bluuebunny/crossref_metadata_2025 huggingface dataset:
Sorbic acid diffusivity in relation to the composition of high and intermediate moisture model gels and foods
Authors: GIANNAKOPOULOS A. , GUILBERT S.
Published: July 2010

The diffusivity at infinite diffusant dilution (D0) of sorbic acid in high and intermediate moisture gels (with various substrates and water contents) and in three foods was evaluated. The determination of D0(25°C) was achieved by tridimensional diffusion in gels cubes or by monodimensional diffusion in infinite food columns. For the same substrate concentration by weight, D0 values of sorbic acid in concentrated sugar solutions decreased slightly when the molecular weight of the sugar was increased. When a liquid substrate such as glycerol was used, D0 values referred to equal concentrations by weight, were higher than in sugar solutions. The diffusion of sorbic acid is related, as a first approximation, to the water content rather than to the water activity of the diffusion medium.
An attempt to elaborate the curing technology for broiler chicken gizzards
Authors: DUDA Z. , MIELNIK M. , KAMIńSKI J.
Published: July 2010

The usefulness of several curing technologies for broiler chicken gizzards was investigated. The specific microstructure of the gizzard tissue is considered to be a crucial feature of this raw material, limiting the selection of the effective curing technology. Curing intact or diced gizzards in nitrate brine and the use of dry curing nitrate blend was unsuccessful, but the use of nitrite brine for curing both was acceptable. However, curing fresh broiler chicken gizzards during comminution in a bowl chopper with the nitrite brine was the most rapid and effective curing technology.
Technical note: Sorption isotherms and monolayer moisture content of raw peas, and peas dehydrated after pressure cooking
Authors: MAZZA G.
Published: July 2010

The moisture sorption isotherms of raw and pre‐cooked Century, MP 888 and MP 889 peas at 10, 25 and 40°C were determined by the standard salt solution technique. Pea cultivars, although different in composition, did not differ in equilibrium moisture content. At 40°C and in the water activity range 0.50 aw 0.90, the sorption capacity of raw peas was higher than that of pre‐cooked peas. All adsorption‐desorption isotherms were of sigmoid shape and the quantity of sorbed water, at a given relative humidity, increased as the temperature was decreased. The monolayer moisture content of pre‐cooked dehydrated peas stored at 40°C was 6.2%, with corresponding equilibrium relative humidity value of about 27%.
Technical note: Application of immobilized cells of Kluyveromyces marxianus for continuous hydrolysis to fructose of fructans in Jerusalem artichoke extracts
Authors: PAREKH S. R. , MARGARITIS A.
Published: July 2010

Dead cells of Kluyveromyces marxianus having inulase (β‐D‐fructo fructanohydrolase E.C.3.2.1.7) activity were immobilized in alginate beads and used as a biocatalyst in a packed bed reactor and a stirred batch reactor. Fructosans of Jerusalem artichoke tubers, after extraction, were utilized for continuous or semi‐continuous production of fructose. In a bed reactor packed with 100 ml of beads, a volumetric productivity of 36 g/l/hr total reducing sugars was obtained with 98% substrate conversion. When operated continuously for 30 days, a half life of 28 days was observed for the biocatalyst. Using artichoke extract containing 20% fructan solution, 98% conversion could be achieved in a batch reactor in 20 hr. Repeated cycling of beads resulted in considerable loss of catalyst from the reactor and subsequent loss in catalytic activity, thus giving a half life of only 14 days.
Rapid dye reduction tests for the determination of microbiological quality of meat
Authors: RAO D. N. , MURTHY V. S.
Published: July 2010

Rapid dye reduction tests have been developed to determine the quality of meat. Three chemical indicators, resazurin and two tetrazolium compounds, were used to correlate the microbial numbers and reduction times in meat samples. Twenty‐five surface samples from sheep carcasses were subjected to each reduction test. Total viable counts given were obtained at 37°C. Resazurin reduction time was 90–120 min when the bacterial counts ranged from 1.5×106 to 7.7×106/cm2. Samples showing bacterial counts between 1.5×106 and 6.0×106/cm2 reduced tetrazolium (NBT) in 360–390 min whereas samples containing bacterial counts of 2.1×106/cm2 took 420–450 min to reduce iodophenyl nitrophenyl tetrazolium (INT) dye. Regression equations relating the number of organisms per cm2 and reduction time were applied to predict the microbiological quality of meat samples from reduction time data. Among the three dyes, resazurin gave the lowest reduction time.
Effect of delayed icing on the storage life of rainbow trout
Authors: DAWOOD A. A. , ROY R. N. , WILLIAMS C. S.
Published: July 2010

Rainbow trout (Salmo irideus), were divided into groups: (1) iced immediately, or (2) kept at 10 °C for 6 hr, (3) 20 °C for 6 hr, (4) 20 °C for 18 hr, (5) 30 °C for 4 hr, (6) 30 °C for 6 hr. Fish in groups 2–6 were iced at the end of the stipulated temperature/time period of holding. Quality was subsequently assessed every 2 days for 14 days during iced storage: sensory assessment using criteria of appearance, texture and odour; chemical assessments by measurement of total volatile bases, hypoxanthine and thiobarbituric acid: microbiological assessments by total bacterial counts at 20 °C/72 hr and 37 °C/48 hr incubation. The results indicate that deamination due to bacterial action and hydrolysis of fats increases progressively with rising temperature prolonged periods of storage prior to icing, and results in final spoilage. Fish iced immediately after delivery and those iced after being kept at 10 °C for 6 hr were acceptable to quality even after 14 days of iced storage. Recommendations are made for maintenance of quality and extension of shelf life.
Descriptive profiling versus direct similarity assessments of soft drinks
Authors: CHAUHAN J. , HARPER R.
Published: July 2010

A set of seven soft drinks was profiled using a check list of descriptors and the same set of products was assessed for similarity by a panel of ten assessors. The profile data were used to generate a matrix of interstimulus distances, and this and the dissimilarity matrix obtained directly from the similarity assessment were examined using multidimensional scaling approaches (MDS/INDSCAL). The two methods yielded broadly similar results in terms of the spatial representation of the stimuli. This was further confirmed on analysis of the data using a multidimensional unfolding program which aimed to highlight any differences between the two sets of dissimilarity measures.
Effect of non‐enzymic browning, starch and sugars on total cyanide determination in cassava by an enzymic assay
Authors: ARIHANTANA M. B. , BUCKLE K. A.
Published: July 2010

Maillard (non‐enzymic) browning pigments and gelatinized starch interfered in the assay of total cyanide in cassava products by an alkaline picrate‐enzymic method. Interference from browning pigments in cyanide determinations was overcome by adding charcoal followed by filtration, while gelatinized starch was precipitated by the addition of ethanol. Glucose, fructose and maltose but not sucrose also interfered in the assay and produced high total cyanide results. A more specific reaction than alkaline picrate is still required for free cyanide estimations in cassava products.
Kinetics of sun and air drying of different varieties of seedless grapes
Authors: RIVA M. , PERI C.
Published: July 2010

The drying kinetics and the quality parameters of seedless grapes were evaluated in a screening test carried out to select the variety or varieties best suited to the production of dried grapes. Experiments were carried out on a pilot scale by sun drying and air convection drying under controlled conditions and with the grapes pretreated by ethyloleate dipping. The kinetics data, analysed according to a simplified form of Fick's law, allow the calculation of a rate constant, which we tried to correlate to the grapes' geometrical parameters: i.e., the berries' average radius and skin thickness. A systematic computing procedure showed that the following simple relationships were well correlated to the experimental values and could be used to forecast drying kinetics:

Sun drying: K= 0. 05–12.8XR2XTh

Air drying: K= 0. 42–87.8XR2XTh

where:

K= rate constant, (per hr),

R= average berries; radius (cm),

Th = average skin thickness (cm × 10−3).

The following scale of drying speeds for the varieties was found:

Ruby > Emerald > Thompson > Delight > Rodi

with a two‐fold decrease of the rate constant value from Ruby to Rodi, which are respectively the fastest and the slowest drying varieties. Composition and colour data show that experimental samples compare favourably with commercial samples of dried grapes, as a consequence of faster drying due to the dipping pretreatment and careful control of drying conditions.
Simplified equation for predicting the freezing time of foodstuffs
Authors: PHAM Q. T.
Published: July 2010

A simple method is presented for predicting freezing times of predominantly aqueous foodstuffs. The method assumes that heat is released at a ‘mean freezing temperature’, common to all foodstuffs. Internal resistance effects are calculated for any shape from a ‘mean conducting path’, intermediate between the shortest and longest distances from surface to centre. The method agrees with published data better than any previously published method, except that of Pham (1984, 1985) from which it was derived. It applies equally well to different materials, geometries and final product temperatures.
Quantitative immunoassay for soya protein in raw and sterilized meat products
Authors: RAVESTEIN P. , DRIEDONKS R. A.
Published: July 2010

An enzyme‐linked immunosorbent assay (ELISA) is described for the quantitative analysis of soya protein in meat products. The assay is applicable to raw and sterilized products and is not dependent on soya variety and type of soya ingredient (concentrate, isolate, etc.). Therefore, the assay can be applied without knowledge of product composition, heat pretreatment and other processing conditions. The ELISA is specific for soya; no interference of other product components has been found. The detection limit of the ELISA is 0.5% soya protein. Qualitative analysis by immunoblotting is possible at much lower concentrations. The antibodies used are specific for sodium dodecyl sulphate (SDS) denatured soya protein subunits. The products are extracted with SDS and 2‐mercaptoethanol, which guarantees optimum recovery of the protein components. Product extracts can be analysed directly by ELISA without removal of the SDS by using nitrocellulose as a solid phase.
Silage from tropical fish 3. Lipid behaviour
Authors: HALL G. M. , LEDWARD D. A.
Published: July 2010

Acid silages were prepared from silverbelly (Leiognathus spp.) at 30°C with 3% (w/w) of 98% formic acid. Lipid oxidation takes place actively during ensilation as demonstrated by changes in fatty acid composition, TBA value and peroxide value. Lipid extraction, with chloroform: methanol or isopropanol, or the addition of an antioxidant before ensilation can limit the build up of lipid oxidation products. Lipid extraction also suppresses the autolysis of proteins in a defatted silage compared with a normal silage when measured by total soluble nitrogen or soluble NPN. The solubilization of collagen appears to be unaffected by lipid extraction perhaps reflecting the non‐enzymic nature of this process. The limited autolysis in defatted silages may be beneficial in restricting the release of free amino acids capable of reacting with lipid oxidation products resulting in a lower nutritional value for silage based diets.
Macromolecular changes associated with the heat treatment of soya isolate
Authors: SHEARD P. R. , FELLOWS A. , LEDWARD D. A. , MITCHELL J. R.
Published: July 2010

The denaturation temperatures of both the 7S and 11S proteins present in a 70 PDI soya flour and an isolate prepared from it, increased by over 30°C as the water content of the system decreased from 90 to 20%. In dilute dispersions (> 70% water), the precipitate formed on heat treatment was almost totally soluble in 3.0% sodium dodecyl sulphate (SDS), irrespective of the heating temperature (20‐120°C). However, in more concentrated systems, heat treatment at 120°C for 1 hr caused increasing amounts of SDS insoluble protein to form as the water content decreased. Such aggregates were also insoluble in beta‐mercaptoethanol (ME), but soluble in mixtures of SDS plus ME.

It is suggested that at low concentrations, heat treated soya proteins are primarily aggregated by hydrophobic interactions but that, on decreasing the water content of the system, disulphide bond formation becomes a significant factor in stabilizing the aggregate.
Extrusion of corn grits containing various levels of hydrocolloids
Authors: MAGA J. A. , FAPOJUWO O. O.
Published: July 2010

Fourteen hydrocolloids, locust bean, agar, guar, alginate, tragacanth, carrageenan, xanthan, pectin, gelatin and Methocels A4M, E4M, F4M and K4M were dry blended with corn grits at levels of 0.1, 0.5 and 1.0%. Twenty percent moisture was added and each product extruded in a Brabender Model PL‐V500 laboratory extruder at temperatures of 50, 75, 100, 125 and 150°C with a 1:1 screw operating at 100 rpm. Locust bean, agar, guar, alginate, arabic and Methocels E4M, F4M and K4M significantly lowered torque at an extrusion temperature of 50°C, but did not in general produce significant reductions at higher extrusion temperatures. In contrast, tragacanth, carrageenan, xanthan, pectin, gelatin and Methocel A4M did not significantly reduce torque over the concentrations and conditions evaluated during the extrusion of corn grits. All the Methocel derivatives lowered yield at low extrusion temperatures. No gum significantly increased yield over the entire extrusion temperature range evaluated. Therefore, certain gums can significantly reduce torque without influencing yield during the extrusion of corn grits.
Rapid in vitro enzymic predictive model for the in vivo digestibility of food proteins
Authors: IHEKORONYE A. I.
Published: July 2010

The absorbance of the deep orange colour produced by incubating protein hydrolysates with trinitrobenzene sulphonic acid was used to follow the liberation of free amino groups. Five animal and five plant proteins were hydrolysed with pepsin‐pancreatin and papain‐pronase E and aliquots were taken every 4 hr. To facilitate proteolysis the proteins were presolubilized in 0.05 M HCl at 70°C for 2 hr with 1.0 ml 0.8% mercapto‐ethanol added to reduce disulphide bonds. An increase in absorbance occurred in all enzymatic digests between 8‐20 hr incubation. No further hydrolysis took place after 20‐28 hr incubation. The extent of the hydrolysis in vitro correlated with in vivo measurements of digestibility and so may serve as a more rapid predictor of digestibility.
Review: Flame sterilization
Authors: RICHARDSON P. S.
Published: July 2010

Flame sterilization is a technique of high temperature, short time processing that is applied to sealed metal cans. The technique is applicable to the processing of both high and low acid products and may be used to exhaust packs to produce a high vacuum when subsequently cooled. The factors affecting the rate of heat transfer and their influence on container requirements and product quality are discussed, together with commercial developments and prospects for flame sterilization processes.
Enhanced deactivation of bacterial lipases by a modified UHT treatment
Authors: BUCKY A. R. , ROBINSON D. S. , HAYES P. R.
Published: July 2010

Lipase was produced by three non‐fluorescent pseudomonads during culturing in resterilized UHT whole milk at 10°C. The enzymes exhibited pronounced thermostability in milk with 85–88 and 82–89% of the original activities retained after heat treatments at 140°C for 5 sec and 80°C for 10 min, respectively. Also, after a single treatment at 60°C for 10 min approximately 95% of the untreated activities remained.

Double heat treatments consisting of either 130 or 140°C for 5 sec followed by 60–80°C for 3 min enhanced lipase deactivation by as much as 40% compared with the combined effect of both higher and lower temperature treatments performed on separate enzyme samples. No significant enhancement of deactivation was noted when samples were heated at 60°C for 3 min followed by 140°C for 5 sec compared with the latter treatment alone.

Lipase deactivation was non‐linear at 60°C following treatment at 140°C for 5 sec; no substantial additional loss of activity occurred at the lower temperature between 5 and 10 min.
Effect of thickness and location of minced fat on cooking times and weight losses of composite beef joints
Authors: BURFOOT D.
Published: July 2010

The effect on cooking time and weight loss of the thickness of minced fat located at the surface or centre of a cylinder of lean M. semitendinosus was examined. All joints were 160 mm longx80 mm diameter and cooked in a natural convection oven at 175°C. Joints with minced fat at the surface cooked more quickly than those with an equal thickness or volume of fat at the centre. Percentage weight losses from the joints with surface fat were greater than those from joints with the same thickness of fat at the centre but the losses were the same for joints with equal volumes of fat. Cooking time decreased and weight loss increased with increasing amounts of minced fat. For comparison, cylinders of unminced fat were also heated; these required much longer to reach 74°C and suffered substantially less weight loss than the cylinders of minced fat. This showed the need for further work to examine the effect of degree of comminution on the heat penetration and weight losses from fat.
Review: Near infra‐red analysis of food
Authors: DAVIES A. M. C. , GRANT A.
Published: July 2010

Near infra‐red (NIR) analysis has been developed over the last 20 years into a routine method for many agricultural commodities and food constituents. The theoretical and statistical framework, which has made this possible, is reviewed and the extent of the applications presented. The development of a NIR method is demonstrated and the difficulties and limitations of the method are discussed. On‐line methods of using NIR analysis are being developed and this is expected to be one of the most important applications for the future use of NIR in the food industry.
Limited multilayer desorption of brown, parboiled rice
Authors: ENGELS C. , HENDRICKX M. , TOBBACK P.
Published: July 2010

Two mathematical models, the BET‐equation and the Caurie‐equation, are used to analyse experimental desorption isotherms of two long‐grain varieties of brown, parboiled rice at different temperatures. Monolayer moisture contents and maximum number of sorbed water layers, estimated by the Caurie‐model, decrease with increasing temperature. From the temperature dependence of the desorption isotherms, isosteric heats of desorption are calculated. For both varieties, the differential heats of desorption are already very small (1.4 kJ/mol) at a moisture content of 20%. Thus, additional moisture behaves almost like pure water.
Effect of preslaughter fasting on the characteristics of pig livers
Authors: WARRISS P. D. , BROWN S. N. , FRANCOMBE M. A. , HIGGINS J. A.
Published: July 2010

Seventy‐seven pigs of about 60 kg liveweight were killed in two experiments, which examined the influence of food deprivation preslaughter on the chemical composition, physical characteristics and eating quality of liver. In the first experiment pigs were fasted for 0, 24 or 48 hr before slaughter. Livers from fasted animals were lighter in weight (P < 0.001) and contained proportionally slightly more water (P < 0.001), fat (P < 0.001) and protein (P < 0.001) but very much less glycogen (P < 0.001) and less lactate (P < 0.001). They had higher pH values (P < 0.001) both just after slaughter and during storage at 2°C for up to 72 hr. They were darker in colour initially (P < 0.05) and after chilling for 72 hr (P < 0.01) partly due to the higher (P < 0.05) concentrations of haem pigments. The second experiment examined how these differences influenced eating quality. It included a control group killed 2 hr after food withdrawal and groups fasted for 12, 24 and 48 hr. After frying, livers from pigs fasted longer were found to be darker in appearance (P < 0.001), less tender (P < 0.001), less juicy (P < 0.001) and, overall, less acceptable (P < 0.001). Livers from pigs fasted longer also lost less weight during cooking (P < 0.05) and were tougher (P < 0.05) based on instrumental measurements. Livers from half of the pigs in each fasting group were stored at 2°C prior to assessment of eating quality; the remaining livers were frozen at −20°C. Freezing had small deleterious effects on the texture (P < 0.01) and juiciness (P < 0.05) of livers but did not influence mean overall acceptability.
Physical stability of chocolate milk
Authors: VAN DEN BOOMGAARD TH. , VAN VLIET T. , VAN HOOYDONK A. C. M.
Published: July 2010

The stability of chocolate milk, made from two different cocoa powders and skim milk, was studied. Three types of instability could be distinguished: sedimentation of cocoa particles, formation of large flocs and formation of light and dark coloured layers (segregation). From adsorption studies and rheological measurements it could be deduced that chocolate milk behaves as a fluid with a weak network. The cocoa particles themselves are incorporated in this network structure. This network is formed by an interaction of protein and protein‐covered cocoa particles in the presence of a suitable stabilizer (carrageenan). Heat treatment has a considerable effect on the interactions. Segregation is supposed to be caused by uniaxial compression of the total network due to gravitational force, and segregation will stop when the gravitational force is counterbalanced by the elastic modulus multiplied by the deformation gradient of the network. The compression may be influenced by the adherence of the network to the container wall.
Characteristics of commercially heat‐treated oat groats
Authors: OOMAH B. D.
Published: July 2010

Oat groats, sampled at various steps in the commercial production of oat flour, were examined to determine the effects of heat treatment on oat quality. The samples were: original cleaned milling oats, conditioned groats, dried groats and cutmeal. The amount of oat protein solubilized by different concentrations of sodium dodecanoate was indicative of the degree of heat treatment received during processing. Pasting characteristics of conditioned groats were lower than those of other oat samples. Dry groats and cutmeal samples had similar protein solubility and pasting characteristics. Lipase activity of grain samples, except cutmeal, were lower than those of flours obtained from them; that of dried groats was negligible. Differences were observed in the three endothermic transitions (starch, protein and amylose‐lipid complex) in the differential scanning calorimetry (DSC) thermograms of oat samples.
Water sorption isotherms of soybean varieties grown in Argentina
Authors: POLLIO M. L. , RESNIK S. L. , CHIRIFE J.
Published: July 2010

Water adsorption isotherms at 25°C of five soybean varieties grown in Argentina were determined; oil contents ranged from 16.7 to 22.7% (dry basis). Equilibrium moisture curves of the different varieties were coincident when the moisture contents were calculated on an oil‐free basis. Water adsorption by soybean oil was negligible compared with the water adsorbed by the non‐oil fraction at the same relative humidities. The adsorption isotherms of all varieties is well described by a single adsorption equation.
Determination of iodine‐bromine numbers of some edible oils with two N‐bromoimides
Authors: DAS C. MOHANA , INDRASENAN P.
Published: July 2010

The iodine‐bromine numbers of some edible oils such as coconut oil, gingelly oil, groundnut oil, mustard oil, olive oil, palm oil and sunflower oil were determined titrimetrically using the N‐bromoimides, N‐bromophthalimide (NBP) and N‐bromosaccharin (NBSA). The proposed excess‐back titration methods were based on quantitative bromination of the glycerides of unsaturated fatty acids present in the oils and both the methods were simple, rapid and accurate.
Accelerated ripening of cheese using liposome‐encapsulated enzyme
Authors: KIRBY C. J. , BROOKER B. E. , LAW B. A.
Published: July 2010

Improved efficiency of liposome encapsulation of a cheese‐ripening enzyme and increased retention of encapsulated enzyme by cheese curd are reported. The economy of enzyme usage for accelerating the rate of ripening of Cheddar cheese has been improved about 100‐fold over previously reported methods. This has made feasible the use of microencapsulated enzymes for large‐scale cheese production. Objective measurement of cheese ripening by proteolytic indices, and subjective evaluation of flavour quality and intensity by trained taste panels, indicate that cheeses are ripened by the microencapsulated enzyme in half the normal time. Investigations aimed at further improving the efficiency and commercial feasibility of the process are reported, and the possibility of using this technology for other aspects of food processing are discussed.
Use of polyols to measure equilibrium relative humidity
Authors: STEELE R. J.
Published: July 2010

Polyols were used to estimate the equilibrium relative humidity (ERH) of foods. Glycerol, ethylene glycol and propylene glycol were found to be suitable for estimating ERH, up to an ERH of 93%, by measuring the refractive index after they had equilibrated in the headspace of a food. The ERH determined by the polyol method agreed with the ERH determined using Sina and Vaisala meters to within 1% ERH for a lithium sulphate slurry, and for foods were usually within 2%. The ERH of prunes determined using the Vaisala meter was about 6% lower than the value obtained by the other methods. Unlike most electronic techniques the polyol method was unaffected by the presence of glycerol, propylene glycol or butylene glycol and so is suitable for measuring the ERH of foods containing these humectants. The polyol method can be used in developing countries where access to sophisticated equipment is limited.
Chemistry of sulphur dioxide in vegetable dehydration
Authors: WEDZICHA B. L.
Published: July 2010

The state of sulphur dioxide in partially dehydrated or dehydrated foods is complex and depends on pH, ionic strength, water activity and concentration, and on the effects of anions and cations on the solubilities of sulphite and disulphite salts. The chemical basis of the preservative action is explained in terms of the nucleophilicity of the sulphite ion and the possible consequences of the changing state of the additive during dehydration are evaluated. The significance of autoxidation of the sulphite ion to its fate in food, and role as an antioxidant, or prooxidant, is critically discussed. The most widely studied reaction of sulphur dioxide in food is its inhibition of non‐enzymic browning; the current state of knowledge concerning the mechanism of this action is explained.

The loss of sulphur dioxide during vegetable dehydration obeys first‐order kinetics. This observation is considered in terms of known first‐order reactions in foods and processes which are limited by rate of diffusion. There are still insufficient data to suggest ways in which the composition of the food could be altered to reduce its requirement for sulphur dioxide during dehydration.
Sensory characteristics of ham and their relationships with composition, visco‐elasticity and strength
Authors: NUTE G. R. , JONES R. C. D. , DRANSFIELD E. , WHELEHAN O. P.
Published: July 2010

Fifty‐two ham samples were assessed by a trained panel of ten assessors for appearance, texture and flavour using twenty‐two descriptive and three hedonic scales. Generalized Procrustes analysis was used to reveal the spatial configuration of the samples, taking account of differences between individual assessors. The first principal axis accounted for 33% of the overall variation and was related to ‘plastic’ and gelatinous appearance, and firm texture. The second principle axis accounted for 17% of the variation and was related to rubbery, firm, plastic and cohesive texture descriptors, and plastic appearance. The third principal axis accounted for 10% of the variation and was related to the appearance and flavour of the product with dominant colour, fatness and saltiness prominent. The mechanical properties were characterized as shear strength, tensile strength and by a model of visco‐elasticity. Firmness increased with shear strength and the gelatinous, plastic appearance was related to the amount of bound water. Cohesiveness and rubberiness increased with ultimate tensile strength and total water content. The equilibrium modulus and principal relaxation times characterized the first two principal axes and gave a good indication of the texture of the products. Ninety‐one per cent of the variation in the combined overall hedonic scores was accounted for by the first principal axis—the preferred ham having a firmer, meaty texture. Shear strength and bound moisture were the two best single mechanical indices of this overall liking.
Thiamine destruction during extrusion cooking as an indicator of the intensity of thermal processing
Authors: GUZMAN‐TELLO R. , CHEFTEL J. C.
Published: July 2010

Assessment of the intensity of high temperature‐short time (HTST) extrusion cooking was studied by measuring the extent XA of thiamine destruction. Small quantities of thiamine hydrochloride (0.1–0.7 g per 100 g) were mixed with wheat flour (containing ∼ 14% water) prior to extrusion experiments. Results indicate that thiamine destruction follows an apparent first‐order reaction and that the rate constant K of destruction, calculated from near isothermal extrusion experiments at 133, 142 or 152°C (product temperature), follows an Arrhenius relationship with an activation energy of 49.9 kJ/mol.

K values were calculated from experimental determination of XA and of the residence time distribution (RTD) in the effective heating zone of the extruder.

The influence of product temperature (just before the die), water content during extrusion and speed of screw rotation on the overall K (for non‐isothermal extrusion experiments) was determined and analysed by multiple regression. Results show that thiamine destruction XA can be predicted by means of a linear mathematical model.

Each experimental XA value can be used, in combination with Arrhenius equation constants and RTD, to express a given extrusion process in terms of equivalent isothermal temperature and equivalent plug flow residence time.
The effect of fermentation temperature, flour type, and starter on the properties of sour wheat bread
Authors: SALOVAARA H. , VALJAKKA T.
Published: July 2010

The effects of the type of wheat flour (white or dark), fermentation temperature (25°C or 30°C) and origin of starter (bakery A compared with bakery B) on acid production and bread properties were examined in a factorial design. The type of flour was the most important factor; with dark flour (ash content 1.64%) the acetic acid concentration in the bread was almost double that from white flour (ash content 0.86%); lactic acid was 30 to 50% higher. Acid production increased as fermentation temperature increased to 30°C, but was not influenced by the origin of the starter.

Loaf specific volume decreased with acid concentrations, but souring lengthened the mould‐free time from 4 days to 5 to 8 days or more as acidity increased. Sour wheat bread had a characteristic taste. Those with higher acidity values were more bitter and pungent.

Rye sour and rye sour bread production technology could also be utilized in white bread making.
Cold shock in fish: its characteristics in bighead
Authors: PARRY R. W. H. , ALCASID M. V. , PANGGAT E. B.
Published: July 2010

A strong cold shock effect was demonstrated in bighead, and this was contrasted with the absence of any such effect in rainbow trout. The influence of chilling temperature and delayed icing on this effect was investigated. Bighead exhibited only weak rigor, which could be distinguished from the profound stiffening that followed icing. The degree of cold shock was similar when fish were chilled to 0, 2, 5 and 11°C, but the effect was not observed at 15 or 30°C. Bighead that were allowed to remain at ambient temperature before icing exhibited less pronounced stiffening when iced; the longer these periods at ambient temperature, the less rigid the fish became when iced. Fish allowed to enter rigor showed no increase in stiffness when subsequently iced.
Enzymic browning of sulphocatechol
Authors: WEDZICHA B. L. , GODDARD S. , GARNER D. N.
Published: July 2010

When sulphur dioxide inhibits the enzymic browning of catechol catalysed by mushroom tyrosinase, the main reaction product is 4‐sulphocatechol. When assessed for its browning potential, this product appears to be unreactive and does not inhibit the enzyme.
Pecan quality after harvesting and moulding of different varieties store at high relative humidity
Authors: PASTER N. , GAGEL S. , MENASHEROV M.
Published: July 2010

Pecan nuts stored in their husks may be subjected to rapid mould deterioration. A study was designed to determine quality characteristics of pecan stored for 7 days before shelling. In addition, the moisture absorption of dry pecans and the increase in mould population of three varieties (Delmas, Moneymaker and Choctaw) stored under controlled conditions of 26 ± 1°C and 85% RH were investigated.

When pecan nuts with husks were stored for 7 days in metal bins soon after harvesting, temperatures inside the bulk rose from 24 to 33°C. However, no notable increase in free fatty acids or in peroxide value of the nutmeals was recorded.

The moisture content of pecan meat influenced fungal infestation: e.g. the moisture content of variety Moneymaker increased rapidly during storage and the final fungal count on this variety was relatively higher than other varieties. The increase in both parameters in Delmas was slower and a smaller fungal population was recorded at the end of the trial.
Sensory profiling and multidimensional scaling of selected Finnish rye breads
Authors: HELLEMANN U. , TUORILA H. , SALOVAARA H. , TARKKONEN L.
Published: July 2010

A vocabulary for the description of the sensory properties of Finnish rye breads was developed as a basis for the design of a practical quality control/product development system to be used in a later study.

Six samples, selected from thirty‐two commercial rye breads, were evaluated for the intensity of twenty‐nine attributes and for similarity between sample pairs. Significant differences were found between samples in the intensity of twenty‐eight of these descriptors. The data were combined by a multidimensional scaling procedure (KYST 2A and PROFIT), which revealed three discriminative dimensions among the samples: (1) from pleasant rye‐like to unpleasant flour‐like; (2) from sweet to bitter; and (3) the presence/absence of a characteristic flavour caused by specific baking conditions (low temperature, long baking time).

The PROFIT procedure identified 20 attributes as important for quality of rye bread samples using multiple correlation coefficients. There were five appearance attributes, two odour attributes, six taste attributes, five texture attributes and overall impression of pleasantness and freshness.
A method of assessing protein adsorption onto ultrafiltration membranes
Authors: LOCKLEY A. K. , WHITE W. J. P. , HALL G. M.
Published: July 2010

A method of assessing protein adherence onto ultrafiltration membranes was developed, based on modification of routine assay procedures. The technique was applied to three different commercially‐manufactured, tubular, ultrafiltration membranes made from cellulose acetate (CA), polysulphone (PS), and polyvinylidene fluoride (PVDF). Samples of each were exposed to bovine plasma solution (10 g/1, pH 6.0) for varying lengths of time, and the resulting adsorption profiles determined. The different membranes varied in the amounts of attached protein. There was considerable variation between different samples taken from the same membrane: this variation tends to increase with time, and may be indicative of surface defects in the membranes.

After 1 hr of exposure to bovine serum albumin (BSA) solution (20 g/1, pH 6.0), the polysulphone membrane had 0.02 g m‐2 attached protein, in close agreement with the value found by other workers using radiometric techniques.
The effect of various hydrocolloids on some physical properties of extruded corn grits
Authors: MAGA J. A. , FAPOJUWO O. O.
Published: July 2010

Fourteen hydrocolloids including Methocels (A4M, E4M, F4M and K4M), locust bean, guar, agar, arabic, alginate, tragacanth, carrageenan, xanthan, pectin, and gelatin gums were extruded at levels of 0, 0.1, 0.5 and 1.0% with corn grits in a Brabender Model PL‐V500 extruder at barrel temperatures of 50, 75, 100, 125 and 150°C with a 1:1 screw operating at 100 rpm. Resulting products were evaluated for density, breaking strength and water absorption. Significant differences were found as influenced by hydrocolloid type/amount and extrusion temperature. In general, hydrocolloid additions significantly increased product density and either increased or decreased breaking strength and water absorption.
The temperature dependence of isosteric heat of sorption of some cereal grains
Authors: AGUERRE R. J. , SUÁREZ C. , VIOLLAZ P. E.
Published: July 2010

An equation predicting the temperature dependence of the isosteric heat of sorption was calculated using the Othmer method. This equation was applied to water vapour pressure isotherms of cereal grains (sorghum, wheat and rough rice) at different temperatures to calculate the isosteric heat and its dependence on moisture content and temperature. The results show a slight decrease of the isosteric heat with increasing temperature. For rough rice grain, the desorption heats calculated by the proposed method at two temperatures were compared with those obtained by the Clausius‐Clapeyron method.
Influence of packaging film permeability and residual sulphur dioxide on the quality of pre‐peeled potatoes
Authors: GIANNUZZI L. , RODRIGUEZ N. , ZARITZKY N. E.
Published: July 2010

The effects of sodium bisulphite concentration and gas permeability of the packaging film on the surface colour, texture, exudate production and microbial growth of pre‐peeled refrigerated potatoes were evaluated to determine shelf‐life and the lowest level of preservative which could be used.

The product was packaged in polyethylene film, or in vacuo, using EVA‐SARAN‐EVA laminate and stored refrigerated. Polyethylene was not adequate in several aspects; packaging in oxygen barrier film allowed reduction of bisulphite levels, and vacuum packaging of 50 ppm bisulphite treated samples doubled the shelf‐life of the product compared with aerobic packaging.
Bread quality and nutritional value of ‘Marraqueta’ and ‘Hallulla’ supplemented with full‐fat sweet lupin flour (Lupinus albus cv. Multolupa)
Authors: BALLESTER D. , CASTRO X. , CERDA P. , GARCIA E. , YANEZ E.
Published: July 2010

‘Marraqueta’ and ‘Hallulla’ breads, widely consumed in Chile, were enriched with 6, 9 and 12% full‐fat sweet lupin flour (FFLF) containing a small amount of alkaloids (0.025%) and 42.8% protein. Physical characteristics of the dough and the chemical composition and biological quality of the breads were investigated. Farinograph measurements showed that water absorption increased gradually from 61.3% for wheat flour to 79.8% for a blend with 12% FFLF. Developing time, weakening of dough and valorimeter value were not severely modified. Different levels of FFLF increased loaf weight as compared to all wheat bread. Protein content increased from 13.2% for the control to about 16% for 12% FFLF breads. Protein efficiency ratio (PER) values significantly increased (P < 0.01) for 12% FFLF breads: ‘Marraqueta’ from 1.10±0.09 to 1.59±0.12 and ‘Hallulla’ from 1.21±0.09 to 1.63±0.07. Apparent digestibility was about 86% and was not changed by FFLF inclusion up to 12%. Twelve per cent FFLF is a recommendable level to enrich ‘Hallulla’ and ‘Marraqueta’ in biological quality without affecting the farinological parameters. The results of acceptability tests will be published in due course.
Effect of water activity on oxidative deterioration of freeze‐dried beef
Authors: QUAGLIA G. B. , SINESIO F. , VECCIA‐SCAVALLI D. , AVALLE V. , SCALFATI G.
Published: July 2010

The effect of water activity on lipid oxidation in freeze‐dried beef was studied. Analytical indices of the extent of oxidation (thiobarbituric acid (TBA) number and Ex 350Ee320 fluorescence ratio) showed that samples of water activity 0.270 underwent less oxidation during 84 days storage in oxygen at 50°C than samples of lower water activity. Samples stored under nitrogen, irrespective of water activity, did not show any oxidation.
The removal of fat, skin and viscera from sand eel flesh by incubation above ambient temperature
Authors: SCOBBIE A. E. , MACKIE I. M.
Published: July 2010

An incubation process for the selective removal of skin, viscera and lipid from the small pelagic species sand eel (Ammodytes tobianus) has been evaluated. The fish were cut transversely into portions (2–3 cm) and then incubated at 40°C and pH 7.0 or pH 4.0 for 60 min with vigorous agitation. The separated flesh, off white in colour and free of skin and viscera was recovered in yields of 20% at pH 7 and 30% at pH 4. The oil content was reduced from 7.3 to 4.1% (pH 7) and to 5.3% (pH 4). Proximate analyses of the final products showed that the process resulted in an increased protein content and a decreased lipid content when compared with whole sand eel flesh. Analyses of the released oil showed only slight losses in some more unsaturated fatty acids during the process. The separated flesh obtained at pH 4 and pH 7 had water‐holding capacities of 2.19 and 2.78 g water/g protein respectively while intact sand eel flesh had a value of 2.62 g water/g protein.
Modified atmosphere packaging of shredded lettuce
Authors: BALLANTYNE A. , STARK R. , SELMAN J. D.
Published: July 2010

A retail package system was used to study the atmosphere modification which developed within packages of shredded Iceberg lettuce, sealed in trays with a range of polymer films of different gas permeabilities (oxygen permeability of 3000 to 10,000 ml/m2/day/atm. at 25°C). Modified atmospheres were produced both naturally by respiration, and by application of gas flushing techniques.

The effects of these modified atmosphere conditions on visual and sensory quality of shredded lettuce was observed by monitoring colour change and development of off‐odours. An equilibrated modified atmosphere containing 1–3% O2 and 5–6% CO2was established with 35 um low density polyethylene film after flushing with 5% O2, 5% CO2 in N2. This resulted in a shelf‐life of approximately 14 days at 5°C, almost double that of the controls.
A simple blanch‐dry process for lipoxygenase inactivation in soybean cotyledons
Authors: SETH K. K. , NATH NIRANKAR
Published: July 2010

Full‐fat flour from unblanched soybeans develops a beany flavour during milling due to lipoxygenase activity; the flour also becomes bitter during storage. The minimum thermal treatment necessary to inactivate lipoxygenase in soybeans before milling was determined. Soybeans were dehulled and cotyledons blanched in water between 80 and 99.3°C. Water blanching for 3 min at 99.3°C was necessary when blanched cotyledons were subsequently sun dried, and the flour had a nitrogen solubility index (NSI) of 37.8% and residual trypsin inhibitor activity (TIA) of 64.2%. Only 1.5 min blanching was necessary to inactivate lipoxygenase in soy cotyledons if they were dried subsequently at 60°C; NSI of this flour was 32.7%, with 44.7% residual TIA.
Effect of temperature on thermal properties of ‘Record’ potatoes
Authors: RICE P. , SELMAN J. D. , ABDUL‐REZZAK R. K.
Published: July 2010

Heating methods were used to measure the thermal diffusivity, specific heat and density of potatoes (c.v. Record U.K.), from 40 to 90°C and for moisture contents of 72 to 79%. Thermal conductivities were calculated: maximum thermal diffusivity was at about 70°C.
Growth inhibition of food‐borne pathogens by lactic and acetic acids and their mixtures
Authors: ADAMS M. R. , HALL C. J.
Published: July 2010

The inhibition of Salmonella enteritidis and E. coli by lactic and acetic acids, individually and as equimolar mixtures, was measured. Results confirm that the undissociated acid is the active antimicrobial species. In weakly buffered media an apparently synergistic interaction is observed between the two acids; this is ascribed to the potentiation of acetic acid in the lower pH environment created by the lactic acid. The effect could account for the stability of vegetable fermentations where no starter culture is used and asepsis is not observed.
Nutrient composition of extruded cowpea products
Authors: AKINYELE I. O. , LOVE M. H. , RINGE M.
Published: July 2010

Three cultivars of cowpeas (Ife brown, Vita 5 and California black eye) were blended with either rice, corn or both rice and corn and banana puree. The blends were dry extruded on a low cost extruder. The average energy content was 440 Kcal/100 g, protein 20% and the trypsin inhibitor activity was reduced by 63–84%. The stachyose contents varied from 0.52 to 2.44%, raffinose 0.16 to 4.32% and sucrose 0.18 to 1.16 g% respectively. The colour of the products was acceptable and there was no evidence of browning in the products.
Purification and heat stability of Cox's apple pulp peroxidase isoenzymes
Authors: MOULDING PATRICIA H. , SINGLETON D. E. , McLELLAN KATHRYN M. , ROBINSON D. S.
Published: July 2010

Three peroxidase isoenzymes, two anionic and one cationic, were isolated from extracts of apple pulp using gel filtration and ion‐exchange chromatography. The homogeneity of the purified isoenzymes was established by isoelectric focusing and staining for peroxidase activity. The isoenzymes varied in their heat stability: the anionic isoenzymes were found to be more heat stable than the cationic isoenzyme. The measured enzymic activity of the isoenzymes was greatest when o‐dianisidine was used as the test substrate. After heating solutions of the anionic isoenzymes at 80–100°C for 2 min, up to 80% of the original enzymic activity was observed to regenerate when the heat‐treated isoenzymes were held at 30°C for 1 hr. Regeneration of enzymic activity following heat inactivation was not observed for the cationic isoenzyme.
Reduction of chilling injury in ripe Alphonso mango fruit in cold storage by temperature conditioning
Authors: THOMAS P. , JOSHI M. R.
Published: July 2010

The influence of ripening temperature and cold conditioning of pre‐climacteric fruits on the incidence of chilling injury (CI) in ripe mango fruits cv. Alphonso during refrigerated storage was investigated. Fruits previously held and ripened at tropical ambient temperature (AT, 27–34°C) developed CI (skin staining or browning) when ripe fruits were subsequently stored at 5, 10, or 15°C for shelf‐life extension. Fruits held and ripened at 20°C1°C, RH 85–90% showed little evidence of CI when subsequently stored at 5 or 10°C up to 14 days. Chilling injury in ripe mangoes was also avoided by holding pre‐climacteric fruits for a minimum period of 30 days at 10°C and then ripening them at 27–34°C. The quality of the ripe mangoes remained good during cold storage for 7 days and were acceptable until 10–14 days with minimal changes in texture, flesh colour, carotenoids, total soluble solids, titratable acids and ascorbic acid. Shelf‐life of ripe mangoes can thus be extended under refrigeration by pre‐storage conditioning.