample were metal -impregnated with 1.0% osmium tetroxide and 1.5% potassium ferrocyanide, reduced with 1% hydroquinone, dried using !he critical-point drying melhod , and ion beam sputter-coated with 2-5 nm …

Age Related Changes In The Microstructure Of Mozzarella Cheese, L. J. Kiely, P. S. Kindstedt, G. M. Hendricks, J. E. Levis, J. J. Yun, D. M. Barbano

Food Structure

Changes that occurred in the microstructure of low-moisture, part skim Mozzarella made with a mixed starter consisting of Streptococcus salivarius ssp. thermophilus and Lacwbacillus delbrueckii ssp. bulgaricus and coagulated with fermentation -produced chymosin , were examined during 50 days of ripening at 4 °C. Im mediately after manufacture (day 3), a homogeneous and continuous phase of amorphous paracasein represented a three-dimensional protein network in the cheese. A large number of irregularly shaped and sized microcavi ties were present. During 50 days of aging , an increase in the porosity of the defatted paracasein matrix was apparent. These changes were coincidental …

Practical Aspects Of Electron Microscopy In Dairy Research, Miloslav Kalab

Food Structure

Milk products are based mostly on casein micelles, fat globules, and whey proteins. The former two constituents are corpuscular and whey proteins become corpuscular when coagulated. Structural changes in these basic constituents during processing have been studied by electron microscopy. This review discusses the structures of yoghurt, curd, cheeses (hard cheeses, mould-ripened cheeses, cream cheeses, and process cheese), cream, milk powders, and nontraditional dairy products. Defects and deviations from traditional structures of these products are explained where the causes are known. Examples of such causes are foaming of milk, presence of unusual ingredients (bacterial polysaccharides, whey protein concentrates), and alterations …

Proceedings From The 29th Annual Marschall Italian Cheese Seminar, Various Authors

Cheese Industry Conference

Three 375 lb vats of cultured low moisture pan skim Mozzarella cheese were produced from the same batch of standardized milk and rennet, but using three different rod (Lactobacillus bulgaricus - Marschall ProduciS - Thennorod) and coccus (Streptococcus thermophilus - Mar chall Product - Thennococcus) ratios (9R:IC, 5R:5C, and !R:9C). The total volume and total colony fonning units of culture added was kept constant for all ratios (i.e., I 02 ml/375 I b). Cheese was made with the ·'no-brine·· chee e making method using a I06°F (41° ) cook temperature, 6.4 draw pH *whey), 5.25 milling pH, and 135°F (57°C) …

Effect Of Draw Ph On The Development Of Curd Structure During The Manufacture Of Mozzarella Cheese, L. J. Kiely, P. S. Kindstedt, G. M. Hendricks, J. E. Levis, J. J. Yun, D. M. Barbano

Food Structure

The impact of varying the pH of whey at whey drainage (5.9, 6.15 or 6.4) on the development of curd structure during the manufacture of Mozzarella cheese was investigated using scanning electron microscopy. Dramatic changes in curd structure were apparent with stage of manufacture , in particular the stretching step which aligned the protein fibers.

Of additional interest is the effect of draw pH on the structure of curd at whey drainage. When whey was drained at pH 6.4, an open poorly fused network of paracasein particles was observed in the cheese curd. Jn contrast, lowering the draw pH (6.15 …

Proceedings From The 28th Annual Marschall Italian Seminar, Various Authors

Cheese Industry Conference

Since 1983, the Wisconsin Milk Marketing Board, funded by the 33,000 dairy farmers, has formed a unique partnership with the Wisconsin cheese manufacturers in their efforts to market the products they make with advertising, promotion, education and research programs.

These marketing programs have focused on Wisconsin's cheese quality and cheese making expertise as the foundation for the strategic direction that WMMB has set for our programs and services. Communications strategy was developed to capitalize on the equity in the name "Wisconsin" which has been confirmed through consumer and foodservice market research.

This presentation will give an overview of WMMB's programs …

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

Food Structure

No abstract provided.

Proceedings From The 27th Annual Marschall Italian Cheese Seminar, Various Authors

Cheese Industry Conference

No abstract provided.

Effect Of Proteolytic Activity Of The Lactic Cultures On Mozzarella Cheese Quality, Wen-Hsu Amos Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Mozzarella cheese market is growing rapidly. Major concerns with cheese meltability and color have arisen in the fast food industry. Pre starter culture was used in this study to improve the physical properties of Mozzarella cheese. Three tests (stretch test, melt test, and browning test) were modified to evaluate the quality of cheese.

A stretch test using the Brookfield helipath viscometer to stretch the cheese sample at 60°C was successful in distinguishing cheeses from different make procedures and from different proteolytic strains. A melt test using a glass tube to hold the cheese flow at 110°C for 60 min …

Proceedings From The 26th Annual Marschall Italian Cheese Seminar, Various Authors

Cheese Industry Conference

No abstract provided.

Proceedings From The 25th Annual Italian Cheese Seminar, Various Authors

Cheese Industry Conference

No abstract provided.

Amino Acid Composition And Structure Of Cheese Baked As A Pizza Ingredient In Conventional And Microwave Ovens, Alenka Paquet, Miloslav Kalab

Food Structure

Amino acid compositions of stirred-curd Mozzarella, stretched Mozzarella, and process Cheddar cheeses were similar and did not change as the result of baking in a conventional oven. D-glutamic acid (D0Glue) and D-phenyl-alanine (D-Phe) were present at low concentrations in all cheese samples, the lowest concentrations having been found in unbaked stirred-curd Mozzarella cheese (2.7% D-Glu of total Glu present and <1.0% D-Phe of total Phe present). The highest concentrations were detected in unbaked stretched Mozzarella cheese (5.6% and 1.2%, respectively). Thechanges were not significant and were not the result of aking, indicating that the heat treatment during baking did n ot cause racemization of the amino acids.

Each cheese had a characteristic structure before baking. The structures of the Mozzarella cheeses were altered by baking in the conventional oven and also in a microwave oven and their original features such as curd granule junction and fat globule …

The Crystallization Of Calcium Phosphate At The Surface Of Mould-Ripened Cheeses, B. E. Brooker

Food Structure

Samples of several different types of mouldripened cheese were examined by light and electron microscopy for evidence of calcium phosphate crystallization near their surfaces , which, it was predicted , should result from the pH changes that take place in the rind during ripening . Transmission electron microscopy showed that characteristic convoluted crystals appeared in the rind as mould growth developed and that there was good evidence that at least some of the crystal nucleation was taking place inside effete hyphae. Light microscopy showed that this coincided with the appearance of birefringent, phosphate-rich crystals in the cheese rind which were …

The Size Distribution And Shape Of Curd Granules In Traditional Swiss Hard And Semi-Hard Cheeses, M. Ruegg, U. Moor

Food Structure

Curd granule junction patterns in hard (Emmentaler, Gruyere, Sbrinz) and semi-hard cheeses (Appenzeller , Tilsiter, Raclette) were visualized on slices and examined using light microscopy and digital image analysis. Horizontal and vertical sections were cut in different zones of the loaves, in order to obtain information on the orientation of the flattened curd granules.

The frequency histograms of the cross section areas could in most cases adequately be described as a log-normal distribution. The median values ranged from 0.97 to 1.15 mm2 and, from 1.31 to 1.68 mm2 for hard and semi-hard cheeses, respectively.

An elliptical form factor was used …

Proceedings From The 24th Annual Marschall Italian Cheese Seminar, Various Authors

Cheese Industry Conference

No abstract provided.

Confocal Scanning Laser Microscopy In Food Research: Some Observations, I. Heertje, P. Van Der Vlist, J. C. G. Blonk, H. A. C. M. Hendrickx, G. J. Brakenhoff

Food Structure

Confocal Scanning Laser Microscopy (CSLM) has advantages over conventional light microscopy and electron microscopy. In particular the possibility to perform optical sectioning, allowing the disturbance free observation of the three-dimensional internal structure, offers new possibilities in microstructural studies of food systems. The technique is further considered to be very valuable in the study of dynamic processes and transport phenomena. Preliminary results are discussed of an investigation into the microstructure of fat spreads, mayonnaise, cheese and rising dough using this CSLM technique.

Proceedings From The 23rd Annual Marschall Invitational, Various Authors

Cheese Industry Conference

No abstract provided.

Mechanical Properties Of Cheese, Cheese Analogues And Protein Gels In Relation To Composition And Microstructure, M. L. Green, K. R. Langley, R. J. Marshall, B. E. Brooker, A. Willis, J. F. V. Vincent

Food Structure

Samples of commercial Cheddar cheese, experimental Cheddar cheeses made from heated, ultrafiltration-concentrated mllks, processed cheese analogues and whey protein gels of defined composition were examined microscopically and some fracture and deformation properties were determined. Surfaces of cheese prepared by critical point drying and those examined frozen were comparable in microstructure. As the concentration factor of the milk used for experimental c heesemaking increased, the cheese became more resistant to reversible deformation, the work required to cut with a wire or break wf th a hammer increased and the microstructure showed that the protein matrix was coarser. The force to deform …

A Fluorescence Microscopic Study Of Cheese, S. H. Yiu

Food Structure

Fluorescence techniques were used to study the microstructure of several varieties of cheese. The size and distribution of fat globules in various cheeses were demonstrated by fluorescent staining using Nile Blue A as a marker. Acridine Orange was used as a dye to detect structural differences between casein matrices of various cheese varieties. Differences between the ripe and the less- ripe zones of Ca membert cheese were detected by staining the cheese sections with Acridine Orange and Nile Blue A separately, and then comparing the re sults of the stainings. The Nile Blue A stain ing s howed that fat …

Proceedings From The 22nd Annual Marschall Invitational, Various Authors

Cheese Industry Conference

No abstract provided.

Effects Of Emulsifying Agents On The Microstructure And Other Characteristics Of Process Cheese - A Review, Marijana Caric, Miroslav Gantar, Miloslav Kalab

Food Structure

Sodium phosphates , polyphosphates, and citrates are melting salts (emulsifying agents) most commonly used in the manufacture of process cheese either alone or in mixtures . Their role during processing is to sequester calcium in the natural cheese, to solubilize protein and increase its hydration and swelling, to facilitate emul sification of fat , and to adjust and stabilize pH.

Changes taking place in natural cheese during processing can be studied by microscopy. Micrographs demonstrating the emulsification of fat , presence of salt crystals, and partial solubilization of protein in labo ratory- made and commercial process cheeses have been used …

Proceedings From The 21st Annual Marschall Invitational Cheese Seminar 1984, Various Authors

Cheese Industry Conference

No abstract provided.

Proceedings From The 19th Annual Marschall Invitational Italian Cheese Seminar 1982, Various Authors

Cheese Industry Conference

No abstract provided.

Electron Microscopy Of Milk And Milk Products: Problems And Possibilities, D. G. Schmidt

Food Structure

Milk and dairy products have frequently been studied by transmission- and scanning electron microscopy. The specimen preparation procedure may considerably influence the final result, and formation of artefacts is frequently observed. In this respect, formation of ice crystals during cryofixation is a well-known phenomenon. But dehydration, to an extent such as is required for embedding procedures, also appears to be harmful to dairy products. Micrographs of thin sections of plastic- embedded samples of casein submicelles show threadlike material, whereas in freeze-etched specimens only spherical particles are found. Similar observations are made when samples of cheese and of concentrated milk are …

Proceedings From The 17th Annual Marschall Invitational Italian Cheese Seminar 1980, Various Authors

Cheese Industry Conference

No abstract provided.

Varieties Of Cheese, T A. Morris

Bulletins 4000 -

While Cheddar cheese is by far the main type as far as English speaking countries are concerned, it is only one of a large number of varieties of cheese which are becoming more universal in production and consumption. In other than English speaking countries Cheddar cheese is almost unknown and yet the consumption of cheese in some of these countries is very much greater. The naming of cheese types has usually been a result of the use of the name of the place where the cheese was first made. Thus cheeses of similar type but produced in a different locality …

Proceedings From The 15th Annual Marschall Invitational Italian Cheese Seminar 1977, Various Authors

Cheese Industry Conference

No abstract provided.

A Process Incorporating Ultrafiltration Concentrated Whey Solids Into Cheese For Increased Cheese Yield, Rodney Jay Brown

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A process which incorporates whey sol ids, primarily protein, into cheese to increase cheese yield and eliminate whey handling problems was evaluated. Whey was concentrated by ultrafiltration to levels of 9.8 to 20.3 percent total solids (4.3 to 7.1 percent protein), heated at 70 C for 30 minutes and added to cheese milk with the coagulating enzyme.

Increase in cheese yield, on the basis of 39 percent moisture, for 10 pairs of samples was 4.0 ± 2.8 (S.D.) percent. This increase was significant at alpha less than 0.001. Moisture and protein content increased while fat content decreased. Setting time and …

Persistence Of Mucor Miehei Protease In Cheddar Cheese And Pasteurized Whey And Its Effect On Sterile Milk Products, Randall Kirk Thunell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Whey from a commercial cheese plant, taken at draining on five separate days, from cheese made with a Mucor miehei coagulant was cooled within 1 h to 4 C. Portions were adjusted from pH 4.2 to 6.4 at .2 pH intervals and subjected to HTST pasteurization at 73.9, 76.6, and 79.5 C for 25 sec. Milk clotting activity in whey was determined before and after pasteurization. Resistance to heat in-activation increased with decreasing pH. All measurable activity was destroyed above pH 5.4 by pasteurization at 79.5 C, above pH 5.8 at 76.6 C and above pH 6.0 at 73.9 C. …

Proceedings From The 14th Annual Marschall Invitational Italian Cheese Seminar 1977, Various Authors

Cheese Industry Conference

No abstract provided.