bluuebunny/crossref_metadata_2025 huggingface dataset:
Volatile flavour compounds of yoghurt
Authors: GAAFAR ABDULLAH M.
Published: July 2010

The volatile flavour compounds of three samples of Egyptian yoghurt were analysed over a two‐week period at 8°C using a simple headspace gas chromatography technique in order to study the changes and relate them to flavour acceptability.

Volatile compounds present were acetaldehyde, diacetyl, acetoin, acetone, butanone, and acetic acid. Acetone and butanone disappeared within the first week of storage, whereas acetaldehyde, diacetyl and acetoin declined steadily but were still present after two weeks. Acetic acid increased to about twice its original level after 10d of storage.

The decreases in acetaldehyde, diacetyl, acetoin, and the increase of acetic acid were closely related to the rapid decrease in product acceptability after 8–10d storage.
Detection of irradiation in scampi tails — effects of sample preparation, irradiation dose and storage on ESR response in the cuticle
Authors: STEWART EILEEN M. , STEVENSON M. HILARY , GRAY RICHARD
Published: July 2010

This paper describes the potential of using ESR spectroscopy for the identification of irradiated scampi (Norway lobster) using the signal induced in the cuticle at 349.5 mT. Freeze‐drying the cuticle gave a larger signal than air‐drying, and peak height was found to be a more reliable method of quantification than double integration of the peak. There was a linear response with increasing irradiation dose. Samples were stored intact at –20°C and +5°C and as dry shell at room temperature for up to 84 d and it was observed that signal intensity was reduced with increased storage time and higher temperature, especially at the higher doses. Thus ESR spectroscopy can be used to detect irradiation in scampi cuticle and has potential for the estimation of irradiation dose.
β‐hydroxyacyl‐CoA‐dehydrogenase (HADH) differentiates unfrozen from frozen‐thawed crawfish (Procambarus clarkii) and trout (Salmo gairdneri) meat
Authors: HOZ L. , YUSTES CLARA , CÁMARA JOSÉ M. , RAMOS MARIA A. , GARCÍA DE FERNANDO G. D.
Published: July 2010

An enzymatic method for differentiation of unfrozen from thawed crawfish (Procambarus clarkii) and trout (Salmo gairdneri) has been developed. The method is based on the release of the β‐hydroxyacyl‐CoA‐dehydrogenase (HADH) during freezing. The HADH activity mean values were 7.9 and 78.9 for unfrozen and thawed trout, respectively. In the case of crawfish, these values were 12 and 70 respectively. Statistical analyses showed significant differences (P 0.001) in both species. Trout could be distinguished with a high confidence level, but for crawfish this level was slightly lower.
Comparison of the main analytical methods used in quality control of tomato paste
Authors: PORRETTA SEBASTIANO , SANDEI LUCA , CRUCITTI PAOLA MARIA , POLI GIOVARRA , ATTOLINI MARIA GLORIA
Published: July 2010

Methods commonly used in quality control analysis of tomato paste were compared as a means of selecting improved means of specification for trade. Methods studied included reducing sugars using Fehling's reagent, HPLC, and enzymatic analysis; total acidity by volumetric titration (with indicator and combined electrode); volatile acidity with two different steam distillation apparatus and separation columns; and citric acid using HPLC and enzymatic methods. The use of nonspecific methods of analysis, such as Fehling's method and volumetric titration using phenolphtalein for total acidity determination, causes significant errors; moreover, the results strictly depend on the concentration of the samples.
Ionized molecules reduce penetration of microwaves into food
Authors: DEALLER STEPHEN F. , ROTOWA NATHANIEL A. , LACEY RICHARD W.
Published: July 2010

The core temperature of a sample of mashed potato with a high ionic content of added salt, potassium chloride, ammonium chloride, monosodium glutamate, sodium citrate, sodium nitrite, potassium nitrate, or D‐lysine increased much less when heated in a microwave oven than did that containing sucrose, glucose, aspartate, glutamine, or no added salts. This is interpreted as being due to a decreased penetration of the microwaves into the food. The technique, its relevance to reheating of manufactured food, and the possible consequential effect of added salt on reduced bacterial kill are discussed.
Preservation of minced pelagic fish by combined methods
Authors: AGUILERA JOSÉ M. , FRANCKE AHDRÉS , FIGUEROA G. , BORNHARDT C. , CIFUENTES A.
Published: July 2010

The stability of unwashed and washed mince from Spanish sardines (Sardinops sagax) treated by mild heating, low pH (5.7–6.0), potassium sorbate (0.05–0.2%), and sodium chloride (2.0–6.0%) was studied. Addition of 6% salt and 0.2% sorbate at pH 5.7 was the best factor combination and when accompanied by heat treatment (10min, 80°C) produced a partly cooked product, microbiologically stable at 15°C for at least 15 d. Washing and mild heat treatment (2min, 80°C) helped to reduce the initial microbial load of the mince by a factor of 100 and, in combination with the above formulation, the product had a storage life of over 15 d at 15°C, compared with less than 3d for the original unwashed mince.
Carotenoid loss in dried red pepper products
Authors: LEE DONG SUN , CHUNG SYUNG K. , YAM KIT L.
Published: July 2010

The carotenoid loss in dried red peppers, whole, and as coarse and fine powders, with and without seeds, was studied under various water activities, storage temperatures, and packaging atmospheres. Carotenoid loss of red pepper is affected by water activity, package atmosphere, storage temperature, and treatment of pepper. Nitrogen flushing or high water activity can increase carotenoid retention. To maintain good colour quality, both high carotenoid retention and low browning, red peppers should be stored in the form of coarse powder with seeds, at water activity below 0.3, and in a nitrogen atmosphere.
Effects of modified atmospheres on textural and cell wall changes of asparagus during shelf‐life
Authors: EVERSON HELEN P. , WALDRON KEITH W. , GEESON JOHN D. , BROWNE K. MARTIN
Published: July 2010

Spears of asparagus cultivator (cv) Regal harvested from a commercial crop on 16 May, 30 May, and 6 June, 1989 were packaged in rigid PVC trays (300g per pack) over‐wrapped with non‐perforated 15 μ stretch PVC (Auto RMF‐A), a similar micro‐perforated film or with a highly perforated control film. Packs were held at 8°C for 1 d, then transferred to 20°C to simulate commercial cool chain distribution and ambient display. Respiration rates as mg CO2 production kg‐1h‐1 were determined for each harvest, and changes in the pack atmosphere composition and weight losses were monitored during shelf‐life. On the day of harvest, and after 3 and 6d shelf‐life, shear force's required to cut through spears and visual quality were determined, and cooked samples were assessed for tenderness, stringiness, flavour, and bitterness by a trained sensory panel. At these intervals, samples of asparagus from each treatment were also extracted for alcohol‐insoluble residues (AIR's), from which the composition of sugars and cell wall phenolics were also determined.

Rates of respiration and the extent of pack atmosphere modification were similar for each harvest; in non‐perforated packs, CO2 increased to > 11% and O2 fell to < 2% and in microperforated packs, CO2 equilibrated to ca 5–6% and O2 decreased to a minimum of ca 6–7%. The shear forces needed to cut stems increased during 6 d shelf‐life; this increase was greatest for control‐packed spears and least for those from non‐perforated packs. Regrowth (elongation of the stem and opening of bracts) was almost eliminated in non‐perforated packs, and much reduced in micro‐perforated packs. Asparagus in micro‐perforated packs became slightly less tender and more stringy, whereas control‐packed spears became much tougher and stringier during shelf‐life; changes in flavour and bitterness were slight. Levels of most cell wallsugars changed little, although some obvious changes were detected during shelf‐life; galactose decreased in all treatments, arabinose decreased and xylose content increased considerably (67%) in control‐packed spears. Similarly, the lignin content of asparagus increased by >400% in control, by 200% in micro‐perforated and by < 100% in non‐perforated packs.

The relationships between instrumental and sensory methods for assessing textural changes in asparagus and the changes in cell wall composition, and the effects of modified pack atmospheres on these changes are discussed. The possible benefits and limitations of modified atmosphere (MA) packaging to retard post‐harvest deterioration, particularly textural changes in asparagus are also discussed.
Perceived taste of NaCl and acid mixtures in water and bread
Authors: HELLEMANN ULLA
Published: July 2010

The perceived intensity of saltiness, sourness, and overall taste of aqueous solutions containing NaCl, acetic, or lactic acid and rye bread samples was rated by 14 assessors. Pleasantness of the bread samples was also rated. Samples were prepared combining four levels of NaCl (0–1.6%), and four levels of acetic or lactic acid (0–0.9%) in water, and three levels of NaCl (0.5–1.7%) and three levels of acid (0.1–0.9%) in rye bread, yielding a total of 16 samples in all in both water series and a total of 9 samples in both bread series. Acetic‐lactic acid mixtures (two ratios) were used as the acid component in the bread samples.

The perceived saltiness increased as the acid concentration was raised with low levels of NaCl in water and with all levels of NaCl in bread samples. Saltiness decreased with increasing acid concentration with high levels of NaCl in water. Sourness was depressed with increasing concentration of NaCl in water. The reduction of sourness by NaCl was more prominent in lactic than in acetic acid solutions. In contrast, sourness was not affected by NaCl in bread samples. The acid component was slightly dominant in terms of overall taste. This, there were noteworthy differences between the two media and the acids in the strength and in the type of inter‐relationships with NaCl. Direct transformation of results from one medium to another may be misleading. It may be possible to achieve marked reduction of NaCl in solid food such as rye bread without a decrease in perceived saltiness or pleasantness by increasing the level of acidity through the addition of acids or through natural fermentation.
Grain morphology and structure in relation to milled product quality in maize (Zea mays L.)
Authors: RAJU G. N. , BHASHYAM M. K. , NARASIMHA H. V. , MURTHY S. SREEDHARA , SRINIVAS T.
Published: July 2010

In studies of the effect of shape and size of 10 varieties maize (Zea mays L.) grains on fat and fibre of its grits, the fat content of the whole grain (3.2–5.7%) was not related to either the shape or size. The fat of germ was positively but weakly related to that of whole grain (r = 0.447*). Removal of around 30% bran by milling reduced both fat and fibre of the grits to about 1% in all varieties except in Shakti opaque‐2 which needed 50% bran removal to achieve the same result. Irrespective of size, flat grains yielded more grits (64–66%), whole germ (0.6–0.9%), bran (28.4–30.0%) and less unmilled grains (3.0–5.1%), than round grains for which the figures were: grits, 52–59%; germ, 0.5%; bran, 25.2–25.6%; and unmilled grains 15–22%. The percentages of fat and fibre in grits freed of germ were 1.2 and 0.90 in large flat, 1.82 and 0.92 in large round, 1.5 and 2.0 in small flat and 2.1 and 2.7 in small round grains respectively. Flat grains yielded more grits of low fat and low fibre than round ones, and large grains than small ones.
Effect of fermentation on ionizable iron in cereal‐pulse combinations
Authors: INDUMADHAVI MALHIREDDY , AGTE V.
Published: July 2010

The average diet in most developing countries is predominantly cereal based. Wheat, rice and millets are major staple foods. Although these diets are sufficient in iron, their low bioavailability is one of the most significant factors for iron deficiency anaemia. Traditional techniques like fermentation show promise in improving iron bioavailability. In vitro ionizable iron was estimated in 31 different combinations of rice, wheat, sorghum, black gram, bengal gram, green gram and coriander in five replicates with or without, fermentation in steamed products. Results indicate that in general cereal pulse combination and fermentation significantly (P<0.05) increase the per cent ape of ionizable iron. Combination effects dominated in rice whilst fermentation dominated in sorghum. There was a significant reduction (P<0.05) in phytate phosphorus on fermentation but no loss of tannin.
Utilization of protein and energy from cooked maize: legume dishes in growing rats compared with a traditional Nigerian dish
Authors: OYELEKE OYEKANMI A.
Published: July 2010

Four dishes were prepared from cooked maize and legumes with a 2:1 maize:legume N ratio using soyabeans (MS), cowpea (MC), bambara groundnut (MB), with groundnut (MG), a popular Nigerian dish, taken as standard.

The protein contents of all three dishes were slightly greater than the groundnut dish with a higher content of lysine, the limiting amino acid in each instance. However the total energy contents were lower, 17.7 MJ Kg‐1 (MC), 18.3 (MS), and 17.5 (MB) compared with 20.0 (MG). In growing rats, there were no significant differences in biological values (BV) nor true N digestibility (TND) but net protein utilization (NPU) (BV multiplied by TDN) was lower, for MB than for the three other dishes.

Although the calculated protein scores, derived from the limiting amino acid lysine, did not parallel the bioassay, both indicated that all three dishes were equal or superior to the groundnut dish. These results suggest that the popular Nigerian maize‐groundnut dish could be replaced by any of the other three dishes without loss of nutritional value, indeed the soyabean dish may even be of higher nutritional value.
Lipid composition of light and dark flesh from sockeye salmon
Authors: PORTER PAMELA J. , KRAMER DONALD E. , KENNISH JOHN M.
Published: July 2010

The five major lipid classes present in the light and dark flesh of 22 freshly caught sockeye salmon were separated by thin layer chromatography on silica gel using a two‐stage development. Each class was then quantitatively analysed for fatty acid composition using gas chromatography. The dark flesh contains over eight times more lipid than does light flesh, and has a greater proportion of triglycerides and monounsaturated fatty acids. The predominant phospholipid in the light flesh is phosphatidylcholine, whereas in dark flesh it is phosphatidylethanolamine. Both light and dark flesh are rich sources of the nutritionally important omega‐3 fatty acids.
Centralized bulk pre‐packaging of pork retail cuts
Authors: SCHOLTZ ELNA , KRÜGER JANSIE , NORTJÉ GERHARD , NAUDÉ RAYMOND
Published: July 2010

The performance of a commercial bulk pre‐packaging system was compared to a laboratory system in terms of quality attributes such as microbiology, colour, odour, and acceptability of PVC‐overwrapped pork retail cuts. A similar retail shelf life of 3 days was achieved after either 0, 7, or 14 days bulk storage with both packaging systems. The colour of the samples from both systems was pale to normal during the trial. After 14 days storage the samples from both systems were still acceptable and had a fresh meat odour. The results show that the commercial system (Cryovac GFII, Darex Africa (Pty) Ltd, Kemptonpark RSA) may be applied successfully for 100% CO2 bulk packaging of PVC‐overwrapped pork retail cuts.
Beef muscle osmotic pressure as assessed by differential scanning calorimetry (DSC)
Authors: BONNET MADELEINE , OUALI AHMED , KOPP JEAN
Published: July 2010

Osmotic pressure, an important physiological characteristic of plant and animal tissues, is difficult to measure, and no convenient and efficient method is so far available. In the present work we developed a differential scanning calorimetry (DSC) method, and estimated the physiological osmotic pressure of intact bovine muscle and post‐mortem variation during the conversion of muscle into meat. We also examined the major role of sample pH in this variation. This method, based on the determination of the melting onset point of frozen muscle's indigenous water, was compared to a freezing point osmometric method and a soaking method. It was concluded that the DSC method appeared more practical and reliable than other methods and could be applied to various animal and plant tissues and fluids.
Kinetic model for osmotic dehydration and its relationship with Fick's second law
Authors: AZUARA EBNER , CORTÉS RAÚL , GARCIA HUGO S. , BERISTAIN CÉSAR I.
Published: July 2010

A two‐parameter equation was developed from mass balance considerations and used to predict the kinetics of osmotic dehydration and the final equilibrium point. The model was tested using kinetic data from ten different experiments and was able to predict water loss and solids gained over long periods of drying. The final equilibrium point was estimated using data obtained during a relatively short period of time. Simple equations were obtained when the model was related to Fick's second law for non‐steady one‐dimensional diffusion through a thin slab, and apparent diffusion coefficients were readily estimated from these equations.
Explosion puffing of bananas
Authors: SACA SONIA A. , LOZANO JORGE E.
Published: July 2010

Banana slices were satisfactorily dehydrated by incorporating explosion puffing into the drying process. Water contents in the range 27–38%, steam temperatures of 152–160°C, internal pressures of 0.8–1.0 Kg cm‐2 and residence times of approximately 1 min were typical explosion puffing conditions. Initial and final drying were performed with hot air at a temperature of 70°C, velocity 3.6 m s‐1, and relative humidity 35%. The increase in porosity obtained by puffing clearly reduced the total drying time compared with conventional air dried (CAD) samples. A simple diffusional model was applied to calculate the effective diffusivities of water vapour during drying of samples with and without puffing treatment. Analytical tests for colour differences, bulk density, porosity, rehydration parameters, and scanning electron microscopy in both puffed and CAD banana samples were also performed.
Post‐harvest ripening in wax‐coated Bocado mango
Authors: CASTRILLO MARISOL , BERMUDEZ ALEXIS
Published: July 2010

The effect of three different concentrations of two commercial wax coatings on some parameters of post‐harvest ripening was evaluated. The rate of loss of fresh weight of mangoes was reduced with both waxes at higher concentrations Chlorophyll degradation of the exocarp (skin) and the increase in mesocarp (flesh) pH normally occurring during ripening was retarded at higher concentrations of both wax coatings. However Primafresh 31 was less effective than Primafresh C at similar treatment concentrations. The results showed that the delayed ripening effects of wax‐coated fruits affected fresh weight loss, exocarp chlorophyll degradation and mesocarp pH change but did not affect mesocarp chlorophyll, sugar, and starch content.
The yeast flora of stored ready‐to‐use carrots and their role in spoilage
Authors: BABIC ISABELLE , HILBERT GHISLAINE , NGUYEN‐THE CHRISTOPHE , GUIRAUD JOSEPH
Published: July 2010

Spoilage of ready‐to‐use grated raw carrots packaged in polymeric films and stored at 10°C was investigated for involvement of yeasts. Cryptococcus albidus was only isolated during the first 3 days of storage, increasing to levels of 105–106g‐1. Candida lambica was more commonly isolated after 3–7 days of storage, and reached 107–108g‐1 after 12 days. Candida sake was present throughout storage, increasing from 105–106 after 3 days to 107–108 after 12 days. In some samples, Candida parapsilosis and Candida tropicalis were also isolated at levels similars to C. sake. All the yeasts isolated at the end of storage were fermentative species and their metabolism was characterized with a Warburg apparatus. Neither the number of yeasts nor the composition of the yeast flora were related to the deterioration of the product. Although Candida lambica inoculated on grated carrots caused spoilage after 12 days at 10°C, the high O2 permeable film was most effective in reducing exudate.
Analysis of the sugar content of fruit juices and drinks using ultrasonic velocity measurements
Authors: CONTRERAS NORMA I. , FAIRLEY PETER , McCLEMENTS DAVID J. , POVEY MALCOLM J. W.
Published: July 2010

The use of ultrasound to determine the sugar content of fruit juices and drinks has been assessed. The velocity of ultrasound and the density were measured in solutions of D‐glucose, D‐fructose, and sucrose at various concentrations (0–40% w/v) and temperatures (10–30°C). The velocity of ultrasound was measured in 50:50wt:wt mixed solutions of sucrose and D‐glucose over the same range of concentrations and temperatures. Measurements of the velocity of ultrasound, the density and the refractive index were made on various fruit juices and drinks at 20°C. The sugar content of the juices and drinks was determined by enzymatic assay. Ultrasonic measurements are shown to predict sugar contents in pure sugar solutions to within 0.2% w/v and in mixed sugar solutions to within 0.5% w/v. The ultrasonic measurements were sensitive to sugar species. It is shown that ultrasound compares well with other techniques for sugar content determination in fruit juices and drinks, and has the advantage that the equipment can be used for on‐line process control. Applications for this ultrasonic technique are proposed.
Alcohol deterpenation of black pepper oil
Authors: PINO JORGE A , BORGES PEDRO , SANCHEZ RAMON
Published: July 2010

The alcohol extraction of black pepper oil using three different oil to 60%‐alcohol ratios was studied. Quantitative composition of the oils was established through their physical constants and gas‐liquid chromatography. The 1:2 oil to 60% ethanol ratio showed the lowest oil recovery but resulted in sesquiterpeneless oil with the lowest terpene content and closest in sensory profile to the original oil.
Hydration of heat‐treated soy protein isolate and its effect on the molten flow properties at an elevated temperature
Authors: HAYASHI NOBUYUKI , HAYAKAWA ISAO , FUJIO YUSAKU
Published: July 2010

The relationship between the flow properties of soy protein isolate (SPI) at 140°C, measured using an extrusion viscometer, and changes in the hydration state were investigated. The state of the water in SPI was analysed by measurement of the freezable water content using differential scanning calorimetry (DSC) and by spin‐spin relaxation rate (R2) measurements using pulsed nuclear magnetic resonance (NMR). The dependence of the flow properties on the state of water was indicated by the correspondence between the water content at which the flow characteristics of molten SPI changed, and the critical water content indicated by DSC measurement of the minimum freezable water content, and by the inflection point in NMR measurement of the spin‐spin relaxation rate (R2).
Stabilized soymilk for ambient tropical storage: a preliminary report
Authors: NSOFOR LESLIE M. , MADUAKO OKWUDIRI
Published: July 2010

The shelf‐stability of soymilks prepared from sterilized (121°C for 15min) water‐soluble extracts of sprouted‐blanched, sprouted‐unblanched, and blanched whole soybeans (control) was evaluated; samples were compared for coagulation, pH, and loss of starch. The extract from sprouted‐blanched soybeans remained uncoagulated for 6 weeks in ambient tropical storage, showed the greatest loss of starch and had the least total solids content (10%). The sprouted‐unblanched soybeans produced an extract which coagulated instantly after sterilization at a pH of 5.6, the lowest pH value for treatment and control samples. The control contained the highest total solids (25%), showed least loss of starch and coagulated after 2 days in ambient tropical storage.
A method for the estimation of the culturing quality of dehydrated mycological media
Authors: BOMAR MIROSLAV T. , KNÖPFEL SILVIA A.
Published: July 2010

A relatively simple technique called ‘multiconidial inoculation method’ was developed to evaluate the culturing quality of dehydrated culture media. Four commercial PDA media were compared for their ability to maintain both the vegetative and fruiting phase of growth of Aspergillus niger. The evaluation was carried out by metric and densitometric methods.
Utilization of pre‐gelatinized tapioca starch in the manufacture of a snackfood, fish cracker (‘keropok’)
Authors: YU SWEE Y. , LOW SHEA L.
Published: July 2010

The use of pre‐gelatinized tapioca starch for the manufacture of ‘keropok’ by drumdrying has been investigated. Processing variables were examined by using five different slurries of water: starch, with ratios of 50:50, 60:40, 70:30, 80:20, and 90:10 at four different temperatures: 120.2°C, 133.5°C, 143.6°C, and 151.8°C. Only ‘keropok’ made from a slurry with a water: starch ratio of 70:30 pre‐gelatinized at 133.5°, 143.6°C and 151.8°C had linear expansion greater than the minimum acceptable value of 77%. ‘Keropok’ containing pre‐gelatinized starch produced at 133.5°C was the most acceptable to a sensory panel.
Comparison of six methylation methods for analysis of the fatty acid composition of albacore lipid
Authors: MEDINA I. , AUBOURG S. , GALLARDO J. M. , PÉREZ‐MARTÍN R.
Published: July 2010

Six methods widely used to produce methyl esters for the gas chromatographic determination of the fatty acid composition of a marine lipid were compared. Four acid‐catalyzed methods (1% H2SO4: CH3OH; 5% HCl: CH3OH; 7% and 14% BF3: CH3OH) and two base‐catalyzed methods [0.5M NaOCH3: CH3OH; (1:4) tetramethylguanidine: CH3OH] were used.

The use of BF3: CH3OH (7% and 14%) gave a lower content of 18:1 n9 than the other methods and produced an artefact (2.7–3.2% of total fatty acid content) eluting between the 20:5 and 24:1 fatty acid methyl esters. No significant differences were obtained between the other four methods.

Accordingly the use of BF3: CH3OH for transmethylation of marine lipids is not recommended. Results obtained in the other four methods showed that all are comparable.
Gelling properties of whey protein isolate: influence of calcium removal by dialysis or diafiltration at acid or neutral pH
Authors: LUPANO CECILIA E. , DUMAY ELIANE , CHEFTEL JEAN‐CLAUDE
Published: July 2010

Dialysis of whey protein isolates (WPI) removed much more calcium when carried out at an acid pH (close to 4.0) than at neutral pH. Diafiltration at acid pH was also effective. The characteristics of thermally‐induced gels prepared from WPI dialysed at acid or neutral pH were studied at pH 3.75 or pH 7.0, respectively, and at calcium concentrations ranging from 0 to about 60mM (with addition of calcium chloride). The water‐holding capacity (WHC) and elasticity of gels increased with decreasing calcium concentration, at both pHs. Gel firmness was maximum at 10–20 mM calcium. The solubility of the protein constituents of WPI gels in a pH 8.0 buffer was high in the case of acid gels (especially at calcium concentrations lower or equal to 20 mM) and low for neutral gels at all calcium concentrations. Protein solubility values in the presence or absence of denaturing and reducing agents reflect the existence of intermolecular disulphide bonds in neutral gels and their absence in acid gels.
Preliminary study of the influence of dextran on the precipitation of legumin from aqueous salt solutions
Authors: PAVLOVSKAYA GALINA E. , McCLEMENTS D. JULIAN , POVEY MALCOLM J.W.
Published: July 2010

Ultrasound has been used to study the behaviour of dextran, legumin (11s globulin of the broad bean Vicia faba) and their mixtures in aqueous salt solutions under different physico‐chemical and thermodynamic conditions. The attenuation coefficient of the solutions was measured as a function of pH (3–10) and ionic strength (0, 0.025, 0.05 M NaCl). The attenuation in the dextran solutions was independent of pH and ionic strength, whereas that in the solutions containing legumin had a maximum value near to the isoelectric point of the legumin (∼φ 5). The magnitude of this maximum depended on the ionic strength of the solution. The cause of the observed attenuation was scattering of ultrasound by precipitated protein. The addition of dextran to solutions where the biopolymers are thermodynamically compatible decreases the attenuation, whereas its addition to solutions where the biopolymers are incompatible increases it. This is because protein precipitation is greater in incompatible systems.
Influence of starch retrogradation on the texture of cooked potato tuber
Authors: JANKOWSKI TOMASZ
Published: July 2010

Texture profile analysis applied to whole cooked potato tubers conditioned at 4 and 20°C has shown a significant improvement in texture quality of the potato influenced by starch retrogradation. Conditioning decreases adhesiveness and fracturability and increases cohesiveness and hardness, especially at the lower temperature. The changes were related to soluble starch content, estimated by the Blue Value Index, and to development of a polymeric network within the gelled starch in cooked tuber.
The effect of particle size of mince, and mesh size of dewatering cloth, on the properties of gels of washed whiting (Merlangius merlangus) mince
Authors: HASTINGS ROSEMARY J. , TAVENDALE MORAG H.
Published: July 2010

Whiting fillet mince was prepared using a Baader 694 bone separator fitted with either a 5 mm drum or a 3 mm drum. The mince from both batches was washed once and dewatered using either muslin cloth (maximum pore size 2 mm) or fine mesh nylon cloth (Maximum pore size 0.7 mm). The yield of washed mince from gutted fish was improved from 27–29% to 34–35% by using the fine mesh nylon. The adhesive forces of the washed minces were very high and showed no consistent variation with drum size or mesh size. The cohesiveness of the gels was higher from minces dewatered using the fine mesh nylon (according to the puncture test, torsion test and sensory gel strength). The colour of the gels was improved both by using smaller mince particle sizes and by dewatering with fine mesh nylon.
Mathematical modelling of the diffusion of ascorbic acid during water blanching of surface frozen potato strips
Authors: LUNA JULIO A. , GARROTE RAUL L. , CARDONA ALBERTO , JEUSETTE JEAN P.
Published: July 2010

Partial freezing is a promising technique in producing good quality french fries, especially for potatoes stored for an extended period and containing large amounts of reducing sugars. The cell damage of the potato strip caused by surface freezing facilitates surface leaching of reducing sugars and other soluble solids like ascorbic acid, preventing undesirable dark colour in the finish‐fried products. A theoretical study to describe the diffusion of ascorbic acid during the water blanching at 50°C of surface frozen potato strips (10 x 10 x 80 mm) is developed. Ascorbic acid profiles as a function of blanching time, position in the potato strip and thickness of the frozen layer are shown as well as average retention as a function of blanching time, frozen layer thickness, apparent diffusion coefficient and mass transfer coefficient of ascorbic acid. Significant changes in the ascorbic acid concentration during blanching are produced in the frozen layer. Ascorbic acid average retention is mainly influenced by frozen layer thickness and temperature, and the mass transfer coefficient is less important.
Immobilized α‐amylase from Bacillus licheniformis: a potential enzymic time—temperature integrator for thermal processing
Authors: CORDT SUSANNA DE , HENDRICKX MARC , MAESMANS GEERT , TOBBACK PAUL
Published: July 2010

Summar

Biphasic and nth‐order models were tested as to their usefulness to fit experimental inactivation data of Bacillus licheniformisα‐amylase, immobilized on glass beads, and were discussed with respect to their suitability to characterize the considered enzymic system as a time—temperature integrator (TTI) to evaluate heat processes. Both isothermal and non‐isothermal inactivation experiments were carried out. Model (kinetic) parameters (rate constant k, activation energy EA and reaction order n) were estimated using a non‐linear regression procedure. The results obtained, especially the activation energy of about 293 kJ mole–1, indicated a potential use of this system as a TTI for heating processes in the temperature range of 96–108°C.
Microorganisms and lipolysis in the ripening of dry fermented sausages
Authors: GARCIA M. LUISA , SELGAS M. DOLORES , FERNANDEZ MANUELA , ORDOÑEZ JUAN A.
Published: July 2010

The actual roles of two strains of microorganisms (Micrococcus‐12 and Lactobacillus‐56) isolated from Spanish dry sausages have been studied by using an aseptic method for making experimental sausages. The fermentation of sugars by lactobacilli is clearly demonstrated by the pH changes and the nitrate and nitrite reduction by micrococci is inferred by the changes in the sausage colour. The lipolysis occurring during ripening of experimental sausages seems to be mainly due to the lipases from meat rather than those elaborated by the organisms used.
Hard‐to‐cook state in cowpeas‐influence of pretreatment and cooking on electrolyte leakage solids‐loss and water absorption
Authors: LIU KESHUN , SHEWFELT ROBERT L. , PHILLIPS R. DIXON , HUNG YEN‐CON
Published: July 2010

The hard‐to‐cook (HTC) state of cowpea seeds was experimentally induced after differential storage of seeds for 12 months. The storage conditions of control seeds were ‐18°C and ambient humidity and those of aged seeds were 30°C/64% relative humidity(rh). HTC was induced by incubation in water at 25–85°C and soaking in CaCl2. Subsequent cooking changes in electrolytes, total solids, water absorption, and swelling were determined. During incubation, control seeds showed a dramatic increase in losses at >45°C while aged seeds exhibited an initial high level of loss at 25°C, implying that a loss of cell membrane integrity occurred as a result of thermal stress or aging.

Water absorption following incubation increased with incubation temperature, but aged seeds absorbed less water than control seeds. During subsequent cooking HTC state, whether induced via aging or treatments, resulted in less leakage, solids loss and water absorption (swelling), although the total leakage for incubation and cooking remained roughly constant. Overall results suggest that an increase in Ca‐uptake capacity of aged seeds or incubated control seeds as reported earlier may result from improved access of cations to the binding sites at intracellular locations.
Detection of 2‐dodecylcyclobutanone in radiation‐sterilized chicken meat stored for several years
Authors: VICTORIA A. , CRONE J. , HAMILTON JOHN T.G. , STEVENSON M. HILARY
Published: July 2010

Results are presented indicating a linear relationship between irradiation dose (10–60 kGy) and the quantity of 2‐dodecylcyclobutanone produced in irradiated frozen (‐46°C) chicken meat. 2‐Dodecylcyclobutanone was found in chicken meat sterilized (at ‐40°C) by gamma and electron beam irradiation 12 years previously and used for toxicity clearance. After freeze‐drying the irradiated chicken samples still contained 2‐dodecylcyclobutanone indicating that it was present in the diets tested. The compound was not detected in chicken meat sterilized by thermal processing 13 years ago. In addition, there was evidence that 2‐tetradecylcyclobutanone was also present in the irradiation sterilized samples.
Dough mixing and breadmaking properties of quinoa‐wheat flour blends
Authors: CHAUHAN GOURI S. , ZILLMAN R.R. , ESKIN N.A. MICHAEL
Published: July 2010

Flour blends of quinoa‐wheat containing 0, 5, 10, 15, and 20% of manually dehulled quinoa meal or flour were evaluated for dough mixing and breadmaking properties and liking of the bread by a small panel. Increasing amounts of quinoa meal or flour increased farinograph absorption and dislike of bread for most of the panel. Dough development time increased with increase in meal but decreased with increase in quinoa flour. At 10% inclusion levels differences in liking from control 100% wheat flour bread were smaller for flour or water extracted meal to most of the panel, than with 10% non‐extracted meal. This suggests that 10% inclusion of flour or water extracted meal may have potential for further investigation.
Evaluation of four high‐protein rice‐soy snack formulations
Authors: MAN YAAKOB B. CHE , KARIM MOHAMAD N.B. ABDUL , KUN TAN T.
Published: July 2010

Four different formulations of rice‐soy snack containing 4.5%, 9.0%, 13.5%, and 18.0% full‐fat soy flour (FFSF) were evaluated for their nutritional values and acceptance. Protein content increased from 9.54% to 15.44% and chemical scores of the snacks from 86 to 100 but there was no difference in Net Protein Utilization although values were higher in snacks than in either rice or FFSF alone. All formulations were well accepted but at the highest level of FFSF (18%) acceptability was significantly (P<0.01) reduced.
Gill air analysis as an indicator of cod freshness and spoilage
Authors: Strachan Norval J. C. , Nicholson Frederick J.
Published: July 2010

Amines, ammonia, and hydrogen sulphide (H2S) volatiles were measured in the gill air of cod, as possible indices of days in ice and extent of spoilage using Gastec detector tubes. Total viable counts and H2S producing organism counts inside the gills and in the flesh of the fish as well as Torrymeter readings of the skin were also taken.

H2S predicted storage period best (±3 days) but no measurement could be made until day 6. The Torrymeter came next (±3.5 days) and then the total viable count (±4 days); other measurements were less effective.
Deteriorative changes in pink perch mince during frozen storage
Authors: Sagar Reddy G. Vidya , Srikar L. N. , Sudhakara N. S.
Published: July 2010

Frozen storage of mechanically deboned pink perch mince for 180 days resulted in a decrease in emulsifying capacity, protein solubility, and relative viscosity while, cook‐loss, water binding capacity in terms of absorbed moisture, and drip‐loss increased. Alteration in protein fractions were observed by polyacrylamide gel electrophoresis and protein break down products (volatile bases) were increased. There was little change in lipid oxidation products (peroxide value and thiobarbituric acid) but a very large increase in free fatty acids. Significant (P < 0.05) correlations existed between several of these changes. Sensory attributes of the cooked mince deteriorated after 90 days. Mechanical deboning and freezing of the pink perch mince could offer a potential means of processing currently wasted by‐catch fish for human food.
Muscle carotenoid content and colour of farmed rainbow trout fed astaxanthin or canthaxanthin as affected by cooking and smoke‐curing procedures
Authors: Choubert Georges , Blanc Jean‐Marie , Courvalin Corinne
Published: July 2010

Carotenoids and colour characteristics were studied in raw, steamed and smoke‐cured muscle of rainbow trout fed synthetic astaxanthin (50 or 100mgkg‐1 diet) or canthaxanthin (100mgkg‐1 diet) for 15 months.

In raw muscle main carotenoid concentration was strongly correlated with hue, chroma, and lightness. Diet and sex effects were significant on most traits, with little or no interaction. Female muscles contained much more carotenoid and were more coloured than male ones. Astaxanthin fed fish were more red than canthaxanthin fed fish.

Significant mean effects of cooking were an apparent increase of carotenoid concentration and an increase of lightness. Hue and chroma were practically unchanged with high correlations between raw and cooked muscle measurements. Lightness increased and differences between sexes and individuals were reduced.

Smoke‐curing induced an increase of carotenoid concentration and a decrease of hue and lightness. Hue of canthaxanthin fed fish when smoke‐cured was similar to that of raw fish fed astaxanthin. Lightness, still dependant on that of the raw muscle, was reduced and differences among diets, sexes and individuals were reduced.
Instrumental and sensory tests of texture of cooked frozen french fries
Authors: Du Pont M. Susan , Kirby Andrew R. , Smith Andrew C.
Published: July 2010

A range of physical tests in parallel with sensory evaluation has been carried out on frozen french fries as a function of frying time. Low strain rate flexure and high strain rate pendulum impact tests show that overall the strength and modulus of samples increases with frying time. A portable instrumented pendulum is able to differentiate between samples. The best correlation between sensory and instrumental measures is on crispness and mechanical strength. Oil and water contents change with frying time and are related to the visible layered structure in the samples. Changes in oil and water contents and structure are least between 4 and 6min. Structural change occurs after 6min corresponding to discontinuities in density, mechanical properties and sensory attributes.
Influence of time‐temperature history and strain history on the melt rheology of soy protein isolate at an elevated temperature
Authors: Hayashi Nobuyuki , Noma Koichi , Hayakawa Isao , Fujio Yusaku
Published: July 2010

Reciprocating extrusion and single extrusion experiments were performed using a completely air‐tight capillary extrusion viscometer in order to elucidate the effects of time‐temperature history and strain history on the melt rheology of soy protein isolate (SPI) at an elevated temperature (140°C). Both histories produced a decrease in the measured pressure drop during extrusion and these effects were strongly dependent on the sample moisture content. For moisture contents above 41% (dry basis), the time‐temperature history effect was predominant more in decreasing the measured pressure drop, whereas the strain history effect was more influential at moisture contents below 30% (d.b.)
Effect of processing and storage on rheological properties of fortified milk and curd systems
Authors: Ramana S. V. , Ramanathan G.
Published: July 2010

Fortified milk systems were prepared by blending pasteurized standardized milk with skim milk powder, peanut flour or peanut protein isolate to 15, 18, 20, and 23% total solids followed by processing at 60°C and 80°C for 30min and storage at 4°C for 24h. Curds were prepared by the lactic fermentation of the processed milk systems. The rheological properties showed that all the systems exhibited pseudoplastic flow. The flow became less Newtonian with increasing total solids, heat treatment, and storage. Curd obtained from the fortified milk processed at 80°C showed increased yield stress and curd strength with the increasing concentration. Degree of heat treatment, total solids content and storage were shown to have a pronounced effect on the apparent viscosity, consistency index, and yield stress of the fortified milk systems.
β‐lactoglobulin denaturation and aggregation reactions and fouling deposit formation: a DSC study
Authors: Gotham Simon M. , Fryer Peter J. , Pritchard Andrew M.
Published: July 2010

The thermal stability of β‐lactoglobulin was studied using differential scanning calorimetry (DSC) as part of a larger investigation into milk and whey fouling. Measurement of kinetics using DSC is very difficult as the resultant trace is the sum of simultaneous denaturation and aggregational enthalpies; the two processes were demonstrated by measurements at different heating rates. β‐lactoglobulin denaturation proceeds via an intramolecular disulphide stabilized intermediate and is irreversible even before the denaturation temperature is reached. Denaturation and aggregational processes can be partially separated by measurements over a range of pH. The literature shows that the rate of fouling decreases as solution pH increases. However, DSC shows that the thermal stability of β‐lactoglobulin decreases as pH increases, particularly above pH 6. It is hypothesised that aggregation rather than denaturation might be the critical step in the formation of fouling deposit.
Reduction of cyanide levels during anaerobic digestion of cassava
Authors: Cuzin Nadine , Labat Marc
Published: July 2010

During the methanogenic fermentation of cassava peel in a plug flow digester, cyanide bound as linamarin in cassava was released as HCN in the fermentation liquor, and then eliminated by the activity of free enzymes and by non‐enzymatic reactions. The raw cassava peel contained (1) the enzyme permitting the hydrolysis of linamarin and the liberation of HCN (linamarase), and (2) a cyanide detoxification enzyme (β‐cyanoalanine synthase). Cyanide removal was sufficiently fast to maintain a cyanide concentration in the fermentation liquor which was non‐inhibitory for the methanogenic microflora.
Solubility of amaranth seed proteins in sodium sulphate and sodium chloride: the main factor in quantitative extraction for analysis
Authors: Soriano‐Santos Jorge , Iwabuchi Setsuko , Fujimoto Kenshiro
Published: July 2010

Nitrogen was extracted more efficiently from amaranth seed with 0.04 M Na2SO4 (5% w/v) than with either 0.09 M or 0.17 M NaCl (5% or 10% w/v), despite both solutions having the same ionic strength (μ= 1). Solubility of saline soluble proteins (albumin ± globulin) was very poor in either water or 1M NaCl, but increased in 0.4M NaCl at alkaline pH between 7 and 10. Globulins were very soluble in 0.4M NaCl at a pH 9. Albumin was the main storage protein. Saline soluble proteins formed very weak gels.
Process parameters for hydrocooling apricots, plums, and peaches
Authors: Dincer Ibrahim , Yildiz Mustafa , Loker Mahmut , Gun Huseyin
Published: July 2010

Freshly harvested apricots, plums, and peaches in crates containing 5–20kg were hydrocooled in flowing water at 1°C and 50mms‐1. The cooling parameters: lag factor, cooling coefficient, and time to half‐cool, determined from the exponential decline in the dimensionless ratio of temperature differences between fruit centre and coolant temperature at time t and at zero time, varied somewhat with crate load. Increasing the load from 5 to 20kg increased the time to half‐cool apricots by 17% and plums and peaches by 39%.
Use of near infrared spectroscopy to evaluate the intensity of extrusion‐cooking processing of pea flour
Authors: BEN‐HDECH HASSANE , GALLANT DANIEL J. , ROBERT PAUL , GUEGUEN JACQUES
Published: July 2010

Twenty‐five different pea extrudates were produced using a Clextral BC45 twinscrew extruder. Near infrared reflectance (NIR) spectra of the extrudates were recorded between 1100 and 2500 nm. the application of principal component analysis (PCA) on these spectral data permitted discrimination between the extrudates produced under moderate, intermediate or severe conditions of extrusion‐cooking. the study of protein quality through solubility experiments, polyacrylamide gel electrophoresis, determination of available basic amino acids and brown colour measurement showed that, under moderate conditions of extrusion‐cooking, protein was only slightly affected. All protein subunits could be restored after solubilization in phosphate buffer containing a detergent and a reducer of disulphide bonds. However, under severe conditions of extrusion‐cooking, the extrudates exhibited a relatively intense brown colour and all protein fractions were implicated in non‐disulphide covalent bonds and underwent some macromolecular degradation. Therefore, the spectral discrimination between pea extrudates which was related to the processing parameters, could also be related to the degree of transformation of these extrudates. Thus, the method may be used to classify an extrudate produced under unknown conditions by projecting its spectrum on the similarity maps obtained by PCA on a known collection of extrudates.