bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Beauvericin Toxicity with the Bacterial Bioluminescence Assay and the Ames Mutagenicity Bioassay
Authors: Fotso J. , Smith J.S.
Published: July 2006

ABSTRACT: The bacterial bioluminescence assay was used to determine the acute toxicity level of beauvericin, which was found to be moderate with an EC50 of 94 ± 9 μg/ml. The Ames test was used to evaluate mutagenicity of this mycotoxin. Assays were carried out on 5 Salmonella typhimurium standard tester strains. The spot test was performed on a single beauvericin concentration of 2 μg/plate. The plate incorporation test was done over a range of concentrations (0.2 to 500 μg/plate), both with and without S9. A negative control and 3 positive controls, 2‐aminofluorene, sodium azide, and dexon, were included in the assays. Beauvericin was nonmutagenic to any of the standard tester strains used, either with or without metabolic activation.
Inactivation Kinetics of Tomato Juice Lipoxygenase by Pulsed Electric Fields
Authors: Min S. , Min S.K. , Zhang Q.H.
Published: July 2006

ABSTRACT: Pulsed electric field (PEF) inactivation models for tomato juice lipoxygenase (LOX) were studied. Tomato juice was treated by PEF with the combinations of electric field strength (0, 10, 15, 20, 30, 35 kV/cm), PEF treatment time (20, 30, 50, 60, 70 μs), and PEF treatment temperature (10, 20, 30, 40, 50 °C). The first‐order inactivation models, Hulsheger's model, Fermi's model, and the 2nd‐order polynomial equation adequately described the LOX inactivation. Calculated D values were 161.0, 112.9, 101.0, and 74.8 μs at 15, 20, 30, and 35 kV/cm, respectively, at 30 °C. The activation energy for the inactivation of LOX by PEF was 35.7 kJ/mol. Applied electric field strength was the primary variable for the inactivation of LOX.
Verification of Cooking Endpoint Temperatures in Beef by Immunoassay of Lactate Dehydrogenase Isozyme 5
Authors: Miller D.R. , Keeton J.T. , Acuff G.R. , Prochaska J.F.
Published: July 2006

ABSTRACT: Ground beef Semimembranosus muscle was inoculated with Escherichia coli, and aliquots were left raw or cooked to 1 of 24 time/temperature combinations. Samples were analyzed by aerobic plate counts for surviving bacteria, total extractable protein, and immunoblot quantification of lactate dehydrogenase isozyme 5 (LDH5). Bacterial thermal death curves exhibited a consistent log decline with increasing temperature and cooking times at a given temperature, which were paralleled by decreases in LDH5 at 61 °C and above. Total protein exhibited a linear time/temperature decline. Immunologic analysis of LDH5 may be suitable for development into a rapid assay method for the verification in beef of cooking endpoint temperatures from 61 °C to 69 °C.
Modeling the Yeast Growth‐Cycle in a Model Wine System
Authors: Nobile M.A. Del , D'Amato D. , Altieri C. , Corbo M.R. , Sinigaglia M.
Published: July 2006

ABSTRACT: The modeling of microbial growth behavior is of great relevance to the control of many industrial processes. In this work, a deterministic model to predict the growth curve of microorganisms, from inoculation to death, is presented. To validate the model a Saccharomyces cerevisiae strain has been used to conduct wine fermentation tests at 25 °C and at 2 different values of initial nitrogen concentration. Cell, nitrogen, ethanol and sugar concentration were monitored over a period of about 1200 h. The proposed model was simultaneously fitted with success to the 4 sets of available data. Moreover, due to the mechanistic structure of the proposed approach, it was possible to quantitatively describe the evolution of R1(t), R2(t), dE(t)/dt, dN(t)/dt, and dS(t)/dt during wine fermentation.
Candida molischianaβ‐Glucosidase Production by Saccharomyces cerevisiae and its Application in Winemaking
Authors: Genovés S. , Gil J.V. , Manzanares P. , Aleixandre J.L. , Vallés S.
Published: July 2006

ABSTRACT: A recombinant Saccharomyces cerevisiae wine yeast strain expressing the Candida molischiana bgln gene encoding a β‐glucosidase (BGLN) has been used to produce this enzyme. Shaking rate, pH, and aeration rate conditions have been optimized to obtain maximum activity to facilitate enzyme purification. The ability of the heterologous enzyme to efficiently release terpenols and alcohols from a Muscat wine glycoside extract and also directly from wine has been demonstrated. Terpenol glycoside content decreased by 50% after 1 mo of wine storage in agreement with results reported for the β‐glucosidase produced by C. molischiana.
Physicochemical Characteristics and Quality of Refrigerated Spanish Orange‐Carrot Juices and Influence of Storage Conditions
Authors: Rodrigo D. , Arranz J.I. , Koch S. , Frígola A. , Rodrigo M.C. , Esteve M.J. , Calvo C. , Rodrigo M.
Published: July 2006

ABSTRACT: The effects of the physicochemical and quality characteristics of various refrigerated mixed orange and carrot juices, and their changes with storage time and temperature were investigated. Density, dry extract, Brix values, acidity, turbidity, formol index, pectinmethylesterase, hydroxymethylfurfural, essential oils, ascorbic acid, and color varied with storage time and temperature. Some of the parameters could be used as indicators of quality loss or spoilage of the juices. The degradation of ascorbic acid corresponded to 1st‐order kinetics. The shelf life of the juices was established at 4 °C and 50‐d storage or at 10 °C and 32‐d storage.
Temporal Release of Flavor Compounds from Low‐fat and High‐fat Ice Cream During Eating
Authors: Chung S.‐J. , Heymann H. , Grün I.U.
Published: July 2006

ABSTRACT: Fat controls the intensity and the release rate of volatile compounds because of its solvent property. Our objective was to understand the effect of fat on the flavor release behavior exhibited while ice cream is eaten. The temporal flavor profiles of ice creams, which contained various fat levels and were spiked with known amounts of selected volatiles, were determined by a temporal modified purge and trap and time‐intensity analyses. Stale and cherry flavors were released faster and at higher intensities as fat content decreased. Fat had the opposite effect on vanilla flavor release. Temporal modified purge and trap analysis was an effective method to observe the release of some flavor compounds.
Understanding Molecular Weight Reduction of Starch During Heating‐shearing Processes
Authors: Van Den Einde R.M. , Van Der Goot A.J. , Boom R.M.
Published: July 2006

ABSTRACT: Recent understanding of the mechanisms underlying the changes in molecular weight of starch as a function of process parameters during thermomechanical treatment, for example extrusion, holds promise towards more effective optimization of thermomechanical processes according to the desired modification of molecular weight. This paper summarizes recent advances in theoretical understanding and experimental methods. Empirical observations from extruder experiments can be better understood on this basis. The current status in this field has opened up potential for developing new equipment in which the main process parameters, which normally occur simultaneously, can be separated and optimized. This will create a much wider window for product‐oriented process design and for new products.
Isolation and Identification of Bitter Peptides of Tryptic Hydrolysate of Soybean 11S Glycinin by Reverse‐phase High‐performance Liquid Chromatography
Authors: Kim I M.‐R. , Kawamura Y. , Lee C.‐H.
Published: July 2006

ABSTRACT: The 21 peptides purified from the bitter fraction of tryptic hydrolysates of soybean 11S glycinin by using gel‐permeation high‐performance liquid chromatography (HPLC) and a series of 3 C18 reverse phase (RP)‐HPLC were in the molecular weight range of 200‐1400 Da and showed mostly the hydrophobicity of less than 1400 cal/mol. Although the primary structures of the bitter peptides from 11S glycinin were not exactly the same as those of the proglycinin, many bitter peptides were basic mimics of the common structure, indicating the significance of the primary structure of a peptide playing a role in the bitter taste perception.
Influence of Endogenous Proteases and Transglutaminase on Thermal Gelation of Salted Squid Muscle Paste
Authors: Park S. , CHO S. , Yoshioka T. , Kimura M. , Nozawa H. , Seki N.
Published: July 2006

ABSTRACT: Thermal gelation of salted squid mantle muscle paste was studied in relation to endogenous proteases and transglutaminase. Myosin in the paste was preferentially degraded into 130‐kDa and 90‐kDa fragments at an optimum temperature of 30 °C. Degradation was inhibited with EDTA or 1,10 phenanthroline, suggesting the presence of metalloproteases. Myosin degradation was markedly reduced above 40 °C. Although 10 mM Ca2+ increased cross‐linking of myosin heavy chains by activating the endogenous transglutaminase, setting effect on thermal gelation of the paste was offset by degradation induced by simultaneously activated calpains. Ca2+ and the alpain inhibitor, E64, significantly improved the breaking strength and strain of thermal gels preincubated at 40 °C.
Moisture Migration in Solid Food Matrices
Authors: Fu Y.‐C. , Tong C.‐H. , Lund D.B.
Published: July 2006

ABSTRACT: The goals of this study were to measure moisture migration in a porous solid matrix simulating a real food (flour dough) and to accomplish heating of the solid matrix. An off‐line technique and a microwave temperature controller system were developed for measuring moisture concentration under isothermal heating condition. A temperature profile of a cylindrical dough sample was achieved by accurate control of microwave energy input and preheated carrier gas temperature. Results showed a simplified 1st order kinetic model adequately predicted moisture loss in dough samples. Effect of temperature on the rate constant was adequately modeled by the Arrhenius relationship. The rate constant was found to be affected by porosity of the dough sample.
Growth Suppression of Inoculated Listeria monocytogenes and Physicochemical and Textural Properties of Low‐fat Sausages as Affected by Sodium Lactate and a Fat Replacer
Authors: Choi S.H. , Kim K.H. , Eun J.B. , Chin K.B.
Published: July 2006

ABSTRACT: The antilisterial effect of low‐fat sausages (<2%) manufactured with a fat replacer and increased level of sodium lactate (SL, 60%) solution was determined during refrigerated storage after inoculation with 103 colony‐forming units/g of Listeria monocytogenes (LM) at the initial storage. The fat replacer prevented moisture loss during cooking or storage. Increased SL in combination with the fat replacer resulted in lower water activity, total plate, and LM counts. In addition, whiteness values decreased (P < 0.05), but yellowness values increased (P < 0.05) with increased SL level. During storage, low‐fat sausages containing at least 3.3% SL and the fat replacer had greater antilisterial effect than the low‐fat control.
Mold‐free Shelf‐life Extension of Bakery Products by Active Packaging
Authors: Guynot M. E. , Sanchis V. , Ramos A. J. , Marín S.
Published: July 2006

ABSTRACT: Total elimination of oxygen (O2) in modified atmosphere packaging of bakery products is difficult to achieve. Because of the typical porous texture of the packaging, air can be retained inside. The effect of O2 absorbers alone or in combination with modified atmosphere on Eurotium amstelodami, E. herbariorum, E. repens, and E. rubrum growth was investigated. Cakes of 0.80 to 0.90 water activity (aw) were packaged with different atmospheres (air, 100% N2; 70% N2:30% CO2) and O2 absorbers of 2 different absorption capacities. The use of absorbers with a suitable absorption capacity led to a significant increase of cakes with mold‐free shelf life, regardless of aw and pH level, at 25 °C.
Improvement in the Microbiological Quality of Ready‐To‐Use Desalted Cod
Authors: Fernández‐Segovia I. , Garrigues R. , Carot J.M. , Escriche I.
Published: July 2006

ABSTRACT: To reduce the microbial load of ready‐to‐use desalted cod, 2 different concentrations of sodium chloride (3.13% and 5.78% in water phase), potassium sorbate (0.14% and 0.20% in water phase), and citric acid (pH 6.10 and 5.77), with 2 kinds of packaging procedures (air or vacuum), have been used. The vacuum packaging was effective only in the samples with 3.13% salt after 28 d of storage, whereas no important differences between both packaging procedures were observed in samples with 5.78% salt. This last salt level only limited the Pseudomonas growth, however it was necessary to combine this salt concentration with potassium sorbate plus citric acid to inhibit mesophilic, psychrotrophic, and molds and yeasts.
Influence of Different Unifloral Honeys on Heterocyclic Aromatic Amine Formation and Overall Mutagenicity in Fried Ground‐beef Patties
Authors: Shin H.S. , Strasburg G.M. , Ustunol Z.
Published: July 2006

ABSTRACT The effects of different unifloral honeys (buckwheat, clover, and sage), carbohydrates (fructose, glucose, and sucrose), and antioxidants (vitamin E, BHT), and Trolox® (6‐hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid) on heterocyclic aromatic amine (HAA) formation and overall mutagenicity in fried ground patties were evaluated. The inhibition of total HAA formation was achieved with buckwheat (55%), clover (52%), and sage (51%); and they also reduced overall mutagenicity 36, 31, and 26%, respectively. The addition of fructose, glucose, or fructose and glucose together, at levels comparable to their occurrence in honey, reduced (p < 0.05) mutagenicity and HAA formation by amounts comparable to that found with honey.
Transglutaminase Inhibitor from Milk
Authors: De Jong G.A.H. , Wijngaards G. , Koppelman S.J.
Published: July 2006

ABSTRACT Cross‐linking experiments of skimmed bovine milk with bacterial transglutaminase isolated from Streptoverticillium mobaraense showed only some degree of formation of high‐molecular‐weight casein polymers. Studies on the nature of this phenomenon revealed that bovine milk contains an inhibitor of transglutaminase activity. Removal of the casein and whey proteins from the milk resulted in a protein‐poor fraction that still inhibited transglutaminase activity at cross‐linking of β‐casein and in several activity assays of transglutaminase. The inhibitor was partially purified by column chromatography and appeared to be a heat labile low molecular weight component. Inhibition of transglutaminase activity was observed with microbial transglutaminase, plasma transglutaminase and guinea pig liver transglutaminase. The inhibiting activity was found in bovine, goat, sheep, and human milk, but could not be detected in horse milk.
Rheological Properties of Chitosan and its Interaction with Porcine Myofibrillar Proteins as Influenced by Chitosan's Degree of Deacetylation and Concentration
Authors: Chen Y.‐C. , Wang C.‐H. , Lai L.‐S. , Lin K.‐W.
Published: July 2006

ABSTRACT Rheological and gelation characteristics of a specific degree of deacetylation (dd 50 to 99) and concentration (0.5% to 1.5%) of chitosan and chitosan/SSP (salt‐soluble protein) mixtures were studied. Results suggested that SSP thermal gelation was interfered with by the positive charges of amino groups of the chitosan molecule. Regardless of degree of deacetylation, increasing chitosan concentration caused stronger interference on SSP gelation and lowered complex modulus [G*]. Loss tangent of chitosan/SSP gel decreased with increasing temperature. Higher level (1.5%) of dd 99 chitosan had the lowest G*, which resulted from ionic interaction with SSP. SDS‐PAGE revealed protein aggregation, indicating possible covalent bond formation.
Electron Donation Mechanisms of β‐Carotene as a Free Radical Scavenger
Authors: Lee J.H. , Ozcelik B. , Min D.B.
Published: July 2006

ABSTRACT The free radical scavenging ability of β‐carotene was studied using free radical 2,2‐diphenyl‐1‐picryl‐hydrazyl (DPPH). As the concentration of β‐carotene in acetone increased, the absorbance of DPPH at 517 nm decreased, which indicates that β‐carotene scavenges free radicals. It was shown that β‐carotene does not work as an antioxidant in soybean oil. The NMR spectrum of DPPH with BHA in CDCl3 showed a new peak at 5.0(d) was formed and the peak at 6.6(d) from BHA was split into 2 peaks, which may be due to the hydrogen atom donation from BHA to DPPH. The NMR spectra of DPPH with p‐carotene did not change during reaction and no peak was formed.
Modeling Rehydration of Porous Biomaterials: Anisotropy Effects
Authors: Weerts A.H. , Lian G. , Martin D.
Published: July 2006

ABSTRACT Based on the dynamics of capillary flow in partially saturated‐porous media, a finite element model is developed to predict the infiltration of water into porous biomaterials, taking into account anisotropy effects. The model is formulated on the physically‐based constitutive relationships of water activity and conductivity. These constitutive properties depend on temperature, moisture, and microstructure. This is in contrast to the constant transfer properties used in previous models developed for food materials. Rehydration of black leaf tea Assam has been simulated. The prediction agreed well with the experimental data of NMR measurements. The hydration rate from cut‐edges is 45 to 200 times faster than that from top to bottom surfaces.
Modified Spore Inoculation Method for Thermal‐Process Verification of Pinto Beans and Green Beans Canned in Two Large Reusable Containers
Authors: McGlynn W.G. , Davis D.R. , Johnson M.G. , Crandall P.G.
Published: July 2006

As an alternative to standard metal cans, 2 large, reusable containers with volumetric capacities 3.6 to 3.8 times larger than a standard #10 can were constructed of nickel‐plated steel. Process times and cold point determinations were previously determined using mathematical approximations of heat‐penetration data. It was necessary to verify the adequacy of these process times using inoculated containers. Because it was impractical to use traditional inoculated can procedures, a modification was developed using spores of Clostridium sporogenes PA3679 immobilized in alginate beads contained in brass tubes. Adequacy of the calculated thermal processes was demonstrated; no viable anaerobic spores survived in the inoculated packs.
Predictive Models for Microbial Inactivation and Texture Degradation in Surimi Seafood During Thermal Processing
Authors: Jaczynski J. , Park J.W.
Published: July 2006

Models for Staphylococcus aureus inactivation and texture degradation during thermal processing of surimi seafood were developed based on the modified thermal‐death‐time (TDT) concept. Validation studies showed good fit between experimental and predicted values. The models allow input of processing parameters, resulting in a surface response that determines microbial inactivation and texture degradation. D‐values for microbial inactivation were determined between 55 and 95 °C. The z‐value, however, was not linear. Therefore, a polynomial equation was used to calculate D‐values at intermediate temperatures. Texture degradation between 55 and 95 °C followed a power function. Therefore, power “n” was used as the degradation rate for modeling purposes. Polynomial equation was used to calculate “n” at intermediate temperatures.
Reduction of Moniliformin in Corn by Heat Processing
Authors: Pineda‐Valdes G. , Ryu D. , Hanna M.A. , Bullerman L.B.
Published: July 2006

The effects of autoclaving, baking, extrusion, frying, and roasting on the stability of moniliformin (MON) in spiked (5 μg/g of MON) corn‐based food products were investigated. Roasting corn meal at 218 °C for 15 min had the most significant effect (p ≤ 0.05) on the reduction of MON (44.6%). Autoclaving creamed corn at 121 °C for 65 min resulted in only 10% reduction of MON. Reductions of MON ranging from 5.4 to 28.9% were observed when corn chips were prepared from spiked masa. MON was reduced by 42.2% when corn muffins were baked and by 26.7% when corn grits were extruded. Overall, MON showed heat stability similar to or greater than other Fusarium mycotoxins such as deoxynivalenol and fumonisin B1
Influence of Packaging Films on the Sensory and Microbiological Evolution of Minimally Processed Borage (Borrago officinalis)
Authors: Giménez M. , Olarte C. , Sanz S. , Lomas C. , Echávarri J.F. , Ayala F.
Published: July 2006

The atmospheres prevalent in borage packaged in 5 different films, together with different water‐vapor permeabilities of the films, determined the evolution of the visual and microbiological quality of borage. PVC films proved inadequate to extend the sensory quality since the samples packaged with the films were spoiled on day 9, whereas among the P‐Plus films, the least permeable film was the most adequate to extend the sensory quality of borage until day 15. For most of the treatments, no correlation between the microbial growth and changes in appearance was found. Thus, some treatments with a fair sensory evaluation had microbial counts higher than those allowed by the European legislation.
Aroma of Canned Peach Halves Acidified with Clarified Lemon Juice
Authors: Saura D. , Laencina J. , Pérez‐López A.J. , Lizama V. , Carbonell‐Barrachina A.A.
Published: July 2006

The aroma composition of canned peaches was studied during the 1st year of storage. Citric acid was substituted with 2 types of lemon juice: turbid and clarified. The volatiles were extracted using a distillation technique and quantified by gas chromatography‐mass spectrometry. A total of 35 aroma compounds were identified and quantified, with the major volatile components being lactones. The removal of monoterpenes, during the tangential flow filtration of the lemon juice, provided an acidifier with high scores in the sensory evaluation. In this study, a product perceived by the consumers as more “natural” was elaborated, and new industrial perspectives were opened for the lemon industry and agriculture.
Consumer Attitudes and Acceptability of Soy‐fortified Yogurts
Authors: Drake M.A. , Gerard P.D.
Published: July 2006

The objective of this study was to determine consumer knowledge of soy and dairy foods and consumer acceptance of yogurts fortified with 2.5% soy protein concentrate (SPC). Consumers were polled from a university campus location (n= 388) and from a local grocery store (n= 159). Consumers filled out a questionnaire requesting demographics information as well as knowledge and attitudes on dairy and soy foods. Consumption of dairy foods was more frequent than consumption of soy foods. Yogurts without SPC received higher acceptance scores than yogurts containing SPC (p< 0.05). Acceptability scores for yogurts increased with frequency of dairy yogurt consumption (p< 0.05). Knowledge of the health claim increased acceptability scores for yogurts (P< 0.05).
Caliciviruses: A Major Cause of Foodborne Illness
Authors: Gerba C.P. , Kayed D.
Published: July 2006

ABSTRACT: The public health impact of infections by human caliciviruses (HuCVs) is increasingly being recognized. The Norwalk‐like viruses (NLV) are the most common cause of outbreaks of nonbacterial gastroenteritis and the most recognized foodborne viral etiologic agents. Factors that contribute to their high burden of infection are low infectious dose, stability in the environment, the diversity of strains, and the lack of long‐term immunity to infection or illness. The recent development of sensitive molecular techniques for diagnosis, quantification, and characterization of these agents has led to the recognition of the importance of NLV infection. Future applications of these approaches to understanding modes of transmission and the effectiveness of control measures holds promise for improved understanding of the epidemiology of HuCVs, as well as important control measures for foodborne transmission. This report reviews what is currently known and understood about human caliciviruses regarding foodborne transmission.
Vascular Infusion as a Means to Improve the Antioxidant–Prooxidant Balance of Beef
Authors: Katsanidis E. , Meyer D. C. , Addis P. B. , Yancey E. J. , Dikeman M. E. , Tsiamyrtzis P. , Pullen M.
Published: July 2006

ABSTRACT: Vascular infusion was used to deliver, via the carotid artery, a rinsing solution of calcium chloride or one of saccharides, sodium chloride, and phosphates, with and without vitamins C, E, or C + E, to beef steers immediately following exsanguination. Moisture, fat, iron, calcium, vitamin E, and cholesterol contents and the development of rancidity (TBARS) on the resulting meat were measured. Meat from infused cattle had slightly higher moisture and lower iron and cholesterol contents due to greater blood removal. When vitamin E was present in the infusion solution, TBARS values were lower for infused meat. Infusion with either the standard solution, calcium chloride, or standard solution plus vitamin C did not consistently affect TBARS values.
Effect of Thermal Processing and Carbon Dioxide‐assisted High‐pressure Processing on Pectinmethylesterase and Chemical Changes in Orange Juice
Authors: Boff J. M. , Truong T. T. , Min D. B. , Shellhammer T.H.
Published: July 2006

ABSTRACT: The effects of high‐pressure processing (HPP), CO2‐assisted high‐pressure processing (HPP + CO2), and thermal processing on the chemical and physical properties of single‐strength Valencia orange juice were evaluated over 4 mo of storage at 4 and 30 °C. The HPP + CO2 juice had the greatest cloud stability and highest ascorbic acid retention. Volatile compound losses were lowest in the HPP juice and lower in the HPP + CO2 juice compared to the thermally processed juice (p < 0.05). HPP + CO2 produced a cloud‐stable orange juice with more ascorbic acid and flavor volatiles than thermally processed juice (p < 0.05).
Fatty Acid Composition and Oxidative Stability of Cold‐pressed Edible Seed Oils
Authors: Parker T.D. , Adams D.A. , Zhou K. , Harris M. , Yu L.
Published: July 2006

ABSTRACT: This study was conducted to determine the fatty acid (FA) compositions and oxidative stabilities of cold‐pressed cranberry, carrot, hemp, and caraway seed oils. The cold‐pressed cranberry and hemp seed oils exhibited higher α‐linolenic acid (18:3n‐3) contents with levels of 22 and 19 g/100 g fatty acids, respectively. Cold‐pressed carrot seed oil contained about 82% oleic acid and had the lowest total saturated fatty acids among all tested oils. Cold‐pressed caraway seed oil had the greatest oxidative stability with an OSI value of 150 hours. In addition, cold‐pressed carrot seed oil had the lightest color while hemp seed oil was the darkest among all the oils tested.
Functional and Bioactive Properties of Quinoa Seed Protein Hydrolysates
Authors: Aluko R.E. , Monu E.
Published: July 2006

ABSTRACT: Quinoa protein concentrate was hydrolyzed with alcalase to obtain a hydrolysate that was fractionated by ultrafiltration using 10000‐ and 5000‐molecular‐weight cutoff membranes. Functional properties of the protein concentrate, protein hydrolysate, and membrane permeates were compared at different pH values. Protein solubility of the hydrolysate and membrane permeates were significantly higher (P= 0.05) than that of the protein concentrate. The protein concentrate had a significantly higher (P= 0.05) emulsifying activity index than the protein hydrolysate and membrane permeates. Membrane fractionation of the protein hydrolysate into lower‐molecular‐weight pep tides significantly reduced (P= 0.05) foaming properties, but it improved radical scavenging activity and the ability to inhibit the activity of angiotensin‐converting enzyme.
Commercial‐Scale Pulsed Electric Field Processing of Orange Juice
Authors: Min S. , Jin Z.T. , Min S.K. , Yeom H. , Zhang Q.H.
Published: July 2006

Effects of commercial‐scale pulsed electric field (PEF) processing on the microbial stability, ascorbic acid, flavor compounds, color, Brix, pH, and sensory properties of orange juice were studied and compared with those of thermal processing. Freshly squeezed orange juice was thermally processed at 90 °C for 90 s or processed by PEF at 40 kV/cm for 97 ms. Both thermally processed and PEF‐processed juices showed microbial shelf life at 4 °C for 196 d. PEF‐processed juice retained more ascorbic acid, flavor, and color than thermally processed juice (P<0.05). Sensory evaluation of texture, flavor, and overall acceptability were ranked highest for control juice, followed by PEF‐processed juice and then by thermally processed juice (P<0.01).
Shelf Life Prediction of Cereal‐based Dry Foods Packed in Moisture‐sensitive Films
Authors: Del Nobile M.A. , Buonocore G.G. , Limbo S. , Fava P.
Published: July 2006

ABSTRACT: A mathematical model able to predict the storage life of cereal‐based dry foods is presented. The developed model was used to assess the influence on the shelf life of cereal‐based dry products of both the water barrier properties of the package and the affinity of the packed food with water. Three different cereal‐based dry foods and 3 different polyamide films were investigated. It was found that the shelf life of the investigated food s, as predicted by means of the proposed model, could be overestimated by about 90% if the dependence of water permeability coefficient on water activity inside and outside the package is neglected.
Bigelow's General Method Revisited: Development of a New Calculation Technique
Authors: Simpson R. , Almonacid S. , Teixeira A.
Published: July 2006

This article describes the development of a comprehensive procedure for broader application of the General Method in calculating thermal processes. In addition to the capability of calculating lethality (or process time to achieve a specified lethality) for a given set of heat‐penetration data, the procedure can also calculate process time or lethality for process conditions different from those of the original heat‐penetration tests. The new procedure was experimentally tested against the Ball Formula Method and numerical finite difference methods. It often safely predicted shorter process times than the Ball Formula Method by accurately accounting for slow come‐up and cool‐down phases of the retort process.
Modeling the Water Barrier Properties of Nylon Film Intended for Food Packaging Applications
Authors: Del Nobile M.A. , Buonocore G.G. , Altieri C. , Battaglia G. , Nicolais L.
Published: July 2006

ABSTRACT: This paper presents a mathematical model able to predict the water barrier properties of nylon film as a function of the water activity at the upstream and downstream side of the film. To validate the model, water sorption and permeation tests were conducted at 25 °C. The fitting and predictive ability of the proposed model was successfully tested by fitting the model to the sorption data and by predicting the nylon water permeability coefficient, respectively. The implications of the adopted approach on practical aspects of packaging were pointed out by comparing the nylon water barrier properties as evaluated by means of a permeation test and that in the real working conditions.
MRI Temperature Mapping and Determination of Liquid‐particulate Heat Transfer Coefficient in an Ohmically Heated Food System
Authors: Ye X. , Ruan R. , Chen P. , Doona C. , Taub I.A.
Published: July 2006

ABSTRACT: Real‐time temperature maps of ohmically heated liquid‐particulate mixtures were acquired using the Proton Resonance Frequency (PRF) shift method incorporated into a fast Magnetic Resonance Imaging (MRI). Noise in the MRI images induced by the electrical heating power was eliminated by a post‐processing algorithm of the PRF shift method and correction phase images. The time‐dependent interface heat transfer coefficients (hfp) were determined during the holding period using the MRI temperature maps and numerical solutions to the Fourier's 2nd law. The calculated values of hfp range from 30 to 105 W/m2K, consistent with literature values for natural convection. These results provide crucial data for understanding the ohmic heating process.
Mild‐Heat and High‐Pressure Inactivation of Carrot Pectin Methylesterase: A Kinetic Study
Authors: Ly‐Nguyen B. , Van Loey A.M. , Smout C. , ErenÖzcan S. , Fachin D. , Verlent I. , Truong S. Vu , Duvetter T. , Hendrickx M.E.
Published: July 2006

ABSTRACT: Pectin methylesterase (PME) was extracted from carrots and purified by affinity chromatography. The thermal high‐pressure inactivation of the PME was investigated in a model system. Under these conditions, the (thermo) stable fraction is not inactivated and the isobaric‐isothermal inactivation followed a fractional‐conversion model. At lower pressures (< 300 MPa) and higher temperatures (> 50°C), an antagonistic effect of pressure and heat was observed. A 2nd‐ and 3rd‐degree polynomial model (derived from available thermodynamic model) was successfully used to describe the heat pressure dependence of the inactivation rate constants. From the purified carrot PME sample, the thermostable PME fraction was isolated. The thermal inactivation of this fraction followed first‐order kinetics.
Critical Factors Affecting the Destruction of Escherichia coli O157:H7 in Apple Cider Treated with Fumaric Acid and Sodium Benzoate
Authors: Chikthimmah N. , Laborde L.F. , Beelman R.B.
Published: July 2006

ABSRACT

Destruction of Escherichia coli O157:H7 in apple cider treated with fumaric acid and sodium benzoate (0.15% and 0.05% w/v, respectively) was determined under pH and storage temperatures that commonly occur in apple cider. At 5°C storage, while destruction of E. coli O157:H7 in the presence of preservatives increased with time, there was little decline in E. coli O157:H7 populations in the absence of the preservatives. Increasing storage temperatures to 15°C and 25°C significantly increased the rate of destruction of E. coli O157:H7 in cider with the preservatives (P < 0.05). Increasing the pH of cider (from 3.2 to 4.7) decreased the rate of destruction of E. coli O157:H7.
Effect of Modified Atmosphere Packaging and Superchilled Storage on the Microbial and Sensory Quality of Atlantic Salmon (Salmo salar) Fillets
Authors: Sivertsvik M. , Rosnes J.T. , Kleiberg G.H.
Published: July 2006

ABSTRACT: Fresh Atlantic salmon fillets packaged under modified atmosphere (MA) (CO2:N2 60:40) and air was stored at superchilled (‐2 °C) and chilled (+4 °C) temperatures. Changes in sensory scores, microbial growth, headspace gas composition, water loss, and pH were monitored during 24 d of storage. The superchilled MA packaged salmon maintained a good quality, with negligible microbial growth (<1000 colony‐forming units [CFU]/g) for more than 24 d based on both sensory and microbial analyses (aerobic plate count, H2S‐producing, and psychrotrophic bacteria). Superchilled salmon in air had a 21‐d sensory shelf life, whereas MA and air‐stored fillets at chilled conditions was spoiled after 10 d and 7 d, respectively.
1‐MCP Treatment Prolongs Postharvest Life of 'Santa Rosa’Plums
Authors: Salvador A. , Cuquerella J. , Martínez‐Jávega J.M.
Published: July 2006

'Santa Rosa’plums were treated with concentrations of 0‐ (control), 0.5‐, or 0.75‐μL/L 1‐methylcyclopropene (1‐MCP) for 24 h at 1°C and stored at 1 °C for up to 40 d. Ethylene and CO2 production, firmness, weight loss, Brix, acidity, color evolution, and ethanol and acetaldehyde concentrations were determined periodically after cold storage and after subsequent shelf life of 5 and 8 d at 20 °C. 1‐MCP strongly inhibited ethylene and CO2 production. Higher values of firmness were observed in 1‐MCP‐treated plums compared with control. 1‐MCP treatment delayed color evolution, reduced acidity loss, and inhibited ethanol and acetaldehyde production. 1‐MCP did not affect weight loss or sugar content.
The Use of Controlled Postharvest Abiotic Stresses as a Tool for Enhancing the Nutraceutical Content and Adding‐Value of Fresh Fruits and Vegetables
Authors: Cisneros‐Zevallos L.
Published: July 2006

This paper proposes a concept based on applying postharvest abiotic stresses to enhance the nutraceutical content of fresh fruits and vegetables. We hypothesize that selected abiotic stress treatments, such as wounding, phytohormones, temperature, ultraviolet light, altered gas composition, heat shock, and water stress, among others, will affect the secondary metabolism of fresh produce and increase the synthesis of phytochemicals with nutraceutical activity or reduce the synthesis of undesirable compounds. Controlled stresses may be used as tools by the fresh produce industry to enhance the health benefit properties of fresh‐cut or whole fresh produce and by the food processing and dietary supplement industries to obtain healthier processed products or enhance extractable nutraceutical yields.
Factors Influencing the Occurrence of Methanethiol in Aqueous Slurries of Soy Protein Concentrates
Authors: Lei Q. , Boatright W.L.
Published: July 2006

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Aqueous slurries of 6 commercial soy protein concentrate (SPC) contained from 9.8 to 21.7 ppb methanethiol, which corresponds to odor values (in water) of 49 to 108. Effects of temperature (5.5, 24, and 65°C), pH (4.8,6.6, and 9.0), transition metals (FeCl3, FeCl2, and CuCl2), lipoxygenase, and EDTA on methanethiol levels in SPC slurries were investigated. Higher temperature (65°C), basic pH (9.0), transition metals, lipoxygenase, and EDTA caused significant increases in methanethiol compared with the control. CuCl2 caused greater increases in methanethiol than FeCl3 and FeCl2. In contrast, treatments with lower temperature (5.5°C) or acidic pH (4.8) resulted in lower levels of methanethiol in all commercial SPC samples examined.
Pectinesterase and Polygalacturonase Activities and Textural Properties of Rubbery Papaya (Carica papaya Linn.)
Authors: Jiang C.‐M. , Wu M.‐C. , Wu C.‐L. , Chang H.‐M.
Published: July 2006

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Comparisons in color of flesh, pectin composition, pectinesterase (PE), polygalacturonase, cellulase activities, and textural properties of normal green papaya (NGP), rubbery papaya (RP), and normal yellow and ripe papaya (NYRP) were conducted. RP contained about 9.7% pectin with a degree of esterification of 53.1%, while NYRP contained about only 1.2% pectin with a degree of esterification of about 23.4%. PE activity (13.6 unit/g fresh weight) than in RP was significantly lower (18.0 unit/g fresh weight) in NYRP (P < 0.05), whereas polygalacturonase activity (46.9 unit/g fresh weight) in RP was higher (27.0 unit/g FW) than in NYRP. Therefore, in combination with the fact that water extract from RP displayed an inhibitory ratio of 36.0% on papaya PE activity, we suggest the presence of certain substances with strong PE inhibitory activity in RP.
Effects of Boiling on Dietary Fiber Components in Fresh and Stored White Cabbage (Brassica oleracea var. capitata)
Authors: Wennberg M.S. , Engqvist G.M. , Nyman E.M.G.‐L.
Published: July 2006

The effects of boiling (10 min) and how differences in cultivars (n= 6), maturity (n= 2), and storage (n= 3) may affect dietary fiber in white cabbage were studied. A great variation in total dietary fiber content between boiled cabbage samples was seen (17.7 to 31.7 g/100 g dry weight basis). Total and insoluble dietary fiber following boiling could be predicted from the initial amount. Average losses for early and late cultivars were similar (about 10%) and were mainly due to insoluble polymers consisting of glucose and partly of uronic acids. The early cultivar ‘Balbro’ was least affected by heat treatment: only 2% total dietary fiber was lost. Harvesting before physiological maturity and short‐term storage increased the loss of soluble polymers (pectic substances), whereas long‐term storage decreased the loss.
Effects of Ascorbic Acid and α‐Tocopherol on Antioxidant Activity of Polyphenolic Compounds
Authors: Murakami M. , Yamaguchi T. , Takamura H. , Matoba T.
Published: July 2006

The effects of ascorbic acid and α‐tocopherol on the antioxidant activity of 15 phenolic compounds were compared with 2 in vitro assays. Combination of ascorbic acid or α‐tocopherol plus polyphenolic compounds resulted in an additive effect as shown with DPPH–HPLC method. With the liposome oxidation method, combination of quercetin or catechins plus α‐tocopherol showed synergistic effects.
Effect of Antioxidants on Consumer Acceptance of Irradiated Turkey Meat
Authors: Lee E.J. , Love J. , Ahn D.U.
Published: July 2006

Antioxidants had no effect on the production of sulfur compounds, color change, and off‐odor intensity of irradiated turkey breast meat, but addition of sesamol + tocopherol or gallate + tocopherol was effective in reducing thiobarbituric acid‐reactive substance values and aldehydes, especially under aerobic conditions. Consumers preferred the color of irradiated raw and cooked meat to nonirradiated meat because the pink color of irradiated meat looked fresher. The packaging method was more important than the antioxidant treatment in reducing irradiation off‐odor because S‐compounds produced by irradiation easily volatilized under aerobic packaging conditions. Therefore, the combined use of aerobic packaging and antioxidants is recommended to improve consumer acceptance of irradiated poultry meat.
Interactions of (β‐Lactoglobulin and High‐methoxyl Pectins in Acidified Systems
Authors: Kazmierski M. , Wicker L. , Corredig M.
Published: July 2006

The interactions that occur when β‐lactoglobulin (β‐lg) is mixed with a high‐methoxyl pectin (HMP) and a modified pectin (mHMP, modified using plant pectinesterase) were examined at pH 3.8. Whereas soluble aggregates formed in β‐lg‐HMP, β‐lg‐mHMP precipitated upon mixing. β‐lg‐HMP mixtures showed soluble aggregates with larger hydrodynamic diameters when heated at 65°C than when heated at 90°C. β‐lg‐HMP mixtures adjusted to pH 6.0 after heating showed that the aggregates formed at 65°C could be dissociated, but the complexes were not reversible after heating at 90°C. A similar effect also was observed when resuspending the°‐lg‐mHMP precipitates at pH 6.0. The behavior of the 2 pectins was attributed to their differences in charge distribution.
Effects of Ascorbic Acid and Antioxidants on the Color of Irradiated Ground Beef
Authors: Nam K.C. , Ahn D.U.
Published: July 2006

Irradiation significantly decreased the redness of ground beef (P < 0.05), and the visible color of beef changed from a bright red to a green/brown, depending on the age of meat. Addition of ascorbic acid (0.1%, wt/ wt) in ground beef prior to irradiation prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. Ground beef with added ascorbic acid had significantly lower oxidation‐reduction potential than the control (P < 0.05), and the low oxidation‐reduction potential of meat helped maintain the heme pigments in reduced form. Sesamol +α‐tocopherol had no effect in stabilizing color of irradiated beef.
Active Modified Atmosphere Packaging of Fresh Fruits and Vegetables: Modeling with Tomatoes and Oxygen Absorber
Authors: Charles F. , Sanchez J. , Gontard N.
Published: July 2006

Design of active modified atmosphere packaging for vegetables was studied by developing a mathematical model predicting gas changes and based on the following independently evaluated parameters: vegetable respiration rate, film permeability, and oxygen absorption kinetic of the absorber. A step‐by‐step model validation was performed on a tomatoes/low‐density polyethylene pouch/commercial iron‐based scavenger system at 20 °C. Without optimization, the model fit experimental data with root mean square error (RMSE) value lower than 1.5. Oxygen absorbers had a strong influence on transient period characteristics by reducing their duration (50 and 100 h with and without absorber, respectively) and suppression of the CO2 peak owing to a rapid oxygen depletion.
High‐Pressure Destruction Kinetics of E. coli(29055) in Apple Juice
Authors: Ramaswamy H.S. , Riahi E. , Idziak E.
Published: July 2006

High‐pressure (HP) destruction of Escherichia coli (29055) in apple juice was evaluated (150 to 400 MPa; 0 to 80 min at 25 °C) based on a dual destruction behavior consisting of pressure pulse and pressure hold (first order rate) effects. Enumeration was carried out in brain‐heart infusion agar (BHIA) and violet‐red bile agar (VRBA) to differentiate between surviving cells with and without injury. A pressure pulse at 400 MPa destroyed the entire population (108 CFU/mL) of E. coli. During pressure‐hold, D values (decimal reduction time) of E. coli decreased with an increase in pressure, and D values from BHIA (survivors including injured cells) were higher than from VRBA (survivors excluding injured cells). Thus, an increasing number of cells were initially injured than killed with HP treatment until finally killed. Pressure dependency of D was described by z‐value model with associated zp values (pressure range to result in a decimal change in D values) of 126 and 140 MPa on BHIA and VRBA.
Growth of Botrytis cinerea and Strawberry Quality in Ozone‐enriched Atmospheres
Authors: Nadas A. , Olmo M. , García J.M.
Published: July 2006

Botrytis cinerea cultures were stored on potato dextrose agar in air with or without 1.5 μL/L ozone at 2 °C. Cultures stored in the presence of ozone grew slower. Strawberry fruits (Fragaria×ananassa cv. Camarosa) were stored for 3 d at 2 °C in air with or without 1.5 μL/L ozone and then transferred to room temperature. Each group was inoculated with B. cinerea grown in air with or without ozone. Visible mycelial growth developed more rapidly on fruit previously stored in air. Ozone‐enriched cold storage of naturally infected ‘Camarosa’ fruit reduced decay incidence, weight loss, and fruit softening, but resulted in a reversible loss of fruit aroma.
The Inhibitory Effects of Brans and Their Aqueous Extracts on the Lipolysis of Tributyrin Catalyzed by Calf Pregastric Lipase
Authors: O'Connor C.J. , Sun D. , Smith B.G. , Melton L.d.
Published: July 2006

The ability of red and white wheat brans and oat bran to inhibit calf pregastric lipase (CPGL)‐catalyzed hydrolysis of tributyrin has been studied in vitro at pH 6.5, 37 °C. Brans that had been presoaked in Bis‐Tris buffer at pH 6.5, 4 °C reduced CPGL activity by 13% to 20% after being soaked for 0.25 h and by 17% to 30% after being soaked for 24 h. Maximum reduction of CPGL activity was seen within 2 to 5 min incubation between coarse red wheat bran and CPGL. The results are discussed in terms of likely inhibitory components within the brans and their water‐soluble components and their roles in inhibiting pregastric and other lipase‐catalyzed hydrolysis of dietary lipids.
Comparison of Two Sensory and Two Instrumental Methods to Evaluate Cookie Color
Authors: Kane A.M. , Lyon B.G. , Swanson R.b. , Savage E.M.
Published: July 2006

Relationships between 2 instrumental and 2 sensory methods for cookie color assessment were determined. For sensory tests, panelists (n = 8 to 10) compared color of cookies (3 formulations × 2 cookie types) to equidistant physical color references in a light booth and to digital color references in a sensory workstation using unstructured line scales. For instrumental methods, the CIELAB color model and hue angle were determined with a spectrophotometer and with graphics software using digital camera images. Analysis of variance (ANOVA) and post‐hoc comparisons verified differences (P < 0.05) among formulations within type by all methods. Except for b* values of chocolate chip cookies, the potential of all color assessment methods were validated by strong linear relationships (r > 0.94; P < 0.001).
Tenderness and Chemical Composition of Elk (Cervus elaphus) Meat: Effects of Muscle Type, Marinade Composition, and Cooking Method
Authors: Dhanda J.S. , Pegg R.B. , Shand P.J.
Published: July 2006

Effects of sodium tripolyphosphate (STPP; 0.1, 0.2, or 0.3%) and 0.5%NaCl on the color, cooking yield, and tenderness of moisture‐enhanced elk longissimus lumborum (LL) and semimembranosus (SM) muscles were assessed. Injected samples had significantly (P < 0.05) lower L, a, and b values and significantly (P < 0.05) higher cooking yields and lower shear force values compared to controls; shear force values did not differ among marination treatments. The amino acid composition of elk meat was typical for those of red meat species. Elk meat was very lean and had a relatively high ratio of polyunsaturated to saturated fatty acids. The present study found that addition of 0.5% NaCl with 0.2% or 0.3% STPP to the marinade was best at improving the cooking yield and tenderness of the resultant products.