bluuebunny/crossref_metadata_2025 huggingface dataset:
A COMPARISON OF SOME CHEMICAL PROPERTIES OF YOGURTS MADE FROM CONTROL AND LACTASE‐TREATED MILKS
Authors: O'LEARY V. S. , WOYCHIK J. H.
Published: August 2010

Certain properties of yogurts made from regular commercial skim milk and from milk which had been treated with lactase enzyme so that 70‐75% of the lactose was hydrolyzed to glucose and galactose were evaluated. Initially faster rates of acid production in lactase‐hydrolyzed milks (LH) during fermentation resulted in somewhat shortened processing times, although a decrease in the rate of acid production occurred earlier during fermentation in the LH milk so that final product pH was similar for both the control and LH yogurts. Control yogurts contained 5.0% lactose and 0.2% galactose while LH yogurts contained 1.6% glucose, 1.5% lactose and 2.1% galactose. Appreciably more lactic acid was produced in LH yogurts and this effect has been related to fermentation by the starter culture organisms of a greater proportion of the available sugar as glucose.
METHOD FOR EVALUATING THE FILTERABILITY OF WINE AND SIMILAR FLUIDS.
Authors: PELEG Y. , BROWN R. C.
Published: August 2010

A method for determination of the filterability of wine was developed. The method is based on evaluation of the filtration curve of a wine filtered through a membrane disc 13 mm in diameter, having a pore size of 0.45 micron. Results of the filterability test were found to be related to plant operation. According to the method developed, a wine is ready for membrane filtration the moment that its filterability test indicates that the differential filtered volume remains unchanged for most of the 60 min determination time. A decrease in the differential filtered volume indicates that the wine contains insolubles/microorganisms, and the rate of the decrease should be considered to be proportional to the load on the membrane. This method is not limited to the wine industry, but can be adapted and/or modified for similar applications, i.e., pharmaceuticals, breweries, fine chemicals.
ABSCISSION AGENT EFFECTS ON ORANGE JUICE FLAVOR
Authors: MOSHONAS MANUEL G. , SHAW PHILIP E. , SIMS DONALD A.
Published: August 2010

The flavor quality of juice products from early‐ (Hamlin), mid‐ (Pineapple) and late‐season (Valencia) oranges sprayed with abscission chemicals to aid in mechanical harvesting, was evaluated and compared with that of similar juice products from untreated fruit. Four commercially available abscission agents were included in this study: Acti Aid®, Release®, Pik‐Off® and ethephon. An expert taste panel distinguished experimental from control juice samples in most tests and generally preferred juice products made from control oranges.
CLOUD STABILITY TEST FOR PASTEURIZED CITRUS JUICES
Authors: HOLLAND RALPH R. , REEDER SAMUEL K. , PRITCHETT DAVID E.
Published: August 2010

A 24‐hr storage test is presented for evaluating. the cloud stability of pasteurized citrus juices. Enzymatic flocculation is accelerated by the addition of a special pectin and a barium salt while controlling pH and temperature. A citrus juice which retains greater than 60% of its initial cloud after 24 hr of this storage will have a satisfactory cloud stability for at least 1 yr under normal conditions.
SUPPLEMENTATION OF ONE‐POUND LOAVES WITH WET ALKALINE PROCESS WHEAT PROTEIN CONCENTRATES: BAKING AND NUTRITIONAL QUALITY
Authors: BETSCHART A. A. , SAUNDERS R. M. , HEPBURN F. N.
Published: August 2010

The baking properties, protein quantity and quality of 1–1b wheat flour loaves supplemented with 10–20% wet alkaline process wheat protein concentrate (WAP‐WPC) were studied. WAP‐WPC was isolated from a pH 9 extract of wheat millrun or shorts by either acid (HCl pH 5) or heat (85°C) and freeze, spray, or drum dried. Acceptable loaves were baked with spray‐ or drum‐dried preparations, with the drum dried, heat precipitated WAP‐WPC performing the best. The lysine content of the control bread, 112 mg/g N, was increased from 177 to 206 mg/g N with the incorporation of 10–20% WAP‐WK. Protein digestibility of loaves supplemented with WAP‐WPC prepared by various methods was ≥90% and the PER ranged from 1.3–1.7 as compared to 0.76 for the wheat flour control.
TRANSIENT STATE HEAT TRANSFER IN STACKS OF HEAT PROCESSED FOOD STORED IN A COMMERCIAL WAREHOUSE
Authors: HAYAKAWA KANICHI , TIMBERS GORDON E.
Published: August 2010

Temperatures in selected locations in the stacks of canned tomato juice and jarred relish, which were placed in an uninsulated warehouse shortly after their production, were determined experimentally. Through careful examination of temperature data collected, mathematical formulas were derived for predicting the temperature response of heat processed food in a warehouse stack For this derivation, a formula for transient state heat conduction in an infinite slab was used. Since the apparent Bio number and thermal diffusivity values of a warehouse stack were required for predicting product temperature by using the derived formulas, a method was developed to determine these two parametric values. A set of computer programs (Fortran IV) were prepared for the computerized prediction of product temperatures by using the derived formulas because they are too complex for manual calculations. There is reasonable agreement between theoretically predicted and experimentally determined temperatures. The maximum difference between the two is 10F° or less during the initial period of warehouse storage. The computational procedure developed in the present investigation will provide invaluable means for determining the proper warehouse storage of heat processed food.
ISOLATION AND PURIFICATION OF Clostridium perfringens ENTEROTOXIN BY AFFINITY CHROMATOGRAPHY
Authors: BARNHART H. M. , BULLERMAN L. B. , BALL ELLEN M. , WAGNER FRED W.
Published: August 2010

Sporulating cells of certain strains of Clostridium perfringens produce an intracellular enterotoxin believed to be the causative agent of C. perfringens food poisoning. Rabbit antibody preparations to both vegetative and sporulating cell extracts were used to purify toxin by differential immuno‐affinity chromatography. Solid phase immune adsorbents were prepared by attaching antibody via α‐amino groups to succinylaminoethyl Sepharose‐4B to give two resins: one binding anti‐vegetative immunoglobulin G (IgG), (V‐resin), the other, antisporulating IgG, (S‐resin). Sporulating cell extract was passed through resin with bound IgG to vegetative cell extract. A large protein fraction representing antigens common to both C. perfringens forms was retained, but toxin was not measurably absorbed to the resin as determined by erythemal activity in rabbits. The toxic fraction was then passed through resin with bound IgG to sporulating cell extract. The majority of the protein did not adhere to this resin; however, that which did, showed erythemal activity in rabbits. Disc‐gel electrophoresis of the protein fraction eluted from resin with bound IgG to sporulating cell extract demonstrated the presence of five components. One elicited erythemal activity in rabbits. The maximum capacity of the V‐resin column was 102 μg of bound protein/ml of resin, and of the S‐resin column, 32 μg of bound protein/ml of resin. A 150‐fold purification was achieved by the procedure. Resins could be used repeatedly.
STABILITY OF STAPHYLOCOCCAL ENTEROTOXIN A TO SELECTED CONDITIONS ENCOUNTERED IN FOODS
Authors: CHORDASH RICHARD A. , POTTER NORMAN N.
Published: August 2010

Changes in serological activity of enterotoxin A were measured by an immuno‐diffusion method. The reducing sugars xylose, lactose, glucose, maltose and fructose did not react with enterotoxin so as to reduce titer under various conditions of concentration, pH, temperature and time but all of these sugars exhibited an enterotoxin protective effect when systems were heated at 60°C. Sodium propionate, sodium benzoate and sodium nitrite at various concentrations did not alter enterotoxin titer when systems were incubated up to 9 days at 21 or 37°C. Sodium sulfite at a solution concentration of 1000 ppm decreased titers under specific conditions that suggest weak complex formation with the enterotoxin. Luxuriant growth of bacteria belonging to the genera Bacillus, Micrococcus, Brevibacterium, Aeudomonas, Proteus, Escherichia, Enterobacter, and yeasts of the genera Candida and Saccharomyces, in several media containing enterotoxin A did not significantly alter exterotoxin titer. Titer was substantially reduced by several species of lactic acid bacteria including L. acidophilus, L. helveticus, L. plantatum, L. mesenteroides, Strep. thermophilus, Strep. faecalis var. liquefaciens, Strep. lactis and P: pentosaceus in MRS broth and by five of the above species in APT broth. Reductions in titer were not simply due to decreases in pH by these organisms. Studies on heat inactivated enterotoxm revealed partial reactivation in phosphate‐buffered saline incubated at 30 and 37°C for 72 hr but not at several other conditions of lower temperature and shorter time.
EMULSION CAPACITY AND FOAM STABILITY OF RE‐EXTRACTED SUNFLOWER MEAL (Helianthus annuus)
Authors: WU J. S. , WISAKOWSKY E. E. , BURNS E. E.
Published: August 2010

Emulsification and foam stabilization attributes of residual lipids in hexaneextracted sunflower meal were determined. Reextraction with various solvents did not markedly affect emulsifying capacity. Methanol washing increased foam stability.
Effect of Needle Tenderization on Salt Absorption, Yields, Composition and Palatability of Dry‐Cured Hams Produced from Packer Style and Skinned Green Hams
Authors: KEMP J. D. , FOX J. D.
Published: August 2010

The effects of needle tenderization on the curing processes and final cured ham properties of packer style and skinless hams were investigated. Skinless hams absorbed salt faster and lost weight faster than packer style hams. Needle tenderized hams also absorbed salt faster and had more weight loss than nontenderized hams in both the packer style and the skinless groups. Two months'aging resulted in excess dehydration and lowered quality in the skinless tenderized group. In skinless hams, curing, salt equalization and aging times were reduced so that acceptable, though mild flavored, hams that met the USDA requirements for weight loss and salt content were produced within 5 wk.
Growth of Clostridium sporogenes and Staphylococcus aureus at Different Temperatures in Cooked Corned Beef Made with Reduced Levels of Sodium Chloride
Authors: WHITING R. C. , BENEDICT R. C. , KUNSCH C. A. , BLALOCK D.
Published: August 2010

Cooked corned beef made with normal (ca.2.5%) or a reduced (ca.1.5%) level of salt were inoculated with either clostridial spores or with staphylococci and incubated at temperatures ranging from 5 ‐ 30°C. Growth of indigenous microflora, staphylococci, or clostridia was similar at both salt levels at a given incubation temperature. However, increasing the abuse temperature greatly increased the growth of all organisms. Outgrowth of clostridial spores occurred in ground cooked corned beef which contained the normal residual nitrite of 40 ‐ 45 ppm; readdition of nitrite to 150 ppm at the time of inoculation markedly reduced growth. Gas production was not a good indicator of clostridial growth.
Effects of Internal Temperature and Thickness on Palatability of Pork Loin Chops
Authors: SIMMONS SHARON L. , CARR TOM R. , McKElTH FLOYD K.
Published: August 2010

Three thicknesses (2.54, 1.90 and 1.27 cm) of pork chops were cutl alternately from 20 paired loins of similar quality. Chops were cooked on Farberware grills or in a convection oven to internal temperatures of 60, 70 and 80°C for sensory and objective evaluations. Juiciness, percent moisture and tenderness decreased and cooking losses increased (P < 0.05) as temperature increased for both cooking methods. Pork flavor intensity increased in oven‐ prepared chops, while no change was observed in grilled chops at each level of increased temperature. Thickness had no effect (P > 0.05) on tenderness, juiciness or total cooking loss of oven‐prepared or grilled chops. The thickest chops received the highest (P < 0.05) pork flavor scores.
Development of a Frankfurter Analog From Red Hake Surimi
Authors: BUCK E. M. , FAFARD R. D.
Published: August 2010

The development of an essentially fat‐free, frankfurter analog from red hake surimi is described. In consumer tests against four commercial brands of frankfurters, the analog competed well with a chicken frankfurter, but neither chicken nor fish achieved the levels of acceptance of beef‐containing products. Warner‐Bratzler shear measurements revealed significant changes in texture in the fish and chicken frankfurters during a 21day storage period at 2°C. The analog proved to have lower populations of certain microorganisms as compared to the other products tested. There was no spoilage detected in any of the products evaluated after 21 days at 2°C. The nutritional advantages of the analog are discussed.
Effects of Toasting on the Quality of Canned Rice
Authors: SHARP R. N. , KATTAN M. W. , SHARP C. O.
Published: August 2010

Parboiled long grain milled rice was toasted to assess the effects of dry heat on the canning quality. Toasting was accomplished by exposing the rice to 170°C for 0, 1.5, 30, 45 or 60 min. Increased toasting time resulted in decreased whiteness and yellowness and increased redness, but the intensity of the color change was diminished by hydration and canning. Toasting time increased the force required to shear the canned product; however, the rate of retrogradation, as measured by amylographic viscosity, seemingly was unaffected by the toasting treatments. Sensory evaluations indicated that preferences for flavor and general appearance of the canned toasted rice were very individualistic.
Nucleic Acid, Fiber and Nutrient Composition of Inactive Dried Food Yeast Products
Authors: SARWAR G. , SHAH B. G. , MONGEAU R. , HOPPNER K.
Published: August 2010

Nucleic acid, ammino acid, dietary fiber, mineral and vitamin composition of six commercial inactive dried food yeasts was studied. Products A and B (autolyzed extract) were produced from Saccharomyces cerevisiae grown on cane‐ and/or beet molasses. Four products were produced from Candida utilis grown on calcium lignosulfate/wood sugars (C), sulfite waste liquor (D) and ethyl alcohol (E and F, autolyzed form). Levels of nucleic acids, protein, most amino acids, folacin and panthothenic acid were higher in C. utilis products than in S. cerevisiae products. Differences between dietary fiber, most minerals and biotin contents of the two species of yeast were, however, small. Autolysis and/or growth on different substrates affected levels of nucleic acids, dietary fiber and most nutrients.
Evaluation of Substrate Potentiality and Inhibitory Effects to Identify High Risk Spices for Aflatoxin Contamination
Authors: MADHYASTHA M. S. , BHAT R. V.
Published: August 2010

Growth and aflatoxin production by A. parasiticus (NRRL 2999) on autoclaved whole, ground and also surface sterilized black pepper, cardamom, red pepper, dry ginger and turmeric were studied. Cardamom did not support detectable fungal growth or aflatoxin production. Black pepper and turmeric appeared to be poor sub‐strates as they supported comparatively less fungal growth and afla‐toxin production. Red pepper and ginger were found to be better substrates for fungal growth as well as for aflatoxin production. Ether and chloroform extracts of cardamom and turmeric inhibited aflatoxin production almost completely. The inhibitory activity of cardamom oil and curcumin indicated that they might be the active principles.
Effect of Temperature on the Moisture Sorption Isotherms and Water Activity Shift of Two Dehydrated Foods
Authors: LABUZA T. P. , KAANANE A. , CHEN J. Y.
Published: August 2010

The water activity (aw) of eight salt solutions was determined at three temperatures (25, 30, 45°C) using a pressure transducer‐vapor pressure manometer. The aws of the salts showed a decrease with increasing temperature, which was explained with the help of a thermodynamic equation. This is opposite to the increase in aw with increase in temperature for foods. Moisture sorption data for fish flour and cornmeal were obtained at 25–65°C. The Guggenheim‐Anderson‐deBoer model was evaluated and shown to be comparable to the Brunauer‐Emmett‐Teller model for prediction of the monolayer. Product was equilibrated at different aws at 25°C then subsequently shifted to 30°C and 45°C in a sealed chamber. The resultant a, change, measured on the Kaymont‐Rotronics, was predictable from the isotherm at each temperature using the Clausius Clapeyron relationship.
Moisture Transfer Properties of Dry and Semimoist Foods
Authors: LOMAURO C. J. , BAKSHI A.S. , LABUZA T. P.
Published: August 2010

Equilibrium moisture content, mass diffusion coefficients, and densities were collected for wheat flour, shredded wheat, raisins, nonfat dry milk, and freeze‐dried apple, turnip, and ground beef at 25 ± 1°C. Flour adsorbing to 0.75 aw had the largest mass diffusion co‐efficient, 1.15 × 10−7 m2/hr and raisins had the smallest value of 0.015 × 10‐7 m2/hr. Two of the food uroducts. flour desorbing to 0.11 aw, and the freeze‐dried turnip, exhibited diffusion coeffcients which were dependent on the moisture content. Most of the foods reached equilibrium within 1 wk based on an objective criterion of no more than a 0.5% dry basis moisture difference over three successive readings at 1 wk interval.
Effects of Polymers on Secondary Nucleation of Ice Crystals
Authors: SHIRAI YOSHIHITO , NAKANISHI KAZUHIRO , MATSUNO RYUICHI , KAMIKUBO TADASHI
Published: August 2010

The kinetics of ice crystallization in various polymer solutions were studied by the thermal response method in a batch crystallizer. Polymers suppress the secondary nucleation of ice crystals, depending on the kinds of polymer and concentration. The decrease of the nucleation rate constant in polymer solutions was related to the increase of viscosity. The effects of polymers on the nucleation rate were also observed in solutions containing low molecular weight compounds.
Effect of Heat Treatment on Bioavailability of Meat and Hemoglobin Iron Fed to Anemic Rats
Authors: JANSUITTIVECHAKUL O. , MAHONEY A.W. , CORNFORTH D.P. , HENDRICKS D.G. , KANGSADALAMPAI K.
Published: August 2010

Efficiency of converting dietary iron from meat, bovine hemoglobin (HB) and ferrous sulfate into hemoglobin was investigated in anemic rats. Raw or autoclaved HB, and raw, autoclaved, boiled, or baked beef round, and ferrous sulfate were mixed into diets to give 36 mg Fe/kg diet. Heat treatments increased the efficiency of converting both HB and meat iron into hemoglobin by the anemic rats. Efficiencies of conversion were 23, 30, 33, 37, 37, 36 or 60 (LSD 0.05/0.01 = 4/6), respectively, for raw HB, autoclaved HB, raw meat, autoclaved meat, boiled meat, baked meat or ferrous sulfate. An in vitro measurement of iron availability in meat correlated poorly with bioavailability determined in rats. Cooking did not significantly affect the bioavailability of meat iron.
Measuring Dietary Fiber in Human Foods
Authors: MARLETT JUDITH A. , CHESTERS JOAN G.
Published: August 2010

Compositions of neutral detergent fiber (NDF) residues and water insoluble fiber fractions extracted by the Southgate method from five foods were determined quantitatively and compared. Neutral saccharide compositions of the two fiber residues, measured by HPLC, were similar for four of the five foods. Uranic acids constituted 4 ‐ 8% of fiber in all foods. When adjustments were made for protein, starch and moisture contents, mean recovery of the two fibers was 97.9 f 3.9%. Gravimetric quantitation of NDF or of a Southgate‐derived insoluble fiber usually yielded a fiber content similar to the chemically determined value, although each of the Southgate residues had to be corrected for starch and/or crude protein content.
Moisture Sorption of Dry Bakery Products by Inverse Gas Chromatography
Authors: HELEN H. J. , GILBERT S. G.
Published: August 2010

Inverse gas chromatography was used to study moisture sorption properties of two bakery products as a function of temperature and food structure. Crackers (high in fat, low in sugar) were found to be more hygroscopic than sweet biscuits. Sorption isotherms at different temperatures were determined to obtain thermodynamic parameters of sorption. Enthalpy and entropy functions as weU as Zimm‐Lundberg clustering analysis suggested different sorption mechanisms in the two systems. Active site binding mechanism was manifested in the cracker system by highly negative enthalpy and entropy changes at low moisture contents. Water‐water interactions were more favored in the sweet biscuit system at the same free energy level. Addition of crystalline sucrose decreased hygroscopicity of the cracker system and increased formation of water‐water interactions.
Influence of Temperature and Time on Cooking Kinetics of Potatoes
Authors: HARADA T. , TIRTOHUSODO H. , PAULUS K.
Published: August 2010

To study cooking kinetics, slices (6 mm thick, 30 mm diameter) of 3 potato varieties were treated in water at 90°, 100° and 110°C for varying times. Sensory, chemical and physical properties were investigated. Changes during cooking at constant temperature were mathematically described by a 0 order (texture, taste) and a 1st order (shear force, dry matter, pectin, soluble amylose, cell size) equation. The starch content remained constant. Temperature dependence of the rate constant could always be described by a first order equation. The z‐values, which are necessary to calculate Cvalue for practical heat treatments, could be determined. Correlations established between kinetics of different properties showed that behavior of certain potato properties may be predicted by shear‐force measurement.
Distribution and Rate of Migration of Curing Ingredients (Nitrite, Salt, Glucose) in Pork Tissue as Affected by Electrical Stimulation
Authors: OCKERMAN H. W. , KWIATEK K.
Published: August 2010

The effect of electrical stimulation of pork carcasses on distribution and rate of migration of curing ingredients (nitrite, salt, glucose) was investigated. Sixty cylindrical triceps brachii muscle samples were prepared at 24 hr post‐stimulation from three pigs (left side stimulated; right side control, not stimulated) and determination for nitrite, salt and glucose were made at 24, 48 and 72 hr post‐curing at each of four cylindrical segment depths of 1.25 cm each. The analysis of variance indicated that electrical stimulation caused significant (P < 0.01) improvement in absorption and migration of curing ingredients (nitrite, salt, glucose) into all depths of the pork cylinder.
Degree of Difference Test Method in Sensory Evaluation of Heterogeneous Product Types
Authors: AUST L. B. , JR. M. C. GACULA , BEARD S. A. , II R. W. WASHAM
Published: August 2010

A degree of difference test and its statistical analysis were developed to replace the traditional triangle test for products which vary during production. Several heterogeneous food products and computer simulated data were used in this study. The result shows that the use of the triangle test with a highly variable product results in a high frequency of false statistically significant results being declared. A degree of difference test which measures and tests perceived differences in taste due to other than product variability via the analysis of variance approach is therefore recommended for dealing with heterogeneous products.
Purification and characterization of a CIostfidium perfringens α‐galactosidase
Authors: DURANCE TIMOTHY , SKURA BRENT
Published: August 2010

Of 21 strains of C. perfringens tested for hydrolysis of α‐galactosides, 10 utilized either raffinose or melibiose while 2 utilized both sugars. Spore production in Duncan Strong medium was superior in the presence of raffinose as opposed to starch in 12 out of 21 strains. C. perfringens M34 yielded 1.2 units of α‐galactosidase/g washed cells. This enzyme had an isoelectric point of 5.6 and a pH optimum for hydrolysis of PNPG of 6.3. Native and monomer molecular weights were 96,000 and 46,000 daltons respectively. Km was 0.20 ± 0.02mM PNPG. Heat stability of the enzyme decreased as purity increased. This trend was partially reversed by addition of 2‐mercaptoethanol, NADH, cysteine, and/or bovine serum albumin to reaction mixture.
Prediction of Beta‐Carotene Decolorization in Model System Under Static and Dynamic Conditions of Reduced Oxygen Environment
Authors: SAGUY ISRAEL , GOLDMAN MARIANA , KAREL MARCUS
Published: August 2010

Predictions of beta‐carotene losses were made with model systems stored under conditions simulating storage of dry foodstuff powders. The mathematical model utilized kinetic data collected under static conditions of water activity and oxygen concentration and was extended for the prediction of beta‐cartone retention under dynamic conditions. Results showed an excellent agreement between actual and predicted retention of beta‐carotene stored under dynamic conditions once the proper correction factor was used. The correction factor was required to compensate for different geometries which affected diffusion limiting reactions.
A Puncture Testing Method for Monitoring Solid Substrate Fermentation
Authors: KRONENBERG H. J. , HANG Y. O.
Published: August 2010

Meitauza, an indigenous Chinese food made from fermented okara (soymilk residue), was used as a model system for monitoring solid substrate fermentations. The Instron Universal Testing machine and Chatillon hand operated force gauge were used to measure the force to penetrate meitauza as an estimation of mycelial binding. Increased firmness during fermentation was caused by fungal growth and not by water loss and surface crusting. Puncture force readings with the Instron were werll correlated (r = 0.86) with Chatillon measurements. The results of this study indicate that textural measurements using puncture force may have valuable application in monitoring the degree of mycelial growth or fermentation in a solid substrate.
Computerized Procedure for Time‐Intensity Sensory Measurements
Authors: GUINARD J‐X. , PANGBORN R. M. , SHOEMAKER C. F.
Published: August 2010

A computerized procedure for time‐intensity (TI) measurements was developed wherein instructions to the judge as well as data collection were handled by a microcomputer. A joystick linked to the computer was used by the judge as an input device for recording perceived intensity of taste with time. TI curves for bitterness of iso‐cuacids in water using both the computerized system and a strip chart recorder showed no significant differences in maximum intensity, time to reach maximum intensity, and duration of bitterness. The computerized system, however, was faster, more accurate, and more interesting for the judges.
Ripening Changes in a Blue‐Mold Surface Ripened Cheese from Goat's Milk
Authors: FURTADO M. M. , CHANDAN R. C.
Published: August 2010

Samples of blue‐mold surface ripened goat milk cheese were analyzed for fat and protein breakdown during ripening. After 2 wk, cheese had a pH of 4.96 and 9.13 micromoles of free fatty acids (F.F.A.)/g fat. After 6 wk, the pH increased to 6.43 and F.F.A. were 160.85 micromoles/g fat. At this time, the cheese rind pH was 7.18 with 253.81 micromoles FFA/g fat. Water soluble protein in the cheese increased from 20.47% at 2 wk of ripening to 26.62% after 4 wk of ripening.
Volatile Components of African Mango
Authors: SAKHO M. , CROUZET J. , SECK S.
Published: August 2010

Volatile components of African mango were isolated by vacuum distillation and fractionation on silica gel or by trapping on Tenax GC. Analysis by combined GC‐MS led to several compounds identified for the first time. Presence in the extract of isolongifolene, eremophilene (17%), and components related to bicyclogermacrene showed the variability of the volatile fraction of mango varieties. Some of these compounds, as well as A‐3 carene, may be typical of local varieties. The African mango studied is also characterized by presence of free acids: acetic (0.7%), butyric (6%) and hexanoic (5%); and ethyl 3‐hydroxybutyrate (5%). These compounds are part of the contribution of lipid metabolism to aroma of mango fruit.
Effect of Methionine Supplementation on Nitrogen Balance in Infants Fed a Low‐Cost Soy‐Oats Formula
Authors: DEL VALLE F. R. , VILLANUEVA H. , REYES‐GOVEA J. , ESCOBEDO M. , MUNOZ M. J. , PONCE J. , VEGA M. , HERNANDEZ M. , VELAZQUEZ G.
Published: August 2010

A nitrogen balance study, comparing a low‐cost soy‐oats infant formula with and without supplemental methionine, was carried out with infants of ages 3 ‐ 26 months at a single equivalent level of nitrogen intake (approximately 850 mg/kg/day). Nitrogen retention was found to be unaffected by methionine supplementation. Com‐ parison of data obtained in this study with previous research re‐ vealed that a critical value for intake of total L‐sulfur amino acids apparently exists in infants 3 ‐ 26 months of age, below which methionine supplementation will increase nitrogen retention, but above which it will not. This value appears to coincide with that of 49 mg/kg/day recommended for infants by the FNB.
Fat Particle Structure and Stability of Food Emulsions
Authors: XU WEN , NIKOLOV ALEX , WASAN DARSH T. , GONSALVES ALEX , BORWANKAR RAJENDRA P.
Published: August 2010

We used a nondestructive Kossel diffraction technique based on the principle of backlight scattering to characterize the structure formation in concentrated model food emulsions. We also measured the effects of temperature, shear, casein micelles and gum on the fat particle packing structure in such systems. Through this technique, we demonstrated the effects of casein micelles on the pair potential of fat particle interactions and shelf life of such systems. We carried out theoretical calculations using a statistical mechanics approach by numerically solving the Ornstein‐Zernike equation with Percus‐Yevick closure for a bidisperse system consisting of fat particles and micelles, and showed that the experimental results were consistent with theoretical simulations.
Solubility of Salmon Myosin as Affected by Conformational Changes at Various Ionic Strengths and pH
Authors: LIN TEIN M. , PARK JAE W.
Published: August 2010

The relationship between solubility and conformational changes of salmon (Oncorhynchus tshawytscha) myofibrillar proteins at various ionic strengths and pH was investigated using myosin as a model system. Solubility of myosin increased with increased KCl concentration up to 0.5M. Further increasing salt concentration resulted in a gradually reduced solubility. In the absence of salt, myosin was slightly soluble at pH>7 or <4. The increased solubility correlated with the increased surface hydrophobicity and relative sulfhydryl content as well as the decreased α‐helicity. At KCl >1.0M, myosin regained its helix structure with a concomitant loss of solubility due to the dominant hydrophobic interaction among nonpolar amino acid residues.
Roasted Chicory Aroma Evaluation by Gas Chromatography/Mass Spectrometry/Olfactometry
Authors: BAEK H.H. , CADWALLADER K.R.
Published: August 2010

Volatiles were isolated from roasted chicory by simultaneous steam distillation‐solvent extraction (SDE) and dynamic headspace sampling (DHS). Many volatile components were identified in SDE (92) and DHS (64) extracts. Many pyrazines and N‐furfurylpyrroles (N‐furfurylpyrrole, N‐furfuryl‐2‐formylpyrrole, and N‐furfuryl‐2‐acetylpyrrole) were identified for the first time in roasted chicory. Aroma extract dilution analysis showed that those extracts from SDE and DHS were similar with respect to predominant aroma‐active components. 2‐Ethyl‐3,5‐dimethylpyrazine, 2,3‐butanedione, 1‐octen‐3‐one, 3‐methylbutanal, and one unknown compound with a chicory‐ and burnt sugar‐like note were the most intense aroma‐active components found in roasted chicory.
Textural Properties of Cold‐set Gels Induced from Heat‐denatured Whey Protein Isolates
Authors: JU Z. Y. , KILARA A.
Published: August 2010

A 9% whey protein (WP) isolate solution at pH 7.0 was heat‐denatured at 80°C for 30 min. Size‐exclusion HPLC showed that native WP formed soluble aggregates after heat‐treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono‐delta‐lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL‐induced gels were harder than salt‐induced gels, and much harder than the protease‐induced gel.
Estimating Water Activity in Systems Containing Multiple Solutes Based on Solute Properties
Authors: ROA V. , TAPIA M. S.
Published: August 2010

A water activity (aw) model for multicomponent systems expressed as a linear first order sum of molalities and requiring only data from binary solutions was tested. The model was developed based on a linear relationship between aw and molality for each solute. Water activity predictions were validated and compared with Ross’equation using aw data reported of different complex electrolyte and nonelectrolyte solutions. The equation proved to have a good predictive application, was extremely simple and exhibited comparable accuracy to Ross’equation in the mixtures considered.
Identification of Fastest Velocity Particle in Tube Flow: Single vs Multi‐particle Approach
Authors: RAMASWAMY H. S. , GRABOWSKI S.
Published: August 2010

Velocities of particles (carrot, parsnip, potato, and Nylon) of different sizes (dp/D=0.25‐0.5) and shapes (spheres, cylinders and cubes) were evaluated in a transparent holding tube (L=3.8m and D=0.05m) with water and water/pectin (up to 1.2%) solutions as carrier liquids (T=20–80°C). Particles were introduced individually or in groups of 2–135, and evaluated with respect to a given type, shape, size and concentration. Results showed that, when densities of particle and liquid were different, the fastest traveling particle in a multi‐particle system was the largest sphere traveling alone in the carrier liquid of highest velocity and viscosity. Conservative values of critical particle velocities were obtained by using the single particle approach.
Process for Low‐fat Cheese from Ultrafiltered Milk
Authors: RODRIGUEZ J. , REQUENA T. , JUAREZ M.
Published: August 2010

Our objective was to optimize the process for making low‐fat cheeses using liquid pre‐cheeses obtained by ultrafiltration (UF). The study was conducted to examine the effects of using different proportions of cow, sheep, and goat milk in different compositions on the characteristics of cheeses, and to determine the effect of heating of the retentate on texture. Using ultrafiltered semi‐skim milk (total protein content of retentate of 13–14%), cheeses with acceptable quality and reduced fat content were produced. Heating of the retentate produced by UF at 68–72°C, 20 s, improved cheese texture.
Effects of High Pressure and Heat Treatment on Pectic Substances and Related Characteristics in Guava Juice
Authors: YEN GOW‐CHIN , LIN HSIN‐TANG
Published: August 2010

Effects of high pressure treatment on guava juice pectic substances and related juice characteristics were investigated and compared with heat treatment. The viscosity and turbidity of guava juice pressurized at 600 MPa and 25°C for 10 min increased slightly; whereas the viscosity of juice heated at 95°C for 5 min decreased while turbidity increased. There were no apparent changes in water soluble, oxalate soluble and alkali soluble pectin in pressurized juice. However, heat treatment of juice decreased water and alkali soluble pectins and slightly increased oxalate soluble pectin. High pressure treatment resulted in no marked changes in pectic and cloud substances of guava juice, and maintained the natural viscous of the juice.
Changes in Apple Juice Flavor Compounds During Processing
Authors: SU S.K. , WILEY R.C.
Published: August 2010

Apple juice flavor fractions were collected at several stages during a commercial process. Replicated experiments were designed to collect samples from untreated pulp, from enzyme treated pulp, after pectinase treatment, after microfiltration (MF), and after pasteurization. Additional juice heating experiments were carried out. Six apple juice flavor compounds were identified based on to retention times and reported studies. The flavor profile changed at the different stages of the production line. Temperatures used (∼57.2°C) for enzyme activation and MF tended to increase flavor compounds in apple juice except iso‐butyl acetate. The higher temperatures used (∼85°C) for pasteurization decreased all flavor compounds except propyl butyrate which increased. Results indicate apple juice may contain heat activated precursors of identified flavor compounds.
Extrusion Cooking Reduces Recoverability of Fumonisin B1 from Extruded Corn Grits
Authors: CASTELO MAURICIO M. , KATTA SARATH K. , SUMNER SUSAN S. , HANNA MILFORD A. , BULLERMAN LLOYD B.
Published: August 2010

A split‐split plot design was used to determine the effects of extrusion cooking on the recoverability of the mycotoxin Fumonisin B1 (FB1). Unextruded and extruded samples of spiked corn grits were analyzed for FB1 by two methods, commercial enzyme linked immunosorbant assay (ELISA) and HPLC. Extrusion cooking resulted in more apparent loss of FB1 with mixing screws than nonmixing screws. Losses of recoverable FB1 (p≤0.05) were observed at 120°C and 160°C with the mixing screws. A linear increase in loss of recoverable FB1 was observed (with the nonmixing screws) as the moisture content increased.
Chemical Spray Conditions for Reducing Bacteria on Chicken Skins
Authors: XIONG HUA , LI YANBIN , SLAVIK MICHAEL , WALKER JOEL
Published: August 2010

Chemical spray parameters, including temperature, pressure and exposure time, were evaluated for their effects on reducing Salmonella typhimurium on chicken skins. Pre‐chilled chicken carcass skins were inoculated with S. typhimurium and sprayed with 0.1% cetylpyridinium chloride (CPC), 10% trisodium phosphate (TSP), or 2% lactic acid (LA). In the CPC spray, the 40°C treatments resulted in the greatest bacterial reduction. The most effective spray temperatures for LA and TSP treatments were 40 to 55°C. All chemical spray treatments at 207–1034 kPa reduced S. typhimurium. The reduction of S. typhimurium was greatest in all treatments when sprayed with 90 sec spray and 90 sec setting time.
Textural Properties and Sensory Quality of Processed Sweetpotatoes as Affected by Low Temperature Blanching
Authors: TRUONG V. D. , WALTER W. M. , BETT K. L.
Published: August 2010

Sweetpotatoes (SP) stored for 9–12 mo after harvest were cut into cylindrical pieces and, following factorial experiments and response surface design, were blanched at 50–80°C for 15–274 min. Instrumental textural properties were measured by uniaxial compression and texture profile analysis. Samples of selected blanching treatments were canned in syrup for textural and sensory evaluations. Both blanching temperature and time had significant effects on firmness. Optimal temperature for maximal firmness retention was about 62°C. For canned SP, the 62°C blanched samples were more intact (2–3‐fold) and firmer (2–7‐fold) than controls. Sensory texture and overall acceptability were greatest for samples blanched at 62°C for 30 or 45 min before canning.
Separation of Egg White Lysozyme by Anionic Polysaccharides
Authors: Yang Ching‐Chuan , Chen Chao‐Cheng , Chang Hung‐Min
Published: August 2010

Anionic polysaccharides (Na‐alginate, Na‐carboxyl‐methyl‐cellulose, high methoxy pectin and κ‐carrageenan) were evaluated for their suitability towards simple and more efficient separation of lysozyme from salted or fresh duck eggs and hen egg whites for use in foods. Only κ‐carrageenan interacted and formed precipitates with lysozyme. Recovery of lysozyme from fivefold diluted salted duck egg whites was 60–65% and 78–81% from fresh duck and hen egg whites using 0.7%κ‐carrageenan. The recovered lysozyme from the salted duck egg whites was stable during storage at 4°C for 35 days.
Extrusion of Soybean and Wheat Flour as Affected by Moisture Content
Authors: Zasypkin D. V. , Lee Tung‐Ching
Published: August 2010

The effect of moisture content (MC) on texture and properties of extrudates with varied ratios of soybean flour (SF) and wheat flour (WF) was studied. A single‐screw extruder was used at screw speed 200 rpm. MCs of blends were 16, 17 or 18%, w.b. The properties of extrudates depended on flow rate of the material during extrusion. The flow rate revealed a nonlinear dependence on the blend composition and the MC at the same volume of filling of the screw feeding section. The expansion ratio of WF or SF extrudates increased with lowering of the MC. Unexpectedly, the expansion ratio decreased with lower MC for the composite extrudates. Optimal extrudate properties at 16% (w.b.) MC corresponded to 80, 90 or 100% (d.b.) WF and 20, 10% or no SF, respectively. At 17 and 18% MC, optimal properties were found for products containing 80 or 90% WF and 20 or 10% SF, respectively.
Hydrogen Peroxide Production by Lactobacillus delbrueckii Subsp. Lactis I at 5°C
Authors: Villegas E. , Gilliland S. E.
Published: August 2010

Cells of Lactobacillus delbrueckii subsp. lactis I produced hydrogen peroxide at 5°C in sodium phosphate buffer (0.2M, pH 6.5) with or without glucose. However, if the cells were starved by preincubation in buffer alone, glucose or sodium lactate were necessary to cause hydrogen peroxide production at 5°C. Hydrogen peroxide production by nonstarved cells was confirmed to be in part due to a NADH oxidase. The production of hydrogen peroxide by starved cells in buffer plus glucose in the early stage of incubation was associated with the production of a small portion of lactic acid which disappeared upon further incubation. Additional experiments revealed that hydrogen peroxide was produced in buffer containing sodium lactate added in place of glucose. Results suggested the presence of a lactate oxidase in the organism which used D‐lactate to produce hydrogen peroxide.
Kinetics of the Irreversible Thermal Denaturation and Disulfide Aggregation of α‐Lactalbumin in Milk Samples of Various Concentrations
Authors: Anema S.G.
Published: August 2010

ABSTRACT: α‐lactalbumin denaturation was first order and was virtually unaffected by milk solids concentration, with a similar denaturation rate at all the concentrations for each temperature investigated. Similarly, disulfide aggregation of α‐lactalbumin was first order and unaffected by milk solids concentration. Only about 70% of the denatured α‐lactalbumin was involved in disulfide‐aggregated complexes with other denatured whey proteins or with the casein micelles. Calculated thermodynamic parameters (activation energies, enthalpies of activation, entropies of activation and free energies of activation) for irreversible denaturation and for disulfide aggregation were similar for all milk concentrations.
Influence of Oxygen, Carbon Dioxide, and Degree of Cutting on the Respiration Rate of Rutabaga
Authors: Zhu M. , Chu C.L. , Wang S.L. , Lencki R.W.
Published: August 2010

ABSTRACT: Both the O2‐consumption and CO2‐production rates of uncut and cut rutabaga were measured in a closed system. Compared to enzymatic and 1st‐order linear models, a 2nd‐order expression was found to best predict respiration rates under the conditions typically found in modified atmosphere packages. The concept of degree of cutting was introduced to quantitatively analyze the effect of wounding on respiration rates. A linear relationship was observed between the respiration rates at a fixed pO2 and pCO2 and the quantified degree of cutting injury. Mathematical expressions were developed that accurately describe the relationship between respiration rates, O2 and CO2 partial pressures, and the degree of cutting.
Free Amino Acids in Dark‐ and White‐muscle Fish as Determined by O‐phthaldialdehyde Precolumn Derivatization
Authors: Antoine F.R. , Wei C.I. , Littell R.C. , Quinn B.P. , Hogle A.D. , Marshall M.R.
Published: August 2010

ABSTRACT: Free amino acids in fish reflect microbial spoilage, and are precursors of biogenic amines, factors of health concern and indicators offish decomposition. The objective of this research was to quantify levels of free histidine, lysine, ornithine and glutamine, which may become originators of highly undesirable histamine, cadaverine and putrescine in fish tissue. Liquid chromatography using o‐phthaldialdehyde (OPA) pre‐column derivatization, gradient elution and a C18 column were used for separation. Histidine was higher in white tissue of mahi‐mahi and tuna than in red tissue. No significant difference in lysine levels was found between the two tissues of tuna. Glutamine and ornithine were higher in red tissue of mahi‐mahi and tuna. Red snapper had higher levels of lysine than histidine.
Volatile and Nonvolatile Amines in Mediterranean Hake as Function of their Storage Temperature
Authors: Baixas‐Nogueras S. , Bover‐Cid S. , Vidal‐Carou M.C. , Veciana‐Nogues M.T.
Published: August 2010

ABSTRACT: The main amines in frozen and fresh hake (Merluccius merluccius) are the natural polyamines, spermidine. The levels of volatile and nonvolatile amines during storage of hake were strogly dependent on temperature. In samples stored at ‐20° only changes in dimethylamine and agmatine were found, whereas major changes were observed in samples stored at higher temperatures. Cadaverine was the major amine formed followed by histamine, putrescine and tyramine. The maximum levels of biogenic amines were lower than those reported for other fish species. Trimethylamine and biogenic amines related to hake spollage showed levels higher in fresh than in frozen samples, whereas levels of natural polyamines were not statistically different.
Application of a Plasma Reactor to Modify Egg Ovalbumin for Improved Solubility
Authors: Gao G.H. , Herald T.J. , Muino P.L.
Published: August 2010

ABSTRACT: A Plasma reactor was used to change the surface structure of ovalbumin and enhance solubility. The gases used to generate the plasmas were air, argon, nitrogen and oxygen. Ovalbumin was exposed to the gases for 10, 20, 30, 60, and 120 min. Unexposed ovalbumin served as the control. Samples were examined by polyacrylamide gel electrophoresis (PAGE), spectrophotometry, fluorometry, differential scanning calorimetry, and circular dichroism. Solubility and hydrophobicity of ovalbumin increased with exposure time, whereas endothermic enthalpy, onset PAGE. No change in CD spectra resulted from the plasma treatment. The structural changes were regarded as conformational adaptability.
Quality Control of Cheese Maturation and Defects Using Ultrasonics
Authors: Benedito J. , Carcel J. , Gisbert M. , Mulet A.
Published: August 2010

ABSTRACT: Ultrasonic velocity in Mahon cheese increased during maturation ranging from 1624 to 1737 m/s. A quadratic equation was used to describe this increase. This equation could be used to assess the maturation time under specific maturing conditions in order to classify the pieces in different categories. Through‐transmission and pulse‐echo techniques were used to detect cracks within the pieces formed by abnormal fermentations. In pulse‐echo mode it was possible to detect all the cracked pieces and also to assess the distance to the surface. These ultrasonic measurements are nondestructive, allowing control over all the pieces of a batch.