Food Science Commons^™

Distribution Of Amylose And Amylopectin In Potato Starch Pastes: Effects Of Heating And Shearing, K. Svegmark, A. M. Hermansson

Food Structure

The microstructure of potato starch pastes and gels in the concentration range 5-10% (w/w) was studied as a function of shear and heat treatment usi.ng light microscopy. Heating induced extensive swelling of potato starch granules, and the swollen granules filled the whole volume of the starch pastes that were subjected to a minimum of shear. The volume of the aqueous phase outside and in the center of the swollen granules is practically negligible compared to the volume occupied by the walls of the swollen granules. The granules with the lowest gelatinization temperatures swelled quickly without restrictions, so that less water …

Effect Of Extruder Die Temperature On Texture And Microstructure Of Restructured Mechanically Deboned Chicken And Corn Starch, V. B. Alvarez, D. M. Smith, S. Flegler

Food Structure

Proximate composition, textural properties and microstructural changes of mechanically deboned chicken/15% corn starch extrudates were evaluated when restructured at die temperatures of 25, 71, 82, 93 , 104 and ll5°C in a twin-screw extruder. Total sol ids and fat content decreased, whereas protein content increased die temperatures were increased. When die temperature was increased from 71°C to 104°C, apparent stress at failure of extrudates increased by 44 kPa , but decreased at a die temperature of 115°C. Changes in the protein matrix, fat globules and starch granules due to changes i n extruder die temperature were observed by scanning electron …

Application Of Scanning Electron Microscopy And X-Ray Microanalysis To Investigate Corrosion Problems In Plain And Enamelled Three Piece Welded Food Cans, James E. Charbonneau

Food Structure

Scanning Electron Microscopy (SEM) and X-Ray Microanalysis (EDS) have been used to investigate rapid detinning, pitting corrosion and cosmetic corrosion in plain tin plate food cans and pitting corrosion, underenamel corrosion, enamel flaking , sulfide black corrosion and stress corrosion cracking in enamelled food cans.

Through the use of SEM - EDS it was determined that (SnL a /FeK a) Y2 X -ray line intensities arc proportional to the tin coating weight on tinplate. The method was applied to a rapid detinning problem in canned grapefruit sections. The cause of the early corrosion failure was found to be reversed tinplate. …

Magnetic Resonance Imaging Of Cheese Structure, M. Rosenberg, M. J. Mccarthy, R. Kauten

Food Structure

Cheese quality and quality evaluation are important in the production and marketing of cheeses. The commercial value and acceptability of bard and semi-bard cheeses are greatly affected by the cheese structure and body features. This is a feasibility study using magnetic resonance imaging (MRI) techniques to evaluate cheese structure.

The results indicate that MRI is a non-destructive method which can provide high resolution images of the inner structure of cheeses, particularly the presence of air and whey pockets as small as 0.1 x 0.1 x I mm. It may be used to study and evaluate eye structure, size, and distribution …

Relationship Between Microstructure And In Vitro Digestibility Of Starch In Precooked Leguminous Seed Flours, Juscelino Tovar, Alicia De Francisco, Inger Bjorck, Nils-Georg Asp

Food Structure

Precooked flours (PCFs) were prepared by milling boiled and freeze-dried red kidney beans, white beans and lentils. As demonstrated by scanning electron microscopy, PCFs were rich in relatively large particles which contained cell structures filled with starch. In contrast, flours from raw seeds contained a large number of free starch granules. The in vitro a-amylolysis rate ofPCFs was remarkably low, but increased after physical and chemical treatments of the flours. Homogenization resulted in the largest increase of hydrolysis rate. The susceptibility to enzymatic hydrolysis was also enhanced when PCFs were preincubated with pepsin or submitted to additional boiling. These treatments …

Recent Developments In The Application Of X-Ray Microanalysis To The Study Of Food Systems, B. E. Brooker

Food Structure

Low temperature scanning electron microscopy in conjunction with X-ray microanalysis can be used to study not only the internal structure of intact bulk food systems but also the distribution of their constitutive chemical elements. However, the considerable practical problems that are usually encountered when performing X-ray analysis on frozen samples include: a) the controlled deposition of a good quality carbon film to prevent charging, b) producing digital elemental distribution maps of elements whose X-ray spectral energy peaks partially or completely overlap and c) controlling the plane of fracture through the specimen and ensuring that the resulting topography allows meaningful analysis …

Microstructure Of Adzuki Beans (Vigna Angularis Cv. Express), Anup Chilukuri, Barry G. Swanson

Food Structure

Scanning electron microscopy (SEM) was used to study and compare the mic rostructure of adzuki, black and Mexican red bean seeds. The two cotyledons of the beans were separated by a deep fissure. A view of seed coat surface of adzuki beans revealed a characteristic pattern of convolutions and cracks, not observed on the seed coat surfaces of black or red beans. The cro sssection of seed coat of adzuki beans exhibited a thick layer of palisade cells in the epidermal layer followed by underlaid multiple layers of tightly packed parenchyma cells. A sub-epidermal layer comprised of a single layer …

Nonfat Dry Milk, Charlotte P. Brennand

All Archived Publications

No abstract provided.

Nonfat Dry Milk, Charlotte P. Brennand

Archived Food and Health Publications

Publication gives drink and dessert recipes that use nonfat dry milk.

Comparison Of The Effects Of Three Different Grinding Procedures On The Microstructure Of "Old-Fashioned" Non-Stabilized Peanut Butter, Clyde T. Young, William E. Schadel

Food Structure

Three different grinding procedures were utilized to prepare "old-fashioned" non-stabilized peanut butters. A leading commercial brand of stabilized peanut butter was used for comparison. The microstructure of each non-stabilized peanut butter was then evaluated with light microscopy and compared to the microstructure of the commercial brand of stabilized peanut butter. Major findings include: (1) dense spatial relationships of protein bodies, starch grains, and cell and tissue fragments that exist in "old-fashioned " non-stabilized peanut butter as compared to the well-dispersed spatial relationships which exist in commercially prepared stabilized peanut butter; and (2) degree of homogenization in the nonstabilized peanut butters …

Practical Methods For Identification Of Rice Endosperm Protein Bodies And Fecal Protein Particles In Light Microscopy, D. L. Barber, J. N. A. Lott, D. A. Harris

Food Structure

Indigestible 1-3 ~m protein 'cores', particles that originate from protein bodies of rice endosperm, were examined in bright-field and fluorescence microscopy, using a variety of histological and histochemical procedures. Our application of histological, histochemical and chemical approaches to a study of the feces of aoimals fed rice-containing diets has resulted in the development of methods for routine identification of insoluble rice fecal protein particles. For the specific identification of rice endosperm storage protein, whether protein bodies, cores or fecal protein particles, aqueous eosin Y stain in conjunction with fluorescence microscopy, and a combination of orange G + aniline blue in …

Textural And Microstructural Properties Of Frozen Fish Mince As Affected By The Addition Of Nonfish Proteins And Sorbitol, K. S. Yoon, C. M. Lee, L. A. Hufnagel

Food Structure

Changes in textural and microstructural properties of washed and unwashed frozen fish mince were studied as affected by the addition of non fish proteins (soy protein isolate, milk protein isolate, egg white, and wheat gluten at 2 , 4 or 6%) and 6% crystalline sorbitol. Soy and milk proteins and sorbitol reduced the hardness of frozen fish mince, while egg white and wheat gluten made the texture firmer without rubberiness developing after frozen storage. All nonfish proteins and sorbitol stabilized the myofibrillar organization by reducing freeze-induced contraction of myofibrils.

The mechanisms of reducing texture hardening appear to be different between …

Effects Of Phosphate And Citrate On The Gelation Properties Of Casein Micelles In Renneted Ultra-High Temperature (Uht) Sterilized Concentrated Milk, Donald J. Mcmahon, Paul A. Savello, Rodney J. Brown, Miloslav Kalab

Food Structure

Milk was concentrated to 3X (volume reduction) by ultrafiltration. Disodium phosphate and sodium citrate were added, and the milk concemrates were homogenized. The concentrates were then heated at 135°C for 50 s in a labora· tory ultra-high temperature (UHT) heating system. Rennet gels were made from heated and unheated milk concentrates and their curd firmness measured using a Fonnagraph. Gel microstructures were ex:amined by electron microscopy.

When rennet was added to unhomogenized milk concentrate before UHT heating, the resultant gel consisted of a strong protein network that encapsulated the fat globules. Pockets of milk serum were associated with the fat. …

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 …

Microstructure And Firmness Of Labneh (High Solids Yoghurt) Made From Cow's, Goat's And Sheep's Milks By A Traditional Method Or By Ultrafiltration, A. Y. Tamime, M. Kalab, G. Davies, H. A. Mahdi

Food Structure

Two types of Labneh (high solids yoghurt) were made from goat's and sheep 's milk: (a) traditional style Labneh was produced by straining yoghurt in a cloth bag, and (b) UF Labneh was made by ultrafiltration (UF) of warm yoghurt. A portion of all products were smoothened by a passage through a lactic curd homogenizer. Irrespective of their origin , the Labneh samples contained 20.5-22.5% total solids (including minerals and un-metabolized lactose), 6.7-8.2% protein, and 7.8- 8.9% fat.

Homogenization markedly decreased firmness of the goat's and sheep's Labnehs and is therefore not re~ commended in industrial production . Firmness of …

The Observation Of The Displacement Of Emulsifiers By Confocal Scanning Laser Microscopy, I. Heertje, J. Nederlof, H.A.C.M. Hendrickx, E. H. Lucassen-Reynders

Food Structure

The stability of food emulsions is an important aspect of the processing and the shelf life of many food systems. In order to control the stability, knowledge of the competitive adsorption of different emulsifiers is required. Current methods to study the displacement of emulsifiers from interfaces are rather laborious. A new method has been developed which is based on the observation of a planar interface between oil and water by fluorescent Confocal Scanning Laser Microscopy (CSLM). The displacement of fluorescein isothio-cyanate- labeled sodium caseinate by monoacylglycerols and proteins has been studied. Quantitative information on the competitive adsorption as a function …

Rheological And Microstructural Changes Of Oat And Barley Starches During Heating And Cooling, K. Autio

Food Structure

Microstructural and rheological changes in barley and oat starch dispersions during heating and cooling were studied by light microscopy and dynamic viscoelastic measurements. The two starch pastes showed similar viscoelastic properties after gelatinization, but during cooling the 20% barley starch pastes heated at 95°C underwent a sharp transition in viscoelastic behaviour probably due to the gelation of amylose. This transition was shifted to lower temperatures at 10% starch concentration.

Microstructural studies of an 8% barley starch dispersion heated to 90°C using the smear technique showed amylose to form a network structure around the granules. The granules in starch paste heated …

Emulsifiers As Additives In Fats: Effect On Polymorphic Transformations And Crystal Properties Of Fatty Acids And Triglycerides, J. Aronhime, S. Sarig, N. Garti

Food Structure

The role of emulsifiers in polymorphic transformations of fats and fatty acids is treated in this paper. Their effect as crystal modifiers in solution-mediated transformations (in fatty acids) is compared to that of a dynamic controller of polymorphic transformations in triglycerides. The importance of chemical structure both in the hydrophilic and in the hydrophobic moieties of the emulsifier for an inhibitory effect on phase transitions has been emphasized. The emulsifier solubility and crystallization behavior in different solvents are probably the main factors affecting its ability to interfere with the kinetics of solution-mediated transformations. On the other hand, certain requirements for …

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

Cheese Industry Conference

No abstract provided.

Gelatin Of Myosin Filament Under High Hydrostatic Pressure, Katsuhiro Yamamoto, Takeo Miura, Tsutomu Yasui

Food Structure

Gelation of myosin filaments under high hydrostatic pressure was investigated. At room temperature myosin filaments in 0.1 M KCl and 20 mM phosphate, pH 6.0, formed gels at 280 MPa and a protein concentration above 2 mg/ml or at 210 MPa and 3 mg/ml. However, no pressure-induced gelation was observed at 140 MPa. The gel strengths of pressure-induced gels were almost proportional to the protein concentration and they were comparable to those of heat-induced gels. The association of myosin filaments and the structural disturbance seemed to coincide with the formation of the gel. The microstructure of the pressure-induced myosin gel …

Crystal Morphology Of Shortenings And Margarines, P. Chawla, J. M. Deman, A. K. Smith

Food Structure

An improved method is proposed for isolation of fat crystals with isobutanol, followed by fixation using osmium tetroxide vapours or cryo-fixation and visualization in the Scanning Electron Microscope (SEM). The cryo-fixation method revealed the presence of well defined needle-shaped or rod-shaped fat crystals. The osmium fixed crystals did not appear as distinct. The crystals existed as single crystals, platelets and spherulites. Polarized light micrographs did not show the details of the crystal morphology that were observed in the SEM.

Microstructure Of Peanut Seed: A Review, Clyde T. Young, William E. Schadel

Food Structure

Mature peanut seed microstructure of importance to the food industry is examined with regard to: (1) anatomy and cytology of peanut seed; (2) the effects of environment on peanut seed; and (3) the effects of various processing procedures on peanut seed. Current peanut seed microstructure research by the authors is directed toward evaluation of the quality of processed peanuts including using TEM, SEM and LM to evaluate the effects of different times of oven roasting at the same temperature, and a method for evaluating quality of homogenization of broken cell and tissue fragments, protein bodies and starch in stabilized peanut …

The Microstructure Of Raw Meat Batters Prepared With Monovalent And Divalent Chloride Salts, Andre Gordon, Shai Barbut

Food Structure

Cold stage scanning electron microscopy (cryo-SEM), transmission electron microscopy (TEM) and light microscopy (LM) were used to examine the effect of NaCl (2.5%), MgC1₂ , CaC1₂ , KCl, LiCl (calculated ionic strength, IS = 0.43) and 1.5% NaCl (IS = 0.26) on the microstructure of comminuted raw meat batters (fat added) and comminuted meat mixes (no fat added). Cryo-SEM revealed that comminuting the lean meat with different chloride salts resulted in the formation of different types of gel structures. Differences were mainly in gel strand thickness, the degree of interlinking between strands and the size of pores within …

Purification And Immunological Reactivity Of Commercial Microbial Milk Clotting Enzyme Preparations, Chima I. Osuala

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Commercial microbial milk clotting enzyme preparations were purified by immunoaffinity chromatography using purified antibody covalently coupled to porous glass beads as the column matrix. Commercial enzyme preparation diluted in 1 mM sodium acetate buffer at pH 5.0 was then biospecifically adsorbed to the column matrix by end-over-end mixing of the glass-antibody complex in the enzyme solution for 12 h at 5°C. The antibody bound enzyme adsorbed glass beads were soaked in .2 M glycine or ethanolarnine at pH 7.0 to block uncoupled reactive sites on the matrix. Following this, the column was washed with 1 mM sodium acetate …

Simulation Of A Penetrometric Test On Apples Using Voronoi-Delaunay Tessellation, Alain-Claude Roudot, Francois Duprat, Eric Pietri

Food Structure

A penetrometer is very useful for evaluating fruit firmness, but no systematic study yet exists on the physical significance attributed to the curve variations. A tissue model, based on computer graphic methods, allows the simulation of penetrometric tests on apples. There are varying physical factors such as intercellular space, cell arrangement, cell stiffness and tissue cohesion. The real forward limit of the plunger may take, and curve fluctuations are due to the periodic evacuation of those cells. The most influential factor in a penetrometric measurement is individual cell stiffness, its variation with depth can be evaluated with the curve mean …

Development Of Sorghum (Sorghum Bicolor (L.) Moench) Endosperm In Varieties Of Varying Hardness, J. M. Shull, A. Chandrashekar, A. W. Kirleis, G. Ejeta

Food Structure

Factors responsible for grain hardness in sorghum are not well understood. Therefore, a study was undertaken to observe differences in the developmental processes of three sorghum varieties which vary in endosperm texture: hard, intermediate, and soft. Grain samples were collected at 5 day intervals beginning at 5 days after half-bloom (DAHB) until physiological maturity (40 DAHB) and prepared for viewing with scanning electron microscopy and transmission electron microscopy.

Comparisons were made between vitreous and floury endosperm portions of each variety and among the three varieties. The major difference between vitreous and floury endosperm was the degree to which the protein …

The Adsorption Of Crystalline Fat To The Air-Water Interface Of Whipped Cream, B. E. Brooker

Food Structure

The interfacial structure of air bubbles in normal and defective whipped creams were compared, using freeze fracturing and transmission electron microscopy , in an attempt to understand the underlying mechanism of t he observed gross differences in their whipping times and overruns . In normal whipped creams sparsely distributed fat crystals were found to have penetrated some of the bubbles and were lying in the plane of the air/water interface.

In defective whipped creams , large numbers of needle-like crystals had penetrated the air/water interface of every bubble and, as a consequence, reduced numbers of fat globules were found to …

Identification And Characterization Of Cocoa Solids And Milk Proteins In Chocolate Using X-Ray Microanalysis, B. E. Brooker

Food Structure

X-ray microanalysis was used to compare the elemental composition of isolated cocoa solids with milk powder. Whereas mllk powder contained similar high levels of calcium and potassium, cocoa sol ids were rich in potassium but contained very small amounts of calcium.

This difference in elemental composition allowed the two populations of particles to be distinguished in digital X-ray maps of frozen and fractured samples of plain , milk and white chocolates examined by cryo-scanning electron microscopy. The size distributions of particles imaged in this way were determined using standard software and were used to distinguish between two white chocolates whose …

Thermotropic Behavior Of Coconut Oil During Wheat Dough Mixing: Evidence For A Solid-Liquid Phase Separation According To Mixing Temperature, Christine Le Roux, D. Marion, H. Bizot, D. J. Gallant

Food Structure

Freeze fracture electron microscopy and differential scanning calorimetry were used to study the behavior of coconut oil during cake batter processing. The greatest modifications of fat crystallization are due to the mixing temperature of batter more than the physical state of the fat before is incorporation and the wheat flour hydration. mixing at a temperature below the melting point of coconut oil involves a liquid/solid fat segregation in the cake batter. The endogenous wheat flour lipids and proteins appear to stabilize this fat partition. These results are likely related to previous observations which correlate loaf volume and mixing temperature of …

Porosity, Specific Gravity And Air Content In Blue Cheeses, K. M.K. Kebary, H. A. Morris

Food Structure

Porosity and specific gravity were determined in Blue cheeses made from (A) homogenized 14% fat pasteurized cream standardized to 3.9% fat with pasteurized skim milk, (B) homogenized 14% fat raw cream standardized to 3.9% fat with raw skim milk, and (C) pasteurized milk (3.9% fat). There were no significant differences between cheeses made from (A) a nd (B) in porosity and specific gravity. Cheeses made from (A) and (8) had greater porosity, lower specific gravity and more, but smaller holes than cheese made from (C). The negative linear relation ship between porosity and specific gravity, and the insignificant differences in …