Food Science Commons^™

Development Of Laboratory Techniques To Mimic Industrial-Scale Nixtamalization, Roxana Yglesias, Anne M. Parkhurst, David S. Jackson

Department of Food Science and Technology: Faculty Publications

A laboratory nixtamalization process was developed to imitate larger scale cooking/steeping conditions. Corn (45 kg) was cooked in a pilot plant gas-fired cook/steep tank and temperature was monitored every 30 sec. Cooling and heating rates were mimicked in the laboratory using a digital temperature programmable hot plate that adjusted grain-waterlime temperature changes at a specified rate. A Response Surface Central Composite Design was used to model pasting and thermal properties of nixtamal and masa as a function of cooking temperature (86-96°C), cooking time (20-40 min), and steeping time (3-11.77 hr). Nixtamal and masa moisture. dry matter loss, nixtamal and masa …

Ctla-4 Signaling Regulates The Intensity Of Hypersensitivity Responses To Food Antigens, But Is Not Decisive In The Induction Of Sensitization, Femke Van Wijk, Sanne Hoeks, Stefan Nierkens, Stef J. Koppelman, Peter Van Kooten, Louis Boon, Leon M.J. Knippels, Raymond Pieters

Department of Food Science and Technology: Faculty Publications

Although food allergy has emerged as a major health problem, the mechanisms that are decisive in the development of sensitization to dietary Ag remain largely unknown. CTLA-4 signaling negatively regulates immune activation, and may play a crucial role in preventing induction and/or progression of sensitization to food Ag. To elucidate the role of CTLA-4 signaling in responses to food allergens, a murine model of peanut allergy was used. During oral exposure to peanut protein extract (PPE) together with the mucosal adjuvant cholera toxin (CT), which induces peanut allergy, CTLA-4 ligation was prevented using a CTLA-4 mAb. Additionally, the effect of …

Etiology Of Oral Disease In View Of Microbial Complexity, Anne C. R. Tanner, Jacques Izard

Department of Food Science and Technology: Faculty Publications

The number of different microorganisms recognized in the oral cavity using molecular methods has more than doubled compared with the number isolated using cultural techniques. This finding necessitates a reevaluation of which species may be pathogens in dental infections. Molecular methods used to determine microbial diversity include broad range target Polymerase Chain Reaction with ‘universal primers,’ and cloning amplicons or denaturing gradient gel electrophoresis to separate DNA fragments before sequencing. These molecular methods have clarified and expanded the taxonomy of oral microbial species. Discrepancies between comprehensive molecular and cultural methods suggest that neither method alone can adequately evaluate associations of …

Functional Consequences Of Genome Evolution In Listeria Monocytogenes: The Lmo0423 And Lmo0422 Genes Encode ΣC And Lstr, A Lineage Ii-Specific Heat Shock System, Chaomei Zhang, Joseph Nietfeldt, Min Zhang, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Listeria monocytogenes strains belonging to phylogenetic lineage II (serotypes 1/2a, 1/2c, and 3a) carry a lineage-specific genome segment encoding a putative sigma subunit of RNA polymerase (lmo0423, herein referred to as sigC), a gene of unknown function (lmo0422) similar to the padR family of regulators, and a gene that is similar to the rodA-ftsW family of cell wall morphology genes (lmo0421). To understand the function of this set of genes, their expression patterns and the effects of null mutations in the lineage II L. monocytogenes strain 10403S were examined. The data are consistent with the three genes comprising an …

Periplasm Organization In Treponema Denticola As Studied By Cryo-Electron Tomography, Jacques Izard, C.-E. Hsieh, C. A. Mannella, Ronald J. Limberger, M. Marko

Department of Food Science and Technology: Faculty Publications

As a spirochete, the genus Treponema is one of the few major bacterial groups whose natural phylogenic relationships are evident at the level of gross phenotypic characteristics such as their morphology. Treponema spp. are highly invasive due to their unique motility in dense media, and their ability to penetrate cell layers. This feature is associated with the helical cell body and the presence of flagellar filaments in the periplasm. Treponema denticola is an oral pathogen involved in endodontic infections and periodontal diseases. The presence and quantity of T. denticola in the subgingival biofilm is correlated with the severity of periodontal …

Evaluation Of Liquid Nitrogen Freeze Drying And Ethanol Dehydration As Methods To Preserve Partially Cooked Starch And Masa Systems, Roxana Yglesias, David S. Jackson

Department of Food Science and Technology: Faculty Publications

Preservation of starch structure/properties. including structures formed during partial or complete cooking, are important when the impact of processing conditions is being studied. Two preservation techniques used to study changes in starch during thermal-mechanical processing are commonly cited in the literature: 1) rapid freezing followed by lyophilization, and 2) a dehydration procedure using alcohols. A comparative determination on how these methods affect various starch structures has not been widely reported. Corn starch samples were collected from the Rapid Visco-Analyser (RVA) at 3 min (swollen granules, 30°C), at the top of the pasting peak (gelatinized granules, 95°C), at the bottom of …

Measurements Of Fitness And Competition In Commensal Escherichia Coli And E. Coli O157:H7 Strains, Lisa M. Durso, David R. Smith, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Although the main reservoirs for pathogenic Escherichia coli O157:H7 are cattle and the cattle environment, factors that affect its tenure in the bovine host and its survival outside humans and cattle have not been well studied. It is also not understood what physiological properties, if any, distinguish these pathogens from commensal counterparts that live as normal members of the human and bovine gastrointestinal tracts. To address these questions, individual and competitive fitness experiments, indirect antagonism assays, and antibiotic resistance and carbon utilization analyses were conducted using a strain set consisting of 122 commensal and pathogenic strains. The individual fitness experiments, …

Development Of A Novel Chloramphenicol Resistance Expression Plasmid Used For Genetic Complementation Of A Flig Deletion Mutant In Treponema Denticola, Linda L. Slivienski-Gebhardt, Jacques Izard, William A. Samsonoff, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

A new expression plasmid containing the fla operon promoter and a staphylococcal chloramphenicol resistance gene, was constructed to help assess the role of fliG in Treponema denticola motility. Deletion of fliG resulted in a nonmotile mutant with a markedly decreased number of flagellar filaments. Wild-type fliG genes from T. denticola and from Treponema pallidum were cloned into this expression plasmid. In both cases, the gene restored the ability of the mutant to gyrate its cell ends and enabled colony spreading in agarose. This shuttle plasmid enables high-level expression of genes in T. denticola and possesses an efficient selectable …

Dna Sequence Analysis Of Regions Surrounding BlaCmy-2 From Multiple Salmonella Plasmid Backbones, W.P. Giles, Andrew K. Benson, M.E. Olson, Robert W. Hutkins, J.M. Whichard, P.L. Winokur, P.D. Fey

Department of Food Science and Technology: Faculty Publications

The emergence in the United States of resistance to expanded-spectrum cephalosporin (e.g., ceftriaxone) within the salmonellae has been associated primarily with three large (>100-kb) plasmids (designated types A, B, and C) and one 10.1-kb plasmid (type D) that carry the bla_CMY-2 gene. In the present study, the distribution of these four known bla_CMY-2-carrying plasmids among 35 ceftriaxone-resistant Salmonella isolates obtained from 1998 to 2001 was examined. Twenty-three of these isolates were Salmonella enterica serotype Newport, 10 were Salmonella enterica serotype Typhimurium, 1 was Salmonella enterica serotype Agona, and 1 was Salmonella enterica serotype Reading. All 23 …

Expanding Nebraska’S Farmers’ Markets And Increasing Consumer Awareness Of Nebraska’S Fresh, Locally Grown Fruits And Vegetables, Food Processing Center

Food Processing Center: Reports

Survey of 300 Nebraska Households Conducted in April 2004 for Nebraska Department Of Agriculture Ag. Promotions Division.

Developing Producer & Small Processor Owned Meat Marketing Enterprises, Food Processing Center

Food Processing Center: Reports

The Food Processing Center at the University of Nebraska-Lincoln, conducted a survey of meat processors in Iowa, Nebraska, Missouri, and Wisconsin in the second half of 2003. The survey was conducted as part of the North Central Initiative for Small Farm Profitability—a USDA funded initiative. The Meat Processors Association in each state provided assistance in sending surveys to over 500 meat processors. Eighty-four meat processors completed the survey for a response rate of 16%.

The survey found that small and very small meat processors in Iowa, Missouri, Nebraska and Wisconsin are actively involved in providing inspected slaughter and processing services …

Regulation Of Transcription Of Compatible Solute Transporters By The General Stress Sigma Factor, ΣB, In Listeria Monocytogenes, Mehmet Sevket Cetin, Chaomei Zhang, Robert W. Hutkins, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Listeria monocytogenes is well known for its durable physiological characteristics, which allow the organism to grow at low temperature and pH and high osmolarity. Growth under high osmolarity depends on the accumulation of compatible solutes, among which glycine betaine and carnitine are the preferred solutes for this organism. Three different transport systems, Gbu, BetL, and OpuC, have been identified in L. monocytogenes which serve to scavenge the preferred compatible solutes. The general stress response regulator σ^B has been shown to play an important role in osmotic adaptation in L. monocytogenes, presumably by directing transcription from one or more …

Regulation Of Transcription Of Compatible Solute Transporters By The General Stress Sigma Factor, ΣB, In Listeria Monocytogenes, Mehmet Sevket Cetin, Chaomei Zhang, Robert W. Hutkins, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Listeria monocytogenes is well known for its durable physiological characteristics, which allow the organism to grow at low temperature and pH and high osmolarity. Growth under high osmolarity depends on the accumulation of compatible solutes, among which glycine betaine and carnitine are the preferred solutes for this organism. Three different transport systems, Gbu, BetL, and OpuC, have been identified in L. monocytogenes which serve to scavenge the preferred compatible solutes. The general stress response regulator σ^B has been shown to play an important role in osmotic adaptation in L. monocytogenes, presumably by directing transcription from one or more …

Method For Mulching An Agricultural Soil Bed Using A Biodegradable Protein Material And A Mulched Agricultural Crop Growing Plot Produced Thereby, Yusuf Ali, Viswas Ghorpade, Robert Weber, Milford Hanna

Department of Food Science and Technology: Faculty Publications

A method is provided for mulching an agricultural Soil bed using a biodegradable protein mulch material. The method includes the preparation of a film forming Solution of a film forming protein material. The film forming protein Solution is then sprayed directly onto a Surface of an agricultural Soil bed. The solution dries to form a thin film of protein material on the Surface of the agricultural Soil bed. The protein material may comprise a plant protein, a milk protein, an animal protein, a whey protein, casein, an egg protein or gelatin. Following a harvest, the mulch material, which is biodegradable, …

Catabolite Repression And Virulence Gene Expression In Listeria Monocytogenes, Stefanie Evans Gilbreth, Andrew K. Benson, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Previous studies have suggested that carbohydrates may affect expression of virulence genes in Listeria monocytogenes. Which carbohydrates influence virulence gene expression and how carbohydrates mediate expression, however, is not clear. The goal of this work was to examine how carbohydrates affect virulence gene expression in L. monocytogenes 10403S. Growth studies were conducted in medium containing glucose and various sugars. Metabolism of arbutin, arabitol, cellobiose, mannose, maltose, trehalose, and salicin were repressed in the presence of glucose. Only when glucose was consumed were these sugars fermented, indicating that catabolite repression by glucose had occurred. To determine whether virulence gene expression …

A Consensus Protocol For The Determination Of The Threshold Doses For Allergenic Foods: How Much Is Too Much?, S. L. Taylor, S. L. Hefle, C. Bindslev-Jensen, F. M. Atkins, C. Andre, C. Bruijnzeel-Koomen, A. W. Burks, R. K. Bush, M. Ebisawa, P. A. Eigenmann, A. Host, Jonathan O. B. Hourihane, E. Isolauri, D. J. Hill, A. Knulst, G. Lack, H. A. Sampson, D. A. Moneret-Vautrin, F. Rance, P. A. Vadas, J. W. Yunginger, R. S. Zeiger, J. W. Salminen, C. Madsen, P. Abbott

Department of Food Science and Technology: Faculty Publications

Background:While the ingestion of small amounts of an offending food can elicit adverse reactions in individuals with IgE-mediated food allergies, little information is known regarding these threshold doses for specific allergenic foods. While low-dose challenge trials have been conducted on an appreciable number of allergic individuals, a variety of different clinical protocols were used making the estimation of the threshold dose very difficult.

Objective: A roundtable conference was convened to develop a consensus clinical protocol for low-dose challenge trials for the estimation of threshold doses for specific allergenic foods.

Methods: In May 2002, 20 clinical allergists and other interested parties …

Presentation Of Allergen In Different Food Preparations Affects The Nature Of The Allergic Reaction: A Case Series, K. E. C. Grimshaw, R. M. King, Julie A. Nordlee, S. L. Hefle, John O. Warner, J. O.'B. Hourihane

Department of Food Science and Technology: Faculty Publications

Background: Characterization of fatal and nonfatal reactions to food indicates that the majority of reactions are due to the ingestion of prepared foods rather than the nonprocessed allergen. In an ongoing study that used a double-blind placebo-controlled food challenge to investigate peanut allergy and clinical symptoms, the observed reaction severity in four of the first six subjects was greater than anticipated. We hypothesized that this was due to differences in the composition of the challenge vehicle.

Objective: The aim was to investigate whether the severity of observed challenge reactions would be repeated on rechallenge with a lower fat …

Tomographic Reconstruction Of Treponemal Cytoplasmic Filaments Reveals Novel Bridging And Anchoring Components, Jacques Izard, Bruce F. Mcewen, Rita M. Barnard, Thomas Portuese, William A. Samsonoff, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

An understanding of the involvement of bacterial cytoplasmic filaments in cell division requires the elucidation of the structural organization of those filamentous structures. Treponemal cytoplasmic filaments are composed of one protein, CfpA, and have been demonstrated to be involved in cell division. In this study, we used electron tomography to show that the filaments are part of a complex with a novel molecular organization that includes at least two distinct features decorating the filaments. One set of components appears to anchor the filaments to the cytoplasmic membrane. The other set of components appears to bridge the cytoplasmic filaments on the …

Functional And Comparative Genomic Analyses Of An Operon Involved In Fructooligosaccharide Utilization By Lactobacillus Acidophilus, Rodolphe Barrangou, Eric Altermann, Robert W. Hutkins, Raul Cano, Todd Klaenhammer

Department of Food Science and Technology: Faculty Publications

Lactobacillus acidophilus is a probiotic organism that displays the ability to use prebiotic compounds such as fructooligosaccharides (FOS), which stimulate the growth of beneficial commensals in the gastrointestinal tract. However, little is known about the mechanisms and genes involved in FOS utilization by Lactobacillus species. Analysis of the L. acidophilus NCFM genome revealed an msm locus composed of a transcriptional regulator of the LacI family, a four-component ATP-binding cassette (ABC) transport system, a fructosidase, and a sucrose phosphorylase. Transcriptional analysis of this operon demonstrated that gene expression was induced by sucrose and FOS but not by glucose or fructose, suggesting …

Approaching Foodservice Establishments With Locally Grown Products, Food Processing Center

Food Processing Center: Reports

This report summarizes the initial findings of a survey of members of the Chefs Collaborative organization. The Chefs Collaborative is a national network of more than 1,000 members of the food community who promote sustainable cuisine by celebrating the joys of local, seasonal and artisanal ingredients. Many of the Chefs Collaborative members have significant expertise in purchasing locally grown food products. The purpose of this research and the following report is to 1) use the expertise gained by members of the Chefs Collaborative organization in order to help producers market their products to the foodservice industry and 2) to examine …

Metabolism Of Fructooligosaccharides By Lactobacillus Paracasei 1195, Handan Kaplan, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Fermentation of fructooligosaccharides (FOS) and other oligosaccharides has been suggested to be an important property for the selection of bacterial strains used as probiotics. However, little information is available on FOS transport and metabolism by lactic acid bacteria and other probiotic bacteria. The objectives of this research were to identify and characterize the FOS transport system of Lactobacillus paracasei 1195. Radiolabeled FOS was synthesized enzymatically from [³H]sucrose and purified by column and thin-layer chromatography, yielding three main products: glucose (G) α-1,2 linked to two, three, or four fructose (F) units (GF₂, GF₃, and GF …

A Response Surface Analysis Of Commercial Corn Starch Annealing, Serap Ozcan, David S. Jackson

Department of Food Science and Technology: Faculty Publications

Native starch is composed of granules that are organized, durable, and morphologically identifiable microscopic structures of amylose and amylopectin molecules (Virtanen and Autio 1993; Snyder 1984). Sahai and Jackson (1994) reported that native starch granules from a single starch source were not homogeneous in character and had different functional properties. Because of their heterogeneity, it should not be expected that starch granules behave uniformly when heated in water (Sahai and Jackson 1996). The extent of heat treatment, starch hydration. and the inherent physical and chemical properties of native starch determine the structure and functionality of starch in a food system. …

The Safety Of Genetically Modified Foods Produced Through Biotechnology, Robert M. Hollingworth, Leonard F. Bjeldanes, Michael Bolger, Ian Kimber, Barbara Jean Meade, Steve L. Taylor, Kendall B. Wallace

Department of Food Science and Technology: Faculty Publications

The Society of Toxicology (SOT) is committed to protecting and enhancing human, animal, and environmental health through the sound application of the fundamental principles of the science of toxicology. It is with this goal in mind that the SOT defines here its current consensus position on the safety of foods produced through biotechnology (genetic engineering). These products are commonly termed genetically modified foods, but this is misleading, since conventional methods of microbial, crop, and animal improvement also produce genetic modifications and these are not addressed here.
The available scientific evidence indicates that the potential adverse health effects arising from biotechnology-derived …

Characterization Of Escherichia Coli O157:H7 From Downer And Healthy Dairy Cattle In The Upper Midwest Region Of The United States, C. M. Byrne, I. Erol, J. E. Call, C. W. Kaspar, D. R. Buege, C. J. Hiemke, P. J. Fedorka-Cray, Andrew K. Benson, F. M. Wallace, J. B. Luchansky

Department of Food Science and Technology: Faculty Publications

While cattle in general have been identified as a reservoir of Escherichia coli O157:H7, there are limited data regarding the prevalence and clonality of this pathogen in downer dairy cattle and the potential impact to human health that may occur following consumption of meat derived from downer dairy cattle. In the present study, conducted at two slaughter facilities in Wisconsin between May and October of 2001, we established a higher prevalence of E. coli O157:H7 in fecal and/or tissue samples obtained aseptically from intact colons of downer dairy cattle (10 of 203, 4.9%) than in those from healthy dairy cattle …

Genome Diversification In Phylogenetic Lineages I And Ii Of Listeria Monocytogenes: Identification Of Segments Unique To Lineage Ii Populations, Chaomei Zhang, Min Zhang, Jingliang Ju, Joseph Nietfeldt, John Wise, Phillip M. Terry, Michael Olson, Stephen D. Kachman, Martin Wiedmann, Mansour Samadpour, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Thirteen different serotypes of Listeria monocytogenes can be distinguished on the basis of variation in somatic and flagellar antigens. Although the known virulence genes are present in all serotypes, greater than 90% of human cases of listeriosis are caused by serotypes 1/2a, 1/2b, and 4b and nearly all outbreaks of food-borne listeriosis have been caused by serotype 4b strains. Phylogenetic analysis of these three common clinical serotypes places them into two different lineages, with serotypes 1/2b and 4b belonging to lineage I and 1/2a belonging to lineage II. To begin examining evolution of the genome in these serotypes, DNA microarray …

Wheat Tortilla Quality: Impact Of Amylose Content Adjustments Using Waxy Wheat Flour, G. Guo, David S. Jackson, Robert A. Graybosch, Anne M. Parkhurst

Department of Food Science and Technology: Faculty Publications

Amylose content is closely related to wheat flour pasting or thermal properties, and thus affects final food qualities. Fourteen flour blends with amylose content ranges of < 1 to 29% were used to study tortilla production and quality parameters. Reduced amylose contents decreased dough stickiness and pliability; low amylose doughs were also very smooth in appearance. Very low flour amylose content was associated with earlier tortilla puffing and poor machinability during baking, darker color, low opacity, larger diameters, and reduced flexibility after storage. Tortilla texture analysis indicated that lowering amylose content gave fresh tortillas higher extensibility; after three or more days storage, however, low amylose flours required more force to break the tortillas and the rupture distances became shorter. These results, as reflected in covariate analysis, were not significantly reflected by the flour blend's protein content, swelling volume/power, SDS-sedimentation volume, mixograph dough development time, or mixograph tolerance score. Based on our observation of an initial increase in extensibility with reduced-amylose tortillas, adding 10-20% waxy flour into wild-type flours should be ideal for restaurant (on-site) tortilla production or circumstances where tortillas are consumed shortly (within a day) after production. The optimal flour amylose content for hot-press wheat tortilla products is 24-26%.

Asian Salted Noodle Quality: Impact Of Amylose Content Adjustments Using Waxy Wheat Flour, G. Guo, David S. Jackson, Robert A. Graybosch, Anne M. Parkhurst

Department of Food Science and Technology: Faculty Publications

Fourteen flour blends of two natural wild-type wheat (Triticum aestivum L.) flours, 'Nuplains' and 'Centura', blended with one waxy flour sample were characterized and processed to Asian salted noodles. The flour amylose content range was

Gelatin Manufacturing Process And Product, Vesselin D. Miladinov, Aristippos Gennadios, Milford A. Hanna

Department of Food Science and Technology: Faculty Publications

The present invention overcomes the deficiencies of the prior art by providing a process for manufacturing gelatin including cleaning a fowl-based source of collagen; subjecting the fowl-based source of collagen to at least one water extraction to extract gelatin from the collagen source; and separating the gelatin from any resulting by-products, wherein the process does not require an initial acid or lime pretreatment step. The present invention also includes a product made from this process.

Chestnut Market Opportunities Assessing Upscale Restaurant Interest In Value-Added Chestnut Products, Food Processing Center

Food Processing Center: Reports

Chestnut trees, and consequently chestnuts, were a large part of American culture at the turn of the twentieth century. The American chestnut, which is one of four primary chestnut species--Japanese, European, and Chinese being the other three--was prominent in many parts of the country but particularly, the eastern part of the United States. The wood from the trees was commonly used in furniture making and the chestnuts from the tree were frequently included on ingredient lists from recipes used during that era. To not be familiar with and eat chestnuts then could be likened to not having heard of and …

Discovering Lactic Acid Bacteria By Genomics, Todd Klaenhammer, Eric Altermann, Fabrizio Arigoni, Alexander Bolotin, Fred Breidt, Jeffrey Broadbent, Raul Cano, Stephane Chaillou, Josef Deutscher, Mike Gasson, Maarten Van De Gutche, Jean Guzzo, Axel Hartke, Trevor Hawkins, Pascal Hols, Robert W. Hutkins, Michiel Kleerebezem, Jan Kok, Oscar Kuipers, Mark Lubbers, Emanuelle Maguin, Larry Mckay, David Mills, Arjen Nauta, Ross Overbeek, Herman Pel, David Pridmore, Milton Saier, Douwe Van Sinderen, Alexei Sorokin, James Steele, Daniel O'Sullivan, Willem De Vos, Bart Weimer, Monique Zagorec, Roland Seizen

Department of Food Science and Technology: Faculty Publications

This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in fermentation, bioprocessing, or probiotics. For those projects where genome sequence data were available by March 2002, summaries include a listing of key statistics and interesting genomic features. These efforts will revolutionize our molecular view of Gram-positive bacteria, as up to 15 genomes from the low GC content lactic acid bacteria are expected to be available in the public domain by …