Food Science and Technology International recent issues

Mechanical and Physical Properties of Soy Protein Films with pH-Modified Microstructures

Mauri, A.N., Anon, M.C. — 2008-07-02

Mechanical, physical, and barrier properties of films obtained from soy protein isolate solutions at different pH were studied and correlated with the structural properties and the microstructure of films. Films obtained at pH 2 and 11, which had denser microstructures and a higher amount of disulfide bonds, showed a higher tensile strength — of about 1.05 MPa — and a higher Young's modulus — of at least 0.15MPa — than the one at pH 8. However, films formed at alkaline pH (8 and 11) exhibited a higher deformation than films at pH 2 — by about 70%. The presence of at least a protein fraction in native state allowed macromolecules to unfold during the mechanical test, reaching greater deformation before breaking. Acidic films exhibited higher water vapor permeability — of about 7 x 10^-11 g/m s Pa — and water content — of about 1.5% — and a lower glass transition temperature — of at least 15 °C — than basic ones, due to their higher hydrophilic nature.

Changes in Fatty Acid Composition of two Muscles from Three Different Iberian x Duroc Genotypes After Refrigerated Storage

Ramirez, M.R., Cava, R. — 2008-07-02

The changes of the fatty acid (FA) profile of 2 muscles Longissimus dorsi and Biceps femoris from 3 Iberian x Duroc genotypes were studied: GEN1: Iberian x Duroc1, GEN2: Duroc1 x Iberian; GEN3: Duroc2 x Iberian. GEN1 and GEN2 are reciprocal crosses while the difference between GEN2 and GEN3 is the Duroc sire line. The genotype Duroc1 was selected for the production of dry-cured meat products while the genotype Duroc2 was selected for meat production. Longissimus dorsi and Biceps femoris BF from the reciprocal cross showed similar changes in FAs profile after refrigerated storage. However, the Duroc sire line affected the FA profiles of intramuscular fat (IMF) and lipid fractions since some differences were found between GEN2 and GEN3. Meat from GEN3 had the highest level of polyunsaturated fatty acids (PUFA) in IMF and lipid fractions as well as the lowest rate of plasmalogens in polar lipid fraction. After storage, meat from GEN3 showed an increase of long chain PUFA in free fatty acids fraction and the highest increase in the ratio DMA/FA [(dimethylacetals/FAs) x 100] after the refrigerated storage, which was indicative of a higher deterioration of this genotype. Therefore, the crossbreeding of Iberian pigs with Duroc selected genotypes (Duroc2) could affect the changes in the FAs profile of meat under refrigerated storage.

Potential of Conceptual Design Methodology for Food Process Innovation

Hadiyanto, H., van Straten, G., Boom, R., van Boxtel, A.J.B., Esveld, D.C. — 2008-07-02

The available time span for food product and process innovation is steadily decreasing, and to increase the efficacy of the development cycles, systematic design procedures can be used to develop new and to redesign existing processes. The Conceptual Process Design (CPD) methodologies used in chemical industry might also be applied in the food industry to rethink their systems and to break down the complexity of problems into several hierarchical levels. The Delft design matrix, a combination of the iterative design procedure, hierarchical decomposition and task driven methods, is a promising tool which can cover the different objectives and criteria of food design. This article analyzes the potential applicability of Delft Design Matrix as a CPD methodology for food process design and illustrates its functionality with the design of a bakery production system.

Note. Genetic Diversity of Food Isolates of Salmonella enterica serovar Typhimurium in India

Saroj, S.D., Shashidhar, R., Bandekar, J.R. — 2008-07-02

The study aimed to determine the genetic diversity of Salmonella enterica serovar Typhimurium isolates from sprouts and fish samples from India. Twenty-eight S. Typhimurium isolates were genotyped by pulsed-field gel electrophoresis and tested for antibiotic susceptibility, plasmid profile, and presence of virulence genes (invA and spvC). Three distinct XbaI-pulsed-field profiles (PFPs) were observed. Out of 22 isolates from sprouts, 20 showed PFP-A and remaining two showed PFP-B. All six fish isolates showed PFP-C. All the strains were sensitive to the examined antibiotics except two strains of PFP-A. Two different plasmid profiles P1 and P2 were observed. P2 was observed only in the antibiotic resistant strains. All strains were positive for the invA, whereas spvC was detected only in sprout isolates. There was no specific pattern in occurrence of the genotypes with respect to seasons. However, PFP-A was dominant and was isolated throughout the year. This is the first report to assess the genotypic diversity of S. Typhimurium obtained in foods from India. As S. Typhimurium is the predominant serotype in India, the data generated in this study would be useful in epidemiological studies during outbreaks of Salmonellosis in India.

Sensory Profile of Mandarin Chilled Juices and Consumers' Acceptability

Carbonell, L., Navarro, J.L., Izquierdo, L., Carbonell, I. — 2008-07-02

Chilled mandarin juices from four different commercial brands, two mandarin juices prepared in our pilot plant and two commercial orange juices included for comparative purposes were scored for acceptability by 100 consumers in a unique evaluation session. Independently, a descriptive profile of the same samples was performed by 10 trained assessors, who quantified 29 sensory attributes. Most consumers preferred mandarin juices although a small group (about 10%) found orange juices more acceptable. No differences in acceptability were observed between samples from diluted concentrates and from direct juice, either mandarin or orange. Among sensory attributes, maximum differences between samples were found for color, pulp (aspect and texture), mandarin odor, mandarin taste, bitterness and persistent taste.

The Effect of Washing, Microbial Transglutaminase, Salts and Starch Addition on the Functional Properties of Sardine (Sardina Pilchardus) Kamaboko Gels

Karayannakidis, P.D., Zotos, A., Petridis, D., Taylor, K.D.A. — 2008-07-02

The functional properties of kamaboko gels, produced from sardine surimi (SS), were evaluated based on three factors: (a) washing conditions, (b) absence or presence of microbial transglutaminase (MTGase), and (c) addition of CaCl₂, MgCl₂, and NH₄Cl. Fish gels prepared from sardine mince washed at pH 5.5 showed the highest L* values and whiteness index (WI). A similar trend was also observed for firmness. Addition of MTGase had a beneficial effect on the L* values and WI as well as on firmness and cohesiveness of kamaboko gels (p<0.05). Fish gels containing CaCl₂ or MgCl₂ were lighter and firmer compared to those containing NH₄Cl (p<0.05). Three transitions, using a differential scanning calorimeter (DSC), were observed during heating of surimi containing 50g/kg of unmodified wheat starch (UWS), occurring at 45.2 °C, 63.3 °C, and 71.4 °C and were substantially the same when UWS was added at higher concentrations (p≥0.05). The thermal gelation of SS, studied with Dynamic Mechanical Analysis (DMA), occurred at three or four distinct stages named: gel softening, low temperature gelation, gel resolution, and high temperature gelation. The cooling process was found to be crucial in surimi gelation since it strongly contributed in the development of gel rigidity.

Enhancement of Modified Atmosphere Packaged Farmed Atlantic Halibut (Hippoglossus Hippoglossus) Fillet Quality by Soluble Gas Stabilization

Rotabakk, B.T., Birkeland, S., Lekang, O.I., Sivertsvik, M. — 2008-07-02

The suitability of soluble gas stabilization (SGS) to dissolve CO₂ into Atlantic halibut (Hippoglossus hippoglossus) fillets prior to modified atmosphere packaging (MAP) were investigated. Two levels of CO₂ partial pressures (200 and 400 kPa) and two levels of time (1 and 2h) with SGS treatment was used in a factorial design, and compared to conventional MAP. Headspace gas volume (mL), headspace gas composition (%), drip loss (%), pH, microbiological characteristics, off-odor and color were assessed on the packaged fillets. Increased partial pressure and increased SGS treatment time before MAP significantly ( p<0.001) increased the CO₂ content in the packaged fillets and counteracted package collapse. No interaction between the time and partial pressure was found. SGS treatment significantly (p = 0.038) reduced aerobic plate count (APC) and psychrotrophic count (PC). APC and PC increased significantly the tree first sampling days during storage (7, 15, and 21) and stabilized from day 21 to day 28. H₂S producing bacteria and Brochothrix thermosphacta was not affected by the SGS treatment. H₂S producing bacteria decreased significantly from day 7 to day 15. SGS treatment decreased the drip loss significantly (p = 0.006). Color and pH were not affected by the SGS treatment. No difference in the off odor was found between the treatments. Based on off odor analysis, the shelf life of the halibut fillet in this trial exceeded 28 days.

Organic Acids and Soluble Sugars in Edible and Nonedible Parts of Damson Plum (Prunus domestica L. subsp. insititia cv. Syriaca) Fruits During Development and Ripening

Garcia-Marino, N., de la Torre, F., Matilla, A.J. — 2008-07-02

The contribution of the seed and pericarp to the content of malic, quinic, citric and fumaric acids, and sucrose, fructose and glucose was determined during development and ripening of damson plum fruits. In whole fruit, (i) malic and quinic acids were the principal organic acids (OA) and their levels varied significantly, the highest being found at the beginning of the late-green stage; and (ii) the content of citric and fumaric acids was scarce but fluctuated remarkably towards development and ripening. In the seed, the levels of malic, quinic and fumaric acid were lower in ripening than at the beginning of maturation, and a notable synthesis of citric was found from the middle of maturation onwards. In mesocarp, however, malic, quinic, and citric acids peaked in the middle of maturation, whereas fumaric acid notably increased towards ripening. In epicarp, the maximum for the quinic and malic was found at the beginning of ripening and maturation, respectively. In the seed, all soluble sugars (SS) studied peaked at the middle of maturation, and while fructose and glucose (the most abundant SS) tended to be stored during ripening, sucrose (the most abundant in the edible part of fruit) decreased. All the SS studied tend to increase in mesocarp and epicarp throughout maturation and ripening.

Capsicum and Mycotoxin Contamination: State of the Art in a Global Context

Santos, L., Marin, S., Sanchis, V., Ramos, A.J. — 2008-04-22

Owing to their usual conditions of production in countries with warm and humid climates and to poor storage conditions, products derived from Capsicum sp. are susceptible to fungal contamination and development, which can lead to the accumulation of mycotoxins in these foods. Thus, products as chilli or paprika can be contaminated with fungal toxins, such as aflatoxins, ochratoxins and other mycotoxins, which pose a serious risk to public health. This study reviews the main aspects regarding mycotoxin contamination of Capsicum, in the context of the importance of this product in a global market and approaches the effect of processing on final contamination of foods, as well as reviews the analytical methodology commonly employed in fungal and mycotoxin analysis in these types of products.

Quality of Ornate Emperor (Lethrinus ornatus) Packed in a Combination of Dry Ice and Wet Ice and Stored Under Refrigeration

Jeyasekaran, G., Anandaraj, R., Ganesan, P., Shakila, R. J., Sukumar, D. — 2008-04-22

Ornate emperor (Lethrinus ornatus) stored under refrigeration (5 °C) in a combination of dry ice and wet ice at an optimum level of 1 : 0.2 : 0.5 (w/w/w) were found to be sensory acceptable up to 12 days without re-icing. Samples stored in wet ice at 1 : 1 (w/w) were acceptable for only 8 days. Total bacterial load ranged from 10⁴ to 10⁶ cfu/g, while total psychrotrophs increased 6 log cycles. Lactic acid bacteria count increased 3 log cycles and H₂S producers increased 4 log cycles. Micrococcus constituted 79% of the flora in fresh fish. Micrococcus (40%) was also the dominant flora in the combination pack, while Alcaligenes (26%) was dominant in wet ice pack. TVB-N content did not exceed the limit in any of the packs. Free fatty acid and hypoxanthine contents reached to 18.27% as oleic acid and 13.36mg/100g, respectively at the end of storage. Total fat was very low (0.26%), but total protein was high (25.5%) in the raw fish. During storage in the combined ice pack, there was a gradual reduction in the salt soluble proteins from 77.1 to 62.9%. Raw fish contain health beneficial -3 fatty acids particularly docosahexaenoic acid (DHA) at a level of 7.15% out of total fat. The loss of this essential fatty acid during storage in the combined pack was only 61%, while in the control pack, the loss was high (88%).

Characterization of Amylose-lipid Complexes Derived from Different Wheat Varieties and their Susceptibility to Enzymatic Hydrolysis

Kwasniewska-Karolak, I., Nebesny, E., Rosicka-Kaczmarek, J. — 2008-04-22

Starches from eight wheat varieties were analyzed for contents of dry matter, protein, pentosans, apparent and total amylose, total lipids, starch lipids, phosphorus, lysophospholipids and amylose-lipid complex (AML). Processes of starch gelatinization, reversible dissociation of AMLs and its susceptibility to degradation by -amylase were monitored by differential scanning calorimetry (DSC). Degree of crystallinity of starches were evaluated based on X-ray diffraction pattern. Starches from different wheat varieties show some slight differences in terms of chemical composition, thermal properties and susceptibility to enzymatic hydrolysis. Endotherms and exotherms of most starch samples obtained by DSC contained single peaks, which indicated that AML complexes existed in one polymorphic form. Only AMLs formed by amylose from Symfonia cultivar was reflected by the double-peak exotherm on cooling of starch gel. Our studies showed that there was no correlation between AML content and enthalpy of its degradation in native starch. During enzymatic hydrolysis of starch AML complex in all examined starches underwent considerable degradation. Enthalpies of dissociation of AMLs, which remained after amylolysis were significantly lowered (80—90%) as compared to that of undigested starch. The susceptibility of AMLs to degradation by -amylase did not depend on its amount (based on calculation from LPLs), but probably on its structure.

A Mass-Transfer Model for the Drying of an Innovative Tomato Gel

Fiorentini, C., Diaz, E. L., Giner, S.A. — 2008-04-22

Partially dehydrated tomato gels are innovative food products of extended shelf life for using in snack preparations. Flexible, sheet-shaped product was obtained by a pectic gelation mechanism induced by dehydration, starting from a formulation based on tomato puree. The drying kinetics of this product was studied in a bench-scale tray dryer operating between 40 and 80 °C at an air velocity of 2m/s. The `in-dryer' weighings of the trays allowed accurate experimental data to be recorded. The observed drying curves were modeled in two stages: for high moisture contents, with a constant drying rate model while at lower moistures, with an analytical-diffusive model, solved for the average sheet thickness. The mass-transfer Biot number in the diffusive model was found to be 1.1, indicating that external and internal resistances to mass-transfer are comparable. An Arrhenius model correctly described the temperature dependence of the water diffusion coefficient in the tomato pectic gel, represented by an activation energy of 22.0 kJ/mol. The model can be used to estimate minimum drying times and can be incorporated in tray dryer simulators for computer prototyping of new designs, and optimization of existing drying facilities.

Phenolics and Antioxidant Activity of Mushroom Leucopaxillus giganteus Mycelium at Different Carbon Sources

Barros, L., Ferreira, I.C.F.R., Baptista, P. — 2008-04-22

This article reports the first approach to the antioxidant potential evaluation of the edible mushroom Leucopaxillus giganteus mycelium obtained in the presence of four different carbon sources: glucose, sucrose, fructose and mannitol. Despite the use of Leucopaxillus mushroom species in chemical industry for extraction of clitocybin antibiotic, the production of its mycelium for pharmacological applications has not been explored. The concentration of antioxidant compounds increased along the growth time as a response to the oxidative stress and therefore free radicals production. The aldohexose glucose proved to be the most appropriate carbon source to increase antioxidant activity, leading to the highest phenols content and lowest EC₅₀ values. Significant negative linear regressions were established between phenols and flavonoids contents, and antioxidant activity, which support that the extracts mechanism of action for the different antioxidant activity assays may be identical, being related with the content in those compounds and their free radical scavenging activity.

Effect of Nut Paste Enrichment on Wheat Dough Rheology and Bread Volume

Gomez, M., Oliete, B., Caballero, P.A., Ronda, F., Blanco, C.A. — 2008-04-22

The study was carried out to investigate the effect of nuts (almond, hazelnut, peanut, walnut) enrichment (5, 10 and 15%) on the rheological properties of dough using alveograph, consistograph and rheofermentometer measurements. The loaf volume (LV) of bread added nut paste was also determined. The increase in nut percentage increases the dough viscoelastic characteristics (tenacity, extensibility, and strength) and mixing time, but decreased the dough consistency and tolerance, and the CO₂ production during fermentation. Loaf volume increased when 5 and 10% of nut paste are added. Dough added walnut paste presented the lowest tenacity, strength and water absorption values, but the highest values in dough development time, tolerance and stability. Dough added almond, hazelnut and peanut paste had a similar behavior during mixing and handling.

Improvement in the Production of Smoked Trout Fillets (Salmo Gairdnerii) Steamed with Liquid Smoke

Dimitriadou, D., Zotos, A., Petridis, D., Taylor, A.K.D. — 2008-04-22

A fish smoking process was applied using a combination of liquid smoke and steaming at pressures up to 1 bar above atmospheric pressure. Drying and brining prior to smoking have not shown any significant effect on the quality of the trout fillets. The nondried and dried for 4 h trout fillets prior to processing were assessed as slightly more acceptable products, processing yield, sensory analysis, instrumental color, pH, available lysine, polycyclic aromatic hydrocarbons (PAHs) and preservation time were estimated. The losses due to processing of the nondried samples were 23.7%, while 28.8% for those dried for 4h. The fillets processed at 1.5 and 2 bar steam pressure were assessed as highly acceptable. Lightness (L*) showed a decreasing trend due to pressure while redness (a*), and yellowness (b*) an increasing one. The destruction of available lysine was low (13.20% ± 1.01) and it was slightly dependent upon the process. No PAHs were detected. The preservation time, studied via total viable count, lactic acid bacteria, existence of Listeria monocytogenes, and sensory analysis, extended to more than 98 days at 4 ± 1 °C. The drying prior to processing seems to affect the preservation time. This processing technique is much simpler, faster, environmental effective, and leads to high quality smoked products.

Effects of Ingredient Incorporation into Sausage Meat on the Micellarisation and uptake of {alpha}-tocopherol by Caco-2 Human Intestinal Cells

Kenny, O., O'Callaghan, Y., O'Brien, N.M. — 2008-04-22

Ingredients are incorporated into meat and meat products to produce a ``healthier'' product. However, the effect of ingredient addition on availability of nutrients endogenous to foods is generally not considered. This study investigated the availability and cellular uptake of -tocopherol from supplemented sausages with the aid of an in vitro digestion procedure coupled with a Caco-2 cell model. Sausages were formulated with the addition of 3% or 10% ingredients (wheat bran, oat bran, soya protein, whey protein, olive oil, linseed oil, sunflower oil, and wheatgerm oil) and subjected to a two-phase in vitro system that simulates the digestive process in humans. Micelles were isolated from the digestate by ultracentrifugation. Of the ingredients selected for addition to sausage meat, only sunflower oil, and wheatgerm oil enhanced the micellarization of -tocopherol, resulting in increased transfer from the test food to micelles. When ingredients were added at the 3% supplementation level, olive oil enhanced cellular uptake of -tocopherol. Cellular uptake was not enhanced further with higher oil supplementation (3% vs. 10%). These results indicated that addition of ingredients to sausages (fibres, protein derivatives or vegetable oils) did not have a detrimental effect on -tocopherol uptake and olive oil at the 3% supplementation level enhanced -tocopherol availability.

Influence of Fruit Development Stage on the Physiological Response to Ethylene in Cantaloupe Charentais Melon

Flores, F.B., Martinez-Madrid, M.C., Romojaro, F. — 2008-04-22

An experiment has been designed and performed using Cantaloupe Charentais melon as climacteric fruit with the aim of finding out at which point of their development they are able to sense the plant hormone ethylene. Fruit were harvested at 20, 25, and 35 days after pollination (DAP), treated for 5 days at 20 °C with 5 ppm of ethylene, and stored for a further 10 days. Nontreated wild type fruit was used as control. Ethylene-treated genetically modified 1-aminocyclopropane-1-carboxylic acid oxidase antisense fruits with inhibited autocatalytic ethylene production were also used to avoid masking effects because of endogenous ethylene produced by control fruits. Ethylene-treated wild type fruits with 25 DAP were able to produce autocatalytic ethylene. A climacteric respiration increase was observed in treated wild type fruit with 25 and 35 DAP. The degreening of the rind was induced by ethylene in the youngest fruit, showing a total dependence on the hormone for its activation. Loss of pulp firmness induced by exogenous ethylene was found only in 20 DAP-fruit. The existence of ethylene-dependent and developmental factors in the regulation of this ripening process was observed.

Use of Modified Atmosphere Packaging with Microperforated Polypropylene Films to Maintain Postharvest Loquat Fruit Quality

Amoros, A., Pretel, M.T., Zapata, P.J., Botella, M.A., Romojaro, F., Serrano, M. — 2008-04-22

Loquat fruits (Eriobotrya japonica Lindl cv. `Algerie') were stored in modified atmosphere packaging (MAP), using five types of microperforated polypropylene (PP) films during 2, 4, and 6 weeks at 2 °C and for a subsequent period of 4 days at 20 °C shelf life (SL) out of the bags. Loquat fruits stored without packaging and in normal air served as control. The atmosphere composition at the steady state depended on the film permeability, ranging from 1.2 to 8.5 kPa for CO₂ and from 19.5 to 13 kPa for O₂ as film permeability decreased. Weight loss was drastically reduced by MAP conditions. Softening, color evolution, and decreases in sugars and organic acids were delayed, these effects also being evident after the SL period. Scores for visual aspect and facility of peeling were also higher for loquat stored in MAP than for controls. Taking into account results form all quality parameters, the most suitable atmosphere for loquat storage was found to be around 2—4 and 16—18 kPa for CO₂ and O₂, respectively, reached in the PA-80 and PA-60 films. In addition, the storage period for optimum loquat quality maintenance was established as 2 weeks of cold storage plus SL for control fruits, while under MAP conditions, storage periods could be extended up to 6 weeks plus SL, especially using PA-80 and PA-60 films.

Effect of Storage on Cloud Stability of Cloudy Apple Juice

Zhao, G.-Y., Wei Zong, , An, G.-J. — 2008-04-22

Cloud stability of particles in cloudy apple juice during its storage for 120 days at 4, 22 and 40 ^°C is conducted. The juices are added with or without ascorbic acid. The cloud stability of juices during storage is studied by optical microscopy, electron microscopy and size distribution analysis of suspending particles combined with a polyphenols component analysis by high performance liquid chromatography. At the beginning of storage, the turbidity of juice added with or without ascorbic acid decreased quickly because particles of larger size in juices aggregated and deposited, and since there are less larger particles at the upper portion of the bottles, the depositing speed of particles decreases. The loss of total phenolic compounds, epicatechin, chlorogenic acid and tannin increases with the increase of temperature and storage time. The polyphenols degraded quickly during the initial period of storage and then it slowed down. The addition of ascorbic acid to the juice can inhibit the oxidation and polymerisation of phenolic compounds to avoid the formation of new small insoluble particles during the storage, and the efficacy of inhibiting between adding 0.024% or 0.006% (w/w) ascorbic acid is not remarkably different.

Food Proteins as Precursors of Bioactive Peptides -- Classification Into Families

Dziuba, M., Darewicz, M. — 2008-03-28

The Bioactive Peptides (BIOPEP) database developed at the Department of Food Biochemistry, University of Warmia and Mazury in Olsztyn was used to determine the profiles of the potential biological activity of food proteins and to classify them into families. Proteins whose amino acid sequences contained fragments with a specified activity and which were a potential source of this activity were divided into families. Among the 44 biological activities of peptides included in the BIOPEP database, 23 were selected for analysis. The number of families was diversified. The largest families were composed of proteins — precursors of antihypertensive peptides and dipeptidyl aminopeptidase IV inhibitors as well as those activating ubiquitin-mediated proteolysis and opioid ones. Only a few proteins included in the database contained in their sequences fragments with the following activities: chemotactic, binding and transporting metals and metal ions, stimulating red blood cells synthesis, inducing contractions of smooth muscles, and hemolytic. Highly numerous families were divided into five sub-families according to the value of the frequency of occurrence of fragments exhibiting given activity (A parameter).

Preparation and Characterization of Osmodehydrated Fruits from Lemon and Date By-products

Masmoudi, M., Besbes, S., Blecker, C., Attia, H. — 2008-03-28

An osmotic dehydration process (ODP) was established in order to formulate osmodehydrated fruits from lemon and date by-products. ODP was conducted at 40°C, maintained using an oven, or a water bath with continuous stirring. The kinetics of the osmodehydration in a water bath showed a better mass transfer. Then, osmodehydrated fruit (ODF) preparations of about 40°Brix were formulated using different isotonic solutions (sucrose, glucose/sucrose, glucose, and date juice). All the formulated products showed better characteristics (lower acidity, higher sugar content, etc.) than the untreated lemon by-product. The isotonic solution composition influenced their physical characteristics such as microstructure and viscosity. In fact, ODF prepared in glucose and glucose/sucrose solutions presented more open structures, lower viscosities, and water holding capacities (WHC) than the others. The products were microbiologically stable during 3 months at 4°C. These results support the valorization of lemon and date by-products as ODF that could be consumed or incorporated as an ingredient in food formulations.

Oxidative Stability of Edible Vegetable Oils Enriched in Polyphenols with Olive Leaf Extract

Salta, F.N., Mylona, A., Chiou, A., Boskou, G., Andrikopoulos, N.K. — 2008-03-28

Commercially available oils (olive oil, sunflower oil, palm oil, and a vegetable shortening) were enriched in polyphenols, by adding olive leaf extract. Addition of the extract was performed in such way that the oils were enriched with 200 mg/kg polyphenols. Total polyphenols of both enriched and commercial oils were estimated by the Folin—Ciocalteau assay, while identification and quantification of individual simple phenolic compounds was performed by GC/MS and of oleuropein by HPLC analysis. The enrichment resulted in the supplementation of the commercial oils mainly with oleuropein, hydroxytyrosol, and quercetin. Antioxidant capacity and oxidative stability of the enriched oils and the commercial ones were assessed by the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH^•) scavenging assay and the Rancimat method, respectively. Both antioxidant capacity and oxidative stability were substantially improved for all the oils studied after supplementation. By the procedure adopted, oils rich in polyphenols, mainly in oleuropein, can be produced with olive leaf extract supplementation.

Correlation between Flavour Compounds and Sensory Properties of Potherb Mustard (Brassica juncea, Coss.) Pickle

Dayun Zhao, , Jian Tang, , Xiaolin Ding, — 2008-03-28

To characterise the flavour of the indigenous Chinese potherb mustard (Brassica juncea, Coss.) pickle, 28 samples representing two typical types with different brining storage time were sourced from 14 cities in the Yangtze River Delta Megalopolis area in China, either short time storage or long time storage pickles sampled from cities open markets. Pickle samples were assessed by descriptive sensory evaluation conducted using a trained panel and an established pickle flavour lexicon. Pickle samples were also analysed for flavour components, as expressed by physico-chemical parameters. The relationships between the flavour compounds and sensory properties of pickles were studied by the partial least squares (PLS) regression method. Results demonstrated that some latent variables both in the independent variables (physico-chemical parameters) and dependent variables (taste sensory attributes) can be extracted to build the PLS models for prediction. PLS1 regression of sensory data revealed that preference was predominantly related to umami taste, whereas umami taste was mainly related to free amino acid of glutamic acid and aspartic acid contents in the pickle juice. The biplot of PLS2 with all the samples and variables explained 100% of the X-variables (instrumental measurements) and 85% of the Y-variables (taste sensory attributes). The prediction abilities of the PLS models obtained yield good results for the prediction of taste sensory characteristics of potherb mustard pickle according to physico-chemical parameters analysis. However, the total instrumental analysing parameters collected for judgement of potherb mustard pickle quality was a rather large set of data, sensory values evaluated by trained panelists are relatively convenient to obtain. These results illustrated the application of multivariate analysis as an effective strategy for improving the quality of potherb mustard pickles.

Mathematical Modelling of Drying of Rough Rice in Stacks

Akal, D., Kahveci, K., Cihan, A. — 2008-03-28

In this study, drying behaviour of rough rice stacks up to 30 cm is simulated with several models. The suitability of models is determined by the statistical analysis by examining the values of correlation coefficient, standard deviation and mean squared deviation. The results showed that the best model to explain the drying characteristics of rough rice stack is the Midilli et al. model and the coefficients and exponent in the Midilli et al. model could be expressed as functions of drying temperatures and stack height. Statistical analyses also showed that among the models with two coefficients, that of Page, and among the models with three coefficients, that of Verma et al. and diffusion approach were acceptable models in expressing the drying behaviour of rough rice in stacks. Among the models considered here, the geometric model appeared to be the worst fit.

Effect of Heating on Onion (Allium cepa L.) Antiplatelet Activity and Pungency Sensory Perception

Cavagnaro, P.F., Sance, M.M., Galmarini, C.R. — 2008-03-28

Onion, in its raw form, is recognized as an antiplatelet agent that may contribute to the prevention of cardiovascular disease. In raw onions, the content of pyruvate, is significantly correlated with antiplatelet activity (AA) and the sensory perception of pungency. However, onion is generally cooked before consumption. Herein, we examine the effect of heating — using different boiling intensities — on the in vitro antiaggregatory activity (IVAA), the pyruvate concentration and the flavor (pungency) of crushed-onion samples. In general, heating is detrimental for onion AA. Boiling for 3 min has no significant effect on platelet aggregation, as compared to raw onion. Heating for 46 min completely suppresses IVAA, whereas samples boiled for > 20 min have pro-aggregatory effects. Significant differences in AA are found between the blood donors. Pyruvate content is not reduced after 30 min boiling. Pungency ratings decrease with the intensity of the heat treatment. Strong significant positive correlations are found between IVAA and pungency, but not between pyruvate and the former two variables. Our results suggest that: (i) in order to obtain the maximum health benefits onions should be eaten raw or moderately cooked, (ii) extensive heating may result in pro-aggregatory effects, (iii) pyruvate is not a good indicator of AA in cooked onions, (iv) the decrease in IVAA and pungency during onion cooking may be due to degradation of sulfur compounds (e.g. thiosulfinates) which are, likely, less tolerant than pyruvate to the high temperatures.

Instrumental Texture Profile Analysis (TPA) of Shelled Sunflower Seed Caramel Snack Using Response Surface Methodology

Gupta, R.K., Sharma, A., Sharma, R. — 2008-03-28

Models capable of predicting product quality of shelled sunflower seed caramel snack have been developed using response surface methodology. The textural profile analysis was conducted on the snacks using a texture analyzer. The quality attributes measured were hardness, cohesiveness, springiness, chewiness, and resilience as a function of sugar and sunflower kernels content. The sugar and shelled seed proportions affect the textural characteristics of the product significantly (p<0.05). The values of hardness, cohesiveness, springiness, chewiness, and resilience varied from 2.048 to 42.030 N, 1.002 to 5.003, 1.138 to 1.69, 2.773 to 228.146N, and 0.301 to 0.779, respectively. The highest values of hardness and chewiness were attained for the product with 70:30 sugar and shelled sunflower seed proportion respectively. Similarly the highest values of cohesiveness, springiness and resilience were observed in 50 : 30, 50 : 40, and 50 : 50 proportions respectively. The lowest values of hardness and chewiness were observed in 50 : 50 (sugar: shelled sunflower seed) proportion respectively. Similarly the lowest values of cohesiveness were observed in 70: 50 whereas the lowest values of springiness and resilience were observed in 70 : 30 proportions respectively. Hardness, cohesiveness, and chewiness trended to increase whereas springiness and resilience decreased with increase in sugar proportion.

Study on Sodium Caseinate Foam Stability by Multiple Light Scattering

Sceni, P., Wagner, J.R. — 2008-03-28

Foams stability is a critical property for food applications. The main destabilisation processes of liquid foams are drainage, disproportionation and collapse. In the present work, destabilisation of foams prepared with sodium caseinate dispersions (2—10% w/w) were studied by multiple light scattering (Quick Scan). Results were corroborated by optical microscopy and a traditional volumetric method. Kinetics of drainage and collapse were fitted by the empirical equation (t) = _max.tⁿ/(tⁿ+tⁿ_1/2) where (t) refers to the volume of drainage liquid ((t) = V(t)) at time t or the normalised area of collapse ((t) = A_c(t)) at time t, while _max refers to the maximum volume of drained liquid (_max = V_max) or the maximum collapse area (_max = A_max), n describes the sigmoidal character of the curve and t_1/2 is the half-life of drainage or collapse, respectively. Disproportionation kinetics was fitted by the exponential decay model BS(t)=a+b exp(-t/k), where BS(t) is the backscattering as a function of time, b refers to the maximum BS and k is inversely related to BS fall rate. From the results obtained it was possible to obtain parameters for destabilisation kinetics and determine the global stability of foams, which increase with the protein concentration.

Evaluation of Peanut Flour Fermented with Lactic Acid Bacteria as a Probiotic Food

Wang, N.-F., Shi, Y.-H., Sun, J., Le, G.-W. — 2008-03-28

The aim of this study was to evaluate the probiotic value of peanut flour fermented with lactic acid bacteria in vitro and in vivo. Four strains including Lactobacillus delbrueckii LD09, Lactobacillus casei LC35, Lactobacillus acidophilus LA51, and Lactobacillus plantarum P9 were screened for their growth and survival in peanut flour. Among all the strains, L. plantarum P9 grew to the highest cell population (9.48 log cfu/g) in peanut flour after 72 h fermentation at 37°C. After 28 days storage at 4°C, no marked change in the viable count of this strain was observed. Peanut flour fermented with L. plantarum P9 could also increase the content of crude protein and the degree of protein hydrolysis. In an in vitro system, the addition of protein from the fermented peanut flour greatly enhanced the survival of L. plantarum P9 in simulated gastric and bile juices. In vivo studies, supplementation with the fermented peanut flour in the diet of mice increased significantly the number of lactobacilli in the fecal samples compared to the control group. At the same time, the number of enterobacteria decreased significantly. These results indicated that peanut flour fermented with L. plantarum P9 strain could be a novel type of probiotic food.

Sensorial and Physicochemical Characteristics of Salmon (Salmo salar) Treated by Different Smoking Processes during Storage

Martinez, O., Salmeron, J., Guillen, M.D., Casas, C. — 2008-03-28

This study compares the effects of four different smoking processes on the sensorial and physicochemical characteristics of Atlantic salmon (Salmo salar) fillets. Two commercial liquid smoke flavourings (FA and FB) and two types of wood used for cold-smoking wood smoke generation (BS: Beech wood and OS: Oak wood) are investigated. Comparisons were made over a 45 day storage period. Control salmon samples (Cn) (i.e., samples that underwent no smoke treatment of any kind) were characterised by their low colour intensity, firmness, fat release and fibrousness and high adhesiveness, pH, TBARS and TMA values, and a strong amine odour. Fillets treated with smoke flavouring FA showed characteristics very similar to those of the Cn samples, however their colour and smoke odour are more intense and their adhesiveness, amine odour and TMA values lower. Fish treated with smoke flavouring FB show low brightness and pH, but high firmness, elasticity, colour intensity and a high expressible water content. Salmon samples smoked with BS or OS smoke had a low intensity amine odour as well as low brightness, pH, TBARS and TMA values, high colour and smoke odour intensities, and a high fat release value. The effect of storage time on sensorial and physicochemical parameters was evident: the values recorded for certain characteristics decrease, such as, colour intensity, elasticity or firmness, and others increase, such as, amine odour, expressible water content or TMA, and some showing a linear relationship with time (elasticity or amine odour intensity).

Effect of Physico-chemical Characteristics of Raw Muscles from Three Iberian x Duroc Genotypes on Dry-cured Meat Products Quality

Ramirez, M.R., Cava, R. — 2008-03-28

The effect of raw material characteristics (longissimus dorsi and biceps femoris) on dry-cured loin and ham quality from three different Iberian · Duroc genotypes was studied: GEN1: Iberian · Duroc1, GEN2: Duroc1 · Iberian; GEN3: Duroc2 · Iberian. GEN1 and GEN2 are reciprocal crosses, while the difference between GEN2 and GEN3 is the Duroc sire line. The line Duroc1 (DU1) was selected for the manufacture of dry-cured meat products, whereas the line Duroc2 (DU2) was selected for meat production with low carcass fat. Raw material and dry-cured meat products did not differ between reciprocal crosses (GEN1 vs. GEN2). However, the genotype of the Duroc sire line affected the quality of meat and dry-cured meat products. GEN1 and GEN2 had higher adipogenic nature and higher postmortem pH than GEN3, and as a result, these dry-cured meat products had better instrumental and sensory quality than those from GEN3. By contrast, meat from GEN3 had lower pH, fat content, and oxidative stability which decreased the quality of dry-cured meat products. Therefore, there was a close connection between raw material and dry-cured meat products quality as it was affected by characteristics related to the genotype such as the adipogenic character and meat quality traits associated with pH.

Regulation by Carbon Dioxide of Wound-induced Ethylene Biosynthesis in the Peel of Citrus Fruit

Zacarias, L., Alferez, F. — 2008-03-28

The effect of carbon dioxide (CO₂) on wound-induced ethylene biosynthesis in flavedo discs of mature orange fruits (Citrus sinensis L. Osbeck) is investigated. Wounding induced a marked and rapid increase on the rate of ethylene production, the content of 1-aminocyclopropane-1-carboxylic acid (ACC) and on the in vivo ACC oxidase (ACO) activity. Incubation of flavedo discs in a 15% CO₂ atmosphere suppressed activation of these processes. Wound-induced ethylene production was inhibited by CO₂ in a concentration-dependent manner but ACO activity was enhanced at concentrations between 1% and 5%. Kinetic analysis of the interaction between CO₂ and ACO activity indicated that high CO₂ acted as a noncompetitive inhibitor. Removal of CO₂ after 24 h incubation did not restore normal rates of ethylene production. CO₂ partially counteracted the increase in ethylene production and ACO activity induced by a pretreatment with an ethylene action inhibitor (STS, silver thiosulfate). This suggested that part of CO₂ action on ethylene biosynthesis might be due to interfering ethylene action. Collectively, the results indicated that ACS activity appeared to be the major regulatory step by which CO₂ suppresses wound-induced ethylene production. ACO was differentially modulated by CO₂, which is being stimulated at low concentrations and inhibited at high concentrations.

Uptake Kinetics and Absorption of Calcium in Apple Matrices

2007-11-27

The purpose of this paper was to study the kinetics of calcium uptake of blanched and not blanched apple tissue during impregnation treatments under vacuum or/and at atmospheric pressure. The relative absorption of calcium in rats, regarding calcium carbonate as reference substance, was also analyzed as a first approach. Apple impregnation is conducted (with and without previous blanching in saturated vapor) in isotonic glucose aqueous solutions containing calcium gluconate and lactate. A 50 mm Hg vacuum pressure is applied for a time t₁ (0—180 min) or atmospheric pressure is used for a process time t₂ (0—7.5 h). Calcium uptake by apple tissue is influenced by system pressure, blanching, and impregnation time, reaching 500—4600 µg Ca/g according to process variables. Preliminary data of true calcium absorption ranges between 74 and 86% regarding calcium carbonate.

Fungitoxic Activity Against Phytopathogenic Fungi and the Chemical Composition of Thymus zygis Essential Oils

Perez-Sanchez, R., Infante, F., Galvez, C., Ubera, J.L. — 2007-11-27

The yield, chemical composition, and antifungal properties of essential oils from six populations of Thymus zygis Loefl. ex L. were studied. Phytopathogenic fungi Pythium irregulare, Rhizoctonia solani, Colletotrichum acutatum, Fusarium oxysporum, and Sclerotinia sclerotiorum showed a clear inhibition in the poisoned food test. Inhibition is tested by EC₅₀. This activity indicator ranges from 86 ppm in the most active oils to 577 ppm. Among the identified components of the oils, 3-octanol and -terpinene had the highest correlation with the antifungal activity. Yield, antifungal activity, and plant morphology, led to the selection of the population T. zygis ssp. gracilis harvested at flowering stage as most suitable for potential agronomical use.

The Effect of Cooking and Drying on the Water-Soluble Vitamins Content of Bulgur

Kadakal, C., Ekinci, R., Yapar, A. — 2007-11-27

Bulgur is a whole-wheat product cooked, dried, cracked, and sifted for sizing. This paper, evaluated the effect of cooking in beaker (90 and 100°C) and in autoclave at 121°C for 17min and drying in a hot-air oven (60, 70, and 80°C) or sun-drying in open air, on the content of several water-soluble vitamins [thiamin (vitamin B₁), niacin, panthothenic acid (vitamin B₅), pyridoxine (vitamin B₆), and riboflavin (vitamin B₂)]. The content of water-soluble vitamins was analyzed by HPLC. Both cooking and drying had a significant effect ( p<0.05) on the content of water-soluble vitamins of bulgur. The cooking in autoclave resulted in a more significant decrease on the thiamin, niacin, panthothenic acid, pyridoxine, and riboflavin content of the samples, when compared with cooking at 90 and 100°C. As the cooking temperature increases, the concentrations of water-soluble vitamins in the samples decreased. The decrease in water-soluble vitamins was higher with open-air sun drying than with hot-air oven drying at 60, 70, and 80°C.

Isolation and Purification of an Anticoagulant from Schizymenia dubyi by Fermentation

Ekanayake, P.M., Nikapitiya, C., De Zoysa, M., Jeon, Y.J., Lee, J. — 2007-11-27

Natural fermentation is a method of extracting anticoagulant compounds from red algae Schizymenia dubyi. Preliminary screening was carried out on the basis of the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) assays. The optimal fermentation time period for the highest APTT, PT, and TT values was found to be 8 weeks. Purification of the fermented sample by DEAE-anion exchange chromatography followed by Sepharose-4B chromatography resulted in a single polysaccharide, which was reconfirmed by a single spot on agarose gel electrophoresis. The purified sample had >1000s APTT activity at 130 µg/mL. The molecular weight estimated by polyaccrylamide gel electrophoresis was >500,000 Da. This is the first report indicating the presence of the anticoagulant compound in S. dubyi.

Influence of Dietary Sorghum (Sorghum vulgare) and Corn Supplemented with Methionine on Cut-Up Pieces Weights of Broiler Carcass and Quality Properties of Breast and Drumsticks Meat

Aksu, M.I., Imik, H., Karaoglu, M. — 2007-11-27

This research was carried out to determine the effects of sorghum (BS = basal diets containing 30% sorghum), corn (BC = basal diets containing corn) and supplemental methionine (BSM = diet BS plus 0.69% methionine, BCM = diet BC plus 0.69% methionine) in broiler diets on the cold carcass weight and cut-up pieces weight of broilers and some chemical, physical and microbiological properties of breast and drumstick meats. A total 240 male (120) or female (120) broiler chicks (Ross-308) were allocated to four dietary treatments (BS, BSM, BC, and BCM groups) in a completely randomized experimental design. At the end of the trial all chicks were slaughtered, and then were stored at 3°C for 24 h. After standard dissection of carcasses, cut-up pieces are weighed. The breasts and drumstick muscles were analyzed for moisture, pH, ash, fat, thiobarbituric acid reactive substances (TBARS), color (L*, a*, and b*), total psychrotrophic, lactic acid, Micrococcus/Staphylococcus, S. aureus, and Enterobacteriaceae counts. Although cold carcass and cut-up pieces weights were positively affected from supplemental methionine containing corn diet. However, weight were not influenced by supplemental methionine in diet containing sorghum and the other groups. While the highest whole breast weight is determined from broilers fed with corn and 0.69% methionine (BCM), the highest drumstick weight was determined from broilers fed with only sorghum (BS). The weights of cold carcasses and cut-up pieces of male broilers were higher than that of female. Except for redness (a* value), other parameters are affected by treatments. The effects of type of meat (breast and drumstick meats) and gender were also variable. The moisture, pH, TBARS, fat, a*, Micrococcus/Staphylococcus and Enterobacteriaceae count were lower ( p<0.05) in breast fillets than drumstick muscles. The moisture, fat, L*, lactic acid bacteria, Micrococcus/Staphylococcus and S. aureus counts were lower ( p<0.05) in female broiler meats than male broiler meats.

Rheological Properties of Chestnuts Processed by Osmotic Dehydration and Convective Drying

Chenlo, F., Moreira, R., Torres, M.D. — 2007-11-27

The effect of osmotic dehydration using sucrose solutions followed by a convective drying on the rheological properties of chestnuts (Castanea sativa M.) has been studied. Prisms of chestnuts (10 x 10 x 15mm) were immersed into sucrose solutions (60% w/w) at different times (1, 2, 8 and 24 h) at 25°C. The samples were dried with hot air at 65°C and 30 % of relative humidity during different times (0, 0.5, 1.5, 3 and 6 h). Finally, the rheological behaviour of chestnuts at different moisture and sucrose content was determined using a universal machine of mechanical tests. Osmotic dehydration kinetics was evaluated determining sucrose and moisture content. Sugar gain and water loss amounts increased with operation time. Drying kinetics analysis showed higher drying rates during first times. Rheological data (stress, strain and modulus of elasticity) changed strongly with water and sucrose content. At high moisture content samples with more sucrose content showed more ductile properties than no pre-treated osmotically samples and at low moisture content the presence of sugar led to harder samples.

Molecularly Imprinted Solid Phase Extraction in a Syringe Needle Packed with Polypyrrole-encapsulated Carbon Nanotubes for Determination of Ochratoxin A in Red Wine

Wei, Y., Qiu, L., Yu, J. C. C., Lai, E. P. C. — 2007-11-27

A novel micro-solid phase preconcentration (µSPP) device is developed by electrochemically depositing molecularly imprinted polypyrrole (MIPPy) over carbon nanotubes (CNTs) packed inside a 22-gauge syringe needle. The ochratoxin A (OTA) template is removed with 1% triethylamine (TEA) in 20:80 v/v acetonitrile—ammonia buffer (20 mM NH₄Cl/NH₃, pH 9.2). This syringe needle is used to extract trace OTA in a red wine sample, and the preconcentrated OTA is eluted with 1% (v/v) TEA in 20:80 v/v acetonitrile—ammonia buffer (20 mM NH₄Cl/NH₃, pH 9.2). The eluate is analyzed by high performance liquid chromatography (HPLC) with fluorescence detection (FD). The results demonstrated a significantly selective enrichment of OTA at sub-ppb levels in the presence of red wine matrix components. Using a sample volume of 0.5mL red wine for preconcentration, it is possible to determine OTA down to a detection limit of 0.04 ng/mL (at 3_B) or a quantification limit of 0.10 ng/mL (at 10_B). The total MIPPy/CNTs-µSPP-HPLC-FD analysis took only 40min, including a µSPP time of 30min, elution time of 20 s, and HPLC analysis time of 10 min. This needle can be reused and hence readily adapted in an autosampler for the processing of multiple samples in series.

Effect of Thickening Agent and Fat in Custard Microstructure Upon in vitro Enzymatic Digestion

Sanz, T., Handschin, S., Nuessli, J., Conde-Petit, B. — 2007-11-27

Custards desserts with and without fat were prepared using either tapioca modified starch or carboxymethylcellulose (CMC) as thickening agents and the changes in their microstructure upon in vitro simulation of mouth, stomach, and small intestine conditions were evaluated by light microscopy. A completely different pattern of behavior was found between starch and CMC custards. After mouth incubation, the partially gelatinized tapioca granules were completely disintegrated by the action of saliva, while the CMC custard is practically unaffected. Fat incorporation did not influence the breakdown of gelatinized starch. Coagulation of the milk protein is observed after stomach incubation. In the starch custards, the fat globules do aggregate with the milk protein, while in the CMC custard they are still embedded in the unaltered network. Intestine incubation completely digests the remaining structures after stomach incubation, although in the CMC custard particles of undigested hydrocolloid are observed. In the presence of fat, micelles are visualized in both custards, which favor the bioaccessibility of lipophilic compounds. The higher digestive resistance of the CMC custards implied the existence of a higher barrier against the release of active compounds from the custard matrix and therefore a higher barrier against bioaccessibility.