FOOD PRESERVATION

Author: ZAMORA RODRÍGUEZ LUCERO MARLENE.
Year: 2003.
University: GIRONA [www.udg.es].
Place of defense: ESCUELA POLITECNICA SUPERIOR.
Place of preparation: UNIVERSIDAD DE GIRONA-INSTITUTO DE TECNOLOGIA AGROALIMENTARIA.

Summary: The bioconservación with lactic acid bacteria (BAL) can be applied to improve the microbiological quality of the blood of slaughterhouse alrgar its life and reduce the potential for immediate processing after harvesting. Native strains were isolated and prepared two collections of BAL mesófilas and another psicrótrofas. We evaluated the potential antagonist of the BAL mesófilas and psicrótrofas to 30Â ° C and 15Â ° C respectively compared to bacteria contaminants usual this product. The BAL showed that antagonism plate (7.1% to 30Â ° C and 11% 15Â ° C) were selected to assess the potential antagonist in the blood, where the inhibitory effect was helped by the addition of a 2% glucose. S.aureus and P.fluorescens were inhibited by most indicators mesófilas strains, in some cases reductions in excess of 7 logs. In terms psicrótrofas bacteria was more sensitive Bacillus spp. Where 8 out of 11 BAL tested enabled reductions in excess of 4 logs and 1 strain even higher than 7 logs: reductions were obtained maximum of 3 logs from E. coli and Pseudomonas was inhibited by the 11 BAL, in some cases with reductions exceeding 5 logs. The strains that presented the spectrum of inhibiting wider (5 to 30Â ° C and 7 a15Â ° C) were identified by molecular techniques by comparing the sequences for the gene coding for the synthesis of 16S ARNr (16S rDNA) with the sequences published in the bases data. 5 strains psicrótrofas were identified as Lactococcus garvieae and 2 as Enterococcus malodoratus / gilvius raffinosus.Las BAL mesófilas belonged to the genus Lactobacillus, 3 of them were identified as Lactobacillus murinus / animalis and one was identified as Lactobacillus reuteri. TA20 which was a great aspectro inhibition at 15 and 30 Â ° C was identifíco as Lactococcus garvieae. As conservation methods of the strains were compararom freeze-drying, spray face freezing to -80Â º c. In general, the methods of drying (lyophilisation and atomization) and maintenance 5Â ° c of the crop is mostraton more effective than freezing.

Author: PLAZA PÒRTOLÉS M. PILAR.
Year: 2003.
University: LLEIDA [www.udl.es].
Place of defense: INGENIEROS AGRÓNOMOS.
Place of preparation: CENTRO UDL-IRTA.

Summary: Immersed in the current dynamics of rationalizing the use of fungicides by the health and environmental problems associated with their indiscriminate use, the study and development of alternative systems in controlling podredumbres in postharvest currently represents one of the lines of investigation in which more dedicated efforts globally, and also in the field of citricultura in particular. In this context, the main objective of this thesis has been to assist in the replacement of synthetic fungicides in postocosecha by the citrus fruit sector, evaluating and developing various alternative methods. Once the conditions of temperature and water activity that allow the germination and growth of Penicillium digitatum, P.italicum and Geotrichum candidum, mmohos responsible for major diseases in citrus postharvest (rotting green, blue and bitter, respectively) (Chapter 1), and the influence of these parameters on its ability to compete (Chapter 2), have been assessed treatments cured (Chapter 3, 4 and 5), the use of essential oils (Chapter 6) and the implementation of strain CPA-2 of the biocontrol agent Pantoea agglomerans (Chapter 7), as alternative methods in controlling these prodrdumbres, focusing studies from a practical point of view allowing for rapid deployment in the sector. The most important conclusions of this thesis has been that the temperature is a key factor in the development of these molds, and that temperatures are usually used during frigoconservación (4Â ° C), G.candidum not growing, but complete germination and furthermore P.italicum grows at a rate twice as fast that P.digitatum in culture medium in vitro. However, the same temperature but in orange, green rot progresses more rapidly, although it is worth mentioning that the rot blue beginning to develop a week earlier. A treatment cured 33Â ° C for 65 hours, reduces by more than 90% incidence of rot green and blue, both in fruits artificially inoculated with natural infection, oranges and lemons that are marketed directly without passing through a period of frigoconservación. In contrast, when the fruits are kept cold for a long period, this trabamiento cure can not be considered sufficiently effective, as the percentage of fruit affected by rotting blue oranges exceeds 60%. With a bathroom with sodium carbonate to 2% for 2.5 minutes later the treatment cured, it is achieved by reducing the incidence of rotting blue rotten fruit until rates between 10-25%, both as oranges and lemons stored in cold even when the pathogen inoculation is done after the implementation of the treatments. Integrating treatment cured 40Â ° C for the first 24 hours process deverdización usually applied in mandarin harvest early, as clementines, is reduced by more than 95% the incidence depodredumbre green and blue fruits preserved on 20Â ° C, and furthermore, when they were harvested with an index of color -0.41, firmness of the skin, soluble solids content and acidity of the fruit are not affected, and colro trade only takes one more day achieved in respect the fruits desverdizados in the traditional conditions of temperature (constantly 20Â ° C). These results are not close to the commercial introduction of treatments cure for the industry. The replacement of gungicidas synthetic natural products such as essential oils, although in vitro have a great effect inhibidior growth P.digitatum and P.italicum, seem far from becoming 8 in a r 6e4 ealidad, and that does not reduce the incidence of rot green or blue, or directly on the fruit or embedded in the wax business. Nor is achieved adequate control envasando fruit treated with essential oils in trays or plastic bags. Moreover, in some cases can be seen fitotoxicidades. Moreover, the agent biocontrol P.agglomerans CPA-2 has become an effective antagonist of the main podredumbres in postocosecha citrus. In previous studies already demonstrated its effectiveness in oranges and tangerines, and this thesis has shown its effectiveness in controlling the rot in green lemons in fruits stored at room temperature as cold, being able even to control inoculations made 15 hours in advance. If, in addition, there is a cure to 33Â ° C for 65h later treatment with the antagonist, completely controlling the incidence of rot green, even those carried out 24 hours before infection with the pathogen.

Author: GUYNOT DE BOISMENU VIACAVA M. ELENA.
Year: 2003.
University: LLEIDA [www.udl.es].
Place of defense: INGENIEROS AGRONOMOS.
Place of preparation: ESCOLA TÉCNICA SUPERIOR D'ENGINYERIA AGRÁRIA.

Summary: The bread and pastry products presented in its fresh and without evasar a shelf life at room temperature very low, with the most common forms of deterioration in the loss of texture, the loss or gain of moisture and the alteration of microbial origin, especially fungal. In recent times, there has been an increase in demand by consumers for products free of additives. The coexistence of prolonging the service life of products through other channels alternatives to the use of preservatives has led to the study of natural substances with antifungal properties, as well as the implementation of modified atmosphere packaging. The objectives of this study were, first, the study of the application of preservatives traditional analogue mass fermented (croissants) and mass raid (muffins). Moreover, it has evaludado in analogues Madeleines the potential use of a number of essential oils as inhibitors of fungal growth. Finally, we have studied the prevention of alteration by changing the atmosphere packaging analogues magdalena. All treatments made has been referred to the interaction with the same pH and the water activity of the product, and have been used fungal species isolated previously from a representative group of products Spanish pastries. It has been found that the type of preservatives weak acids (potassium sorbate, calcium propionate and sodium benzoate) are not effective in the conservation of pastry products with a pH near neutral. Moreover, it has been observed that the use of potassium sorbate to concentration legally permitted (0.2%) in products with a pH around 4.5 and a water activity of less than 0.80, is effective in the fungal damage control for a month. However, the same dose used in a product with a pH slightly higher (5.5) would be effective only to maintain life for shorter periods. The other two preservatives were even less effective in controlling the deterioration of these fungi pH. Simultaneously, it has been detected antifungal activity in the essential oil of bay leaves, cloves, thyme, rosemary, lemongrass and cinnamon leaf, to be added to the culture medium (+-0.1%) or the incubation atmosphere. However, their subsequent implementation in similar magdalena has not been effective. Alternatively, changes in the atmosphere packaging has always proved effective in controlling the deterioration of fungal analogues magdalena. There has been a total control of fungal growth in analogues with a pH close to neutrality and a water activity in the range of 0.80 to 0.90 while using blends with high levels of CO2 (close to 100% ), as by the inclusion of oxygen absorbers with modified atmosphere packaging with gas mixtures or even air. Finally, the activity of sorbate postasio has been enhanced through their joint application with modified atmosphere packaging with CO2 levels between 30 and 70%. As a general conclusion, the present study thesis that, in conditions of low water availability is possible to maintain stability deproductos both slightly acidic pH as close to neutrality, without the need for the addition of preservatives. The use of preservatives on the type of weak acid is not effective in controlling the deterioration of products with a pH near neutral. However, the control of fungal deterioration of this type of product can be carried out successfully by modified atmosphere packaging.

Author: SALGADO BLANCO AURORA.
Year: 2003.
University: VIGO [www.uvigo.es].
Place of defense: FACULTAD DE CIENCIAS DE OURENSE.
Place of preparation: FACULTAD DE CIENCIAS DE OURENSE.

Summary: The heart of onion variety is a traditional sausage crudo-curado developed in galicia (spain). In this Doctoral Thesis, in order to define the raw materials and processes used in the preparation of this sausage was initially a survey among processors artisans and industrialists. Subsequently, it conducted a thorough biochemical characterization of the final product, both artisanal and industrial power source, trying to make uan differentiation between the two types of sausage pack to the values of the various biochemical parameters. Finally, we proceeded to the characterization of the biochemical process madurativo, studying the compositional parameters and physical fractions nitrogen and the classical parameters degradativos of fat along the maturation of 7 lots of chorizo procedures developed by artisanal and 4 industrially manufactured.

Author: GARCÍA FONTÁN M. CAMINO.
Year: 2003.
University: VIGO [www.uvigo.es].
Place of defense: FACULTAD DE CIENCIES DE OURENSE.
Place of preparation: FACULTAD DE CIENCIAS DE OURENSE.

Summary: The Sausage onion variety is a traditional ambutido crudo-curado developed in Galicia (Spain). In this Doctoral Thesis has done an exhaustive microbiological characteristics of this sausage, as a prelude to obtaining a crop originator leading to a product homgénero of high quality and constant sanitariamente safe. In three partidad of Sausage onion procedures developed by artisanal and industrially manufactured in three samples of mass before embutir and Chorizo to 2,7,14,21,28 and 42 days maduración.En each sample he recounted the microbiota aerobic mesófila total microbiota halotolerante, staphylococci, microbiota acidláctica, Enterobacteriaceae, enterococci and molds and yeasts. As might be expected of a fermented food, the microbiota acidoláctica was the group microbial majority during the maturation of all lots of chorizo studied, resulting in their counts some sampling points even higher than those seen par wing microbiota aerobic mesóifila total.La microbiota halotolerante followed a similar trend to that of the microbiota aerobic mesófila total, but with values well below counts. At each sampling point for each lot, from where the plates are made by the counts of microbiota acidoláctica (MRS agar), the microbiota halotolerante (PCA +7.5% NaCI), were taken from each of these groups microbial random 10 cepas.Un total of 428 isolates agar MRS And 423 isolated GWP +7.5% NaCI that were identified using proven methodologies. Agar MRS It showed a very high selectivity párale aislamientode bacrerias lactic, while the selectivity of the PCA +7.5% NaCI for the isolation of Micrococcaceae; among staphylococci, predominated Staphylococcus sylosus and Staphylococcus saprophyticus. It was tested for antimicrobial activity of tosas lactic acid bacteria isolated and identified using strains indicator Enterococus faecalis, Enterococus faecium and Listeria monocytogenes.Soló the dialysis of 5 strains Lactogbacillus sakei showed antimicrobial activity attributable to what may prove a bacteriocina.

Author: FERNÁNDEZ DUMONT ANTONIO.
Year: 2003.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE VETERINARIA.
Place of preparation: FACULTAD DE VETERINARIA (UCM).

Summary: The possibility of exchanging both leaders as systems secretion and processing involved in the biosynthesis of various bacteriocins can be exploited to achieve the production of heterologous these peptides antimicrobianos.En this work has been the production of bacteriocins lactococina A pedicina PA-1 and colicina V in Lactococcus lactis.Además, has been the production of a protein eucariota, the cytokine interleukin-2 in the same especie.Para It has been necessary to introduce three genes: (a) a structural gene hybrid with the merger, in the same reading frame of the sequence encoding the leader of the lactococina A and propéptido interest (prolactococina A propediocina PA-1, procolicina Vo proninterleuquina-2) and (b) genes IcnC and LcnD, encoding elsistema secretion and processing of lactococina A. The structural genes hybrids were constructed in such a way that his expression was controlled by the inducible promoter of the misina (PmisA). Process autoregulation of biosínteeis of nisin has been successfully implemented pair production of heterologous peptides in various species and genera of bacteras lácticas.Para therefore requires three key elements: (a) a strain containing the gene nisRK, (b) the addition of nisin as inducing molecule, and C that the gene of interest is controlled by the developer PmisA.Las strains they were employed as host L. Lactis FI5876, producing a layer of nisin, and L.lactis FI7847, a strain not bacteriocinogénica.Las two strains containing transposón Tn5301, which carries the agrupaciónde genes of nisin, including genes nisRK.En the case of L. Lactis FI7847, the gene structure of nisin (nisA) has undergone a delección preventing their expression and, consequently, the production of this bacteriocina. The introduction of two plástidos compatible (a derivative of pTG262 with the structural gene for hybrid and underivado of pIL277 with genes IcnCD) L.lactis FI7847 and FI5876 led to the breeding of new strains producing lactococina A pediocina PA-1, colicina Vo interleuquina-2.En el caso de los dderivados FI7847, era necesario que los cultivos fueran inducidos previamente con cantidades subinhibitorias de nisina.Los derivados de L.lactis FI5876 mantuvieron intacta la capacidad de producir nisina de la cepa parental.En consecuencia , derivatives were obtained from L.lactis FI5876 coproducer of lactococina A and nisin, pediocina PA-1 and nisin, colicina V nisin and interleukin-2 and nisin. The productivity of lactococina Ay pediocina PA-1 exceeded significantly to that obtained previously (Martinez, 1999) in heterologous related systems of production that are not using the inducible promoter of the nisina.En for the coproduction of colicina V nisin is the first bacteria láctivcas able to co-produce a bacteriocina affecting bacteria, Gram-positive (nisins) and one that affects Gram-negarivas (colicina V). None of the supernatants obtained from the lactococos recombianates producers affected the bacteriocins the proliferation of intestinal cells HT-29.Finalmente, interleukin-2 produced by derivatives of L.lactis FI7847 and FI5876 expressed as biological activity induced cell proliferation CTLL-2.

Author: PEREZ LOPEZ ANTONIO JOSE.
Year: 2003.
University: MIGUEL HERNÁNDEZ DE ELCHE [www.umh.es].
Place of defense: ESCUELA POLITECNICA SUPERIOR DE ORIHUELA.
Place of preparation: ESCUELA POLITECNICA SUPERIOR DE ORIHUELA.

Summary: The work done in this thesis consisted in the study of different parameters and sensory físico - químicos in 11 varieties grown in España.Los parameters mandarin most prominent and significant varieties introduced between varieties were content fiber in the edible portion, parameters color, mineral content and volatile compounds in juice mandarina.El content fiber was higher in all varieties of mandarins studied regarding how other citrus oranges; parameters of color were different in all varieties remain an important measure parameters A value of face-to improve the color of the juices citricos.La composicción ore (micronutrients) was significantly different depending on the type of crop to which they were subjected the samples (or traditional ecological farming) rather than by differences in load variedades.La compounds voaltiles was different, being the best varieties from hibridaciones not like the variety fortune.

Author: TRUJILLO NAVARRO YANINE YUBISAY.
Year: 2004.
University: NAVARRA [www.unav.es].
Place of defense: ETS INGENIEROS AGRÓNOMOS.
Place of preparation: ETS INGENIEROS AGRÓNOMOS.

Summary: In order to optimize the use of preservatives has studied the reduction and / or replacement of employment disulfito sodium, which is harmful to the health of the consumer, for a treatment of organic nature that offers at least similar results in terms of the life of the potato cv.Monalisa minimally processed, with no decrease in quality producto.Para It used solutions disulfito sodium and N-Acetil-L-Cisteína alone and in combination withthe ascorbic acid and cítrico.El minimum processed potatoes consisted of disinfection, washing, peeling, cut, treated drained and stored for a period of 14 days at a temperature of 4C. The evolution dela quality and life of minimally processed potato was determined during the storage period from the sensory characteristics (appearance and odor), physicochemical (color, pH, contained residual disulfito sodium, gas composition in the interior Package) and micro (mesophiles and psicrótrofos). experimental development was carried out in two partes.La first part consisted in the selection of treatment that would minimize the dose of disulfito sodium from the combinations tested and also better preserve the baseline characteristics the fresh potato in a greater period of time, thereby reducing its use from the combination with acid orgánicos.La second part pilot was conducted with the aim of replacing sulfites by a treatment based solely on the use of preservatives organic withthe that obtain a quality and useful life in the potato minimally processed, the same or better than that achieved with the treatment of disulfito sodium selected in the first part. From the results it was observed that the treatment inhilbe effectively enzymatic browning and controls the growth of aerobic microorganisms during 14 days in storage 4C is the combination of 0.1% disulfito sodium and 0.5% acid cítrico.Estos same results were obtained by the replacement of disulfito sodium in the treatment of 0.5% N-Acetil-L-Cisteína in combination with 2% citric acid.

Author: PASSARO CARVALHO CATARINA PEDRO.
Year: 2004.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS AGRÓNOMOS.
Place of preparation: DEPARTAMENTO DE TECNOLOGÍA DE ALIMENTOS.

Summary: The physical and metabolic stress imposed on fresh produce during the harvest is very common, but visible alteration of the same can not speak to bequeath to the point of sale, and also often altering that is not related to their true origin. Thus, this research comes before the need to identify the metabolic changes associated with different types of stress which is subject to the fruit during the harvest. The overall objective of the research was to develop a methodology for analysis of metabolic changes caused by the factors involved during the harvest of citrus fruits and determine its useful life. Thus we developed a new analytical system for measuring respiration rates and the production of volatile in nuts, simulating the conditions experienced by the product during storage and avoiding the generation of anaerobic atmosphere, allowing detect metabolic changes before the visible manifestation the symptoms of stress. The main results can emphasize that the analysis system developed allows detection of very short-term changes in the rate of respiration and production of volatile (Acetaldehyde and ethanol) induced by stressful situations in citrus fruits, be possible to apply it to other products. Inoculation of P.digitatum in lemon fruits of the variety "Verna" creates an increased rate of breathing before dela visual manifestation of symptoms of infection, and this parameter can be used as an early indicator of potential problems caused by microorganisms in citrus fruits. The waxing increases the latent period of P.digitatum and reduces its growth rate on the fruits of lemon "Verna", while delaying the metabolic changes in the fruit, thus increasing its useful lifetime. With the proposed methodology, we can construct a model of development P.digitatum from metabolic changes experienced by the result, defined a phase of incubation and a logarithmic growth phase of the fungus. The analysis system continuously developed has helped detect a direct correlation between the rate of respiration and senescence of fruit, although very useful in the detection of potential stress situations limiting the period of life of the fruit during the harvest. In addition, he suggested the possibility of quantifying the effectiveness of a specific treatment of conservation in terms of its effect on reducing the rate of respiration.

Author: LARRAZABAL FUENTES MARÍA JOSÉ.
Year: 2004.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS AGRÓNOMOS.
Place of preparation: DEPARTAMENTO DE TECNOLOGÍA DE ALIMENTOS.

Summary: In this paper we study the optimization process marinated salmon, considering three points. The first, related to the implementation of techniques marinated, alternatives to the traditional process Dry (S), which consist of immersion salmon solutions concentrated decloruro sodium and sucrose, (IV) and without (I) implementation of a pulse vacuum, which will improve the effectiveness, efficiency and product quality. The second aspect relates to the preservation of traditional product and the application of antimicrobials, whether natural (such as spices dill, thyme and pepper) or chemical (potassium sorbate). The third aspect is considered referred to the optimization of the dissolution used in the process in terms of its composition and its relationship with mass salmon, and the stability of marinated product by the technique more effective. In addition, we studied the possibility of reusing the dissolution cycles marinated in a row. Our results indicate that the techniques I and IV are more effective and have higher yields and uniformity that S, which improves the quality of the final product. As for the study of the life of the traditional product (S), stored in refrigeration, was limited to 1 week due to the growth of microorganisms and no positive results were obtained by applying such as antimicrobial agents, dried species, and their oils / or emulsions thereof to marinated salmon. Moreover, the technique I marinated, allows the incorporation of citric acid and potassium sorbate to the product during the marinating process, without affecting their organoleptic and physical-chemical characteristics, which will get longer life until 22 days, cooling 5Â ° C. In addition, it is possible to reuse the dissolution in several consecutive cycles of marinated, thus reducing the costs of marinating process.

Author: URESTI MARIN ROCIO MARGARITA.
Year: 2004.
University: VIGO [www.uvigo.es].
Place of defense: FACULTAD DE CIENCIAS DE OURENSE.

Summary: In this thesis developed a process for obtaining restructured protein fish low in salt using transglutaminase as a binding agent. This process can be used to take species from the wildlife acopañamiento shrimp, which because of its small size are currently wasted and that their meat can be mechanically recovered for use in developing restructured. We developed the formulation of a functional food by adding pectins amidadas low metoxilo. The use of this additive pair producing restructured fish and their effect on the mechanical properties sy funcionale son had been documented. We developed a formula to get restructured using low-salt milk proteins (Caseinato sodium and cheese whey proteins). It documented for the first time, the changes caused by pressurization (400 to 600 MPa) for short time (1 to 5 minutes) on the mechanical properties and functional restructured fish products. These conditions are considered process by the manufacturers of equipment altaspresiones Hydrostatic as currently most appropriate intervals to ensure the microbiological quality and profitability of the process (data provided by the company Avure Techology Inc.). We discovered the existence of a mechanism different from gel to gels obtained by high pressures and obtained by cooking. Just as the existence of a mechanism for joint gels that are pressurized prior to cooking. It was found to inhibit protein aggregation induced by the pressure to obtain raw products microbiologically safe, using high pressure and the addition of a baroprotector (sorbitol 8%). The resutlados obtained from studies of high pressure have developed a hypothesis regarding the mechanism of gel that is induced when using high pressure. The proposed mechanism suggests that there are weak links are formed between adjacent proteins, physically induced by the pressure without denaturing (conformational changes in the protein). The subsequent firing induces protein denaturation and aggregation. What explains the different mechanisms for gels cocidos-presurizados and presurizados-cocidos.

Author: TARRAZÓ MORELL JOSÉ.
Year: 2004.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS AGRÓNOMOS.
Place of preparation: DEPARTAMENTO DE TECNOLOGÍA DE ALIMENTOS.

Summary: In this paper an attempt has been made to study the transfer of the area involved in the osmotic dehydration of fruits, using different osmotic agents in order to reap the benefits that they can provide the vacuum impregnation. Segments pineapple (Ananas its varieties) Cayenne Lisa, 10 mm thick were subjected to two treatments osmotic dehydration solutions of sucrose and glucose 50 Â ° Brix and temperatures of 30.40 and 50 Â ° C, for a while processing 10 , 20,30,40,60120180 and 300 minutes. After genetic treatments was determined for each time the values of weight, moisture, Â ° Brix and water activity. Collected data has been calculated the effective diffusivity of mass equation using the integrated law Fick foils semi-infinitas and for shorter times. It has also been obtained activation energy from the equation Arrenhius.

Author: ARGÒELLES FOIX ANGEL.
Year: 2004.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS AGRÓNOMOS.
Place of preparation: DEPARTAMENTO DE TECNOLOGÍA DE ALIMENTOS.

Summary: In this dissertation is intended to address two common problems in the use of water activity on food. On the one hand the slowness of experimental methods for determining the activity of water in food and the high cost of equipment used by another and the poor definition of thermodynamics some food systems used in the calculation d the sorption isotherms of the same. Many of the chemical reactions, microbiological, and so on. Linked to the deterioration of genetic foods are related to its water activity. In chapter 2 of this research work aims to develop a new team for the determination of the water activity, based on a new methodology developed for the purpose, to reduce as far as possible the inconvenience presented those used so far. Chapter 3 is part of a comprehensive study in which, with a different approach to traditional and focuses on the nature of multi polifásico and food systems analyzes the distribution of water and salt prevailing between the two phases (liquid phases and solid phases) for products of animal origin salted developed mathematical equations that can predict the activity of water in each of the phases that control the different situations that arise when amending the moisture content in whole or in salt systems in that provision is important phase transitions, as is the case of salted meat products.

Author: GUILLEN ARCO ANTONIO FABIAN.
Year: 2004.
University: MIGUEL HERNÁNDEZ DE ELCHE [www.umh.es].
Place of defense: E.P.S.O.
Place of preparation: E.P.S.O.

Summary: The 1-MCP is an inhibitor of ethylene from the fruits, and therefore is able to delay ripening fruits in maintaining quality during storage in post-recolección. This thesis has studied the effect of using different doses of 1-MCP in plums and apricots in order to optimize the use of 1-MCP. Given the fact that producers are forced to collect the fruits in a state of maturity immature be studied further that effect the implementation of 1-MCP on fruits collected in different states of maturation. In addition designed an experiment in which additional attempts were made to evaluate the effectiveness showed that this compound when the fruits were packed or on the contrary were prepared in bulk. We also evaluated the effect it had on 1-MCP on the antioxidant activity of the fruits as well as their influence on the organoleptic quality, nutritious and functional. Also established the maximum lifespan of plums and apricots taking into account all the parameters analyzed among which we highlight: respiration rate, ethylene production, PCA content, weight loss, color, firmness, soluble solids, acidity , sugars, organic acids, anthocyanins, polyphenols and total antioxidant activity. The 1-MCP was effective in delaying the various parameters of maturity in all varieties studied. The best applied dose was 500ppb, with the state of maturity that best repondió treatment the advanced state of maturity. Also treatment with 1-MCP was more effective when done with the fruits arranged in boxes that if on the other hand was with the fruits prepared in bulk. In addition to maintaining the organoleptic properties and nutritious, 1-MCP was effective in maintaining the functional properties of the fruits and antioxidants. The 1-MCP lengthened the life span of fruit between 2 and 3 weeks that the fruits that received no treatment.

Author: HERNÁNDEZ SOMARRIBA LESBIA LUCÍA.
Year: 2004.
University: ZARAGOZA [www.unizar.es].
Place of defense: FACULTAD DE VETERINARIA.
Place of preparation: FACULTAD DE VETERINARIA.

Summary: The rainbow trout (Oncorhychus mykiss) and golden (Sparus aurata) are two species of great importance in aquaculture Spanish However, in recent years the market for these species has been overwhelmed by the influx of products third countries such as gold from Greece. Moreover, in the Spanish market is detected a change in the attitude of consumers, who have varied in the direction of greater responsiveness of the processed products or easy preparation, all because of the existing systems and family life labor. Marinated technology is presented as an alternative to produce a safe product ready for consumption. The objectives of this research work were: a) To optimize the technological process to produce rainbow trout marinated and golden. B) To assess the effect of the use of a gas mixture (50% CO2/50% N2) for packaging fillets marinated and valuing the potential benefits presented in front of the vacuum packaging. C) Study the life of marinated fillets of rainbow trout and golden packaged stored in refrigeration through physical and chemical analysis, microbiological and sensory. E) conduct qualitative research market for the new product developed (golden marinade). The main findings were: 1) The brine comprising 8% of salt and 2% acetic acid, which is best suited to get fillets with organoleptic characteristics acceptable for consumption. 3) The atmosphere packaging (50% CO2/50% N2) and vacuum packaging, compared with the air gives better benefits conservation especially from the point of view oxidative. 4) With the method of marinating vacuum was reduced to 5 hours, the time required for obtaining fillets marinated, whereas with the traditional method requires 6 days. 5) Both the traditional marinated as marinating vacuum can obtain a final product safe from the point of view microbiological, physico, comply with the rules laid down for this type of semi and was very positively evaluated by a panel of tasters. 6) The study of consumers is an excellent source of information on attitudes towards this new product for its ease of handling and possible improvements or technological innovations.

Author: VALVERDE VERACRUZ JUAN MIGUEL.
Year: 2005.
University: MIGUEL HERNÁNDEZ DE ELCHE [www.umh.es].
Place of defense: E.P.S.O..
Place of preparation: E.P.S.O..

Summary: The table grape is a highly perishable fruit after harvest, current conservation techniques presented postharvest problematic (waste, phytotoxicity, resistors). This thesis has been tested two non-polluting technologies, using Aloe vera gel as edible coating and the other a modified atmosphere packaging assets along with the addition of essential oils (eugenol, menthol and thymol) as antimicrobial agents. We conducted a conservation refrigeration and a subsequent study of useful life to 20Â ° C. The analytical determinations were ethylene and respiratory rates and concentration of gases within the packaging, lost weight, color changes, contained in antocianos totals and anthocyanins, changes in firmness and content of cell wall and pectins, soluble solids content, acidity, organic acids and sugars and maturity index. Also identified parameters related to functional quality as the total antioxidant activity and polyphenols, as well as counts microbilógicos and sensory analysis of the samples. The results showed that both the processes of maturation as well as functional quality counts microbiological and sensory analysis improved in the grapes treated with Aloe vera and essential oils regard to their controls. Therefore treatments provided an effective alternative to the traditional post-harvest techniques and improved quality significantly in the fruits preserved in the cold during the study of life.

Author: Warczok Justyna.
Year: 2005.
University: ROVIRA I VIRGILI [www.urv.cat].
Place of defense: Escola Tècnica Superior d'Enignyeria Química.
Place of preparation: Escola Tècnia Superior d'Enginyeria Química.

Summary: From consumers point of view the food fresh-like appearance is a primary criterion in making a purchase decision. In response to consumer demand, research in the food industry aims to develop mild food preserving methods. A promising pre-treatment method is osmotic dehydration (OD), which is the subject of this study. Osmotic dehydration provides a high quality product with a high content of naturally occurring vitamins and microelements. OD involves soaking foods (fruit, vegetables, fish and meat) in a hypertonic (osmotic) solution i.e. concentrated sugar, salt, alcohols or soluble starch solutions, which partially dehydrates the food. During the process, two major simultaneous counter-current flows occur: the solute is transferred from the solution into the food and water flows out of the food into the solution, which is stronger than the previous one. Despite the advantages of OD and its simplicity, the industrial application is bottlenecked by the problem of how to manage the spent solution. Thus, from the process and economic point of view it is necessary to find an effective recycling method. The main objective of the present study is to evaluate membrane separation processes that reconcentrate osmotic dehydration spent solutions. The reconcentration is performed using nanofiltration, direct osmosis and osmotic membrane distillation. The nanofiltration (NF) process is carried out using a cross-flow filtration plant with flat sheet and tubular membranes. Direct osmosis is studied in two modes: off-site and on-site. During off-site direct osmosis (off-site DO), osmotic and stripping solutions are brought into contact in a membrane module. During on-site direct osmosis (on-site DO), however, the osmotic solution is reconcentrated at the same time as the osmotic dehydration process. Off-site DO was performed using NF membranes and NaCl as the stripping solution (SS), while on-site DO was performed with a microfiltration membrane and hypertonic sucrose solutions. During osmotic membrane distillation (OMD), NaCl and CaCl2 were tested as SS. In order to get detailed information about the influence of the membrane properties on the process performance, the NF membranes were characterised. The membrane properties evaluated were: topology, morphology, zeta potential, contact angle and chemical composition of the filtration layer. Because the most common osmotic agents used in fruit osmotic dehydration, are sugar solutions (sucrose, glucose or syrups), a sucrose solution of different concentrations (5-60 ºBrix) was used as the model for the membrane separation study. Apples were osmotically dehydrated to obtain actual osmotic solutions (OS) and to study how reconcentrated osmotic solutions affect the properties of osmodehydrated apples. The maximum sucrose concentration obtained during the nanofiltration process (24 ºBrix) restricts NF application to diluted solutions (e.g. in the fruit juice pre-concentration step). Of the membrane properties analysed, the separation layer characteristics were found to be decisive for achieving high fluxes and retention. Membrane contactor techniques (direct osmosis and osmotic membrane distillation) made it possible to concentrate highly viscous sucrose and osmotic dehydration solutions. During OMD, water fluxes were higher when CaCl2 was used as the stripping solution. The fluxes were higher despite the higher viscosity of CaCl2 and suggest that water activity is the decisive SS property if high water fluxes are to be achieved in OMD. Off-site and on-site direct osmosis gave lower fluxes than OMD and, since hydrophilic membranes were used, some solutes were transferred between the feed and stripping solutions. The apples osmodehydrated during the on-site DO were used in the sensory analysis. The panellists indicated that the apples that were osmodehydrated using the reconcentrated s 8 olution 386 were the best. As the final step, a feasible osmotic dehydration process with a coupled membrane contactor reconcentration step was proposed and osmotic membrane distillation was seen to be the most suitable process for carrying out OS reconcentration.

Author: Briñez Zambrano Wilfido José.
Year: 2005.
University: AUTÓNOMA DE BARCELONA [www.uab.es].
Place of defense: Facultad de Veterinaria.
Place of preparation: CENTRE ESPECIAL DE RECERCA PLANTA DE TECNOLOGIA DELS ALIMENTS.

Summary: SUMMARY Study of the inactivation by ultrahigh-pressure homogenization of microorganisms in liquid food. Assessment of the processes of cleaning and disinfecting equipment (doctoral thesis). The main objective of this thesis was to evaluate the Doctoral bacterial inactivation using Ultra High Pressure Homogenisation (UHPH) 300 + 30 MPa strains of Listeria innocua ATCC 33090, Escherichia coli ATCC 10536, Escherichia coli O157: H7 CCUG 44857, Staphylococcus aureus ATCC 13565 and Staphylococcus carnosus CECT 4491 inoculated in whole milk, skimmed milk and orange juice. Also, we try to study the effect of temperature input of milk and juice in the machine high pressure on the lethality and production of sublethal damage in these microorganisms, as well as the ability of these to survive, to recover and grow conditions after cooling treatment UHPH. Since there were no previous protocols for cleaning and disinfecting machine UHPH to ensure proper disinfection between a trial and another, the experiment 1 objective was to evaluate the efficacy bactericidal as decimal reduction (DR) of a mixture of peracetic acid and peroxide hydrogen (PAHP) against strains of Staphylococcus, Listeria and E.coli in the presence of different types of organic matter, exposure times and concentration of disinfectant. We also compare the resistance of pathogenic and non-pathogenic strains of these genres in search of alternative microorganisms for use in the evaluation of disinfectants in the development of a procedure for cleaning and disinfecting efficient method for the machinery of UHPH. Once evaluated and adjusted, the process of disinfection, the experiment 2 was to evaluate the effectiveness of bactericidal treatments UHPH against Listeria innocua ATCC 33090 inoculated in UHT milk and orange juice UHT, and study the effect of temperature entry on the machine to lethality and production of sublethal damage in this microorganism. Also studied their ability to survive, grow repaired and stored in refrigeration after treatment of UHPH. Experiments 3 and 4 were intended to evaluate the inactivation by UHPH of Escherichia coli ATCC 10536 and Escherichia coli O157: H7 CCUG 44857 inoculated on UHT milk, skimmed milk and UHT orange juice UHT, considering the effect of temperature input milk and juice, in the values of lethality and capability of treating sublethal damage in these strains. They also studied the ability of these microorganisms to survive, grow and repair itself during its conservation 4.0 Â ° C after treatment UHPH. The experiment 5 was intended to assess the inactivation induced UHPH in Staphylococcus aureus ATCC 13565 and Staphylococcus carnosus CECT 4491 inoculated in UHT milk and orange juice UHT, considering the effect of temperature input sample values in lethality, as well as the production of sublethal damage in these strains, and their ability to survive, grow repaired and stored at low temperatures after treatment UHPH. With regard to evaluation of disinfectant, Staphylococcus spp. Showed greater resistance to low concentrations of disinfectant that strains of Escherichia coli and Listeria spp. The egg was organic matter with greater capacity interfering while orange juice introduced lower capacity interfering. However, PAHP was effective (reductions> 5 log CFU / mL) at 8 concent 105th rations higher than 0.1% and 10 minutes of exposure in all cases. No statistical differences were found between pathogenic and non-pathogenic strains of the same group. With regard to treatment of inactivation by UHPH, Listeria innocua ATCC 33090, while the temperature input as the type of matrix influenced significantly (P? 0.05) its inactivation, which was greater at a temperature input 20 Â ° C. The treatments for UHPH not damaged in sublethal Listeria innocua. During storage at 4 Â ° C after the treatments, counts of Listeria innocua milk grew about 2 logarithmic units between days 0 and 9, while in orange juice fell 2.5 logarithmic units between days 0 and 18. The level of inactivation was similar for both strains of Escherichia coli in milk and sublethal damage were not detected after treatment both in milk and in orange juice. The temperature input and the type of matrix influenced (P? 0.05) the degree of inactivation in strains of Escherichia coli, reaching its peak at a temperature input 20 Â ° C. The evolution of viable counts during storage to 4.0 Â ° C pressurized sample was similar in whole milk and skimmed milk, although the strain E. Coli ATCC 10536 showed no significant difference between day 0 and 9 storage, while the strain E. Coli CCUG 44857 showed a decline of approximately 0.3 logarithmic units. In orange juice, the strains of Escherichia coli showed a downward trend and increased strain CCUG 44857 was more resistant to low pH, maintaining high counts for the day 27. In strains of Staphylococcus, temperature input, matrix and the strain influenced significantly (P? 0.05) level of inactivation, reaching their highest levels in 20 Â ° C. There was no damage after sublethal treatments in either case. The evolution of viable counts of both strains showed a sharp downward trend after the day 3 storage to 4.0 Â ° C in orange juice, whereas the strain Staphylococcus carnosus CECT 4491 showed a decline trend and strong resistance when he was inoculated in milk and pressurized at low temperatures. The PAPH was effective against all strains tested at concentrations above 0.1% and exposure times exceeding 10 minutes for all types of organic materials studied. The treatments UHPH whole milk, skimmed and orange juice to 300 + 30 MPa and a temperature input 6 and 20 Â ° C were efficient to reduce viable counts of Listeria innocua ATCC 33090, Escherichia coli ATCC 10536, Escherichia coli O157: H7 CCUG 44857, Staphylococcus aureus ATCC 13565 and Staphylococcus carnosus CECT 4491. The case fatality rate increased with temperature input, suggesting a clear effect of temperature on the values of lethality. The type of matrix significantly influenced both the effectiveness of treatments UHPH as capacity growth during the subsequent period of storage at low temperatures. The treatments UHPH not damaged sublethal apparent in either case. The technology of UHPH can offer a prominent alternative to pasteurization of milk, juice and other food liquids combined with the possibility of increasing the temperature input samples before the process.

Author: CABEZA HERRERA ENRIQUE ALFONSO.
Year: 2005.
University: LEÓN [www.unileon.es].
Place of defense: FACULTAD DE VETERINARIA.
Place of preparation: FACULTAD DE VETRINARIA.

Author: CEBALLOS CHAN GERMÁN ENRIQUE.
Year: 2005.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS AGRÓNOMOS.
Place of preparation: DEPARTAMENTO DE TECNOLOGÍA DE ALIMENTOS.

Summary: papaya, in order to assess the feasibility of using these treatments in obtaining papaya minimally processed. It has been characterized the kinetics of the process for sheet papaya and has analyzed the effect of treatments, reaching 20 Â ° Brix and the liquid phase of the fruit on physicochemical properties, optical, mechanical respiration rate and microbial load. From kinetic study shows that the actual ownership of transport tissue papaya and process performance increase when using the dissolution osmotic more diluted and when applied pulse vacuum in the presence of calcium in the dissolution. From this point of view, the treatment would be more advisable to dissolve 45 Â ° Brix, applying a pulse vacuum and adding calcium. The treatments behaved osmotic changes in the transparency, brightness and color purity of the samples when applied pulse gutted, but there are no significant changes due to other factors. From the study of the mechanical properties suggests that, to best preserve the texture, it must treat the papaya with little concentrated solutions, calcium and atmospheric pressure. These aspects are recommended treatments at atmospheric pressure, calcium and 45 Â ° Brix. Treatments involving osmotic changes in the respiratory pattern of the fabric of papaya, depending on the operating conditions. Treatments with pulse vacuum imply greater restriction on the transport of oxygen leading to higher coefficient values respiratory and greater empowerment of anaerobic routes. The growth of microorganisms in the samples dried begins 3 days later than in the fresh samples.