bluuebunny/crossref_metadata_2025 huggingface dataset:
Methods of preparation of fatty acid methyl esters (FAME). Statistical assessment of the precision characteristics from a collaborative trial
Authors: Cert A. , Moreda W. , Pérez-Camino M. C.
Published: October 2008

The official regulations for the control of the olive and olive pomace oils of the European Union (EU) and International Olive Oil Council (IOOC) include the determination of fatty acids in order to be applied to several purity criteria. The determination of fatty acids require the preparation of the fatty acid methyl esters (FAME) for the subsequent analysis by gas chromatography with good precision and reproducibility. Among the methods used in the laboratories of both the industries and the official institutions looking after the olive oil control, the ones selected were: 1) cold methylation with methanolic potash and 2) hot methylation with sodium methylate followed by acidification with sulphuric acid in methanol and heating. A statistical assessment of the precision characteristics were performed on the determination of fatty acids using both methods by a collaborative trial following the directions included in the AOAC regulation (AOAC 1995). In oils with low acidities, the results obtained for both methylation methods were equivalent. However, the olivepomace oil sample (acidity 15.5%) showed significative differences between the fatty acid compositions obtained using both methylation methods. Finally, the methylation with the acidic+basic method did not yield an increase of the trans-isomers of the fatty acids.
Sucrose polyesters from poultry fat as non-ionic emulsifiers
Authors: Megahed Mohamed G.
Published: October 2008

Poultry fats are rich in palmitic and oleic acids are produced as by-products from poultry industries. These fats can be utilized in the preparation of emulsifiers. Sucrose esters of poultry fat are prepared from low-cost poultry fat and sucrose by esterification. The yield of sucrose esters prepared in this work exceeds than 85%. The hydrophilic-lipophilic balance (HLB), surface tension, interfacial tension and stability index (SI) were evaluated and compared with standard emulsifiers prepared from pure palmitate and oleate esters. Concerning the stability of emulsions, the values of interfacial tension and HLB were higher for the sucrose esters of poultry fat.
β-carotene in sunflower oil oxidation
Authors: Yanishlieva N. V. , Raneva V. G. , Marinova E. M.
Published: October 2008

The oxidation kinetics of sunflower oil (SO), as well as of pure triacylglycerols of sunflower oil (TGSO) in the presence of different concentrations (0.001-0.02 %) β-carotene was studied. The process was performed at high (kinetic regime) and low (diffusion regime) oxygen concentrations at room temperature in the dark and under daylight. The results from the oxidation of SO and TGSO at 100ºC in the presence of β-carotene were also presented. It was established that in the antioxidant-free lipid system, the β-carotene did not give any antioxidative protection. It worked as a prooxidant during the oxidation at room temperature and at sufficiently high oxygen concentration, the effect being more pronounced in the dark than under daylight. β-carotene increased the stability of tocopherol-containing SO during its oxidation at room temperature and under daylight. This effect is more strongly expressed in a kinetic regime of oxidation. The synergism of β-carotene with the tocopherols was characterized by the stabilization factor F and the activity A. In the kinetic regime of oxidation F and A varied in the interval F=2.0-6.3, and A =2.7-21.0. In the diffusion regime F=1.3-1.5, and A=1.5-2.8.
Geographical characterisation of virgin olive oils of the denomination of protected origin les garrigues by their fatty acid profile
Authors: Motilva María José , Ramo Tomás , Romero María Paz
Published: October 2008

Main fatty acid composition from Les Garrigues (Lleida. Spain) virgin olive oils were evaluated in three consecutive harvests (1995/96 to 1997/98). Results show that the variability is due to climate events and geographical area of production. Principal Components Analysis was applied to fatty acid composition of olive oil classified in two agroclimate geographical zones. The two first principal components accounting for 80 percent of the variance. A stepwise selection algorithm in discriminant analysis was used to obtain one discriminating function amongst the two zones. Above 83 % for the 188 observations used to fit the model were correctly classified. To verify the model, 20 additional oil samples from 1998/99 harvest were added to the data set and 84,6 % were correctly classified.
A comparison of γ-irradiation and microwave treatments on the lipids and microbiological pattern of beef liver
Authors: Farag R. S. , Daw Z. Y. , Mahmoud Ebtesam A. , El-Wahab Safaa A. E. ABD
Published: October 2008

The effects of γ-irradiation (0, 2.5, 5 and, 10 kGy) and microwaves (generated from an oven at low and defrost settings for 0.5, 1 and 2 min) treatments on the chemical composition and microbiological aspects of beef liver samples were studied. The chemical and microbiological analyses were performed on the non-treated and treated beef liver immediately after treatments and during frozen storage (-18ºC) for 3 months. The chemical analyses of beef liver lipids showed that acid, peroxide and TBA values were slightly increased after irradiation treatments and also during frozen storage (-18ºC). On the contrary, iodine value of the treated beef liver was decreased. Irradiation treatments remarkably reduced the total bacterial counts in beef liver. The percent reduction of bacterial load for beef liver exposed to microwaves generated from an oven at defrost mode for 2 min and after 3 months at -18ºC was 62%. The bacterial load for beef liver exposed to γ-irradiation at 10 kGy after 3 months at -18ºC was decreased by 98%. Hence, γ-irradiation treatment was far better than microwave treatment for reduction of the associated microorganisms with beef liver. Salmonellae was not detected in non-irradiated and irradiated beef liver throughout the storage period.
Studies on changes in lipid profiles of new varieties of rape during seed maturation
Authors: El-Shami Safinaz M. , Hassanein Minar M.M. , El-Mallah M. Hassan
Published: October 2008

Changes in lipids of three newly developed varieties of rapeseed during seed maturation were studied. Triacylglycerol molecular species, fatty acid composition, whole sterol, and four sterol lipids as well as tocopherol were determined at different maturation stages. It was found that marked variations in some lipids were observed in one variety than the other. Efficient methods of analysis employed in this investigation and the individual lipid components, even in very minor quantities, were accurately detected. Marked varietal changes in lipids compositions during seed maturation manifest themselves, to some extent, in three new rapeseed varieties. Changes in lipids of maturing seeds were interpreted in the frame of probable conversion-interconversion reactions that may occur during seed maturation.
Fractionation of commercial hexane and use of its fractions as extracting solvent of cottonseed oil
Authors: Megahed Ola A.
Published: October 2008

The problem of producing off-graded cottonseed oil using locally produced commercial hexane as extracting solvent has explored this research. It was aimed in this work to investigate whether this problem can be solved by controlling the boiling range of the extracting solvent. Four different hexane fractions of different boiling ranges were prepared from commercial hexane. The boiling range of commercial hexane was 62-68ºC while the boiling ranges of the four fractions were 62- 64, 64-65, 65-66 and 66-68ºC. Commercial hexane and the prepared four hexane fractions were then used to extract cottonseed oil from a fixed seed sample. The five crude oil samples were then refined and bleached and their colours were measured. The results have shown that the heaviest hexane fraction ( b.r 66-68ºC) produced the lightest coloured oils. The colour index of the bleached oil using this heavy cut was 190 compared to 350 using the original commercial hexane. However, the production of a commercial hexane cut having a narrow boiling range will be costly. Therefore, this research has been extended to investigate the suitability of a heavy petroleum cut which has a boiling range as wide as that of commercial hexane to extract cottonseed oil. The boiling range of this cut was 66-72ºC. The obtained results proved that the extraction of cottonseed oil using that heavy petroleum fraction produces much lighter oil than the use of conventional hexane solvent.
Chemical characteristics of Solanum sisymbriifolium lam seed oil and residual seed meal
Authors: Nolasco S. M. , Quiroga O. E. , Pereyra A. , Wiese B.
Published: October 2008

Seeds from Solanum sisymbriifolium Lam harvested at Olavarría (Buenos Aires, Argentine) were defatted with hexane and the raw oil obtained with a yield of 20,6 % dry basis. The physicochemical characteristics of crude oil were: refractive index: 1,4610 (at 25ºC), iodine value: 112,8; saponification index: 170,0; unsaponifiable matter: 14,0 % and free fatty acid content: 2,4 (mg KOH/g). The fatty acid composition of seed oil was studied by gas-liquid chromatography. Major fatty acids of seed oil were: linoleic (52,3%), oleic (23,4 %) and palmitic acid (16,4 %). The residual seed meal contained moderate level of crude protein (14,75%, dry basis), low level of available lysine (2,25 g/16gN) and high content of crude fiber (51,5%, dry basis). Total and phytic acid phosphorous, calcium, ash, sugar and polysaccharides contents are reported.
Obtention and uses of protein hydrolysates
Authors: Vioque Javier , Clemente Alfonso , Pedroche Justo , Yust María del Mar , Millán Francisco
Published: October 2008

A review on the obtention of plant protein hydrolysates for food use has been carried out. First, the components and factors that participate in the hydrolysis are described. Then a description of the different types of hydrolysates is done: limited hydrolysates (between 1% and 10% degree of hydrolysis) that are used to improve functional properties of foods; hydrolysates with variable degree of hydrolysis that are used as flavourings; by last, extensive hydrolysates (degree of hydrolysis above 10%) that are used as protein suplement in the diet or with a defined composition for the treatment of specific illness.
Assessment of the fatty acid patterns in vegetable oils, fats and fat-rich foods commonly consumed in Egypt
Authors: Hussein Laila , Ali Mahmoud , Abouelhassan Ali , Grzeskiewicz Stanislaw , Cantellops Dennis
Published: October 2008

Forty-one individual food samples were analyzed for their fatty acid contents by gas-liquid chromatography using capillary tubes. The samples belonged to 5 different food groups and included vegetable oils, butter & ghee, animal fats, dairy products, fishes, chicken & meats and other popular dishes. The results show that maize oil was lowest in its total saturated fatty acid content (11%) and richest in linolenic acid. On the other hand, total saturated fatty acids made up 42-62 % of the total fatty acid patterns of the lamb and camel fat tallow, respectively. Long chain polyunsaturated fatty acids (C20-C22) with two to six double bonds were present only in fishes. Estimate of fat intake amounted to 36 grams per subject per day and the % contribution of the analyzed fats was presented. The ratio of polyunsaturated to saturated fatty acids amounted to 0.96; which falls within the optimum dietary goals.
Effect of drought stress on qualitative characteristics of olive oil of cv Koroneiki
Authors: Stefanoudaki Evangelia , Chartzoulakis Kostas , Koutsaftakis Aristidis , Kotsifaki Fani
Published: October 2008

Quality characteristics (acidity, peroxide values, K232, K270, oxidative stability) and chemical compositional data (fatty acids, sterols and triacylglycerols) were studied in virgin olive oil samples from olive trees, cv Koroneiki, subjected to different water regimes. Experimental trials were carried out using three-year old own-rooted olive trees (Olea europaea L) variety Koroneiki. Plants were subjected to two irrigation treatments to maintain soil water potential to -0.03 MPa and -1.5 MPa. Results showed that irrigation significantly increased the fruit oil content and the oxidative stability and peroxide value of the resulting oil. Olive oil from fruits of irrigated trees showed significant higher values in total saturated fatty acids. Total sterols were also significantly influenced by irrigation. Acidity and specific absorption coefficients K232, K270, of olive oils were not significantly affected.
Evolution of the emulsification kinetics and rheological properties of oil-in-water emulsions prepared with two different impellers
Authors: Sánchez M. C. , Berjano M. , Guerrero A. , Gallegos C.
Published: October 2008

This paper deals with the emulsification kinetics, rheological properties and droplet size distribution of oil-in-water emulsions, stabilised by non-ionic surfactant, using two different impellers, an anchor and a helical ribbon impeller. The geometric differences found between the impellers used produce a different flow pattern, that influences on the kinetics of emulsification, and so, on the droplet size distribution (DSD) and the rheological properties of the final emulsion. There are significant differences on DSD when the emulsion is processed with different impellers at low agitation speed. The mechanical spectrum of these emulsions can be explained taking into account their DSD. However, at higher agitation speeds, the mechanical spectrum can not be explained on basis their DSD.
Lead and cadmium content in sunflower oil
Authors: Roca Cruz A. , Cabrera Vique C. , Lorenzo Tovar M. L. , López Martínez M. C.
Published: October 2008

We have studied the lead and cadmium content in 21 samples of sunflower oil from Andalucía (Southern Spain). These elements are toxicological importance and the sunflower oil is widely consumed in Spain. Samples were mineralized with nitric acid and vanadium pentoxide as catalyst, and ana lyzed using electrothermal atomization atomic absorption spectroscopy. The temperature-time programme for the graphite furnace was optimized for each element, and the accuracy, precision, sensitivity and detection limit of the method were evaluated. Concentrations of lead ranged from not detectable to 167.58 μg/kg and cadmium concentrations ranged from 0.87 to 8.30 μg/kg. The data obtained are not excessive and similar to those mentioned by other authors; however, one sample of the total analyzed surpassed the limit of 0.1 ppm of lead proposed by the Spanish and European Legislation. A statistical significative correlation has been established between Pb and Cd levels (p < 0.05). The contribution of the sunflower oil to Pb and Cd dietary intake has been estimated as 0.84 and 0.09 μg/day, respectively.
Effect of the lupin protein/surfactant ratio on the flow and textural properties of oil-in-water emulsions
Authors: Raymundo A. , Empis J. , Sousa I. , Gallegos C. , Franco J. Mª.
Published: October 2008

The influence of different surfactant/lupin protein ratio on the shear-flow and texture properties of oil-in-water emulsions was investigated in this work in order to find a synergistic effect between both types of emulsifiers. With this aim, texture, steady-shear flow and droplet size measurements were carried out. Different surfactants (Tween 20 and three sucrose esters) showing different phase behaviour in water solution were studied. From the experimental results it can be concluded that emulsions stabilised by mixtures of both, low- and high-molecular-weight emulsifiers, show lower values of steady-state viscosity and textural parameters than those found when lupin protein was the only emulsifier used, in spite of a higher average droplet size. The evolution of emulsion textural and flow parameters with the composition of the mixture used as emulsifier can be explained on the basis of the phase behaviour of the low-molecular-weight emulsifier, modifications on the composition at the interface and hydrophobic interactions between both type of emulsifiers.
The development of a web page for lipid science and research. Main web sites of interest
Authors: Farran A. , Pascual J. , Grillo J. , Codony R. , Boatella J.
Published: October 2008

Internet provide access to a huge of scientific and technical information on Internet which is not validated by any committee of experts. This information needs filtering in order to optimize user access to these resources. In this paper, we describe the development of a WEB page outlining the activity of our research team Food Lipids Quality and Health. The WEB page seeks to fulfil the following objectives: to communicate the activities of the team, to use effectively the resources that Internet offers and to promote their use among the team. We report on the methods used in achieving these objectives. Finally, a large number of WEB addresses related to Lipids are presented and classified. The addresses have been selected on the basis of their usefulness and interest value.
Hydroxamic acid surface active agents
Authors: Ahmed M. H.M. , Mahmoud A. A. , El-Sawy A. A.
Published: October 2008

p-Hydroxy phenyloctadecanol and p-hydroxy phenyloctadecanoic acid were used as new precursors for the preparation of surface active hydroxamic acid including different moles of propylene oxide. The hydroxamic acid was prepared by the reaction of propenoxylated products with sodium chloroacetate, followed by methyl esterification and the resultant product reacted with hydroxyl amine hydrochloride to give the hydroxamic acid. The structures of prepared hydroxamic acid were confirmed by spectroscopic study. The surface activity of prepared hydroxamic acid was studied; the results revealed that, the prepared hydroxamic acid has pronounced surface activity, the alcohol substrate shows a surface activity superior than the acid substrate.
Characterization of the lipid fraction of some Galician (NW of Spain) traditional meat products
Authors: Rodríguez María Pilar , Carballo Javier , López Mercedes
Published: October 2008

The lipid fraction of five Galician (NW of Spain) traditional raw-cured meat products (chorizo rosario, chorizo de cebolla, androlla, botillo and lacón) was characterized by determining in 10 units of the final product of each variery the degree of acidity and the indexes of peroxides, iodine, saponification and TBA. The average values obtained for the degree of acidity of the five products studied varied between 2.31 % and 3.94 % of oleic acid obtained in androlla and lacón, respectively, which shows that all these products undergo a moderate lipolysis. However, the results obtained for the peroxide and TBA indexes, expressed in meq of O2/Kg of fat and mg of malonaldehide/Kg of product, respectively, in chorizo rosario (14.74 and 0.46), chorizo de cebolla (14.12 and 1.75), androlla (12.98 and 1.07), botillo (11.24 and 0.73) and lacón (30.50 and 6.99) show the existence of very intense autooxidative phenomena throughout ripening. All the products showed similar values for the iodine index, about 70 % of iodine absorbed. The average values of saponification index expressed in mg KOH/g of fat determined in chorizo rosario and chorizo de cebolla, 171.42 and 172.80, respectively, were significantly lower than those found in lacón (177.92), androlla (178.31) and botillo (180.43).
Influence of the slow drying at low-temperature in the carotenoid content of two pepper varieties (Capsicum annuum L.). Biosynthetic and/or degradative balance as a function of the processing conditions
Authors: Pérez-Gálvez A. , Garrido-Fernández J. , Lozano-Ruiz M. , Montero-de-Espinosa V. , Minguez-Mosquera M. I.
Published: October 2008

A study of drying process at low temperature of two varieties of pepper for paprika (Capsicum annuum L. cv Jaranda and Jariza) according to the traditional techniques of La Vera region is carried out controlling simultaneously the characteristics of the fruits before and after of the dehydration process and the conditions used. Correspondences have been found between the initial moisture of the fruits, the drying parameters (temperature and time), and the increase and/or loss (including its corresponding quantity) in carotenoid pigment content. The favorable conditions to produce a pigment content increase, that indicates the existence of a biosynthetic process, are those including a healthy raw material with high moisture values and temperature of dried moderate - low (50 ºC) without extending unnecessarily the dehydration time (just to obtain the adequate texture for the grinding).
Thermal stability of some metal-palmitate soaps which find various industrial applications
Authors: Fouda M. F.R. , Yousef Elham A.A. , Mohamed S. S. , Shoeb Zein E.
Published: October 2008

The soaps of alkaline earth's and transition elements and closed ‘d’ orbitals were prepared by the double decomposition method by the reaction between metallic salts and sodium palmitate. The thermal stability of these soaps was studied in order to throw the light on their suitability for using as catalysts or lubricants. The soaps of alkaline earth's were found to be more stable than transition and ‘d’ closed shell soaps.
Interactions in interesterified palm and palm kernel oils mixtures. I-Solid fat content and consistency
Authors: Grimaldi Renato , Guaraldo Gonçalves Lireny Aparecida , Gioielli Luiz Antonio , Simões Ilka S.
Published: October 2008

Palm oil (PO) and palm kernel oil (PKO) compositions (100/0, 80/20, 60/40, 50/50, 40/60, 20/80 and 0/100) were interesterified in laboratory scale under predetermined conditions (0.4% sodium metoxide, 20 minutes, 100oC). The fourteen samples, before and after interesterification, were characterized by solid fat content (SFC) and consistency. Results showed a presence of eutectic system at PO and PKO compositions, mainly at 80/20, 60/40 and 50/50 fractions, proved through isosolids and isoconsistency diagrams. The incompatibility among the oils was decreased after reaction and improved the composition plasticity, demonstrated by the increment of solids value and yield value at room temperature.
Oxidative evaluation of oils mixture of legumes of the Sonoran Desert with maize and soy oils during the storage
Authors: Ortega-Nieblas M. , Robles-Burgueño M. R. , Vázquez-Moreno L.
Published: October 2008

During storage, oils from seeds of wild legumes of the Sonoran Desert have shown greater stability than oils derived from conventional sources. In this work, oxidation process was evaluated during the storage (122 day) of mixtures of oils: Mezquite Prosopis juliflora, Gatuña Mimosa grahamii, Palo fierro Olneya tesota, Vino rama Acacia constricta, Palo de brea Cercidium praecox and Palo verde Parkinsonia aculeata with oils from soy and maize. Ratios were 1:1, 2:1 and 3:1. Evaluated parameters included: Peroxides (P.V.), Iodine (I.V.), Acid (A.V.), p-Anisidine (p-A) values. Results showed that mixtures containing wild and maize oil showed 2-4 meq/Kg as initial values of iodine, while after 122 days of storage the value was 4-7 meq/Kg. Mixtures containing soy oil presented 3-6 meq-Kg initially, and 8-15 meq-Kg were detected at the end experiment. No differences were observed in I.V. and A.V. values in maize mixtures. On the contrary, mixtures containing soy oil presented increments in I.V. Also, A.V. presented a slight increment in 1:1 mixtures. p-Anisidine values presented and small increment in maize mixtures (3:1 ratio) while this increment was larger in mixtures containing soy oils and Gatuña or Palo fierro oil. These latter oils when were mixed with maize oils presented the lowest increments in all evaluated indexes.The oils of palo fierro and blended gatuña with oil of corn didn’t present changes in their concentration in the palmitic and araquidic acid during the storage. The concentration of the oleic acid in the mezquite oils (3:1), gatuña (1:1, 2:1 and 3:1), vinorama (3:1), as well as the linoleic and erucic acids in gatuña in their three mixtures didn’t present changes neither alteration during the storage, for what you are considered the oils of palo fierro, gatuña and vinorama the most stable in the present study.
Modeling of oil extraction from olive foot cake using hexane
Authors: Kadi Hocine , Fellag Hocine
Published: October 2008

In this work, the influences of the factors, which can have effect on oil extraction from olive foot cake using hexane, are studied. From the experimental results, a mathematical model for calculation of the extraction yield is proposed. The statistical tests used to obtain this model show that the yield does not depend on the granulometry and the stirring rate, but depends on the temperature, the contact time and the liquid-solid ratio (L/S). Also, it depends on interactions between time and temperature and interactions between time and L/S. The comparison of the results given by the experiment and the model allows us to say that the model is satisfactory.
Composition and qualitative characteristics of virgin olive oils produced in northern Adriatic region, Republic of Croatia
Authors: Giacometti Jasminka , Milin Cedomila
Published: October 2008

Istria and Island Krk are located in the Northern Adriatic region, Republic of Croatia. The majority of oils produced on the islands of this Region correspond to extra virgin classification as a consequence of olive cultivars (Debela, Naska, Rosulja, Slatka, Buza, Carbonera, Bianchera, Leccino). The characterisation of these oils is little known. The objective of this work was the characterisation of virgin olive oils during the 1997/98, 1998/99 and six months of 1999/2000 harvest. Acidity, peroxide value and UV absorption constants were determined for all samples. Fatty acid composition, sterol and aliphatic alcohol contents, saturated fatty acids in the 2-position of the triglyceride and trilinolein content were determined for the virgin olive oils during 1997/98 harvest. The chemical analyses were supported by the determination of polyphenol content expressed as caffeic acid, squalene and α-tocopherol content.
Direct olive oil analysis
Authors: Valcárcel M. , Gallego M. , Cárdenas S. , Peña F.
Published: October 2008

The practical impact of “direct analysis” is undeniable as it strong contributes to enhance the so-called productive analytical features such as expeditiousness, reduction of costs and minimisation of risks for the analysts and environment. The main objective is to establish a reliable bypass to the conventional preliminary operations of the analytical process. This paper offers a systematic approach in this context and emphasises the great field of action of direct methodologies in the routine analysis of olive oil. Two main types of methodologies are considered. On the one hand, the direct determination of volatile components is systematically considered. On the other hand, simple procedures to automatically implement the preliminary operations of the oil analysis using simple devices in which the sample is directly introduced with/without a simple dilution are present and discussed.
High resolution nuclear magnetic resonance: From chemical structure to food authenticity
Authors: Mannina Luisa , Segre Annalaura
Published: October 2008

Nuclear magnetic resonance (NMR) is a powerful technique able to give us a relevant contribution in food analysis. In this review, some practical aspects of this technique (sample preparation, acquisition time, relaxation delay, etc) as well as some methods of spectral assignment of the spectra (2D and 1D selective technique) are reported. Some examples of NMR quantitative analyses are reported. In particular, the results relative to the NMR study of olive oils are discussed, among these: the comparison between conventional analyses and the NMR analysis in the olive oil characterization; the NMR determination of minor components such as squalene, cyclo-arthenol and chlorophyll in olive oil; the panel test and its relationship with NMR data; the geographical characterization of olive oils.
Chemiluminescence methods (present and future)
Authors: Jimenez A. M. , Navas M. J.
Published: October 2008

This article provides a general review of chemiluminescent methods in some of their recent applications in drug analysis, sea water analysis or antioxidant activity of natural and synthetic products (including olive oil). Practical considerations are not included in the review since the main interest is to state, through the aforementioned applications, that chemiluminescence has been, is, and will be a versatile tool for Analytical Chemistry in future years.
Applications on thermostable polar capillary GC columns
Authors: Rodríguez-Estrada M. T. , Frega N. , Lercker G.
Published: October 2008

The composition, the effect of processing and storage, and the overall quality of food lipids can be evaluated by gas chromatography (GC). GC analyses are carried out on non-polar or polar capillary columns, which separate the various lipid components according to their polarity and boiling points. However, there are components with high-boiling points that require higher temperatures in order to be better resolved. Thermostable polar GC columns with a relatively low column bleeding, can be used for this scope. These columns generate GC traces with different separation characteristics, which can lead to the identification of components that cannot be completely resolved with non-polar GC columns. Thermostable polar GC columns are suitable for the separation of different lipid classes and can be utilised for a fast screening of the total unsaponifiable matter of the oil or lipid extract. A series of examples for the analysis of food lipids with thermostable polar GC columns, are here described.
Solid phase extraction: Applications to the chromatographic analysis of vegetable oils and fats
Authors: Panagiotopoulou P. M. , Tsimidou M.
Published: October 2008

Applications of solid-phase extraction for the isolation of certain lipid classes prior to chromatographic analysis are given. More information was found for sterols and related compounds, polar phenols and contaminants such as polycyclic aromatic hydrocarbons. Detailed analytical protocols are presented and discussed in many cases.
Chemometrics: From classical to genetic algorithms
Authors: Leardi Riccardo
Published: October 2008

In this paper the fundamentals of Chemometrics are presented, by means of a quick overview of the most relevant techniques for data display, classification, modeling and calibration. Two emerging techniques such as Genetic Algorithms and Artificial Neural Networks will also be presented. Goal of the paper is to make people aware of the great superiority of multivariate analysis over the commonly used univariate approach. Mathematical and algorithmical details are not presented, since the paper is mainly focused on the general problems to which Chemometrics can be successfully applied in the field of Food Chemistry.
Validation of analytical methods
Authors: Boqué Ricard , Maroto Alicia , Riu Jordi , Xavier Rius F.
Published: October 2008

In this paper we shall discuss the concept of method validation, describe the various elements and explain its close relationship with fitness for purpose. Method validation is based on the assumption that a series of requirements are fulfilled and we shall explain how these requirements are selected, the way in which evidence is supplied and what work has to be carried out in the laboratory. The basic principles of method validation and the different ways to validate a methodology, by inter-laboratory comparison or performing an in-house validation, are also described.
Linear viscoelasticity of liquid crystalline phases for a ethoxylated nonylphenol nonionic surfactant/water system
Authors: Cordobés F. , Moros J. E. , Franco J. M. , Gallegos C.
Published: October 2008

In this work the linear viscoelastic behaviour of micelar and liquid-crystalline phases in a polyoxy-ethylene glycol nonylphenyl ether (EOa=10)/water system was studied. A linear viscoelastic characterization using small amplitude oscillatory tests was carried out. The Maxwell and Generalized Maxwell models fit the linear viscoelastic functions of micellar and hexagonal phases respectively, fairly well. On the other hand, the lamellar phase shows a plateau region characteristic of highly structured systems. As may be deduced from the experimental results, dynamic measurements constitute an effective method to study the structural changes occurring in phase diagrams.
Influence of malaxation time of olive paste on oil extraction yields and chemical and organoleptic characteristics of virgin olive oil obtained by a centrifugal decanter at water saving
Authors: Di Giovacchino L. , Costantini N. , Ferrante M. L. , Serraiocco A.
Published: October 2008

Experimental tests were carried out to ascertain the influence of malaxation time of olive paste on extraction yields and qualitative characteristics of virgin olive oils obtained by a centrifugal decanter at water saving. Results show that malaxation time has to be no less than 45 minutes to have a satisfactory oil extraction yield. Furthermore, it was ascertained that the malaxation time, protracted up to 90 minutes, does not have influence upon qualitative and organoleptic characteristics of oils. Only the total phenols content of oils changed significantly when the malaxation time of olive paste increased from 15 to 90 minutes. However, in this research has been demonstrated that in some cases the total phenols content of oils increased during the first 30-45 minutes of malaxation and after it diminished. This is due to the variation of total phenols content of vegetable water that in the first time increased and after diminished very quickly. Because of the partition equilibrium law, the total phenols content of oil changed in the same way. Finally, results show that the composition of volatile substances of head-space of oils did not change increasing the malaxation time of olive paste obtained from good quality olive fruits.
Stability of potato chip fried in vegetable oils with different degree of unsaturation. Effect of ascorbyl palmitate during storage
Authors: Masson L. , Robert P. , Dobarganes M. C. , Urra C. , Romero N. , Ortiz J. , Goicoechea E. , Pérez P. , Salamé M. , Torres R.
Published: October 2008

Four vegetable oils with different polyunsaturated/saturated fatty acid ratio (P/S): 5.2 for sunflower oil, 3.,4 for canola rapeseed oil, 0.4 for a blend of palm oleic and canola rapeseed oil (80:20), and 0.3 for palm olein were assayed for stability of crisps fried in these oils during storage at 60º C. The action of ascorbyl palmitate with special attention to its synergistic effect on the natural antioxidants was also tested. by addition to the fried potatoes. The evolution of the oxidative stability was measured through peroxide value, quantitation of tocopherols and tocotrienols, and induction time (IT) by means of Rancimat. Oil degradation during frying was very low as both polar compound percentages and natural antioxidant had similar levels to those present in refined oils. Evolution of analytical parameters during storage results indicated that oil unsaturation degree or P/S had a much more importance on stability of the product than had the content and type of natural antioxidants and the addition of AP. Nevertheless, addition of AP to the fried potatoes had a significant effect resulting in higher retention of natural antioxidants, higher IT and lower PV at any storage time
Effectiveness of the antioxidants BHA and BHT in selected vegetable oils during intermittent heating
Authors: Tsaknis John , Lalas Stavros , Protopapa Evangelia
Published: October 2008

The heating performance of olive oil was compared with that of corn oil, olive-residue oil and 50:50 mixture of olive oil and corn oil. The oils were heated intermittently for two hours per day at a temperature of 175 ± 5° C for five consecutive days. Under such conditions thermal and oxidative decomposition of the oils takes place. Free fatty acid content, peroxide values, E1%1 cm, at 232 and 270nm, polar compounds, colour and viscosity, of the oils all increased, whereas the iodine values, smoke points, polyunsaturated fatty acids content and tocopherol concentration decreased. The effectiveness of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) at a rate of 200 ppm in retarding the deterioration of oils during static heating (175 ± 5° C), was studied and it was found that BHA gave a slight protection to the olive-residue oil and the BHT gave some protection to the corn oil, while both antioxidants were relatively ineffective in the other oils.
Optimization of chemical esterification process of saponificated and acidulated soybean oil deodorizer distillate
Authors: Facioli Nara Lúcia , Barrera-Arellano Daniel
Published: October 2008

In this research work, it was optimized the reaction conditions for the chemistry esterification of unsaponifiable matter in soybean oil deodorizer distillate. The process involves (i) alkaline hydrolysis of saponifiable matter; (ii) acidulation of soaps and (iii) acid catalyzed esterification of resulting total fatty acid. To determine the best process conditions to get the higher conversion rates of total fatty acids to ethylic esters, preserving the tocopherols, it was used, to analyze the results, the response surface methodology in a 2nd order factorial planning. In the step (i) saponification of soybean oil deodorizer distillate saponifiable matter using NaOH:total fatty acids molar ratio = 2:1, temperature = 80º C and reaction time of 40 min. In the step (ii) the resulting soaps were rapidly and stoichiometrically converted in free fatty acids with sulfuric acid (23 %), using an acid molar excess of 50 %, at 80º C, for 40 min and under atmospheric pressure. In the step (iii) the optima conditions for the esterification reaction of soybean oil deodorizer distillate were: ethanol:total fatty acids molar ratio from 6.4 to 11.2:1, SO2H4 concentration from 0.9 to 1.5 % and reaction time from 1.3 to 2.6 h, with ethyl esters conversion rates up to 98 %. The mathematical model obtained is predictive and statistically significant (p
A short review about oil hydrogenation and its implementation in a supercritical process: sunflower oil case
Authors: Ajzenberg Nancy
Published: October 2008

With 25 millions tons per year, the hydrogenated oil production is on the top in the food market. In this review we deal with the sunflower seed oil hydrogenation with special attention to the economy of the product, the reaction kinetic and parameters studies (like reactor, isomers production, catalyst). Furthermore we point out the necessities to use a new process considering ecological, safety and economic requirements. Then, using new catalysts based on Pt (instead of Ni) and a supercritical solvent, the trans isomers level can be reduced. Furthermore, the supercritical technology improves the process regarding reaction rate and solvent treatment.
Optimum conditions for enzymatic degradation of some oilseed proteins
Authors: Taha F. S. , Ibrahim M. A. , El-Zanaty E. A.
Published: October 2008

Soybean, sesame seed, and rice bran meal proteins were hydrolyzed with two enzymes, namely, papain and bromelain. Experiments were carried out to elucidate the optimum condition for each enzyme when acting on each substrate seperately. Results revealed that the highest relative activities for papain were achieved with E/S 0.06 , 0.29, 0.19 and pH 7.2, 7.0, 7.0 for soybean, sesame,and rice bran meal proteins, respectively. Optimum temperature for papain while hydrolysing the three substrates was 50 ºC. When using bromelain optimum E/S resulting in highest relative activities were 0.067, 0.058 and 0.21 for soybean, sesame,and rice bran meal protein, respectively. Optimum pH was 6.0 and optimum temperature was 45 ºC for bromelain when hydrolysing the protein of the three substrates. A numerical correlation of enzymatic behaviour for the different substrates was calculated.
Effect of degree of hydrolysis on the functional properties of some oilseed proteins
Authors: Taha F. S. , Ibrahim M. A.
Published: October 2008

Hydrolyzing soybean, sesame, and ricebran meals with papain and bromelain enzymes under previously determined optimum conditions was accomplished. Aliquots were withdrawn from the bulk hydrolysates at different time intervals to determine the rate of enzymatic degradation,as well as the degree of hydrolysis of the hydrolysates at different time intervals. Twelve hydrolysates were then chosen with low and high degree of hydrolysis. They also represented hydrolysates from the three substrates hydrolysed with the two enzymes used. Some functional properties of the twelve hydrolysates were examined and then an attempt to correlate the functional properties with the degree of hydrolysis was done. The investigated functional properties included: wettability, dispersibility, flowability, bulk density,nitrogen solubility index,water absorption capacity, oil holding capacity, gelation, thermostability, emulsifying capacity and foam stability.Results showed a direct relation between increasing degree of hydrolysis and nitrogen solubility and dispersibility. Wettability, flowability and emulsifying capacity gave better results with low degree of hydrolysis.
The effect of different processing stages of olive fruit on the extracted olive oil polyphenol content
Authors: Vekiari S. A. , Koutsaftakis A.
Published: October 2008

In the present study the distribution of olive fruit polyphenolic fraction through the phases of olive oil extraction by a classical and a centrifugal system has been investigated. Olives of two Cretan origin varieties were used. Consequently, samples from different stages of oil extraction with and without their polyphenols were stored for a month under 64 ºC by periodical testing their peroxide value. In olive oils extracted by the centrifugal factory a large reduction of polyphenols content was noticed during their elaboration that reached to the half amount compared with that of classical type. During oven test the control sample of olive oil obtained from the separation phase of centrifugal system was oxidized easier than that of classic one. The variation of polyphenol content as well as of the main olive oil quality characteristics with the temperature and the mixing time was also studied for a period of time.
Comparison of different olive oil extraction systems and the effect of storage conditions on the quality of the virgin olive oil
Authors: Vekiari S. A. , Papadopoulou P. , Koutsaftakis A.
Published: October 2008

Se ha estudiado el efecto de los diferentes métodos de extracción del aceite de oliva en distintos parámetros de calidad del aceite, tales como el índice de peróxido y los coeficientes de extinción K232 y K270. Se ha extraído el aceite de oliva usando el sistema tradicional de Theocharis, sistemas por centrifugación Alfa-Laval y Amenduni y mixto tipos Rapanelli Sinolea y Decanter. El aceite ha sido analizado antes y durante su conservación en botellas de polietileno en ausencia de luz, con luz difusa y con luz solar. El aceite conservado en la oscuridad tuvo el índice de peróxido mas bajo. En general el proceso de oxidación fue lento en la oscuridad y mas rápido en luz difusa y en presencia directa de luz solar.
Reducing the bloater spoilage incidence in fermented green olives during storage
Authors: Asehraou A. , Peres C. , Faid M. , Brito D.
Published: October 2008

Fermented green olives of the variety “Picholine” were brined in 5% NaCl solutions, which were adjusted to pH 4.00 and 5.00 with lactic acid. Potassium sorbate was added to the brine at 0.05 % and the assays were inoculated with Lactobacillus plantarum strain I159, and Pichia anomala strains S18 from our collection. The pH values and microbial counts including Gram negative bacteria, yeasts and moulds, and lactic acid bacteria were followed during 6 months of storage. Results showed that even if the olives were inoculated with a high gas producing yeast (P. anomala S18), the attack of the fruits by the “bloater” spoilage was drastically reduced in the assays adjusted to pH4, added with potassium sorbate and inoculated with L. plantarum, without affecting the organoleptic characteristics of the product.
Effect of two methods of grilling on the oxidative rancidity and cholesterol oxidation in beef and chicken shawerma
Authors: Al-Ismail Khalid
Published: October 2008

The effect of direct blue and charcoal radiation heat grilling on the oxidative rancidity of fat and cholesterol oxidation in beef and chicken shawerma was studied during the first 3 hours of grilling process. The oxidative rancidity of the fat was measured by thiobarbituric acid value (TBA), while that of cholesterol by evaluating the concentration of 7-ketocholesterol. No significant effect (p≤ 0.05) of the source of the grilling radiation heat was found on TBA values or 7-ketocholesterol content. The degree of unsaturation of the fat had significant effect (p≤0.05) on TBA and 7-ketocholesterol values. TBA values and 7-ketocholesterol for both samples grilled either by direct blue or charcoal radiation heat reached maximum values after 30 min of the heat treatment then they remained relatively constant throughout the rest time of the experiment.
Assessment of the process of cottonseed oil bleaching in hexane
Authors: Megahed Ola A.
Published: October 2008

This work has been initiated to assess the feasibility of bleaching cottonseed oil in miscella as a processing step next to alkali refining in miscella. Alkali refining of cottonseed oil in miscella has several advantages over conventional refining technologies with respect to oil quality, oil losses and process cost. Therefore, the process efficiency of the bleaching of cottonseed oil in presence of hexane (at a volumetric ratio of 1:1), has been studied and compared to that without solvent. The process efficiency has been evaluated according to the decolourization capacity, the oil losses on spent earth, the filtration rate of the oil from the clay and the acidity of the bleached oil as well as its peroxide content. The bleaching in presence of hexane was carried out at 25ºC whereas that by conventional bleaching at 110ºC. Different clay loads were used in each of the two bleaching techniques and the colour indices of the oils before and after bleaching determined in each case. The results were used to predict Freundlich adsorption equations for the oil pigments in both cases. These equations were then used to predict the colour of the oils obtained by bleaching of refined oils of different grades. The results have shown that oil decolourization is more efficient in presence of solvent when the starting oil is of an acceptable grade and the reverse is true for low grade oils. Also, the possibility of oil oxidation during bleaching is less in presence of solvent. Moreover, the bleaching in miscella has proved two other additional advantages over conventional bleaching. The filtration of oil from clay is much faster in miscella bleaching and the oil losses on spent earth is lower. This will be reflected on the overall process economy.
Analysis of different technological alternatives for low-fat, semi-hard, washed-curd cheeses production
Authors: Candioti M. C. , Palma S. M. , Sabbag N. , Perotti M. C. , Bernal S. M. , Zalazar C. A.
Published: October 2008

In the present paper the addition of a commercial fat substitute based on whey proteins, alone or in combination with goat rennet and with a food grade protease, is analyzed. Six different cheeses were produced: a control with whole milk (3.3 % of fat), and five experimental with partially skimmed milk (1.8 % of fat) without additions and with different combinations of the fat substitute, the goat rennet and the food grade protease. Results of analytical controls performed at the beginning and at the end of ripening show that low fat cheese without additions was the best of experimental. Addition of fat substitute, alone or in different combinations with goat rennet or with food grade protease, was negative for the sensory characteristics.