bluuebunny/crossref_metadata_2025 huggingface dataset:
Water Vapor Uptake by Fat‐Free Apple Chips Decreased by Emulsifiers
Authors: Konopacka D. , Plocharski W.
Published: July 2006

The critical moisture sorption times of fat‐free apple chips varied from 29 min at 82% RH and 30 °C to over 24 h both at 34% RH, 20 °C and at 45% RH and 10 °C. Some emulsifiers added to the solution of carbohydrates used to treat apple slices before drying effectively decreased chip hygroscopicity. It was found that sodium stearoyl‐2‐lactate, sucrose esters, monoglycerides and their citric acid esters did not adversely affect flavor or texture of apple chips. During 3 h of exposure at 20 °C and 54% RH chips treated with these emulsifiers adsorbed from 14 to 25% less moisture than the untreated ones.
Inactivation of Peach Polyphenoloxidase by Exposure to Pulsed Electric Fields
Authors: Giner J. , Ortega M. , Mesegué M. , Gimeno V. , Barbosa‐Cánovas G.V. , Martín O.
Published: July 2006

The effect of exponential decay pulsed electric fields on peach (var. Miraflores) polyphenoloxidase (PPO) was evaluated. Electric field intensities ranged from 2.18 to 24.30 kV/cm. Pulses of 0.02 and 0.08 ms width were applied in mono‐ and bipolar mode. A 70% maximum reduction in enzymatic activity was achieved after 5 ms using 0.02 ms width pulses in bipolar mode at 24.30 kV/cm. Peach PPO activity decreased following an exponential decay kinetic model. Rate constants ranged from 9.0 to 138 μS‐1 in monopolar mode, and from 8.7 to 235 μS‐1 in bipolar mode. An exponential decay model may describe the relationship between residual PPO and input electric energy.
Antibacterial Activities of Chitosans and Chitosan Oligomers with Different Molecular Weights on Spoilage Bacteria Isolated from Tofu
Authors: No H.K. , Park N.Y. , Lee S.H. , Hwang H.J. , Meyers S.P.
Published: July 2006

Seven bacteria were isolated from spoiled tofu and identified as Bacillus sp. (S08), B. megaterium (S10), B. cereus (S17, S27, S28, S32), and Enterobacter sakazakii (S35). In a paper disc test with 6 chitosans and 6 chitosan oligomers of different molecular weights, chitosans showed higher antimicrobial activity than did chitosan oligomers at a 0.1% concentration. Results of inhibitory effects of 6 chitosans on growth of Bacillus sp. (S08) failed to detect viable cells after incubation for 24 hrs at 37 C, even at 0.02% concentration. With B. megaterium (S10) and B. cereus (S27), a 3 to 4 log cycle reduction was found in the chitosan‐treated group. The growth of Enterobacter sakazakii (S35) was completely suppressed in the presence of 0.04% chitosan except for 1 chitosan product. The minimum inhibitory concentration of chitosan differed with products and isolates, ranging from 0.005% to above 0.1%.
Occurrence of Histamine‐Forming Bacteria in Albacore and Histamine Accumulation in Muscle at Ambient Temperature
Authors: Kim S.H. , Price R.J. , Morrissey M.T. , Field K.G. , Wei C.I. , An H.
Published: July 2006

Distribution of histamine‐producing bacteria in fresh albacore and their proliferation in muscle during storage at 25 °C were monitored. Histamine formers constituted a minor portion of the bacterial flora in albacore. Only weak histamine formers were detected in the gill and skin of fresh fish after enrichment. Histamine formers were isolated from the muscles when APC reached >107 CFU/g during storage. Hafnia alvei was most prevalent in both fresh and temperature‐abused fish. The most prolific histamine former, Morganella morganii, was rarely isolated even from spoiled muscles. The prevalence of weak histamine formers resulted in low levels of histamine accumulation in muscle, 67.1 mg/100 g, for 6 d of storage.
Sensory Characteristics of Fresh‐Cut Spinach Preserved by Combined Factors Methodology
Authors: Piagentini A.M. , Güemes D.R. , Pirovani M.E.
Published: July 2006

Fresh‐cut spinach was treated with citric acid and ascorbic acid solutions and packaged in monooriented polypropylene (OPP) bags or low density polyethylene (LDPE) bags. Sensory attributes, chlorophyll retention, and weight loss were evaluated throughout refrigerated storage. Mathematical models were developed to analyze and predict the effect of the citric acid and ascorbic acid concentrations and storage time on off‐odor development, general appearance, wilting, browning, and color. Sensory attributes of fresh‐cut spinach decreased with storage time. Type of film affected off‐odor development, but did not influence visual sensory attributes. Chemical treatment and type of packaging film did not affect chlorophyll retention. Both types of packaging film controlled weight loss.
Effect of γ‐Irradiation on Phenolic Acids in Strawberries
Authors: Breitfellner F. , Solar S. , Sontag G.
Published: July 2006

ABSTRACT: The content of phenolic acids in strawberries was determined before and after gamma‐irradiation in the dose range 1 to 10 kGy. Fresh whole strawberries were irradiated, acid‐base‐hydrolyzed, and purified on polyamide columns. The compounds were analyzed by reversed‐phase chromatography and detected with a diode‐array detector. Dose/concentration relationships were obtained for gallic acid, 4‐hydroxybenzoic acid, cinnamic acid, p‐coumaric acid, and caffeic acid. Whereas radiolysis of the individual acids in aqueous solutions led to their efficient degradation and to a notable hydroxylation, in the complex matrix of food no hydroxylation products were formed and only the amount of 4‐hydroxybenzoic acid was affected by irradiation (build up: 0.68 ± 0.04 mg kg−1kGy−1).
Rosemary Extracts as Inhibitors of Lipid Oxidation and Color Change in Cooked Turkey Products During Refrigerated Storage
Authors: Yu L. , Scanlin L. , Wilson J. , Schmidt G.
Published: July 2006

ABSTRACT: Water‐soluble rosemary extracts were evaluated for their inhibitory effects on lipid oxidation and color change in cooked turkey products during storage. Changes were measured in thiobarbituric acid‐reactive substances, hexanal production and color of the cooked turkey samples containing 0, 100, 250 and 500 ppm water‐soluble rosemary extracts, at storage day 0, 1, 2, 3, 5, 7, 10, and 13. The rosemary extracts showed significant protection of lipid oxidation and color change in cooked turkey. Higher levels of water‐soluble rosemary extracts were more effective in delaying quality loss in cooked turkey at all tested storage times.
Mechanisms of Pink Color Formation in Irradiated Precooked Turkey Breast Meat
Authors: Nam K.C. , Ahn D.U.
Published: July 2006

ABSTRACT: Precooked turkey breast meat was aerobically packaged or vacuum‐packaged and irradiated at 0, 2.5, or 5.0 kGy. CIE color, reflectance, oxidation‐reduction potential (ORP), gas production, and lipid oxidation were determined at 0, 7, and 14 d. Irradiation increased redness of vacuum‐packaged meat, and the redness was distinct and stable under vacuum. Irradiation decreased ORP and produced carbon monoxide (CO). This indicated that the pink color was caused by the heme pigment‐CO complex formation. The reflectance of meat and the absorption spectra of myoglobin solution supported the assumption that denatured CO‐myoglobin is the pigment in irradiated precooked turkey breast.
Evaluation of the Antioxidant Effects of Dried Milk Mineral in Cooked Beef, Pork, and Turkey
Authors: Cornforth D.P. , West E.M.
Published: July 2006

ABSTRACT: This study was done to determine the optimum level of dried milk mineral (MM) to inhibit lipid oxidation in various ground meats. Cooked ground beef and pork required 2% MM to maintain thiobarbituric acid (TBA) values < 1.0 after 14 d refrigerated storage, compared to 1% MM for ground turkey. TBA values of cooked ground beef were lower (p < 0.05) when MM was added in water suspension, rather than as a dry powder. Among MM components (phosphate, calcium, and citrate), polyphosphates most effectively maintained low TBA levels during storage. MM probably chelates soluble iron to colloidal calcium phosphate particles, thus removing iron as a catalyst for lipid oxidation.
Flow Distribution of Food Materials in an Annular Extrusion Die
Authors: Deo I. , Karwe M.V.
Published: July 2006

ABSTRACT: The objective of this study was to determine the effects of die geometry, food material and operating parameters on flow distribution in an annular extrusion die. A diverging annular die with a conical insert was designed such that the eccentricity of the central conical core could be maintained at 0, 1, and 2 mm. Corn syrup, cornstarch, cornmeal, and wheat flour were extruded through the die using a twin‐screw extruder at varying mass flow rates. It was found that perfect geometrical alignment was very critical in achieving flow uniformity, and should be considered as the important factor in practical applications. The type of food material and mass flow rate had negligible effects on the flow distribution.
Gelation Kinetics of Agars from Pterocladia capillacea Examined by Dynamic Rheometry
Authors: Lai V.M.‐F , Lii C.‐Y.
Published: July 2006

ABSTRACT: The changes in storage modulus (G′) during isothermal gelation of agar fractions from Pterocladia capillacea were kinetically investigated with respect to the curing condition, agar concentration, and the molecular property of agar. Generally, the reciprocal of gelling time, the maximal increasing rate of G′, and the rate constants of Avramipseudo‐1st‐order kinetics correlated with the curing conditions more significantly than with the molecular properties examined. This tendency was opposite to the result based on simple 2nd‐order rate constant. And, the effects of molecular size on rheological and kinetic parameters were greater than those of the 3,6‐anhydro‐galac‐tose content examined. After verification of the kinetic data obtained, potentially molecular changes during gelation process are illustrated.
Chemometric Formulas Based on Physical Properties of Single‐cooked Milled Rice Grains for Determination of Amylose and Protein Contents
Authors: Okadome H. , Toyoshima H. , Shimizu N. , Akinaga T. , Ohtsubo K.
Published: July 2006

ABSTRACT: Chemometric formulas for predicting amylose content (AC) and protein content (PC) were developed based on the surface and overall physical properties of single‐cooked milled rice grains as predictive variables. The formula with 8 predictors for AC determination exhibited the highest accuracy (coefficient of determination: R2= 0.952, standard error of calibration: SEC = 1.77) for calibration and the lowest standard error of prediction (SEP = 2.07) for unknown samples (AC: 0 to 30%). The formula with 7 predictors was effective in enhancing the prediction accuracy (SEP = 1.32) among non‐waxy samples in a narrow range of AC (15 to 20%). The formula with 8 predictors for PC determination showed a higher accuracy (R2= 0.449 and 0.470) for both calibration and prediction than that of a conventional 3‐grain method (R2= 0.168 and 0.124). It was possible to accurately determine AC using physical measurement of single grains instead of chemical analysis.
Emulsion Stability and Water Uptake Ability of Chicken Breast Muscle Proteins as Affected by Microbial Transglutaminase
Authors: Ruiz‐Carrascal J. , Regenstein J.
Published: July 2006

ABSTRACT: Using response surface methodology, the effect of microbial transglutaminase (TG) concentration and incubation time (IT) after emulsification, but before creaming, on the functional properties of chicken meat proteins was examined. TG improved the stability of emulsions (ES) made with a high‐salt chicken meat protein extract, although TG did not significantly affect the amount of protein incorporated into the emulsion cream layer. IT significantly enhanced ES when incubated at 40 °C, but not at 4 °C. TG increased the water uptake ability (WUA) of both chicken muscle and chicken muscle protein extract incubated at 40 °C and 4 °C. Similarly, TG increased the protein and water content of the pellet formed in the WUA test. TG therefore appears to be a useful method to enhance the stability and yield of meat batters.
Microbial and Sensory Assessment of Milk with an Electronic Nose
Authors: Korel F. , Balaban M.Ö.
Published: July 2006

ABSTRACT: An electronic nose (e‐nose) was used to assess milk odor inoculated with Pseudomonas fluorescens or Bacillus coagulans, and odors were correlated with microbial loads and sensory scores. Sterile whole, reduced‐fat, and fat‐free milk were inoculated, stored at 1.7, 7.2, and 12.8 °C, and evaluated at d 0, 3, 5, 7, and 10 by e‐nose and sensory panel. Aerobic plate counts were performed. E‐nose readings, microbial counts, and sensory data were analyzed using discriminant function analysis. The e‐nose discriminated differences in odor due to microbial load and sensory data. This may lead to a rapid method for determining sensory evaluation and microbial loads of milk.
Nature of the Inactivation Curves of Bacillus Pumilus Spores Heated Using Non‐isothermal and Isothermal Treatments
Authors: Ruiz P. , Ocio M.J. , Cardona F. , Fernández A. , Rodrigo M. , Martínez A.
Published: July 2006

ABSTRACT: Isothermal and non‐isothermal heat resistance studies were carried out on Bacillus pumilus spores. The non‐isothermal study revealed a non‐linear behavior of the survivor curve, which was revealed as a tail after an isothermal study. Results indicated that the spores obtained by isolating cells from colonies of the tail section were more heat resistant than the original ones (D104°c= 0.15 and 1.9 min for spores from the original population and from the tail, respectively). Application of the Weibull distribution model to analyze the tail produced good results at the 3 temperatures studied. Nevertheless, when the model was applied to curves having both concave downward and concave upward sections a poor result was obtained, with an accuracy factor greater than 1.
Goat Cheese Flavor: Sensory Evaluation of Branched‐Chain Fatty Acids and Small Peptides
Authors: Salles C. , Sommerer N. , Septier C. , Issanchou S. , Chabanet C. , Garem A. , Quéré J.‐L. Le
Published: July 2006

ABSTRACT: Small peptides (MW < 1000 g/mol) and volatile fatty acids of goat cheese were studied for their favorite properties. The threshold values of 4‐methyl‐ and 4‐ethyl‐octanoic acids‐responsible for the typical goat note were evaluated at pH 5 for orthonasal aroma in a citrate buffer and for retronasal aroma after incorporation in a cheese model. Though the concentration of the 4‐ethyl‐ was lower than the concentration of the 4‐methyl‐octanoic acid in goat cheese, its relative impact on the typical goat flavor appeared more important because of its much lower threshold value. The small peptides, isolated by nano filtration of the ultrafiltered water‐soluble extract at pH 5, were incorporated in the cheese model. Sensory evaluations with omission tests did not allow us to find any taste activity for this peptidic fraction.
Determination and Confirmation of Chloramphenicol Residues in Swine Muscle and Liver
Authors: Li T.L. , Chung‐Wang Y.J. , Shih Y.C.
Published: July 2006

ABSTRACT: Average high‐performance liquid chromatography (HPLC) recoveries of chloramphenicol (CAP) in swine muscle and liver ranged from 91.3 to 94.2% and 93.1 to 103.7%, respectively, with coefficients of variation ranging from 1.4 to 4.3% and 1.1 to 11.2% for each tissue sample. The method described was repeatable and reproducible in swine muscle and liver, with a limit of quantification of 15 ng/mL and a limit of detection estimated at 5 ng/mL. The limit of identification of CAP was 25 ng/mL, 5ng/mL, and 20 ng/mL for HPLC/PDA, GC/MS selected ion monitoring (SIM), and LC/MS analysis, respectively.
Flavor and Storage Stability of Potato Chips Fried in Cottonseed and Sunflower Oils and Palm Olein/Sunflower Oil Blends
Authors: Pangloli P. , Melton S.L. , Collins J.L. , Penfield M.P. , Saxton A.M.
Published: July 2006

ABSTRACT: Potato chips fried in cottonseed (CSO) and sunflower (SFO) oils and 20 and 40% palm olein oil (POO):SFO blends were stored at 23 to 25 °C for 0‐, 3‐ and 6‐wk in dark (DS) and in 1.5‐1.7 footcandles of light (LS). During DS, peroxide values (PV) increased only in chips fried in SFO. In LS, PV increased at lower rates in chips fried in POO blends than in CSO or SFO. Sensory evaluation showed potato chip flavor intensity was similar among oils/blends and unchanged during storage, but intensities of oxidative rancidity and off‐flavor increased in chips fried in CSO at 6‐wk LS. This off‐flavor most likely was due to 1‐decyne identified by SPME analysis. Addition of POO to SFO improved the stability of chips as measured by PV without sacrificing potato chip flavor.
Binding Properties of 2‐Pentyl Pyridine to Soy Protein as Measured by Solid Phase Microextraction
Authors: Zhou A. , Boatright W.L. , Johnson L.A. , Reuber M.
Published: July 2006

ABSTRACT: The binding properties of 2‐pentyl pyridine (2‐pp) were investigated for soybean protein isolates (SPI) and the beta‐conglycinin and glycinin soy protein fractions. The glycinin fraction had the highest binding affinities for 2‐pp, followed by beta‐conglycinin fraction, and then SPI. More 2‐pp was bound by SPI and beta‐conglycinin or glycinin fractions under alkaline conditions than under neutral conditions, which exhibited more binding than acidic conditions. More 2‐pp was also bound at high temperature (74 °C) than at 25 °C, but greater binding affinity of 2‐pp was observed at 4 °C than at 25 °C. With increased NaCl concentrations, the binding affinity of 2‐pp decreased. Exposure to UV light increased binding of 2‐pp to all types of soy protein.
Effect of Water Activity on the Stability to Oxidation of Spray‐Dried Encapsulated Orange Peel Oil Using Mesquite Gum (Prosopis Juliflora) as Wall Material
Authors: Beristain C.I. , Azuara E. , Vernon‐Carter E.J.
Published: July 2006

ABSTRACT: Mesquite gum solutions (30% w/v) were used to emulsify orange peel oil in an oil‐gum solids ratio of 0.25. Emulsions were spray dried in laboratory scale equipment. The powders were stored in aw(s) from 0.108 to 0.743 at 35 °C. Quantitative analysis of limonene oxide indicated that the sample at 0.628 showed a very good stability against oxidation after thirty d, without caking and stickiness occurring. At this water activity the system was within rubbery state, and the moisture content corresponded to that of the minimum integral entropy.
Modeling of O2and CO2 Exchange Dynamics in Modified Atmosphere Packaging of Burlat Cherries
Authors: Salvador M.L. , Jaime P. , Oria R.
Published: July 2006

ABSTRACT: A simple mathematical model has been applied to estimate the optimal conditions for modified atmosphere packaging (MAP) of Burlat cherries. The model describes gas exchange in flexible packages, taking into account the respiration rate of the fruit and the transmission rate of gases through the film. The model predicts the evolution of the gas composition inside the package at different conditions. To verify experimentally the model estimations, Burlat cherries were packaged in air and in 3 mixtures of gases at 2 temperatures using 3 different films. Experimental results agree satisfactorily with the predicted values if the O2 concentration is higher than 2 %.
Imaging of the Fermentation Process of Bread Dough and the Grain Structure of Baked Breads by Magnetic Resonance Imaging
Authors: Takano H. , Ishida N. , Koizumi M. , Kano H.
Published: July 2006

ABSTRACT: Fermentation processes of bread doughs were traced by MRI (magnetic resonance imaging), which suggests that punching and rounding treatment after the first fermentation promotes the development of elasticity and extensibility of gluten fibrils that makes thin grain walls of the pores connecting between adjacent pores with small holes, and a thin smooth crust after baking. While pore generation was small, expansion of the dough was low, gluten networks formed were large and coarse, and gluten fibrils were undeveloped in the frozen dough. Prefermentation could not essentially alleviate the inferior properties of the frozen dough. The grain structures of the bread using frozen dough were characterized by thick network walls without the connection between pores and a thick crust with rough surface.
Survival of Escherichia Coli 0157:H7 on Vacuum‐Packaged Raw Beef Treated with Polylactic Acid, Lactic Acid, and Nisin
Authors: Mustapha A. , Ariyapitipun T. , Clarke A.D.
Published: July 2006

ABSTRACT: The antimicrobial effect of 2% low molecular weight polylactic acid (LMW‐PLA), 2% lactic acid (LA), 200 IU nisin (Nisaplin™)/mL, and combinations of nisin and each acid on Escherichia coli O157:H7 on raw beef was investigated. Fresh beef, inoculated with E. coli O157:H7 and treated with each solution, was vacuum packaged and stored at 4 °C for 28 d. At day 28, counts of samples treated with LMW‐PLA, NPLA, LA, and NLA were significantly reduced to 3.13,2.91, 2.99, and 2.83 log10 CFU/cm2, respectively. However, the antimicrobial effect of LMW‐PLA and LA was not significantly different from each other and Nisaplin did not enhance the effects of either acid against this organism.
Low Temperature Alcoholic Fermentations in High Sugar Concentration Grape Musts
Authors: Llauradó J. , Rozès N. , Bobet R. , Mas A. , Constantí M.
Published: July 2006

ABSTRACT: Low temperature fermentations can increase the quality of wine produced from some aromatic grape varieties. However, these fermentations in musts with a high sugar content may have limitations. The fermentation kinetics and the composition of the resulting wines of 5 different musts have been compared. Maximum fermentation rates correlated well with the available nitrogen. The correlation between the available nitrogen and fermentation rates improved if selected amino acids are corrected for the total sugar content. We propose this new nitrogen parameter as a way of predicting fermentation rates. Must fermentations at low temperatures yielded wines with lower levels of acetic acid, acetaldehyde and ethyl acetate, which can be considered to be positive.
Influence of Protein Source, Type, and Concentration, and Product Form on the Protein Quality of Commercial Enteral Formulas
Authors: Castillo G. , ÁAngeles Sanz M. , ÁAngeles Serrano M. , Hernández A.
Published: July 2006

ABSTRACT: The total, protein, and nonprotein nitrogen, 3 amino acids (lysine, histidine, and tyrosine), available lysine, and in vitro protein digestibility in enteral formulas were determined. Available lysine and protein digestibility were lower in the liquid formulas tested than in the powdered formulas. The protein quality of the formula made from soy protein isolate (soy) was lower than that of the formulas made from casein, and the protein quality of a low‐protein formula was lower than that of the standard formulas. There was a statistically significant correlation between the available lysine content and protein digestibility in the polymeric formulas. New methods are required for assessing the protein quality of formulas containing hydrolyzed proteins.
Insoluble Grape Material Present in Must Affects the Overall Fermentation Aroma of Dry White Wines Made from Three Grape Cultivars Cultivated in Greece
Authors: Karagiannis S. , Lanaridis P.
Published: July 2006

ABSTRACT: Musts from 3 grape varieties were used to elucidate the effect of the presence of grape solids in must on the volatile composition of the resultant white wines. Volatile compounds were analyzed by GC/MS and GC/FPD except H2S, which was measured spectrophotometrically. Increasing quantities of grape insoluble material decreased the substances that enhanced aroma of Savatiano and Batiki wines. Simultaneously, the levels of compounds that degrade wine aroma, when formed in large amounts, were increased. However, in Muscat of Hamburg wines, the levels of some volatiles were not influenced by must turbidity in the same way as in wines of the other cultivars.
Electronic and Human Nose in the Detection of Aroma Differences Between Strawberry Ice Cream of Varying Fat Content
Authors: Miettinen S.‐M. , Piironen V. , Tuorila H. , Hyvönen L.
Published: July 2006

ABSTRACT: The capability of an electronic nose, MGD‐1, in the detection of aroma differences among 5 samples of strawberry ice cream of varying fat content (0,9, or 18% dairy or vegetable fat) was compared with the human nose. R‐indices were determined to detect sensory differences. In addition, the headspace compositions of samples were determined with static headspace gas chromatography. The effect of the amount of fat on the aroma release could be detected with all three methods. The headspace of the nonfat sample was very different from the other samples, but samples containing 9 or 18% of fat were also differentiated. The type of fat did not significantly affect the aroma release. The MGD‐ 1's capability for detecting the aroma differences was fairly comparable with the sensory and the static headspace gas chromatographic method.
Physicochemical Properties of Starches Obtained from Three Varieties of Chinese Sweet Potatoes
Authors: Chen Z. , Schols H.A. , Voragen A.G.J.
Published: July 2006

ABSTRACT: Starches isolated from 3 typical types of Chinese sweet potato varieties (XuShu18, SuShu2, and SuShu8) were characterized and compared with starches isolated from potato and mung bean. The 3 sweet potato starches differed in granule size; particle size distribution; protein, lipid, and phosphorus contents; pasting behaviors; swelling patterns; and syneresis. The retrogradation tendencies, measured both by setback ratio and by syneresis, differed for the 3 starches, although the amylose contents were quite similar (19.3 to 20.0%). Physicochemical properties of all 3 types of starches are evidently different from each other and from those of potato and mung bean starches. Keywords: sweet potato, starch, gelatinization, retrogradation, swelling, syneresis
Purification and Characterization of Aminopeptidase from Chicken Intestine
Authors: Jamadar V.K. , Jamdar S.N. , Dandekar S.P. , Harikumar P.
Published: July 2006

ABSTRACT: An aminopeptidase was purified 839‐fold with 15% recovery from chicken intestine by a procedure involving ion exchange, gel filtration, hydrophobic interaction and affinity chromatography. The enzyme is a heteridimer of subunits 94000 Da and 66000 Da. The substrate specificity of the enzyme was in the order ala > arg > leu‐β‐naphthylamide. The enzyme was strongly inhibited by bestatin, puromycin, and 1, 10‐phenanthroline. The aminopeptidase showed maximum activity at pH 6 and 40 to 50 °C. The enzyme significantly differs from the hitherto known major classes of aminopeptidases from chicken tissues in terms of molecular weight and biochemical characteristics.
Film Composition Effects on Diffusion of Potassium Sorbate Through Whey Protein Films
Authors: Ozdemir M. , Floros J.D.
Published: July 2006

ABSTRACT: The effect of film composition on potassium sorbate diffusion in whey protein films was studied using mixture response surface methodology. The model developed for potassium sorbate diffusivity was statistically significant (P < 0.01) with no significant lack of fit. The diffusivities of potassium sorbate in the films at 25 °C varied between 5.4 and 9.8 × 10−11 m2/s. Amounts of protein, sorbitol, beeswax, and potassium sorbate in the films significantly affected potassium sorbate diffusion coefficients. Increasing the relative amounts of protein and beeswax in the films decreased potassium sorbate diffusivity, while increasing the relative amounts of sorbitol and initial potassium sorbate in the films increased the diffusion of potassium sorbate. Strong interactions were observed between protein and beeswax, and potassium sorbate and beeswax. Keywords: edible films, whey protein, potassium sorbate, diffusivity, mixture design
Evaluation of Process Parameters in the O/W/O Multiple Emulsion Method for Flavor Encapsulation
Authors: Cho Y.‐H. , Park J.
Published: July 2006

ABSTRACT: The multiple emulsion/cold dehydration method was developed for the flavor encapsulation. The effects of various process parameters on the emulsion stability and flavor retention were investigated. Microfluidizer (at 68 MPa) produced more stable emulsion with small uniform droplets than pressure‐homogenizer. Increasing the gum arabic content created a highly viscous emulsion, which resulted in a stable O/W emulsion. The stability of an O/W/O multiple emulsion was highly affected by the type of emulsifiers and the most stable emulsion was prepared using the blend of Span 80 and PGPR. Well‐formed microcapsules having high flavor retention (71%) was obtained when ethanol/water mixture solution of 9:1 was used as a dehydrating agent.
Selective Precipitation of Lysozyme from Egg White Using AOT
Authors: Shin Y‐O. , Rodil E. , Vera J.H.
Published: July 2006

ABSTRACT: Lysozyme from egg white was purified using the anionic surfactant, di‐(2‐ethylhexyl) sodium sulfosuccinate (Aerosol‐OT or AOT), as a precipitating ligand. Upon addition, AOT formed an insoluble lysozyme‐surfactant complex with lysozyme and precipitated from the egg white solution. The lysozyme was then recovered as a solid from the insoluble complex using acetone, while AOT remained in the acetone phase. The precipitation efficiency was highest when the pH of the egg white solution was between 6 and 9. A molar ratio of 15 between surfactant and lysozyme provided 80% precipitation efficiency. The recovered lysozyme product was free of surfactant, and retained its original enzymatic activity.
Resistance of ‘Tulare’ Walnut (Juglans regia cv. Tulare) to Aflatoxigenesis
Authors: MAHONEY N. , MOLYNEUX R.J. , MCKENNA J. , LESLIE C.A. , MCGRANAHAN G.
Published: July 2006

ABSTRACT: The ability of tree nuts to inhibit production of aflatoxins by Aspergillus flavus was investigated in vitro. Walnuts were much more resistant to aflatoxin formation than almonds or pistachios. The walnut cultivar ‘Tulare’ showed complete suppression of toxin production. Kernel without seed coat had no activity and the inhibitory factor(s) were shown to be specifically located in seed coat tissue. When seed coat was added back to ‘Tulare’ kernel media, aflatoxin was decreased to the detection limit or below. Aflatoxin production declined rapidly with seed coat maturity and was independent of growing location and rootstock. Breeding programs could increase resistance, enhancing marketability and safety of walnuts for human consumption.
Simultaneous Recovery of Four Heat‐injured Foodborne Pathogens from a Four‐compartment Thin Agar Layer Plate
Authors: Wu V.C.H. , Fung D.Y.C.
Published: July 2006

ABSTRACT: We have developed and tested a 1‐step resuscitation thin agar layer (TAL) system (nonselective agar overlaid on selective agar) to effectively recover heat‐, acid‐, cold‐, and salt‐injured foodborne pathogens in liquid foods. Each TAL unit was designed for the recovery of one injured population. To improve operation efficiency we have developed a single 4‐compartment Petri dish to simultaneously recover heat‐injured Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, and Yersinia enterocolitica. No significant difference occurred between the single recovery unit and the 4‐compartment unit for enumeration of 4 heat‐injured pathogens (P > 0.05). This 4‐compartment TAL system is at least 4 times more efficient than the single TAL system.
Chitosan Treatment Affects Yield, Ascorbic Acid Content, and Hardness of Soybean Sprouts
Authors: NO H.K. , Lee K.S. , Kim I.D. , Park M.J. , Kim S.D. , Meyers S.P.
Published: July 2006

ABSTRACT: The effects of molecular weights, concentrations and solvents of chitosan, soaking times, and soybeans/chitosan solution ratios on growth and quality of soybean sprouts were investigated. Among 5 chitosans, treatment with 493 kDa chitosan was the most effective in increasing total weight, vitamin C content, and hardness. Use of acetic acid rather than lactic acid as a chitosan solvent increased hypocotyl weight and vitamin C content. Soaking of soybeans in chitosan solution for 8 h increased total weight by 13% and vitamin C content by about 10%. Optimal cultivation conditions involve soaking in 0.05% chitosan with 493 kDa in 0.05% acetic acid for 8 h and a soybean/chitosan solution ratio of 1:4.
Rapid Analysis of Volatile Release from Powders using Dynamic Vapor Sorption Atmospheric Pressure Chemical Ionization Mass Spectrometry
Authors: Dronen D.M. , Reineccius G.A.
Published: July 2006

ABSTRACT: It is hypothesized that a dynamic vapor sorption instrument coupled with an atmospheric pressure chemical ionization mass spectrometer (APCI‐MS) may be useful for rapid analysis of volatile release from dry food materials. Preliminary data from a related system (Vapor Generator Instrument‐APCI‐MS) was used to monitor release of volatiles from spray‐dried food polymers as a function of relative humidity at 40 °C. The system demonstrated differences in volatile release as a function of volatile compound, relative humidity, and food polymer. Comparison of these data with data collected using traditional shelf life study methodologies, and concerns for the ability of the method to accurately reflect time‐dependent changes are discussed.
Analysis of Headspace Volatile and Oxidized Volatile Compounds in DHA‐enriched Fish Oil on Accelerated Oxidative Storage
Authors: Lee H. , Kizito S.A. , Weese S.J. , Craig‐Schmidt M.C. , Lee Y. , Wei C.‐I. , An H.
Published: July 2006

ABSTRACT: Oxidative stability of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and volatile and oxidized volatile compounds in 2 types of DHA‐enriched fish oil, triacylglycerol (TG) and ethyl ester (EE), were studied during storage at 80 °C with aeration. The rate of DHA autoxidation was higher than that of EPA. DHA in EE form was more susceptible to autoxidation than in TG form. Thirty‐one volatile compounds were identified in EE and 23 volatile compounds in TG. (E)‐2‐pentenal, 2‐(1‐pentenyl) furan, and (E,E)‐2,4‐heptadienal were commonly detected as oxidized volatile compounds from TG and EE fish oil. These volatile oxidized compounds might be formed mainly from the oxidation of DHA and EPA, the main fatty acids of the oil.
Effect of Peanut Butter Manufacture on Vitamin E
Authors: Chun J. , Ye L. , Lee J. , Eitenmiller R.R.
Published: July 2006

ABSTRACT: The effect of peanut butter manufacture on vitamin E originating from raw peanuts (Arachis hypogaea L., runner‐type) was determined. Tocopherols were quantified by normal‐phase high‐performance liquid chromatography. No significant differences were observed in tocopherol (T) values between 1998 and 1999 crop raw peanuts or between raw peanuts and peanut butter except for γ‐T (P > 0.05). Oil and stabilizer added to the roasted peanuts during peanut butter processing provided 4% of α‐T in the finished peanut butter. Retention of total tocopherols during peanut butter manufacture was 95%. Mean α‐T values (mg/100 g) of commercial peanut products ranged from 12.3 (peanut oil) to 4.1 (dry roasted peanuts).
Microscopic Structure of Opalescent and Nonopalescent Pecans
Authors: Wakeling L.T. , Mason R.L. , D'Arcy B.R. , Caffin N.A. , Gowanlock D.
Published: July 2006

ABSTRACT: The ultrastructure of pecans was investigated using light microscopy, environmental scanning electron microscopy, scanning electron microscopy, and transmission electron microscopy. Specific methodology for the sample preparation of pecans for electron microscopy investigations was developed. Electron microscopy of the ultrastructure of opalescent (discoloration of the interior) and nonopalescent kernels revealed that cellular damage was occurring in opalescent kernels. The damage was due to cell wall and membrane rupture, which accounted for the release of oil throughout the kernel. This rupture is due to the lower level of calcium in the cell membranes of opalescent pecans, as shown by energy dispersive X‐ray spectrometry, making them more susceptible to damage.
Effects of Irradiation on Properties of Cured Ham
Authors: Houser T.A. , Sebranek J.G. , Lonergan S.M.
Published: July 2006

ABSTRACT: The quality characteristics of cured ham, treated with ionizing radiation (4.5 kGy) at different points in the curing process, were compared during a 90‐d storage period. Irradiation treatments included irradiation of raw uncured ham, raw‐cured ham, cured cooked ham, and a nonirradiated control. Irradiation processing increased lipid oxidation for all treatments. The raw‐cured treatment resulted in significantly lower L* values compared with the control regardless of storage period. All treatments except for cured cooked ham had lower b* values over the storage period. Irradiation of cured cooked ham resulted in higher off‐odor scores than all other treatments immediately following irradiation thus indicating a change in quality.
Linking Sensory Descriptors to Volatile and Nonvolatile Components of Fresh Tomato Flavor
Authors: Tandon K.S. , Baldwin E.A. , Scott J.W. , Shewfelt R.L.
Published: July 2006

ABSTRACT: Twelve tomato selections were evaluated for their flavor components using sensory and chemical/instrumental measurements. Regression analysis was performed to develop prediction models for the sensory descriptors. Significant prediction models were obtained for most descriptors. Both volatile and nonvolatile flavor components influenced the aromatic descriptors, but the volatile components provided more consistent relationships. Sucrose equivalents provided more significant correlations with descriptors than did soluble solids. Tomatoes described as full flavored by the breeder were characterized by higher sugars, soluble solids, aromatic volatile compounds, and lower amounts of organic acids than those considered to be of poorer flavor by the breeder. These data provide quantitative linkages of aromatic volatile compounds, sugars, and acids with specific flavor notes.
Using Both Chemical and Biological Fingerprints for the Quality Study of Estrogenic Licorice (Glycyrrhiza uralensis)
Authors: Teng S.‐C. , Tsai H.‐J. , Tsai M.‐C. , Lee W.‐M. , Chen I.‐C. , Lin C.‐C.
Published: July 2006

ABSTRACT: The quality of phytoestrogenic licorice was studied by using both chemical and biological fingerprints. A recombinant yeast strain that consists of an estrogen responsive element linked with a reporter gene (ADE2) and a transformed human estrogen receptor–containing plasmid was used for screening and evaluation of estrogenic activity in licorice. Several estrogen‐like components in licorice were screened, and licoisoflavone B and formononetin were identified. Licorice extracted with 70% ethanol showed 5 different patterns of chemical fingerprints (LR‐A, LR‐E, LR‐F, LR‐H, LR‐K), as identified by chromatographic analysis. Among these, LR‐E exhibited the strongest estrogenic activity, whereas LR‐A, LR‐F, and LR‐H were in the middle, and LR‐K had the weakest activity.
Predictive Analysis of Cocoa Procyanidins Using Near‐Infrared Spectroscopy Techniques
Authors: WHITACRE E. , LIVER J. O , VAN DEN BROEK R. , VAN ENGELEN P. , REMERS B. K , VAN DER HORST B. , TEWART M. S , JANSEN‐BEUVINK A.
Published: July 2006

ABSTRACT A near‐infrared reflectance (NIR) spectroscopy technique for the prediction of procyanidins in cocoa beans (Theobroma cacao) has been developed. A select group of cocoa liquors from different origins used for the manufacture of chocolate were analyzed to determine quantitative levels of procyanidin oligomers (monomer to decamer) using normal‐phase high‐performance liquid chromatography. The calibration set included seasonal, environmental, and fermentation variations to cover the concentration range of procyanidins found at naturally occurring levels. The sample set was analyzed on FOSS NIR System II 6500 spectrophotometers and partial least‐squares algorithms developed. Very good calibration statistics were obtained for the prediction of the total procyanidin oligomers (r2 = 0.983) with standard deviation/standard error of cross validation ratio (SD/SECV) of 5.68. A global version of this calibration, involving 20 Foss instruments produced a calibration r2 = 0.98 with a SD/ SECV = 6.20. Procyanidins have attracted increasing attention because of the rapidly growing body of evidence associating these compounds with a wide range of potential health benefits. A rapid method for the analysis of procyanidins in cocoa liquors would be beneficial in quality‐control environments and would provide cost benefits to manufacturing operations.
Comparison of Functional Characteristics of Modified Corn Gluten Meal In Vitro and in an Emulsified Meat Model System
Authors: HOMCO‐RYAN C. L. , RYAN K. J. , BREWER M. S.
Published: July 2006

ABSTRACT Corn gluten meal (CGM) was pH‐adjusted (6.6) and particle‐size reduced (MC7, 7 μm; MC38, 38 μm) then compared with native CGM and soy protein isolate (SPI) for emulsifying activity (EA) and emulsifying stabilization (ES), oil‐binding capacity (OBC), and water‐holding capacity (WHC) in vitro and in an emulsified meat model system. MC7 and MC38 had EA, ES, and OBC, which was superior to native CGM; no significant change occurred in water solubility. In 1% and 2% NaCl solution, MC7 and MC38 resulted in more stable emulsions than SPI. In an emulsified meat model system, SPI had superior ES to CGM‐based substances; however, reheated cook losses did not differ.
Integration of Rapid Derivatization and Gradient Elution Techniques for Enhanced High‐Performance Liquid Chromatography Analysis of Key Amino Acids in Wheat Flour
Authors: FERMIN B. C. , RADINSKY J. A. , KRATOCHVIL R. J. , HALL J. E. , O Y. M. L
Published: July 2006

ABSTRACT A rapid pre‐column derivatization process before ultraviolet chromatographic analysis using a Pico‐Tag C18 column was developed in combination with modified gradient elution techniques for the analysis of key amino acids (proline and glutamine) in wheat flour. With use of a vacuum concentrator at 45°C, the pre‐column derivatization process was significantly accelerated before entering a reverse‐phase high‐performance liquid chro‐matography. When running at an optimized scheme—in which the gradient elution started at a flow rate of 1 mL/ min and then gradually increased to 1.3 mL/min in 22 min, followed by reset to 1 mL/min at 45 min—the profiled mobile phase mixture was able to yield chromatograms with desirable retention factor and resolution. Keywords: proline, glutamine, glutamic acid, reverse‐phase HPLC, resolution
Kinetic Analysis of Osmotic Dehydration Carried Out with Reused Sucrose Syrup
Authors: MOYANO P. C. , ZÚÑIGA R. N.
Published: July 2006

ABSTRACT Processing times required to achieve a target level of soluble solids were determined in apple pieces during sequential osmotic dehydrations carried out with reused sucrose syrup, in which new loads of fruits were charged in each turn. Effective diffusivities for water and sucrose in apple pieces were experimentally determined as a function of syrup soluble solids. A computer program was written to predict soluble solids change both in apple pieces and in syrup during the sequential osmotic dehydration process. Experimental data on the change of soluble solids for apples and syrup for 10 batches arranged in 2 sets of 5 were obtained. A good agreement between observed and predicted values of soluble solids in both fruit and the syrup was obtained, with root mean square values ranging from 1.3% to 4.6%.
Effects of Soy Glycinin Addition on the Conformation and Gel Strength of Two Pork Myosin Types
Authors: LÓPEZ‐DÍAZ J. A. , RODRÍGUEZ‐ROMERO A. , HERNÁNDEZ‐SANTOYO A. , SOTELO‐MUNDO R. R. , DE LA BARCA A. M. CALDERÓN
Published: July 2006

ABSTRACT The pale, soft, and exudative (PSE) condition in pork meat has been associated with protein dena‐turation that leads to loss of functional properties. The effect of soy glycinin addition to model systems of actomyosin from PSE or normal meat on biophysical properties was evaluated. Although the functional properties depended on actomyosin concentration, a 75% actomyosin/25% glycinin mixture presented acceptable properties with both types of actomyosin. This combination was used to investigate protein‐protein interactions. Gel strength correlated with intermediate a‐helical content and protein aggregation. Changes in protein secondary structure probably added to protein denaturation appear to be necessary to improve gelation and water retention in PSE actomyosin‐glycinin combinations.
Modeling Wound‐induced Respiration of Fresh‐cut Carrots (Daucus carota L.)
Authors: SURJADINATA B. B. , CISNEROS‐ZEVALLOS L.
Published: July 2006

ABSTRACT A mechanistic model based on synthesis and inactivation of enzymes, associated to the respiration pathway, was proposed to describe wound‐induced respiration of fresh‐cut produce. Carrots (Daucus carota L.) were cut into slices, sticks, a combination of both, and shreds to obtain different wounding intensities, defined by the ratio of new area created to tissue weight (A/W). Respiration rates obtained at 10°C showed a typical increase, a maximum peak, and a decrease until reaching steady state. A 2‐phase exponential decay equation described the process, with the obtained key parameters relating to A/W. This model can be used to understand wound‐induced respiration and the possible implications in produce quality changes and packaging design.
Evaluation of Sensory and Microbiological Changes and Identification of Proteolytic Bacteria during the Iced Storage of Farmed Turbot (Psetta maxima)
Authors: RODRÍGUEZ Ó. , BARROS‐VELÁZQUEZ J. , OJEA A. , PIÑEIRO C. , AUBOURG S. P.
Published: July 2006

ABSTRACT Sensory and quantitative microbiological analyses were performed in farmed turbot (Psetta maxima) during iced storage. Sensory analyses revealed a shelf life of 19 d for farmed turbot. The production of total volatile base nitrogen (TVB‐N) and trimethylamine‐nitrogen (TMA‐N) was low and reached levels close to 40 mg TVB‐N/ 100 g muscle and 3.5 mg /TMA‐N/100 g muscle, even after 40 d of refrigerated storage. The pH value of turbot muscle increased from an initial value of 6.3 to close to 7.0 after 29 d of iced storage. Microbial growth was slow in iced turbot: total aerobic counts reached levels below 7 log colony forming units/g units even after 40 d of storage. Lactic acid bacteria—mainly Lactobacillus delbrueckii subsp. delbrueckii and Lactococcus lactis subsp. lactis strains—were predominant among the proteolytic strains isolated from iced turbot. Proteolytic strains of L. lactis subsp. lactis, Brochothrix thermosphacta, Plesiomonas shigelloides, Proteus vulgaris, and Pantoea species were also isolated from temperature‐abused turbot, such proteolytic strains being predominant with respect to nonpro‐teolytic microorganisms, suggesting a preferential role of such proteolytic bacteria in the spoilage of turbot. The slow bacterial growth, together with the relative predominance of lactic acid bacteria over Gram‐negative microorganisms, may be related to the extraordinary maintenance of the quality and extended shelf life of farmed turbot.
Lethality of Listeria monocytogenes in Fully Cooked and Vacuum Packaged Chicken Leg Quarters During Steam Pasteurization
Authors: Murphy R. Y. , Driscoll K. H. , Arnold M. E. , Marcy J. A. , Wolfe R. E.
Published: July 2006

ABSTRACT Fully cooked chicken leg quarters (160 g to 300 g) were injected to contain 107 to 108 colony‐forming units (CFU)/g of a 5‐strain Listeria monocytogenes culture. The inoculated leg quarters were vacuum‐packaged in 0.08‐mm‐thick packaging films and then pasteurized at 96°C via steam. The heat transfer coefficient was about 760 W/m2 K in the steam cooker. Seven log10 (CFU/g) reduction of L. monocytogenes was achieved in about 22 min of steam treatment. Results from the inoculation tests agreed with the process lethality model prediction using the kinetic values that were obtained for the same product. This information helps industry to validate the lethality of L. monocytogenes in similar products during postcook pasteurization.