ANTIOXIDANTS IN FOODS

Author: DÁVALOS HERRERA ALBERTO.
Year: 2004.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE FARMACIA.
Place of preparation: FACULTAD DE FARMACIA, UNIVERSIDAD COMPLUTENSE DE MADRID.

Summary: The involvement of reactive oxygen species (ROS) in cardiovascular disease, certain cancers, cataracts, etc., and / or the aging process, warrant supplementation of the antioxidant diet as a strategy to reduce sound and practical the level of oxidative stress and prevent diseases associated with it. Moreover, there is little doubt that the consumption of fruits and vegetables rich in antioxidant compounds reduces the risk for chronic diseases and other associated with aging. In any case, the first step is ccnfirmar that these antioxidant compounds are absorbed at the gut and are available in the human body. This memory has studied the antioxidant activity of phenolic compounds in nature as well as of various foods, beverages, dietary supplements, food additives, and prosthetic hydrolysates of egg white and whey. In the same form, has begun studying the bioavailability of a phenolic compound representative (quercetin), quantifying its plasma after the intake of foods rich in this compueto. To measure the antioxidant activity has been used several methodologies: neutralize DPPH radical (DPPH method) and peroxilo (method ORAC-FL), and inhibition of the oxidation of linoleato of Metilo (method MeLo) and lipoproteins low dendisdad (LDL method). For some of these methodologies have been proposed new conditions as they improve their operability, and new calculations that facilitate comparison between samples and studies. The antioxidant activity of the compounds has been linked to its chemical structure that determines its solubility and other physico-chemical properties. The activity of complex samples has been found to influence both the content antixodiantes, with the potential synergies between them and antagonistic, as the matrix of the food / supplement. The observed variability in the antioxidant activity of each type of samples, especially in the complete food antioxidants, justifying the need for standardization in terms of antioxidant activity, using methodology (s) appropriate reference. For the analysis of quercetin in human plasma has developed a simple and robust analytical methodology, consisting of an enzyme pre-treatment, in a liquid-liquid extraction, and an analysis by HPLC-DAD. It has been found that the baseline quercetin in human plasma after intake rose wine and onions, the increase being much higher in the second case. The method developed could be used in the study of the bioavailability of other phenolic compounds.

Author: RUIZ RAMÍREZ JORGE LUIS.
Year: 2004.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: FACULTAD DE VETERINARIA.
Place of preparation: ESCUELA DE POSTGRADO.

Summary: This Doctoral Thesis aims to determine the relationship between compositional parameters: water activity (aw), content (X) content NaCl, pH of the raw material and the relationship non-protein nitrogen / total nitrogen with the parameters of instrumental texture muscle pork and cured ham. It conducted four experiments. The Pilot 1 objective was to determine the relationship between different levels of X-aw and texture parameters in samples of muscle biceps femoris of hams cured with varying degrees of drying. Experiment 2 was intended to verify this relationship in Lomo cured, establish profiles texture, and X aw in a meat product encostrado and observe the relationship of these parameters in another muscle anatomically different from those of pernil, in this case muscle longissimus dorsi. Experiments 3 and 4 were targets determining the effect of the content of added NaCl, pH of the raw material and the non-protein nitrogen of the final product on the relationship between X and hardness, cohesiveness and elasticity in muscles dry cured, matured during 45 days (experiment 3), and cured hams matured during 289 days (experiment 4). The relationship between X and the aw with the hardness in cured ham and loin cured was not linear. The hardness increased to the extent that fell X aw. Below values X 0.6 and aw of 0.7, the hardness of the cured ham increased substantially which could relate to the phenomenon of encostrado that can be seen on the outside of cured ham. The ratio of X aw with the cohesiveness and resilience was linear. The cohesiveness and resilience deljamón curing, curing and loin muscle healed fell as fell X / aw. There was no effect on the type of muscle (semimembranosus vs. biceps femoris) on the parameters of texture in muscle healed. In cured ham semimembranosus muscle hardest submitted that the biceps femoris. For values of X lower 0.7 the cohesiveness tended to be higher in muscle biceps femoris. The amount of added NaCl affected significantly (P less 0.05) the relationship between X and hardness. The muscles healed largest NaCl added presented hardest when the pH SM24 lower 5.7 but not when the pH SM24 increased 6.2. In cured ham there was no direct effect on the amount of NaCl on the parameters of texture, but the rate of proteolysis. The hams cured with high values index proteolysis had lower hardness, cohesiveness and greater elasticity than those hams cured with low index values proteolysis. The continuous determination of the value of X on the surface of the cured ham and loin can allow regulate drying parameters to maintain the value of X on the surface above the critical value of about 0.6 for cured ham and 0.8 for spine cured and thereby achieve avoid encostrado and improve the quality of drying.

Author: Carreras Ferrer Irene.
Year: 2004.
University: GIRONA [www.udg.es].
Place of defense: Departament de Química. Facultat de Ciències.
Place of preparation: Universitat de Girona.

Summary: The phenomena including oxidative and lipid oxidation are a major liable for any loss of quality meat and meat products. As a result of these processes are generated compounds that can affect flavor, color and texture of the meat decreasing acceptability by consumers and reducing its nutritional value. On the other hand, oxidative stress is related to the etiology of various diseases common in our society. The meat chicken and turkey are particularly sensitive to oxidative processes due to their high proportion of polyunsaturated fatty acids compared with other types of meat. The antioxidant supplementation in the diet of certain animals is one of the most effective strategies for protecting meat oxidation. Another aspect that affects the quality and safety of beef is the presence of residues in animal tissues for human consumption, a portion of which may come from the administration of antibiotics. In this work, we studied the eficcia three antioxidant compounds, tocopherol, - carotene ylicopeno, added in different concentrations and combinations to the diet of chickens and pavso. It identified the oxidative stability of the muscle tissue of breast and thigh by analyzing the values of TABARs, the activities of enzymes antioxidants GSHPx, and SOD and CAT from a sensory standpoint. Also analyzed the concentrations of vitamin E present in both muscles. Furthermore, we investigated the presence of residues of the antibiotic enrofloxacin and its metabolite in the muscle and liver tissues of both species after drug administration with or without withdrawal period. Finally, given the apparent relationship between the metabolism of certain antibiotics and oxidative phenomena, was assessed the possible interaction between fármco and vitamin E supplemented to the diet. Vitamin E at doses of 100 ppm and 200 ppm in chickens and turkeys respectively, behaved as an effective antioxidant decreasing rancidez of both breast meat as thigh. The dose of vitamin E needed to achieve a significant increase dela oxidative stability of beef varied depending on the species and the biochemical characteristics of the tissue analyzed. The carotene, supplemented in the diet of chickens and turkeys together with vitamin E, not only expressed antioxidant properties but is enmascaró effectiveness dela vitamin E. The licopeno, whose use in animal nutrition did not exist previously published studies, showed no effective antioxidant in chicken meat at a dose of 10 ppm. With respect to the analysis of antibiotic residue was observed that after the period of withdrawal of the drug residue levels of enrofloxacin and its metabolite declined notablamente. It should be noted that differences were apparent depending on the species and tissue considered to be waste in some cases in excess of the maximum permissible limits. On the other hand, there was a relationship between vitamin E and enrofloxacin supplemented in the diet, both seemed to depend on the dose of antioxidant as drug metabolism. This interaction involving both levels of vitamin E and the presence of residues of anrofloxacina in muscle tissue, highlighting the importance of not underestimating possible interactions 8 between di 2ac stintos compounds present in the animal diet.

Author: GARCÍA ALONSO FRANCISCO JAVIER.
Year: 2005.
University: MURCIA [www.um.es].
Place of defense: FACULTAD DE VETERINARIA. UNIVERSIDAD DE MURCIA.
Place of preparation: UNIVERSIDAD DE MURCIA.

Summary: Oxidative stress is involved in the development of many chronic diseases and the aging process. The purpose of this research was to evaluate the effectiveness of a product rich in phenolic compounds, produced with grapes, cherries, raspberries, blackberries and currants. For the evaluation of the effectiveness antioxidant, were carried chemical tests, in vitro studies using cultured cells and intervention studies in humans. The product showed a high total antioxidant activity (similar to red wines) in chemical testing based on the abstraction of free radicals and reducing capacity in the ferric iron. In studies in cell cultures were used two human cell lines: the line carcinoma liver HEpG2 and line myeloid leukemia U937. The product exerted a protective effect against the oxidative stress induced by tert-butil hidroperóxido and hydrogen peroxide. This resulted in an increase in cell viability and decreased lipid peroxidation, damage to DNA and generation of intracellular reactive oxygen species. For the evaluation of the efficacy in vivo antioxidant were conducted two studies of speech in humans. The first, a study of intervention 2 weeks in a group of elderly (65-92 years), showed no significant improvement in the total antioxidant status of the participants. In fact, the group showed a level of oxidative damage, primarily at the level of DNA and lipoproteins, higher than that of a reference group of younger adults, which corroborates the increased oxidative damage during the aging process. The second study evaluated the short-term effect (6 hours after ingestion) consumption of a group of healthy individuals of 23-43 years old. The results of the study indicate the rapid absorption of phenolic compounds, binding to the lipid fraction of blood serum and the reduction of serum lipid peroxidation. On the contrary, after the intake of the product was observed effect prooxidante transitional increased serum protein oxidation. This effect could be due to oxidative processes mediated by sugar products, which involve Maillard reactions.

Author: Parras Masa María del Pilar.
Year: 2005.
University: MURCIA [www.um.es].
Place of defense: Facultad de Veterinaria.
Place of preparation: Facultad de Veterinaria.

Summary: With this research is intended to study the antioxidant activity of free radicals and recruiter food (truffles and mushrooms, oat bran and wheat, coffee from different origins and enriched milk and yogurt) whose composition appear structures qeu independently have been widely described with antioxidant activity. In addition to assess how some technological processes that are used by consumers or the industry may decrease or increase the antioxidant activity or prooxidante of these products. The analytical methods used were testing lipid peroxidation, testing of the deoxyribose, the trial of peroxidase, the test Rancimat, testing TEAC and testing of linoleic acid. The results of this study indicate that the canned mushrooms and truffles show significant losses of antioxidant activity, while frozen products showed smaller proportion of losses. The antioxidant activity of the cereal resists thermal storage and processing. The way to develop coffee (filtering, Italian, espresso) has no effect on the antioxidant activity. It remains fourteen weeks (date consumer preference that the manufacturer sets) storage conditions of consumer households. In addition, the temperature range selected by the company for roasted coffee shows no variation in antioxidant capacity nor the maintenance of hot coffee in the coffee maker for six hours. The analyzed yogurt and milk fortified with vitamin E are good recruiters of free radicals. The results also show that these products could be used as ingredients in the preparation of dishes and that the degree of protection they provide resists high temperatures and remain in effect for at least four semanas.B

Author: Egea Sánchez María Isabel.
Year: 2005.
University: MURCIA [www.um.es].
Place of defense: Facultad de Biología.
Place of preparation: Facultad de Veterinaria.

Summary: It has been characterized antioxidant activity of different foods of vegetable origin: a) seven food spices commonly used in desserts: anise, cinnamon, ginger, mint, nutmeg, vanilla and liquorice, and b) apricot Búlida; through various tests uptake of free radicals and oxidative stability studies under conditions of global warming. It has also conducted a comparative study between the antioxidant activity of selected foods and various antioxidant additives commonly used in the food industry. On the other side were selected for each different food preservation techniques according to their marketing possibilities: a) treating ionization (0, 1, 3, 5 and 10 kGy) for them spices, and b) freezing apertización, lyophilization, ionization (0, 0.5 and 1 kGy) and treatment with 1-mcp (1000 ppb), the latter two in combination with refrigeration for the apricot; studying the effect of these treatments on the same antioxidant systems. IN the case of apricot with ionizing radiation and 1-MCP has also studied the effect of these treatments on quality post-harvest. Spices and apricot showed high antioxidant activity, in many cases even exceeding that of synthetic additives, BHA, BHT and propilgalato. The effect of irradiation did not affect the antioxidant properties at the doses used in spices. Instead apricot were observed at the dose of 1kGy a decrease of some antioxidant systems. Such treatment despite reducing yields of ethylene apricot, not lengthened the life of any of the doses tested. The defendant's industrial apricot affected in a different way to antioxidant activity. The lyophilization not altered, frozen fell slightly, especially when the fruits are escaldaban previously. The apertización originated the biggest changes, but not always to the detriment of their quality antioxidant. Combination treatment with 1-MCP and cooling 2Â ° C, caused an increase in antioxidant potential in the apricot which resulted in certain advantages for the conservation of it, prolonging 7 days its useful shelf life, with respect to untreated fruits.

Author: SAMANIEGO SANCHEZ CRISTINA.
Year: 2005.
University: GRANADA [www.ugr.es].
Place of defense: FACULTAD DE FARMACIA.
Place of preparation: DPTO.NUTRICION Y BROMATOLOGIA. FACULTAD DE FARMACIA DE GRANADA.

Summary: THE STUDY OF THE THESIS DOCTORAL REALIZO ARE IN SAMPLES OF EXTRA VIRGIN OLIVE OIL TO NAME OF ORIGIN OF THE CAMPAIGNS OLIVARERAS FOR THE YEARS 2001-2002, 2002-2003 and 2003-2004. IN FIRST PLACE IS ABORDAN TESTS FOR DETERMINING THE QUALITY OF OIL SUBJECT OF STUDIES (INSAPONIFICABLE, CONTENT IN WAX AND CONTENTS OF TOTAL POLYPHENOLS) AND SECOND PLACE IN ANTIOXIDANTS DISCOVER THE CHARACTERISTICS OF THE SAME FOR WHEREOF SE DETERMINO CONTENT IN ESCUALENO AND BETA CAROTENO THAT REVISTEN GREAT IMPORTANCE DESPITE ENCONTRARSE IN LOW CONCENTRATIONS. PONEN POINT TO LATER IS DIFFERENT METHODS OF MEASURING THE CAPACITY ANTIOXIDANTE THROUGH ACTION ESPECTROFOTOMETRICAS And FLUORIMETRICAS (ABTS, DPPH, ORAC And BETACAROTENO / LINOLEICO). ABORDO BY LATEST IS THE STUDY OF COMPONENTS OF OIL IN ANTIOXIDANTS SAMPLES FROM HUMAN PLASMA HEALTHY VOLUNTEERS

Author: SAMANIEGO SÁNCHEZ CRISTINA.
Year: 2005.
University: GRANADA [www.ugr.es].
Place of defense: FACULTAD DE FARMACIA.
Place of preparation: DPTO. NUTRICIÓN Y BROMATOLOGÍA - FACULTAD DE FARMACIA DE GRANADA.

Summary: The study of the doctoral thesis was performed on samples of extra virgin olive oil with an appellation of origin in the olive-growing campaigns for the years 2001-2002, 2002-2003 and 2003-2004. First addresses tests to determine the quality of oils under study (insaponificable contained in waxes, and index polyphenols total), and secondly know the same genetic characteristics antioxidants, which determines the content and escualeno beta carotene, which are of great importance despite being at low concentrations. Then they point to different methods of measurement of the antioxidant capacity through measures espectrofotométricas and fluorimetricas (ABTS, DPPH, ORAC and BETACAROTENO / LINOLEICO). Finally the board is studying the antioxidant components of the oil in human plasma samples from healthy volunteers.

Author: ARTAJO MEDINA LUZ STELLA.
Year: 2006.
University: LLEIDA [www.udl.es].
Place of defense: E.T.S. de Ingeniería Agraria.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIERÍA AGRARIA - UNIVERSIDAD DE LLEIDA.

Summary: Abstract Biophenols encompass a major group of secondary plant metabolites that display a wealth of structural variety and a large diversity of significant biological activities. An area of special interest concerning olive and flaxseed is their phenolic profile and its direct influence on the quality of derived-products and the production of potential functional foods. In response to this opportunity, the role of phenolic compounds during olive oil extraction process and their presence in flaxseed was the basis of the doctoral investigation. Two important areas: transfer and antioxidant function of phenolics during olive oil extraction were investigated. The influence of irrigation treatments, ripening index of olive fruit and different technological aspects in the production of olive oil allowed having a better understanding of the transference and transformations of the phenolic compounds. Quantitative data, in terms of transfer, were established for concentrations of phenolics in olive paste, pomace, wastewater and olive oil phases. Some of these products and by-products have been studied and proven to be effective source of phenolic antioxidants. Therefore, isolation and purification of particular phenolics were performed to evaluate their individual antioxidant activity through the oxidative stability parameter. The bitter index, a sensorial attribute, was also evaluated as function of the addition of phenolic compounds. Simple alcohols, phenolic acids, secoiridoids, secoiridoid derivatives, flavonoids and lignans were studied. The addition of the mentioned phenolic compounds on refined and extra virgin olive oil had a remarkable effect on the oxidative stability of the oils. Gallic acid, hydroxytyrosol (3,4-DHPEA), caffeic acid, luteolin and the dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA) were found to be effective antioxidants. Flaxseed phenolic fraction vas also studied.Diverse studies on the extraction of phenolics provided a basis for establishing an analytical method to evaluate the phenolic composition of flax. A solvent extraction followed by hydrolysis tratements resulted in the identification of the main phenolic compounds ocurred in flaxseed including secoisolariciresinol diglycoside (SDG). A subsequent study to undersatand the flasxeed antioxidant systema was developed using reconstituted flour meals whit commercial oil and analyzing hulls and dehulled flour meals. Peroxide and aldehyde values were determined during two weeks of storage. It appeared that SDG and phenolic acids (ferulic and p-coumaric glycosides) might not be responsible of the main flasxeed antioxidant function.

Author: Gimeno Gómez Elisa.
Year: 2006.
University: VALENCIA [www.uv.es].
Place of defense: E.T.S. de Ingeniería (ETSE).
Place of preparation: Instituto de Agroquímica y Tecnología de Alimentos.

Summary: Currently, in a definitive way, food additives are part of the daily food consumption. It is clear that the food they are on the shelves of supermarkets are increasingly sophisticated and with better properties, both for its preparation for consumption, so that consumers spend the time and effort. On the other hand, have a longer period of life, not enrancian have better look, better texture and fewer calories, to mention some advantages paste of garrofín has been used in the food industry for decades. The traditional applications found sequestrant as a thickener and water and its use in combination with different gelling agents, is the basis for the production of various foods structured, in which the composition is determining the mechanical properties of late. The hydrocolloids such as rubber garrofín are high molecular weight polymers that bind to a large amount of water, change the rheology of the aqueous system in which they find themselves. Generally a dispersion of 1%, reaching the 45Â ° C, begins to increase its viscosity. To fully develop it is necessary to heat up 85Â ° C with a stirring constantly for 30 minutes. Once cooled dissolution until 25Â ° C, has at least 2300 centipoises (mPa) but can reach 3500 centipoises according seed quality and the method of manufacture. The main features to be taken into account in the solubility of hidrocolides are as follows: -