STUDY OF CASEIN MICELLES IN GOAT MILK BY TRANSMISSION ELECTRON MICROSCOPY

1996 ◽  
Vol 86 (2-3) ◽  
pp. 193-193
Author(s):  
Franc¸oise MICHEL ◽  
Alice PIERRE
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Goat Milk ◽  
Casein Micelles ◽  
Transmission Electron

Changes in Size of Casein Micelles Caused by Growth of Psychrotrophic Bacteria in Raw Skim Milk

1984 ◽  
Vol 47 (1) ◽  
pp. 16-19 ◽  
Author(s):  
JONATHAN P. BURLINGAME-FREY ◽  
ELMER H. MARTH
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Skim Milk ◽  
Bacterial Activity ◽  
Casein Micelles ◽  
Psychrotrophic Bacteria ◽  
Ph Values ◽  
Psychrotrophic Bacterium ◽  
Transmission Electron

Raw skim milk was inoculated (1%, v/v) with a proteolytic psychrotrophic bacterium that previously was isolated from milk. The inoculated skim milk was incubated at 7°C for 0, 3, 5 and 7 d. The pH values for the milk were 6.6, 6.5, 6.45 and 5.95, and the numbers of psychrotrophs/ml were 1.0 × 104 8.9 × 107, 9.0 × 108 and 2.5 × 108 for days 0, 3, 5 and 7, respectively. Samples of milk were negatively stained, examined with transmission electron microscopy and distribution of sizes of casein micelles was determined. The average and (mode) sizes of micelles were 849 (789), 1030 (634), 761 (634) and 405 (316) Angstroms for milks after days 0, 3, 5 and 7, respectively. Another set of samples was prepared from skim milk immediately after it was acidified to pH values of 6.6, 6.5, 6.45 and 5.95. The average and (mode) sizes of micelles were 891 (766), 875 (615), 913 (766) and 840 (615) Angstroms for milks having pH values of 6.6, 6.5, 6.45 and 5.95, respectively. Changes in size of micelles in the incubated samples resulted from bacterial activity other than small changes in pH.

scholarly journals Antimicrobial Activity of Silver Nanoparticles Synthesized Using Goat Milk against Pathogens of Selected Vegetables

2019 ◽  
pp. 1-10 ◽  
Author(s):  
T. A. Ihum ◽  
C. C. Iheukwumere ◽  
I. O. Ogbonna ◽  
G. M. Gberikon
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Goat Milk ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

This study was carried out to determine the antimicrobial activity of silver nanoparticles synthesized using goat milk against pathogens of selected vegetables. Synthesis of Silver nanoparticles was done using Goat milk, and characterized using Ultra Violet-Visible absorption spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X- ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Maximum absorbance of Goat milk synthesized AgNPs was observed at 417 nm, with FTIR peaks at 3455 cm−1, 1628 cm−1, 1402 cm−1, 1081 cm−1 and 517 cm−1, indicating that proteins in Goat milk (GM) were the capping and stabilization molecules involved the synthesis of AgNPs. Transmission electron microscopy analysis showed that the biosynthesized particles were spherical in shape having a size of 10-100 nm, X- ray diffraction (XRD) pattern agreed with the crystalline nature and face-centered cubic phase of AgNPs. Evaluation of the antimicrobial activity of AgNPs synthesized using GM against the indicator strains (Staphylococcus aureus CIP 9973, Pectobacterium carotovorum Pec1, Enterobacter cloacae AS10, Klebsiella aerogenes OFM28, Proteus mirabilis UPMSD3 and Escherichia coli 2013C-3342) isolated from selected vegetables, was carried out using the Agar diffusion assay at different concentrations of 25, 75 and 100 µl/ml. The present study demonstrated that the AgNPs synthesized using Goat milk have potent biological activities, which can find applications in diverse areas.

Milk gel Structure: II. Relation between firmness and ultrastructure of heat-induced skim-milk gels containing 40–60% total solids

1974 ◽  
Vol 41 (1) ◽  
pp. 131-135 ◽  
Author(s):  
Miloslav Kalab ◽  
V. R. Harwalkar
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Skim Milk ◽  
Close Correlation ◽  
Gel Structure ◽  
Casein Micelles ◽  
Ammonium Persulphate ◽  
Total Solids ◽  
Transmission Electron

SummaryMilk gels varying widely in firmness were examined by both scanning and transmission electron microscopy, and a close correlation was found between their ultrastructure and firmness. In gels containing 40 and 50% total solids (14 and 17% protein respectively), casein micelles appeared as individual entities linked by some bridging material. At 60% total solids (20% protein), the micelles were fused and offered a considerably higher resistance to a penetrometer probe. Likewise some additives to gels, such as ammonium persulphate and CaCl2, caused the micelles to fuse. These chemicals appreciably increased firmness of such gels. In gels containing hexametaphosphate, a known inhibitor of gelation, most of the casein micelles were disintegrated; these gels were soft.

Milk-gel structure. IV. Microstructure of yoghurts in relation to the presence of thickening agents

1975 ◽  
Vol 42 (3) ◽  
pp. 453-458 ◽  
Author(s):  
Miloslav Kalab ◽  
D. B. Emmons ◽  
A. G. Sargant
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gel Structure ◽  
Casein Micelles ◽  
Transmission Electron ◽  
Short Fibres ◽  
Pregelatinized Starch ◽  
Large Clusters ◽  
Small Clusters ◽  
Thickening Agents

SummaryThe effects of 3 different thickening agents on the microstructure of yoghurt were examined by scanning and transmission electron microscopy. Unsupplemented yoghurt consisted of casein micelles fused together and linked in long chains; they seldom appeared in clusters. The addition of 0·5% gelatin caused no observable change in the yoghurt structure. Carrageenan (0·4%) formed a markedly fibrillar microstructure which connected large clusters of casein micelles. The fibres were thin and long and no free terminations were observed. Pregelatinized waxy maize starch (2%) appeared under scanning electron microscopy in the form of short fibres and sheets. The fibres frequently had free terminations and only some of them were connected with small clusters of casein micelles. Transmission-electron microscopy did not distinguish between pregelatinized starch and carrageenan additives.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Sign in / Sign up

Export Citation Format

Share Document