The key role of ovalbumin in lipid bioaccessibility and oxidation product profile during the in vitro digestion of slightly oxidized soybean oil.

The behaviour of slightly oxidized virgin and refined soybean oils during in vitro digestion was studied by 1H nuclear magnetic resonance (1H NMR) and solid phase microextraction-gas chromatography/mass spectrometry. The main objectives were to analyze lipolysis extent and oxidation during digestion, and to assess the impact of two different proportions of ovalbumin on both processes. At the same time γ-tocopherol fate was monitored, when possible, by 1H NMR. The results reveal that the initial oxidation degree of the oils negatively influences the lipolysis extent, reducing the bioaccessibility of the major oil components, which include some essential fatty acids. Although the low ovalbumin proportion tested does not significantly affect lipolysis, this is greatly enhanced when ovalbumin is added at a high level, improving lipid bioaccessibility. It has also been shown that oxidation does not seem to have occurred to a great enough extent during digestion for it to be detected from polyunsaturated acyl group degradation. Moreover, the changes observed in the oxidation product profile of the starting oils after digestion can be considered to be due mainly to the transformation of the initially present hydroperoxides, whose concentration diminishes in the digested samples to give hydroxy-dienes, epoxides and aldehydes. In presence of a high ovalbumin proportion, hydroperoxide reduction to hydroxy-dienes is favoured and lower levels of aldehydes and epoxides are observed. This latter could be due to a diminution in their generation and/or to their reaction with ovalbumin. A high proportion of this protein in the system also increases γ-tocopherol bioaccessibility.

A thorough insight into the complex effect of gamma-tocopherol on the oxidation process of soybean oil by means of 1H Nuclear Magnetic Resonance. Comparison with alpha-tocopherol.

The effect of γ-tocopherol in proportions between 0.02 and 2% by weight on the accelerated storage process of refined soybean oil is studied by 1H NMR, and compared with that of α-tocopherol. Whereas the lowest γ-tocopherol enrichment level does not affect oil evolution, at higher concentrations both γ- and α-tocopherols initially accelerate acyl groups degradation and hydroperoxides generation, more as higher is the tocopherol concentration, this effect being less marked for γ-tocopherol. However, after this initial stage, the rates of acyl groups degradation and hydroperoxides formation decrease with tocopherol concentration. Furthermore, in the case of γ-tocopherol, the higher the enrichment degree, the later hydroperoxides decomposition occurs, so that, unlike α-tocopherol, γ-tocopherol delays the generation of most secondary oxidation products (aldehydes, (E,E)-keto-dienes, epoxy-keto-enes, (E)-epoxystearates and alcohols) with the exception of some epoxides. Similarly to α-tocopherol, γ-tocopherol modifies the oil oxidation pathway at the highest addition level, promoting the formation of compounds with (Z,E)-isomerism, although less noticeably than α-tocopherol.

Prooxidant effect of α-tocopherol on soybean oil. Global monitoring of its oxidation process under accelerated storage conditions by 1H nuclear magnetic resonance.

The effect of adding α-tocopherol in proportions ranging from 0.002 to 5% in weight on the oxidative stability of soybean oil was studied. For the first time, the oxidation process under accelerated storage conditions including evolution of the molar percentages of the several types of oil acyl groups, and formation and evolution of various kinds of oxidation products comprising hydroperoxides, hydroxy-dienes and other alcohols, epoxides, aldehydes and keto-dienes, was followed by 1H nuclear magnetic resonance. It is proved that, except in the lowest proportion, α-tocopherol not only exerts a prooxidant effect on soybean oil but also modifies its oxidation pathway, affecting the oxidation products generation rate, their nature, relative proportions and concentrations. It is noticeable that the highest α-tocopherol concentrations induce the generation of some toxic compounds at earlier stages of the thermoxidation process and sometimes in higher concentration, such as certain oxygenated α,ß-unsaturated aldehydes and monoepoxides derived from linoleic groups.

Influence of fat and phytosterols concentration in margarines on their degradation at high temperature. A study by (1)H Nuclear Magnetic Resonance.

The objective of this work was to study the influence of several factors, especially fat and phytosterols concentration, on the behavior of margarine under thermo-oxidative conditions. For this purpose, margarines with similar compositions in acyl groups, but differing in the concentration of both fat and phytosterols, were heated at 180°C. The changes in the main components of margarine lipids and the formation of new compounds throughout the thermal treatment were monitored by (1)H Nuclear Magnetic Resonance. The results show that the presence of high concentrations of phytosterols seems to have an antioxidant effect, since it slows down the thermo-oxidation rate of margarine and, consequently, the generation rate and concentrations of secondary oxidation products such as some aldehydes, epoxides and alcohols. The oil-water ratio also seems to have an important effect on margarine behavior, in such a way that the lower the fat concentration is, the higher its thermo-oxidation rate.

¹H Nuclear Magnetic Resonance monitoring of the degradation of margarines of varied compositions when heated to high temperature.

In this study, (1)H Nuclear Magnetic Resonance was used to monitor the evolution of three margarines of varied compositions when submitted to heating at 180°C in an oven with aeration. Heating causes degradation of polyunsaturated acyl groups and this depends not only on their unsaturation degree, but also on the concentration of the different acyl groups. The evolution of monounsaturated groups varies depending on the disappearance rate of the groups with higher unsaturation degree. Heat treatment also causes hydrolysis reactions that lead to a reduction in 1-monoglycerides and an increase in 1,2-diglycerides, especially in the margarines with higher water content, as well as degradation of some vegetable sterols. Different types of aldehydes and epoxides were identified and quantified, above all in the margarine with the highest proportion of polyunsaturated groups, especially linoleic; some of these are toxic, such as 4-hydroxy- and 4,5-epoxy-2-alkenals.

Characterisation of the lipidic components of margarines by 1H Nuclear Magnetic Resonance.

In this work, (1)H Nuclear Magnetic Resonance ((1)H NMR) has been used to study the lipidic fraction of margarines of different compositions, determining simultaneously both major components, which is to say triglycerides, and other minor ones, such as 1- and 2-monoglycerides, 1,2-diglycerides, vegetable stanols and sterols, and sorbic acid. The results show a wide variety of acyl group compositions, with polyunsaturated groups ranging from 22% to 50%, monounsaturated from 23% to 50%, and saturated from 21% to 55%. 1,2-Diglycerides and vegetable stanols and/or sterols have been detected in all the studied margarines, in concentrations varying between 2.73 and 26.06 mmol/kg, and between 3.40 and 240.01 mmol/kg, respectively. A good agreement has been found between the results obtained by (1)H NMR and some composition data of these margarines, showing the usefulness of this technique to analyse the lipidic composition of margarine in a quick and easy way.

Contamination of cheese by polycyclic aromatic hydrocarbons in traditional smoking. Influence of the position in the smokehouse on the contamination level of smoked cheese.

This paper sets out to determine the polycyclic aromatic hydrocarbon (PAH) contamination degree of a traditionally smoked cheese: Herreño cheese, which comes from one of the Canary Islands. Its PAH profile is thoroughly studied by means of gas chromatography-mass spectrometry in SIM mode, and compared with that of an unsmoked cheese. Furthermore, a parameter not previously studied is evaluated, namely the influence of the position of the individual cheeses in the smokehouse on their PAH contamination level. Heavy PAH, among which are included most of the carcinogens, are very scarce and their concentrations low. In fact, benz[a]anthracene, together with chrysene+triphenylene, are the only heavy PAH detected in all of the smoked samples studied. The concentration of benzo[a]pyrene, detected only in 1 of the samples, is below the limit established in Spain for the rind of smoked cheese. In contrast, high concentrations of light PAH have been found, especially of naphthalene and its alkyl derivatives, whose effect on human health is not yet well established. The results derived from the analysis of the PAH profile suggest the potential usefulness of certain ratios between some pairs of PAH (phenanthrene/anthracene, naphthalene/acenaphthylene) to provide information on the PAH contamination source. Furthermore, differences have been found, depending on the position of the cheeses in the smokehouse, those placed in the path followed by the smoke being more contaminated. Therefore, the findings of this study could help in improving the design of smokehouses, to decrease the PAH contamination degree of smoked cheese.

Occurrence of polycyclic aromatic hydrocarbons in artisanal Palmero cheese smoked with two types of vegetable matter.

Palmero cheese is a fresh smoked cheese from the Isle of Palma (Canary Islands), manufactured with goat's milk. To guarantee its safety, the occurrence of polycyclic aromatic hydrocarbons (PAH) in artisanal Palmero cheese smoked with 2 types of vegetable matter (almond shells and dry prickly pear) was studied. The determination of PAH includes extraction and clean-up steps, followed by separation, identification, and quantification of PAH by gas chromatography-mass spectrometry in selected ion-monitoring mode. The most abundant PAH are those with 2 and 3 aromatic rings. Although the highest total PAH concentrations corresponded to the cheeses smoked with almond shells, the degree of PAH contamination of the cheeses studied was lower than that found in other cheeses smoked in the traditional way. The nature of the vegetable material used for smoking seemed to have an influence on the type of PAH formed, especially on alkylderivatives and some light PAH. However, despite the artisanal, and consequently variable, production process of these cheeses, many similarities have been found among their PAH profiles. In fact, relatively constant relationships are observed between the concentrations of certain pairs of PAH. Benzo(a)pyrene was only present in 2 samples, and in much lower concentrations than the maximum allowed legal limits. Therefore, according to the results obtained, it appears that it is possible to obtain a safe product without renouncing the artisanal character or the sensory properties of this type of cheese.

Headspace solid-phase microextraction as a tool to estimate the contamination of smoked cheeses by polycyclic aromatic hydrocarbons.

Headspace solid-phase microextraction (HS-SPME) was used to study polycyclic aromatic hydrocarbons (PAH) in smoked cheeses. Two types of fiber coatings and different extraction conditions were tested. The results reveal that the use of an 85-microm polyacrylate fiber immersed in the headspace of the samples at 70 degrees C for 60 min is suitable for the detection of PAH with no more than 4 aromatic rings. To determine if a relationship can be established between the results obtained using a solvent extraction technique and HS-SPME, 6 samples of smoked cheese previously studied by a solvent extraction method were analyzed by HS-SPME, and the results obtained by both methodologies were compared. Polycyclic aromatic hydrocarbons were identified and quantified by gas chromatography-mass spectrometry operating in selective ion monitoring mode. Among the PAH determined by the solvent extraction method, only those with 4 aromatic rings or less were detected by HS-SPME and, consequently, this technique does not allow one to determine the PAH content of smoked cheese samples under the conditions of the study. Nevertheless, the relationship between the results obtained by both techniques for some PAH revealed that HS-SPME could be useful as a screening method to distinguish among samples with different degrees of PAH contamination.

Components detected by means of solid-phase microextraction and gas chromatography/mass spectrometry in the headspace of artisan fresh goat cheese smoked by traditional methods.

The study of the headspace components of fresh smoked goat cheese, was carried out by means of solid-phase microextraction using a polyacrylate fiber followed by gas chromatography/mass spectrometry. The samples studied were six artisan Palmero cheeses manufactured following traditional methods and smoked using pine needles. The cheese regions studied were exterior, interior, and a cross section. In total, more than 320 components were detected, the exterior region being the richest in components, among which were acids, alcohols, esters, hydrocarbons, aldehydes, ketones, furan and pyran derivatives, terpenes and sesquiterpenes, nitrogen derivatives, phenol, guaiacol and syringol derivatives, ethers, and others. In addition to typical cheese components, typical smoke components were also detected; these latter were present especially in the headspace of the exterior region and only those in significant concentrations in the exterior region were also detected in the interior. The main components were acids and phenolic derivatives. These latter compounds play an important role in the flavor of this cheese, and their relative proportions together with the presence of specific smoke components derived from pine leaves may be considered of interest in order to distinguish this cheese from others smoked with different vegetable matter.

Polycyclic aromatic hydrocarbons in liquid smoke flavorings obtained from different types of wood. Effect of storage in polyethylene flasks on their concentrations.

Smoke flavorings are widely used as an alternative to the traditional smoking techniques. Smoke generation conditions can determine the level of polycyclic aromatic hydrocarbons (PAHs) in the smoke and, consequently, in these preparations. In this paper, the influence of the wood source on the formation of PAHs is studied. For this purpose, five liquid smoke flavorings, obtained from different types of wood, were used. Sample aliquots, including deuterated internal standards, were subjected to an alkaline treatment, extracted by liquid-liquid partition and cleaned up by means of silica tubes, followed by gas chromatography-mass spectrometry analysis. The results reveal that the flavoring obtained from poplar wood presents the highest number and concentrations of both total and carcinogenic PAHs, even though the levels of these latter are very low. It has also been observed that the storage of smoke flavorings in polyethylene flasks reduces the concentration of some PAHs.

Study of several aspects of a general method for the determination of polycyclic aromatic hydrocarbons in liquid smoke flavourings by gas chromatography-mass spectrometry.

The effectiveness of the steps of a general method, which includes alkaline treatment of the samples, extraction, clean-up and analysis, for the determination of polycyclic aromatic hydrocarbons in liquid smoke flavourings and smoked foods have been studied, by using mixtures of pure polycyclic aromatic hydrocarbons and of smoke flavouring compounds. All these products were applied to samples of liquid smoke flavourings in order to test the effectiveness of each step of the method, as well as to investigate its effect on real samples, and thus obtain a suitable procedure for the study of polycyclic aromatic hydrocarbons in liquid smoke flavourings. The alkaline treatment has been proved to be necessary because of its capability for removing some smoke components. Both cyclohexane and dichloromethane are able to extract polycyclic aromatic hydrocarbons with high recovery percentages; however, cyclohexane is more adequate due to its lower ability to extract other smoke flavourings components. It is important to note that the elution sequence of polycyclic aromatic hydrocarbons during the clean-up step is quite different depending on the solvent used to dissolve the extract, which determines the ability of this process to isolate polycyclic aromatic hydrocarbons for their accurate identification and quantification by gas chromatography-mass spectrometry in selected ion monitoring mode. Finally, the PAHs present in a liquid smoke flavouring and their concentrations were determined; it was observed that, despite the different extraction solvents and clean-up procedures used, the results were very similar.

Determination of polycyclic aromatic hydrocarbons in commercial liquid smoke flavorings of different compositions by gas chromatography-mass spectrometry.

The presence of polycyclic aromatic hydrocarbons (PAHs) in five commercial liquid smoke flavorings, used in the European food industry, was studied. The samples were subjected to an alkaline treatment, extracted with cyclohexane, cleaned up by means of solid-phase extraction tubes, and analyzed by gas chromatography-mass spectrometry. Three different procedures for the cleanup were tested. The results revealed the presence of 34 PAHs, some of them with methyl substituents. In all cases, the concentrations of compounds of low molecular weight were much higher than those of high molecular weight. Relationships between smoke flavoring compositions and PAH levels were also studied. Three of the samples contained high levels of both total and carcinogenic PAHs. Benzo[a]pyrene was also detected in these three samples, but its concentration did not exceed the 10 microg/kg level fixed by the FAO/WHO. Finally, a relation was found, first between the concentrations of total carcinogenic PAHs and benzo[a]pyrene and also between the concentrations of pyrene and benzo[a]pyrene. The latter ratio reveals that pyrene concentration could be very useful in predicting the level of benzo[a]pyrene and, consequently, in estimating the carcinogenicity arising from the presence of benzo[a]pyrene and other carcinogenic PAHs.

[Evolution of the prevalence of HIV-1 infection in drug addicts in the Community of Madrid (1985-1986)]. / Evolución de la prevalencia de la infección por el VIH-1 en los drogodependientes de la Comunidad de Madrid (1985-1996).

BACKGROUND: To evaluate the evolution of the HIV infection in the drug addicts of Madrid. PATIENTS AND METHODS: Data of 2,234 patients that entered for the first time in a Psychiatric Hospital Detoxication Unit of Madrid from October 1985 to december 1996 were recorded. RESULTS: There was a reduction of the percentage of addicts infected by the HIV (of the 66 to 25%), also in the IVDUs men (of the 70 to 37.6%), but not in women. There was an increase in the number of addicts that had never injected drugs (of the 7 to the 45%). CONCLUSIONS: Despite the reduction of HIV infection rate in drugs addicts in Madrid, it remains still very high.

Food as a source of polycyclic aromatic carcinogens.

Polycyclic aromatic hydrocarbons (PAH) belong to a large chemical family comprising many different compounds with important biological activity in mutagenic and carcinogenic processes. PAH have been detected in both raw and processed foods. The presence of PAH in non-processed foods is associated with environmental pollution from both human and industrial activities, whereas contamination of processed foods can be caused by certain preservation and processing procedures. Both toxicological and epidemiological studies have shown a relation between such compounds and tumor development. The data indicate that PAH must undergo a biotransformation process that causes the formation of biologically active metabolites. In this process, the presence of an enzyme complex that is induced by different xenobiotics is implied, making the toxicity of such compounds hard to predict. As setting a threshold limit below which toxicity could be considered negligible is difficult, the presence of PAH in foodstuffs should be reduced to as low as possible by controlling environmental contamination and all procedures that could cause PAH contamination during food processing, preserving, and packaging.

[Neuropsychological changes in drug addicts infected with human immunodeficiency virus]. / Alteraciones neuropsicológicas en drogodependientes infectados por el virus de la inmunodeficiencia humana.

The early organic mental disorder, caused by the human immunodeficiency virus type 1 (HIV) in the drug dependents (DD), if it is not taken into account, can disturb the diagnosis of the neuropsychiatric and the toxic disorders. The authors attempt to outline, with several neuropsychological tests (visuo-perceptual, memory, attention) and with the physical and neurologic exploration, if cognitive abnormalities are present in two groups of DD after detoxification period. The first group is infected by the HIV (n: 48), and the second one is not (n: 33). Differences can be found only in the Bender visuo-perceptual test, which are not justified by the divergences found between the groups about the drug dependence history and the present drug of abuse intake. The importance of the early diagnosis of these abnormalities is argued in order to get a suitable treatment of the possible neuropsychiatric complications in the DD development, and restrain the extent of the cognitive damage by HIV infection.

[Profile of drug addicts admitted to a hospital detoxification unit during a four-and-a-half year period]. / Perfil de los drogodependientes que ingresan en una unidad de desintoxicación hospitalaria durante un período de cuatro años y medio.

It realize a overall and evolutionarily (6 months periods) study concerning the 1,313 drug dependents that were admitted to the Detoxication Unit of the Hospital Psiquiátrico de Madrid, since October 1985 to March 1990. The sociodemographic, drug dependence history, the Physical and toxicological state at admittance, the inpatient evolution, and the familiar and personal psychopathological history variables were evaluated. It bring out that the 45% are dependents to another drug apart from the heroin, the gradual increase in the mean age and in the use of the cocaine, a decrease in the use of the cannabis, anyway the appearance of the buprenorphine addition. There is a gradual decrease, in the period studied, of the antibodies HIV carrier rates. It shows that there is a relationship between this. The poly drug dependents have more legal incidences, psychopathological personal histories (heroin and alcohol and/or benzodiazepines addiction), use more the i.v. route and the HIV seroprevalence are the greatest.

[Prevalence of infection by the human immunodeficiency virus type 1 in drug addicts in Madrid, over a 5 year period]. / Prevalencia de la infección por el virus de la inmunodeficiencia humana tipo 1 en drogodependientes de Madrid, durante un período de 5 años.

BACKGROUND: Firstly, to evaluate the annual levels of seroprevalence of antibodies against the type I human immunodeficiency virus in a sample of 1,232 intravenous drug users (IVDU) admitted for treatment to a hospital detoxication unit i Madrid over a period of 5 years. Secondly, attempt to distinguish the existence of variable which differentiate seropositive and seronegative IVDU. METHODS: Data concerning sociodemographic profile and history of addiction were collected. The detection of antibodies vs HIV was carried out by the enzyme immunoanalysis technique which was confirmed by indirect immunofluorescence methods and western blot if positive. RESULTS: There was a diminution in the levels of seropositivity during the 5 years evaluated (74%, 65%, 66%, 62% and 59%, p less than 0.05) with the infection by the HIV being more frequent in those addicted for a longer period of time, with more attempts at treatment, who had initiated drug dependence at an earlier age, had been in prison, and who, apart from heroin, also consumed benzodiacepins++ and/or alcohol. CONCLUSIONS: A decrease in the levels of annual seroprevalence of HIV anti antibodies was found and the group of seropositive IVDU presents particular characteristics emphasizing the need for promoting treatment programs with adequate retention capacity for drug users.

[Factors affecting the course of hospital detoxication of drug addicts]. / Factores que inciden en la evolución de la desintoxicación hospitalaria de drogodependientes.

BACKGROUND: Despite the long waiting list (2-3 months) for entering the Detoxication Unit of the Psychiatric Hospital in Madrid, some of the drug addicts (DA) voluntarily give up treatment. This study attempts to outline the differences between the DA who successfully complete the treatment and those who fail. METHODS: Anamnestic personal and family data and information concerning drug dependence collected from the clinical history of 1,313 DA admitted between October 1985 and March 1990 were analyzed. The sample was divided into 2 stages; the first being up to October 1988 in which adrenergic drugs (clonidine and guanfacine) were used and the second in which an opiacium agonist (methadone) was also taken. Two groups have been made according to the success and failure of the treatment. RESULTS: In the first stage, the number of failures was greatest among those subjects with prison records (42% vs 27%, p less than 0.0001), heroin and cocaine addicts (33% vs 15%, p less than 0.001) and those whose urine analysis proved positive for cocaine on the day of hospital admission (46% vs 21%, p less than 0.0001). No differences were found in the second stage. CONCLUSIONS: The possible usefulness of opiacium agonists vs adrenergic agonists in the detoxication of heroin and cocaine drug addicts are discussed in accordance with the knowledge obtained by other authors in preclinical studies.