Food Science Commons^™

Can Antibiotic Test Kits Be Useful?, Bart Weimer

Archived Food and Health Publications

Publication discusses whether or not antibiotic test kits are useful and what the various results mean.

Ua12/12 Your Healthstyle, Wku Wellness Center

WKU Administration Documents

Newsletter created by the Wellness Center regarding services, health and fitness.

Collapse Of The Proton Motive Force In Listeria Monocytogenes Caused By A Bacteriocin Produced By Pediococcus Acidilactici, Douglas P. Christensen, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

The effect of pediocin JD, a bacteriocin produced by Pediococcus acidilactici JD1-23, on the proton motive force and proton permeability of resting whole cells of Listeria monocytogenes Scott A was determined. Control cells, treated with trypsin-inactivated bacteriocin at a pH of 5.3 to 6.1, maintained a pH gradient and a membrane potential of approximately 0.65 pH unit and 75 mV, respectively. However, these gradients were rapidly dissipated in cells after exposure to pediocin JD, even though no cell lysis had occurred. The pH gradient and membrane potential of the producer cells were also unaffected by the bacteriocin. Whole cells treated …

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) …

Changes Over Time In Sensory Thresholds Of Individuals With Diabetes Mellitus And The Relationship To Food Preference, Marnie Ricks Spencer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of time on taste threshold was examined in 30 diabetics and 30 control subjects (ages 22-30) who had participated in a sensory study 14 years previously. Detection and recognition taste thresholds for sweet (sucrose), salty (sodium chloride), sour (citric acid), and bitter (quinine sulfate) were assessed using triangle testing. Food preferences related to concentration of the stimuli in model food systems were tested using a nine-point hedonic scale. Mashed potatoes were used as the carrier for different levels of salt. A beverage composed of water, sucrose, and citric acid was varied to measure preferences for sweet and sour …

The Role Of Lactose In The Age Gelation Of Ultra-High-Temperature Processed Concentrated Skim Milk, Venkatachalam Narayanaswamy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this research was to relate lactose reactivity and age gelation of UHT processed concentrated milk. Skim milk was pasteurized, diafiltered batchwise to reduce lactose concentration to less than 0.05%, and UF concentrated to 3X (one-third volume reduction). Lactose and sucrose were then each added at 3% or 6% w/v to part of the concentrate. The five samples, control (

All samples stored at 4°C and 20°C gelled after 21 weeks of storage. The viscosity changed slightly during the first 19 weeks of storage but increased suddenly (> 100 cPs) just before gelation. Samples stored at 35°C did …

Effects Of Stabilizers And Ph Adjustments On Milk Proteins In Uht-Treated Citrus Juice/Skim Milk Blend Drink, Sandra M. Newman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A UHT-processed skim milk (85%)/orange juice (15%) drink was developed. Product integrity and stability were maintained by two methods. Proper homogenization of the blend before UHT processing stabilized a drink formulation containing .25% carboxymethyl cellulose and .025% carrageenan. Adjusting the pH of the blend (pH 6.3 and 6.5) resulted in a different stabilization. After 28 days at room temperature, settling of milk solids was 5.2% of volume height in the prehomogenized sample and 86.9% of volume height in the same blend that had not been homogenized prior to UHT processing. After storage, the two treatments were analyzed to verify that …

A New Method For Measuring Macroparticulate Systems Applied To Measuring Syneresis Of Renneted Milk Gels, Jonathan R. Maynes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Syneresis is an integral part of cheese manufacture. The rate and extent of syneresis affect the properties of cheese. There are many factors that affect syneresis, but measured results vary because of inaccuracies in measuring techniques. To better control syneresis, an accurate mathematical description must be developed. Current mathematical models describing syneresis are limited because of inherent error in measuring techniques used to develop them. Developing an accurate model requires an accurate way to measure syneresis.

The curd becomes a particle in a whey suspension when the coagulum is cut. The most effective technique to measure particle size, without interference, …

Effects Of Potassium Lactate, Encapsulated Citric Acid And Storage Temperature On Microbial Growth And Shelf Life Of Pork Sticks, Yen-Kan Su

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A new product, pork sticks, was developed. Optimum shelf life and safety were major concerns associated with this product. Potassium lactate (3%) or citric acid (0.5%, 0.56%, 0.60% or 0.66%) was added to pork sticks to determine their effects on microbial growth, sensory evaluation, and shelf life when stored frozen (-20°C), refrigerated (2°C), or at room temperature (22°C). Two raw materials, pork blade meat (shoulder meat; 91% lean, 9% fat) and regular 80:20 pork trim (80% lean, 20% fat) were used. The consumer panel preferred lean pork sticks made from blade meat over high-fat pork sticks made from regular 80:20 …

Properties Of Low-Fat Yogurt Made From Ultrafiltered And Ultra-High Temperature Treated Milk, Richard Alan Dargan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Yogurts were made from intermediate-high temperature (100, 110, 120, and 130°C for 4 or 16 s), ultra-high temperature (140°C for 4 or 16 s), and vat heat (82°C for 20 min) treatments of skim milk fortified to 5% protein by either ultrafiltration or the addition of nonfat dry milk (NDM). Whey protein denaturation in heated milks increased with temperature and holding time from indirect plate heating and was highest in vat-heated milks. Whey protein denaturation and yogurt water-holding capacity increased with protein levels in the fortified milks compared to skim milk. Penetrometer gel strength and stirred viscosity in 21 day-old …

Zeta-Potential Of Casein Micelles As A Factor In Age Gelation Of Ultra-High Temperature Processed Concentrated Skim Milk, Douglas W. Olson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of ultra-high temperature processing by direct steam injection and room temperature storage of pH-adjusted and unadjusted 3X (volume reduction) skim milk retentate and the effect of storage at various temperatures of 3X skim milk retentate without pH adjustment on their ζ-potential, viscosity, and pH were determined. Pasteurized skim milk was concentrated to 3X by ultrafiltration. In the pH study portions of skim milk retentate were adjusted to pH 6.38 ± .02 with HCl and 6.85 ± .01 and 7.32 ± .02 with NaOH between ultrafiltration and ultra-high temperature processing. In the storage temperature study, storage temperatures used for …

Characterization Of Pigments Responsible For Red Or Pink Discoloration In Cooked Pork, Viswasrao M. Ghorpade

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The pigments responsible for pink or red discoloration in cooked vacuum-packaged meat products {bratwurst (pork and beef), ground pork, and pork roasts} were investigated. In bratwurst, this study attempted to characterize the red pigment that appears upon refrigerated storage, and to determine the effect of pH, cooking and storage temperature, and sodium lactate on incidence of red discoloration. Myoglobin was identified in the exudate of samples with red discoloration. Myoglobin levels of cooked products were significantly lower in samples of low initial pH (5.5) or cooked to higher than normal internal temperature (74°C). Red discoloration was associated with microbial growth. …

Influence Of Process Parameters In The Manufacture Of Cottage Cheese Curd From Ultrafiltered Skim Milk, Ronald Michael Raynes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A processing procedure for the manufacture of directly acidified cottage cheese curd from 16% total solids ultrafiltered retentate was developed. The effects of preacidification of skim milk before ultrafiltration and heat treatment of retentate were investigated to improve the functional and sensory qualities of retentate curd.

Retentate directly acidified with phosphoric acid and glucono-delta-lactone to pH 4.7 formed a dense, rubbery curd that could not be handled well in a vat. A heat treatment of 71.1°C for 30 min applied to the retentate resulted in a curd with acceptable handling properties. However, this heat treatment caused the curd to shift …

Estimation Of Selected Milk Protein Genetic Variants By Multi-Component Analysis Of Amino Acid Profiles, Carol M. Hollar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Cation-exchange fast protein liquid chromatography separated whole casein into β-casein A², A¹, and B, K-casein, α_s1-casein, and α_s2-casein fractions as well as γ-caseins and several unidentified peaks using a urea-acetate buffer at pH 5 and a NaCl gradient. The whole casein fractions eluted in the following order: breakdown products of β-casein and unidentified peaks; β-casein A², A^l, and B; additional breakdown products of β-casein and unidentified peaks; K-casein; α_s1-casein; and α_s2-casein. The calculated composition of the four major caseins correlated well with values obtained …

Pesticide Use On Apples Grown In Connecticut: 1990, James L. Turner Ii, Candace L. Bartholomew

Storrs Agricultural Experiment Station

No abstract provided.

A Low-Temperature Scanning Electron Microscopy Study Of Ice Cream. Ii. Influence Of Selected Ingredients And Processes, K. B. Caldwell, H. D. Goff, D. W. Stanley

Food Structure

The objective of this study was to examine the influence of processing parameters, viz., incorporation of polysaccharide stabilizers, freezing rates, and storage times and temperatures on the microstructure of ice cream. As the freezing rate was reduced, ice crystals and air bubbles increased in size. However, quenchfreezing also contributed to poor texture; thus an optimum freezing rate exists for the production of suitably- sized ice crystals and texture in ice cream. Model systems of polysaccharide stabilizer solutions were seen to have a characteristic network structure when quenchfrozen which was altered by the addition of sucrose. Stabilized ice cream initially had …

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 …

Ultrastructural Changes In Cherimoya Fruit Injured By Chilling, Margarita Gutierrez, Maria Del Mar Sola, Luis Pascual, Maria Isabel Rodriguez-Garcia, Alberto M. Vargas

Food Structure

Cherimoya (Annona cherimola Mill.) is an important fruit crop that is grown in the South of Spain. Ultrastructural modifications of cherimoya fruit were studied after low-temperature storage. When cherimoya was stored at 4 oc for 6 days, the starch grains did not suffer degradation and the cell walls remained intact. The membrane systems were severely damaged , result ing in a loss of cell compartmentalization. Cherimoya rewarmed to 22 0 C after 9 days of low temperature storage is not able to recover , showing the irreversibility of the ultra structural changes. In addition, disorgani zation of the internal lamella …

Thermal Processing Effects On Rice Characteristics, Shuh-Ming Chang, Hsiu-Chen Yang

Food Structure

Whole kernels of four cultivars of milled rice were treated under different conditions according to our traditional methods such as boiling, steaming, autoclaving or roasting with sand. During the vari ous processing conditions, the moisture contents of the kernel , heating temperatures, pressures and heating times were varied. In this paper, the physicochemical properties of those processed samples were investigated and compared.

Based on degree of gelatinization , water absorption index , water solubility index , swelling power, viscoamylograms and X-ray diffraction patterns, the propenies of waxy rice samples arc different from that of non -waxy rice samples. They are …

Summer Salad Recipes, Utah State University Extension

All Archived Publications

No abstract provided.

A Moving Optical Fibre Technique For Structure Analysis Of Heterogeneous Products: Application To Different Foodstuffs, J. C. Akkerman, C. G. J. Bisperink, A. D. Ronteltap

Food Structure

The macro structure of many soft heterogeneous products can be studied by a moving optical fibre technique . The method i s based upon an optical sensor that penetrates into the heterogeneous medium. The optical sensor discriminates between materials differing in refractive index or in scattering properties. Coupling of the signal of the optical sensor to its position reveals the spatial distribution of the materials in the product. Applications shown include bread, soft ice-cream, chocolate mousse and draining curd. The major advantages of the method are its speed and ease; moreover, the sample is hardly disturbed by the sensor. The …

Objective Measurement Of The Visual Aspect Of Dry Sausage Slices By Image Analysis, A-C. Roudot, F. Duprat, M.-G. Grotte, G. O'Lidha

Food Structure

The visual aspect of food is a problem very often neglected for different reasons; one being the difficulty of modelling vision. However, it has been shown that , on simple synthetic images, automatic sorting in the same manner as human vision is possible.

Distribution heterogeneity of spots within an image is one important parameter for its characterization. A new algorithm was tested over simple numerical pictures that gave good agreement with visual appreciation. Images of twenty dry sausage slices were analyzed and different factors corresponding to aspect structure were calculated. Principal component analyst:s based on these factors all owed discrimination …

Effects Of Processing On The Microstructure Of Oat (Avena Sativa) Bran Concentrate And The Physicochemical Properties Of Isolated B-Glucans, K. Autio, Y. Malkki, T. Virtanen

Food Structure

Fluorescence microscopy was used to study the microstructure of oat cell walls during concentration of oat bran and isolation of ,B-glucans. The bran concentrate separated from c.v. Nasta contained mainly the aleurone and subaleurone endosperm layers, whereas that separated from a commercial bran mixture contained more endosperm . In contrast to Nasta, the commercial bran mixture contained ,B-glucan degrading enzymes, which survived the ,B-glucan isolation procedure. In the presence of enzymes, the solubility and yield of ,B-glucans improved but the viscosity decreased when it was measured at the same ,B-glucan concentration. For inactivation of the enzymes, 80% ethanol at 78 …

Structure And Rheology Of String Cheese, S. Taneya, T. Izutsu, T. Kimura, T. Shioya

Food Structure

String cheese samples ranging in pH from 5.0 to 5.9 were prepared by kneading Mozzarella curd and stretching it 2 to 80 times. Rheological properties were examined by compression, stress relaxation , and flow property tests. Stringiness was tested by a device specifically designed for this purpose: a standardized string was pulled from the sample at a direction perpendicular to the orientation of the curd and the amount of fibres resulting from this process was quantitated using digital image analysis.

Force-deformation curves implied that the curd prepared by kneading may be considered to be an incompressible viscoelastic body similar to …

Computer Modeling: The Adjunct Micro Technique For Lipids, J. W. Hagemann, J. A. Rothfus

Food Structure

Chemistry by computer provides access to microsystem information not readily achieved by other means. Simple computational analysis of saturated triglyceride polymorphism by molecular mechanics within constraints provided by X-ray data show that polymethylene interactions determine hydrocarbon crystal properties when they account for more than 60 percent of the total molecular interaction energy. Modeling predicts multiple , nearly equivalent, a -form triglycerides and a -form character in liquid near-crystalline triglycerides. Symmetrical molecules pack better than asymmetric molecules in a-form configurations and transform readily to 13'forms if activated sufficiently to disrupt lateral chain interaction and allow dimensional displacements during transformation. The formation …

Microstructure And Texture Of Khoa, G. R. Patil, A. A. Patel, Paula Allan-Wojtas, Miloslav Kalab

Food Structure

Khoa, a partially dehydrated milk product indigenous to India, was prepared from buffalo milk by boiling it vigorously in an open pan and reducing its volume to approximately 25% within 30 min. The hot semi-solid product (Khoa pat) was held at 20•c for 3 h (fresh, cooled Khoa) or 48 h (swred Khoa); the products were either worked with a pestle in a mortar for 5 min or were left without working.

Structural features of Khoa were studied by light microscopy and electron microscopy. Freshly prepared coo led Khoa had a granular structure consisting of protein granules several hundred micrometers …

Importance Of Enzymes To Value-Added Quality Of Foods, J. R. Whitaker

Food Structure

New uses of enzymes are of major importance for value-added quality of foods. At the production and postharvest handling levels, enzymes associated with maturation , color , texture, flavor and nutritional changes are important. Recent examples are discussed which include longer storage prior to initiation of ripening , deletion or control of genes that result in softening1 browning and other quality defects and the enhancement of genes that improve the nutritional quality of foods. At the processing level, new uses of enzymes are described to change the properties of proteins and lipids , to eliminate off-flavor in beers and sterilized …

Light Microscopy Measurements Of Ice Recrystallization In Frozen Corn Starch Pastes Using Isothermal Freeze Fixation, C. Ferrero, M. N. Martino, N. E. Zaritzky

Food Structure

Isothermal freeze fixation was used to analyze ice recrystallization by light microscopy in a 10 % (W/W) frozen corn starch paste during storage at temperatures in the range of -5 to -20 °C.

Different formulations were tested in order to obtain a suitable fixative for this method of indirect observation of the ice crystals. A solution of formaldehyde, ethanol and water (10:45:45 V:V) was selected because it minimized substitution-induced distortion and contraction of the matrix. The diffusion coefficients of the selected fixative in the frozen system were measured at different temperatures in conditions of unidirectional mass transfer in a semi …

Scanning Electron Microscopy And Ultraviolet Absorption Microspectrophotometry Of Plant Cell Types Of Different Biodegradabilities, D. E. Akin, L. L. Rigsby

Food Structure

Phenolic components within cell walls are the greatest limitation to biodegradation of plants, but the location and types of compounds within specific walls are poorly understood . Leaf blades of warm-season (Coastal and Coastcross-1 bermuda grasses and sudangrass) and cool-season grasses (orchardgrass and tall fescue) and leaflets of legumes (alfalfa and lespedeza) were evaluated before and after incubation with rumen microorganisms for 7 days to determine cell types and wall structures most resistant to biodegradation. UV absorption microspectrophotometry was used to characterize aromatics within selected undegraded cell types, which had been shown in digestion studies to vary in biodegradability, from …

Heat-Induced Structural Changes In Acid-Modified Barley Starch Dispersions, K. Autio, K. Poutanen, T. Suortti, E. Pessa

Food Structure

The effect of heat treatment on the gel formation and microstructure of barley starch dispersions , hydrolyzed with I M HCI for 0.5, 1.0 and 4.0 hours , was studied by dynamic viscoelastic methods and by light microscopy . The effects of acid hydrolysis on the molecular weight of amylopectin and amylose were studied by high -performance liquid chromatography (HPLC) with post-column iodine staining.

Microstructural studies of 8% hydrolyzed barley starch dispersions heated to 90 0 C showed that even a short acid treatment induced considerable changes in the granule structure. The molecular weight of amylopectin decreased substantially. As the …