Food Science Commons^™

Transmission And Scanning Electron Microscopy Of Peanut (Arachis Hypogaea L. Cv. Florigiant) Cotyledon After Roasting, Clyde T. Young, William E. Schadel

Food Structure

Changes in the microstructure of peanut (Arachis~ L. cv. Florigiant) cotyledon after roasting at a temperature of 160°C for 16 minutes were investigated with transmission and scanning electron microscopy. Thermal modifications were documented with photomicrographs of t he cytoplasmic network , protein bodies, starch grains and cell-to-cell junctions after oven roasting. These thermal modifications include disruption of the cytoplasmic network, distension of protein bodies, decreased stain affinity of starch grains , and disintegration of middle lamellae in some cell-t o-cell junctions.

Microscopic Measurement Of Apple Bruise, N. K. Kim, Y. C. Hung

Food Structure

Microstructural differences between unbruised and bruised apple tissues were evaluated. Cell connections appeared to be looser in bruised tissue than in unbruised tissue. Bruised tissue exhibited more empty regions which are not occupied by cells than unbruised tissue. Empty reg ions in unbruised and bruised tissues were about 0.7 and 2.4 per mm2, respectively, comprising 0.7% and 2.7% of the respective total volume. Stereology is a body of mathematical methods relating three-dimensional parameters defining a structure to two- dimensional measurements. Two methods based on a stereological principle were also used to quantify the fraction of total volume occupied by cells. …

The Role Of Cell Wall Structure In The Hard-To-Cook Phenomenon In Beans (Phaseolus Vulgaris L.), Ilan Shomer, Nachman Paster, Pinhas Lindner, Rosa Vasiliver

Food Structure

Differences in structure, water uptake and efflux of solubles were found between normal and hard-to-cook beans (Phaseolus vulgaris L.) The staining characteristics of hard beans were different from those of the normal in both non-cooked and cooked tissue, especially in the cell walls. The three zones of the cell wall - the middle lamella, the primary and the secondary walls - were found in both normal and hard-to-cook beans. The primary cell wall of both normal and hard beans was partially degraded upon cooking, as seen by bright fields within the fibrillar pattern. The ultrastructure of the non-cooked secondary cell …

The Use Of The Scanning Electron Microscope In Investigating Container Corrosion By Canned Foods And Beverages, E. J. Helwig, H. E. Biber

Food Structure

Over the years the canned food industry has experienced corrosion problems with some foods packed in metal containers. Although most of these are minor, the net e ffect can represent significant financial loss in the industry. It is important to determine the cause of these problems, not only to assign proper responsibility but a lso to avoid recurrence of the probl em in the future. The scanning electron microscope SEM, coupled with energy dispersive x-ray microanalysis, plays an important role in these studies. Stress corrosion cracking in packs of tuna and potatoes, pitting corrosion related to light colored fruits, and …

Light And Scanning Electron Microscopy Of The Peanut (Arachis Hypogaea L. Cv. Florunner) Cotyledon After Roasting, Clyde T. Young, William E. Schadel

Food Structure

Changes in the microstructure of peanut (Arachls ~ L. cv Florunner) cotyledons after roasting at a temperature of 160°C (16 min) were investigated with light and scanning electron microscopy. Major changes included: (1) pitting and pock -marking of the epidermis of the cotyledons caused by the escape of steam and on released during roasting; (2) loss of cellular organization of the cytoplasmic network surrounding the Jipid bodies, protein bodies, and starch grains ; (3) alteration of the structures of cytoplasmic network. lipid bodies, and protein bodies; and (4) heat destruction of some middle lamellae of cell - t o-cell junctions.

An Enzyme/Surfactant Treatment And Filtration Technique For The Retrieval Of Listeria Monocytogenes From Ice Cream Mix, Kelly-Ann Hale, Stephanie Doores, Rosemary A. Walsh

Food Structure

This study combines an enzyme/surfactant treatment with centrifugal ion and prefiltration to solubilize food constituents in a dairy product containing listeria monocytogenes, remove the constituents by a second filtration and examine the isolated bacteria under the scanning electron microscope. Treatment of an ice cream mix with a combined 2% (w/w} trypsin and 2% (w/w) Tween 80 so lution for 20 minutes at 35 °C resulted i n proteolysis of the dairy mix without lysing the bacteria. Centrifugation at 4300 x g for 20 minutes at 5°C concentrated the bacteria in the form of a pellet which was subsequently purified through …

Microstructure And Firmness Of Processed Cheese Manufactured From Cheddar Cheese And Skim Milk Powder Cheese Base, A. Y. Tamime, M. Kalab, G. Davies, M. F. Younis

Food Structure

Processed cheese (10 different types) was made from Cheddar cheese and a cheese base produced from reconstituted skim milk powder by blending and melting with commercial emulsifying salts at 9Q<>C. In one experiment, the cheese base was subjected 10 accelerated cheese ripening by added enzyme. The finished products had 50.1- 53.5% total solids, 18.2-19.3% protein, 47.4-49.7% fat in dry matter, and 2.7-3.0% salt in water; pH was 5.3-5.4 after three months of storage at 10 C and 30 C.

The experimental cheeses were markedly firmer than the control cheeses. All processed cheeses exhibited a similar pattern of firmness whereby …

Changes In The Rheology And Microstructure Of Ropy Yogurt During Shearing, J. A. Teggatz, H. A. Morris

Food Structure

Rheological and microstructural changes that occurred in ropy yogurt during shearing were observed. Yogurt made with an exopolymer-producing (ropy) strain of Lactobacillus delbrueckii subsp. bulgaricus and non-ropy strain of Streptococcus thermophilus was subjected to an increasing shear rate from 0-833 s-1 using a Haake Rotovisco RV2. Shear stress niticeably increased to a peak value and then decreased to a plateau value as the shear rate continued to increase. Samples taken at eight different shear rates were examined by scanning electron microscopy (SEM). At low shear rates, the exopolysaccharide (EPS) existed as a filamentous network attached to the lactobacilli and casein …

Scanning Electron Microscopy: Tissue Characteristics And Starch Granule Variations Of Potatoes After Microwave And Conductive Heating, J. Huang, W. M. Hess, D. J. Weber, A. E. Purcell, C. S. Huber

Food Structure

In order to determine cytological effects of microwave heating compared to conductive heating, whole potatoes were heated in a microwave oven in plastic bags for 0.5, 1 and 2 minutes and in boiling water for 5. 10 and 20 minutes. Both heating treatments caused swelling and partial disruption of starch granules. However, as observed with scanning electron microscopy, swelling patterns of starch granules were different in potatoes using the two heating processes. In conductive heating potatoes were heated from the outside to the inside. Microwave heated potatoes were heated fairly uniformly in different regions of tubers. The weight loss of …

Fat Polymorphism And Crystal Seeding Effects On Fat Bloom Stability Of Dark Chocolate, T. Koyano, I. Hachiya, K. Sato

Food Structure

The effects of seeding with fine crystal powders on the physical properties of dark chocolate are re viewed in terms of the polymorphism and crystallization behavior of cocoa butter (CBJ and of its major fat constituents. The polymorphic structure of four symmetric mixed acids saturated -oleic-saturated (Sat-0- Sat) triacylglycerols (TAGs I [POP (1 ,3-dipalmitoyl-2- oleoyl-glyceroll ;SOS I 1 ,3-distearoyl-2-oleoyl-glycerol); AOA (1 ,3-diarachidoyl-2-oleoyl-glycerol); and BOB 11 ,3-dibehenoyl-2-oleoyl-glyceroi)J. and of tristearoylglycerol (SSSI are briefly explained. An attempt is made at replacing the currently used tempering meth ~ ad in the chocolate solidification process, by a simple cooling technique using fat seed crystals. …

The Role Of The Interfacial Protein Film In Meat Batter Stabilization, A. Gordon, S. Barbut

Food Structure

The microstructure of meat batters made with equal ionic strengths of NaCl, MgC1 2 , CaCl2 and KCl (IS- 0.43) and a reduced-NaCl batter (IS- 0.43) were examined by scanning and transmission electron microscopy. Micrographs revealed that fat globules with smooth and rough protein coats were present in all treatments. The roughly-coated globules were prevalent in the unstable batters. Pores were observed in the interfacial protein film (IPF) surrounding the globul es and were more prevalent in the globules with rough protein coats. Fat was seen to exude from the pores in both types of globules, Fat globules were shown …

Applications Of Microscopy In The Paper Industry: Case Histories Of The Mead Corporation, A. J. Leonardi, B. A. Blakistone, S. W. Kyryk

Food Structure

Microscopial application in the Mead Corporation are herein discussed: 1) defining proper starch cook for maintaining paper quality, 2) microbial degradation of paperboard used for beverage cartons, and 3) examination of high oxygen barrier plastic cups for hermetic seal and barrier construction. Visualization of the cooked starch by iodine staining and polarized light (PL) microscopy is a quick diagnostic aid to Mead mills. Scanning electron microscopy (SEM) and particularly PL proved useful in examining fiber biodegration by fungi on Coated Natural Kraft beverage cartons. Nomarski differential interference contrast (DIC), PL, and SEM aided in qualifying lid materials for Mead's Crosscheck …

The Structure-Function Relationship Of Polymeric Sorbents For Colloid Stabilization Of Beer, Gabriela Basarova

Food Structure

This review considers the research relating to the formation of non-biological haze in beer. The basic information regarding mutual interactions of haze-causing substances with precipitating, enzymatic, and adsorptive stabilizers of beer is discu ssed. The main haze-causing compounds in beer are polypeptides and polyphenols. To reduce the levels of these compounds in beer, adsorptive stabilizing agents are usually used during filt ration. Electron microscopy and methods measuring the surface and dimensions of adsorbent particles and the volumes and diameters of their pores make it possible to assess morphological properties and suitability of the stabilizers for beer filtration. Determination of the …

Effect Of High-Pressure Homogenization On A Sterilized Infant Formula: Microstructure And Age Gelation, Y. Pouliot, M. Britten, B. Latreille

Food Structure

Age thickening and gelation of an Infant formula was Induced by applying high pressure homogenization prior to in-can sterilization. The Initial viscosity of the preparation increased with Increasing homogenization pressure. Thickening rate upon storage, as monitored by viscosity changes, was also proportional to the pressure applied during homogenization. Optical and electron micrographs of 6 month-old samples showed evidence of aggregation. The effect of dissociating agents on the viscosity and microstructure of these samples suggested a contribution of hydrogen bonds and calcium bridges to the gel integrity. The alteration of the mineral balance of aged samples also Indicated a gel strengthening …

A Method For The Examination Of The Microstructure Of Stabilized Peanut Butter, Clyde T. Young, William E. Schadel

Food Structure

A method for light and scanning electron microscopy of damaged resting peanut seed tissue was adapted as a research tool for evaluating the microstructural features of commercially available stabilized peanut butter. This method was used in the present study to evaluate the degree of homogenization of stabilized peanut butter by examining the spatial relationship which exists among the microstructural features. Light and scanning electron microscopy of three commercially available stabilized peanut butters revealed varying degrees of homogenization of broken cell and tissue fragments, protein bodies, and starch grains within a matrix of stabilized oil.

The Effect Of Tumbling, Sodium Chloride And Polyphosphates On The Microstructure And Appearance Of Whole-Muscle Processed Meats, P. D. Velinov, M. V. Zhikov, R. G. Cassens

Food Structure

The properties of a whole-muscle processed meat were determined. The complex action of socium chloride, polyphosphates and mechanical agitation caused extraction of myofibrillar protein, swelling of fibers and loss of cross-strations. A new functional ability was found for the extracted proteins to form a fine cover or membrane on the surface of the whole muscle during cooking. These changes produced a product with improved cooking yield and color appearance.

Polymorphism Of Triglycerides A Crystallographic Review, L. Hernqvist

Food Structure

In order to understand I he role of fat in food systems detailed knowledge about the arrangement of triglyceride molecules is useful. The triglyceride molecules in a fat can be packed in alternative ways, each crystal form having different melting points. This phenomenon is called polymorphism.

Based mainly on X-ray studies (single-crystal, powder diffraction , scattering) and Raman spectroscopy the structure of the different polymorphic forms, a, sub-a, P'2. P't and~. are explained. The emphasis is on work done in the author's laboratory.

There is a close relationship between the polymorphic forms which is persistent also in the liquid state …

Particle Characteristics Of Flake-Cut Meat, P. R. Sheard, A. Cousins, P. D. Jolley, C. A. Voyle

Food Structure

The size of flake-cut meat is an Important quality determinant of comminuted meat products which. potentially. depends upon a large number of factors. Temperature and whether or not the meat is pre-broken have a major Influence on the resulting particle size distribution, as does aperture size. Meat flaked at -7'C produced two to three times more flakes than at -3' C. Under some conditions the particles produced were as little as 0.4 mm thick and characteristically were thicker at one end.

High speed photography, used to visualise the cutting action. Indicated that size reduction occurs In a controlled manner providing …

Preparation Of Cereals And Grain Products For Transmission Electron Microscopy, Donald B. Bechtel

Food Structure

This tutorial specifically addresses the techniques used in the processing of cereals and grain products for various aspects of transmission electron microscopy. Methods covered include sample treatment, chemical and physical fixation, dehydration, embedding, sectioning techniques, immunocytochemistry, enzymatic digestions, carbohydrate localization, and lectin binding. The primary goal is to provide information on the preparation of cereals and cereal-based products for microscopic analysis and to assist the reader in solving technical problems associated with studying cereals or other difficult-to-prepare samples.

Encapsulation Of Viscous High-Fat Foods In Calcium Alginate Gel Tubes At Ambient Temperature, Ivan A. Veliky, Miloslav Kalab

Food Structure

Viscous high-fat foods such as cream, egg yolk, or mayonnaise are co-extruded with a 3% sodium alginate solution from a syringe into a 50 mM calcium chloride solution. The food sample passes through the inner tube of a double needle assembly while the alginate solution is simultaneously extruded through a mantle surrounding the inner needle. As the sodium alginate solution forms a gel on contact with calcium ions, the food sample becomes encapsulated in the calcium alginate gel formed on the surface of the food sample. The encapsulation procedure may be carried out within a temperature range between 0 C …

Chemical Evaluation And Biological Vitamin A Activity Of The Major Carotenoids In The Hybrid Carrot Beta Iii, Cynthia M. Schweitzer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Genetically enhanced high-carotene Beta III hybrid carrot was compared to a commercial carrot cultivar, Nantes Coreless, for carotene content and macronutrient composition. Beta III contained more than twice the total carotene content of Nantes Coreless, with α-carotene/β-carotene ratios higher in Beta III. Total solids from protein, lipids, and carbohydrate were greater in Beta III than in Nantes Coreless. Beta III contained about five times the amount of sucrose and one-fifth the amount of glucose and fructose than Nantes Coreless or reported literature values.

Comparison of the bioavailability of carotenes in Beta III and Nantes Coreless to purified β-carotene and retinyl …

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 …

Plasmin In Milk: Activity Measurement, Effect Of Environmental Factors, And Correlation With Milk Coagulation, Eric D. Bastian

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bovine plasmin activity was measured on H-D-valyl-L-leucyl-L-lysyl-4-nitroanilide by following absorbance changes at 405 nm. Steady-state kinetic parameters V_max, K_m, K_I, and K_I' were estimated. Bovine plasmin is competitively inhibited by casein and has a K_cat of .0158 ΔA₄₀₅/min/nM, K_m of .107 mM substrate, and K_I of .86 mg/ml casein. Bovine plasmin can be measured directly in bovine milk without interference from casein.

A total of 380 milk samples from nineteen Holstein (one herd) and nineteen Jersey (one herd) cows was collected monthly during one lactation period. Samples …

Influence Of Processing Parameters On Nutrient Recovery During Ultrafiltration Of Milk And Meltability Of Pasteurized Process Cheese Food Made From The Retentate, Susan Kay Fortier Collinge

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three batches of milk were ultrafiltered to 60, 65, or 70% volume reduction before diafiltration. Starting diafiltration at 70% volume reduction took less time and water without affecting nutrient recovery.

Whole milk was heated to 60, 72, and 82°C for 16 s. Milk representing each heat treatment was divided into three batches, one unacidified (pH 6.6), the others acidified to pH 6.2 and 5.8. The milk was ultrafiltered, diafiltered, and concentrated to 5x (80% volume reduction). Retentate was inoculated with .5% lactic culture and incubated at 28°C to pH 5.1. Each lot of fermented retentate was evaporated under 76 kPa …

A Quantitative Assessment Of Minerals Of Toxicological Importance In Utah Fast Foods, Lisa R. Williams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

X-ray flourescence (XRF) and atomic absorption spectrophotometry (AAS) measurements for manganese, iron, copper, and zinc were compared for 96 samples of 21 foods from different sources. Correlation coefficients were 0.94 for manganese, 0.99 for iron, 0.93 for copper, and 0.91 for zinc for XRF vs. AAS determinations.

Similiar comparisons were performed on 228 samples of fast foods purchased in Utah retail outlets. Correlation coefficients ranged from 0.91 for copper to 0.97 for iron and zinc. Comparisons of values generated by XRF for manganese, iron, copper, zinc, selenium, arsenic, and aluminum to values certified by the National Bureau of Standards indicated …

Proteolytic Activity Of Some Milk-Clotting Enzymes On K-Casein And K-Casein Macropeptide, Khalid M. Shammet

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This work reviews studies of bovine K-casein and specifically K-casein macropeptide. Properties of K-casein, its structure and heterogeneity, proteolytic activity of some milk clotting enzymes on K-casein, and K-casein sensitive bonds are discussed. Macropeptides of other species are also presented. The carbohydrate moieties of bovine macropeptide together with their biological and physiological functions are reviewed.

Macropeptides were produced by enzymic hydrolysis from whole casein solution using crystalline chymosin (EC 3.4.23.4). Trichloroacetic acid (final concentrations 2, 8 and 12%) was added after 5, 30 and 60 min of incubation to precipitate protein and inactivate the enzyme. The filtrate was then exhaustively …

Soluble And Insoluble Dietary Fiber In Cooked Common Bean (Phaseolus Vulgaris) Seeds, Joe S. Hughes, Barry G. Swanson

Food Structure

The common bean (Phaseolus vulgaris) requires cooking for extended periods of time prior to consumption. In this investigation both quantitative and microstructural changes in common bean dietary fiber as a result of cooking were examined. Cooking resulted in a slight decrease in soluble dietary fiber and a marked increase in insoluble dietary fiber. The increase in insoluble dietary fiber was responsible for a 15 -30 percent increase in total dietary fiber.

Scanning electron microscopy was used to examine the microstructure of uncooked and cooked bean flours and the insoluble and soluble dietary fiber fractions of these two fl ours. In …

Image Analysis Of The Fat Dispersion In A Comminuted Meat System, Peter A. Koolmees, Piet C. Moerman, Monique H.G. Zijderveld

Food Structure

In a series of experiments on a comminuted meat system, image analyses were conducted to quantify changes in structure as affected by polyphosphate, fat level, and chopping time and temperature. Four batches of comminuted meat were investigated which contained neck beef, pig head meat, rino, ice, salt (2%), fat at a level of either 27 or 40%, and polyphosphate at a level of either 0 or 0. 5%. Structural changes in different stages of comminution coincided with a shift in size distribution, shape factor, density and area percentage of fat particles. The density of the protein matrix (matrix defined as …

Vacuole Formation In Wheat Starchy Endosperm, D. B. Bechtel, A. Frend, L. A. Kaleikau, J. D. Wilson, P. R. Shewry

Food Structure

The formation of vacuoles in wheat (Triticum aestivum cv. Highbury) starchy endosperm cells was studied using electron microscopy. Some vacuoles were always present, even in the coenocytic cytoplasm. The first formed endosperm cells were highly vacuolated, but became filled with cytoplasm as they grew older. Various-sized pieces of cytoplasm were found in vacuoles of developing endosperm cells, probably as a result of autophagic sequestration. The membranes of the autographic vacuoles appeared to originate from the rough endoplasmic reticulum and from extensions of already-formed vacuoles. Autographic activity was confirmed by localizing the hydrolytic enzyme acid phosphatase within the vacuoles. The rough …

Effect Of Heating To 200 C On Casein Micelles In Milk: A Metal Shadowing And Negative Staining Electron Microscope Study, V. R. Harwalkar, Paula Allan-Wojtas, Miloslav Kalab

Food Structure

Milk was heated to 200 C for 3 min in sealed inverted-Y-shaped glass vials and reacted with a glutaraldehyde solution at that temperature. Electron microscopy of the metal-shadowed and negatively stained samples revealed that casein micelles in the milk did not disintegrate extensively at the high-temperature used but, rather, became enlarged. Some of them were found to be either clustered or distorted.