Thesis (M.S.)--State University of New York at Binghamton, Dept. of Systems Science and Industrial Engineering, 2007. / Includes bibliographical references.

No description available.

Revised 06/2015; Originally published: 07/2006 / 3 pp. / Nutritious food is an important part of individual health and wellness. One way to ensure food is nutritious is to check the date on packages. The date is a guideline to help consumers use food when it is at its peak quality or before spoilage begins. Proper storage conditions and times are also essential in keeping healthy food safe to consume.

The purpose of this study was to develop a food quality index that can provide practical information to both consumers and professional people. The Index of Food Quality (IFQ) is a simple computerized tool based on a concept of nutrient density. The IFQ was designed to organize and clarify the present body of food composition data into a form that is directly applicable to dietary problems. The IFQ provides a method of analyzing food quality based on energy needs. The nutrient contents of foods are compared to essential nutrient standards with calories as a common denominator. In developing the IFQ, the nutrient standards were usually derived from the FDA's recommended Daily Allowances (USRDA), and the value of 2300 kcal represented an average adult requirement for energy. An index number of "1" for a particular nutrient in a given food indicates that the amount of that food yielding just sufficient energy per day to maintain weight and good health will also contain exactly the recommended daily allowance of that nutrient. We developed an index number for each nutrient in each food considered in this study. A profile of index numbers was then derived for each food. One can assess whether he is meeting the RDA by calculating whether the foods he eats additively give a value of one or greater for each nutrient area. A computer program was developed that computes the nutrient indices and prints them in tabular and bar graph forms. The program is written in FORTRAN and was developed for use with a Burroughs B6700 digital computer, but is readily compatible with the IBM 360/40 system as well. The program can evaluate a single food, various foods, and combinations of foods (i.e., diets, menus, or recipes) by printing its (their) nutrient profile. The graphs reflect the nutrient quality of a food, whether it is used as a sole source of energy or as it usually contributes to the diet (serving size). Menus, recipes, and diet profiles are presented as the sum of the nutrient contents of their individual foods and are printed as composite graphs. Nutrient data is being stored on tape and on disk. As it becomes available, new data may be written out on the disk file for later intra or inter-program use, either adding to or updating old values in the library. The IFQ program is completely flexible because every parameter can be expanded and/or modified to fit the data at hand. It can be adjusted to represent guidelines for a general population or be tailored to reflect individual or special group needs. In general, the program can compare any type of data to a reference value and produce the results in a bar graph profile. Data input is minimal. The program requires only the processing of the entry cards and a single index value per food or ingredient to print a typical graph. Modification in output requires only a code change in the entry cards and/or the input of additional special nutrient values not already stored on disk. The efficiency and speed of the modern high-speed computer coupled with a program that requires a minimum of card handling makes the IFQ a useful, rapid, and inexpensive tool for nutritional analysis and planning.

<p>Unwanted fungal growth is one of the most common causes of food spoilage throughout the world, and is causing health risks for both humans and animals and economical losses for the food- and agricultural industries. In Europe the mycotoxin producing Fusarium species F. sporotrichioides, F. culmorum, F. poae and F. graminearum is of greatest importance, due to their production of the trichothecene deoxynivalenol (DON) among other mycotoxins. Today’s conventional determination methods of these Fusarium species is time-consuming and quicker screening methods directly on cereals is therefore of interest to develop. In this project a species-specific PCR-protocol targeting the trichodiene synthase (tri5) gene in F. sporotrichioides, F. culmorum, F. poae and F. graminearum was used to evaluate two different DNA-extraction methods for cereals. The PCR-protocol was first verified with pure fungal cultures and optimized with a PCR-gradient before it was applied on cereals. The PCR-gradient resulted in a background reduction in the PCR-analysis of F. sporotrichioides infected cereals.</p><p>The two methods, called the Hammer-method (cereals was crushed with a hammer) and the Nitrogen-method (cereals were crushed in a mortar together with liquid nitrogen), is both combinations of a published DNA-extraction method (CTAB-based) for cereals and a DNA-purifying kit (chaotropic agent-based). Within these two methods some modifications were made and a comparison of the results showed that the Nitrogen-method indicated to be more stable than the Hammer-method. Too few analyses have though been made for a definite conclusion. A verification of the Nitrogen-method showed that the PCR-protocol can be considered as stable and reliable also on cereals but the DNA-extraction method for cereals is still to be optimized and stabilized. Sonification of the cereals is under consideration for further tests and studies.</p> / <p>Mögelsvampsinfektioner av spannmålsprodukter är ett av de vanligaste problemen inom mat- och jordbruksindustrierna runt om i världen. Enligt FNs Food and Agriculture Organization beräknas att cirka 25 procent av världens spannmålsgrödor är infekterade med mykotoxinbildande mögelsvampar vilket kan leda till stora hälsorisker för konsumenterna och ekonomiska förluster för mat- och jord-bruksindustrierna. Mykotoxiner är sekundära produkter från svampens ämnesomsättning som troligen har betydelse för svampens överlevnad, men kan ge toxiska effekter hos människa och djur. I Europa är mögelsvampsläktet Fusarium den vanligaste och viktigaste av mykotoxinbildande svampar och producerar de för jordbruksnäringen två viktigaste mykotoxingrupperna trichotechener och fumonisi-ner.</p><p>På grund av den breda förekomsten av dessa Fusarium-svampar finns det idag ett behov av att utveckla snabba och pålitliga metoder för att detektera och identifiera mögelsvamparna redan direkt på de färska spannmålen. Under hösten 2002 startades projektet Bestämning av potentiella mykotoxin-producerande Fusariumsvampar med PCR-metodik vid Mikrobiologiska enheten på Livsmedelsver-ket i Uppsala. Projektet syftar till att utveckla en molekylärbiologisk bestämningsmetod där identifie-ringen av svamparna sker med hjälp av dess DNA istället för via mikroskopiska undersökningar. Det-ta examensarbete har varit en del av det projektet och har i huvudsak inriktats på att utveckla en stabil metod för själva utvinningen av svamp-DNA från de färska spannmålen. De slutsatser som nåtts är att de utvinningsmetoder som examensarbetet omfattade inte kan anses stabila i nuläget utan behöver utvecklas och stabiliseras ytterligare. Vad gäller de molekylärbiologiska metoderna har de kunnat visas stabila även på färskt spannmål.</p>

Unwanted fungal growth is one of the most common causes of food spoilage throughout the world, and is causing health risks for both humans and animals and economical losses for the food- and agricultural industries. In Europe the mycotoxin producing Fusarium species F. sporotrichioides, F. culmorum, F. poae and F. graminearum is of greatest importance, due to their production of the trichothecene deoxynivalenol (DON) among other mycotoxins. Today’s conventional determination methods of these Fusarium species is time-consuming and quicker screening methods directly on cereals is therefore of interest to develop. In this project a species-specific PCR-protocol targeting the trichodiene synthase (tri5) gene in F. sporotrichioides, F. culmorum, F. poae and F. graminearum was used to evaluate two different DNA-extraction methods for cereals. The PCR-protocol was first verified with pure fungal cultures and optimized with a PCR-gradient before it was applied on cereals. The PCR-gradient resulted in a background reduction in the PCR-analysis of F. sporotrichioides infected cereals. The two methods, called the Hammer-method (cereals was crushed with a hammer) and the Nitrogen-method (cereals were crushed in a mortar together with liquid nitrogen), is both combinations of a published DNA-extraction method (CTAB-based) for cereals and a DNA-purifying kit (chaotropic agent-based). Within these two methods some modifications were made and a comparison of the results showed that the Nitrogen-method indicated to be more stable than the Hammer-method. Too few analyses have though been made for a definite conclusion. A verification of the Nitrogen-method showed that the PCR-protocol can be considered as stable and reliable also on cereals but the DNA-extraction method for cereals is still to be optimized and stabilized. Sonification of the cereals is under consideration for further tests and studies. / Mögelsvampsinfektioner av spannmålsprodukter är ett av de vanligaste problemen inom mat- och jordbruksindustrierna runt om i världen. Enligt FNs Food and Agriculture Organization beräknas att cirka 25 procent av världens spannmålsgrödor är infekterade med mykotoxinbildande mögelsvampar vilket kan leda till stora hälsorisker för konsumenterna och ekonomiska förluster för mat- och jord-bruksindustrierna. Mykotoxiner är sekundära produkter från svampens ämnesomsättning som troligen har betydelse för svampens överlevnad, men kan ge toxiska effekter hos människa och djur. I Europa är mögelsvampsläktet Fusarium den vanligaste och viktigaste av mykotoxinbildande svampar och producerar de för jordbruksnäringen två viktigaste mykotoxingrupperna trichotechener och fumonisi-ner. På grund av den breda förekomsten av dessa Fusarium-svampar finns det idag ett behov av att utveckla snabba och pålitliga metoder för att detektera och identifiera mögelsvamparna redan direkt på de färska spannmålen. Under hösten 2002 startades projektet Bestämning av potentiella mykotoxin-producerande Fusariumsvampar med PCR-metodik vid Mikrobiologiska enheten på Livsmedelsver-ket i Uppsala. Projektet syftar till att utveckla en molekylärbiologisk bestämningsmetod där identifie-ringen av svamparna sker med hjälp av dess DNA istället för via mikroskopiska undersökningar. Det-ta examensarbete har varit en del av det projektet och har i huvudsak inriktats på att utveckla en stabil metod för själva utvinningen av svamp-DNA från de färska spannmålen. De slutsatser som nåtts är att de utvinningsmetoder som examensarbetet omfattade inte kan anses stabila i nuläget utan behöver utvecklas och stabiliseras ytterligare. Vad gäller de molekylärbiologiska metoderna har de kunnat visas stabila även på färskt spannmål.

El principal objetivo de esta tesis ha sido evaluar la capacidad de la tecnología de ultra alta presión de homogeneización (UHPH) como alternativa a la pasteurización convencional para garantizar la seguridad y calidad de los alimentos líquidos. Para probar la eficacia de la UHPH y garantizar la seguridad microbiana de los alimentos se inoculó Listeria monocytogenes y/o S. enterica serovar Senftenberg 775W en diferentes alimentos líquidos como son huevo entero líquido, leche y zumo de frutas (naranja y uva). y se trataron a 150, 200 y 250 MPa en el caso del huevo liquido y a 200, 300 y 400 MPa en el de leche y zumos de frutas, realizándose la evaluación de su supervivencia durante el almacenamiento en refrigeración a 4ºC durante 20 días en las muestras de huevo y 12 días en las muestras de leche y zumo de frutas. Los recuentos de células viables y dañadas se realizaron utilizando agar triptona soya enriquecida con extracto de levadura y el mismo medio suplementado con sal. Para evaluar los factores que pudieran afectar a la inactivación bacteriana en la eficacia del tratamiento UHPH, se estudió la influencia de la concentración bacteriana baja (3 log CFU/ml) y alta (7 log CFU/ml) en huevo y leche, así como la influencia del contenido de grasa en leche (0.3, 3.6, 10, y 15% de grasa). Adicionalmente, con la finalidad de explicar algunos de los resultados de supervivencia de los patógenos inoculados en los zumos de frutas se estudió la eficacia a la respuesta de ácido tolerancia (ATR) en la protección de Listeria monocytogenes y S. enterica en fase exponencial o estacionaria en zumo de naranja y uva conservados a 4 y 25ºC. En huevo, el tratamiento a 250 MPa disminuyo los recuentos de Salmonella enteritidis serovar Senftenberg 775W a niveles similares a los obtenidos en la pasteurización térmica, produciéndose una disminución posterior por debajo de los límites de detección durante el almacenamiento 4ºC, aunque se detecto su presencia. En las muestras de leche (0.3 and 3.6%), se observó que 300 y 400 MPa dañaban considerablemente a L. monocytogenes, pero durante el almacenamiento fue capaz de recuperarse y desarrollarse. No obstante, los mayores valores de letalidad se consiguieron en las muestras de leche con un contenido de 15 y 10% de grasa. En las zumos, el tratamiento a 400 MPa inactivó completamente Salmonella enteritidis serovar Senftenberg 775W, este cepa se mostró mas sensible que L. monocytogenes a los tratamientos UHPH aplicados. Sin embargo, al finalizar el periodo de almacenamiento del zumo de uva control y homogenizado no se detectaron recuentos de L. monocytogenes, lo que podría ser atribuido a la presencia de compuestos naturales de la uva con efecto antilisteria. La respuesta de ácido tolerancia se indujo a L. monocytogenes y Salmonella enteritidis serovar Senftenberg 775W para evaluar si se presentaba un efecto protector ante estrés por acidez. Se observó que las células en fase estacionaria mostraban una resistencia natural a pH bajos. Tomando como modelo al zumo de naranja, se evaluó el efecto de la UHPH en la actividad enzimática (pectin metilesterasa) y microbiológica (bacterias aerobias mesófilas, psicotrófas, ácido lácticas y levaduras), en los atributos físicos (turbidez y distribución del tamaño de partícula), en las propiedades bioactivas (contenido de Lacido ascórbico, carotenoides y polifenoles), en la actividad antioxidante y en otros los parámetros generales de calidad (color, pH, °Brix, acidez titulable, azúcares reductores y índice de oscurecimiento no enzimático). Los tratamientos UHPH aplicados consistieron de dos temperaturas de entrada (10 o 20ºC), tres niveles de presión (100, 200 y 300 MPa) y dos tiempos de retención (≤ 0.7 o 30 segundos). Los resultados se compararon con los resultados obtenidos por pasteurización térmica (1 o 2 min a 90 ºC). Los tratamientos de UHPH iguales o superiores a 200 MPa fueron igualmente efectivos que la pasteurización para el control de la actividad enzimática y de las bacterias alterantes del zumo no apreciándose actividad enzimática ni incremento de los recuentos microbianos tras 50 días de almacenamiento a 4ºC. Los zumos tratados por UHPH tuvieron la mejor distribución de tamaño de partícula y los mejores valores de turbidez en comparación con los zumos pasteurizados, obteniendo una mayor reducción de del tamaño de partícula en las muestras tratadas a 300 MPa. La retención de L-acido ascórbico y carotenoides dependió de la presión aplicada y específicamente de la temperatura alcanzada durante el tratamiento. El contenido de flavonoides se incrementó en el zumo con los tratamientos por UHPH, obteniendo el mayor contenido a 200 y 300 MPa. Además, los zumos tratados por UHPH mostraron niveles de capacidad equivalente antioxidante trolox (TEAC) mayores que los de los zumos frescos o pasteurizados. Además, se realizó un estudio sensorial de preferencia y aceptabilidad en zumo homogeneizado en las condiciones consideras de elección (20ºC de temperatura de entrada y 300 MPa) y se evaluó la vida útil a 6ºC y 20ºC por 90 días. En el estudio de aceptabilidad, la muestras tratada por UHPH obtuvieron la menor puntuación en términos de valoración de color con respecto a la muestra pasteurizada. Durante los 90 días de almacenamiento a 6ºC los recuentos de las muestras tratadas por UHPH así como las pasteurizadas se mantuvieron por debajo del límite de detección (1 Log CFU/ml). / The main objective of this thesis has been to evaluate the capacity of the ultra-high pressure homogenization (UHPH) technology as alternative to the conventional pasteurization in ensuring the safety and quality of liquid foods. To test the effectiveness of the technology to guaranty the microbial safety of foods we inoculated strains of Listeria monocytogenes and/or S. enterica serovar Senftenberg 775W into different liquid foods such as whole egg, milk and fruit juices (orange and grape). They were submitted to a single cycle of UHPH treatment at 150, 200 and 250 MPa for liquid whole egg and at 200, 300, and 400 MPa for milk and fruit juices. The effectiveness of the UHPH treatments over low (3 log CFU/ml) and high (7 log CFU/ml) bacteria loads was evaluated in both liquid whole egg and milk. Moreover, the influence of milk fat content (0.3, 3.6, 10, and 15% of fat) in the Listeria monocytogenes inactivation by UHPH treatments was also studied. Samples counts were followed during of storage at 4ºC over 20 days for liquid whole egg and 15 days for milk and fruit juices. Viable and injured bacterial counts were evaluated by means of a differential plating method using tryptone soy agar enriched with yeast extract and the same medium supplemented with salt. Additionally, with the purpose to explain some of the results of the survival of pathogens inoculated in fruit juices, the effectiveness of the response acid tolerance (ATR) on the protection in the exponential or stationary phase of Salmonella Seftenberg and L. monocytogenes inoculated in orange and grapefruit juice during their conservation at 4 °C and 25ºC was studied. In liquid whole egg, UHPH treatments at 250 MPa effectively reduced Salmonella enteritidis serovar Senftenberg 775W to similar levels than reported for thermal pasteurization. Surviving Salmonella counts decreased below the detection limit during the storage of the liquid egg at 4ºC, although Salmonella was immunologically detected during all the storage period. In milk samples which a low fat concentration (0.3 and 3.6 %), pressures of 300 and 400 MPa damaged considerably L. monocytogenes cells but they were able to recover and grow up during the subsequent cold storage. Nevertheless, higher lethality values were achieved in milk with the highest fat content (15 and 10%). In fruit juices, UHPH treatments at 400 MPa inactivated completely Salmonella enteritidis serovar Senftenberg 775W, being this strain more sensitive than L. monocytogenes to the UHPH treatments applied. However, in grape juice L. monocytogenes viable counts were undetectable at the end of storage in both control and pressurized samples, which could be attributed to the presence of natural compounds with antilisterial effect. Acid tolerance response (ATR) was induced in L. monocytogenes and Salmonella enteritidis serovar Senftenberg 775W to assess if it was able to protect cells from a most severe acid stress. Cells in stationary phase, used on the UHPH experiment with juices, showed a natural resistance to low pH values. Taking orange juice as food model, we also evaluated the effect of UHPH treatments on enzymatic activity (pectin methylesterase PME) and microbiological (mesophilic aerobic bacteria, psychrotrophic aerobic bacteria, lactic-acid bacteria and yeast) spoiling activity, as well as on physical attributes (cloud stability and particle size distribution), bioactive properties (L-ascorbic, carotenoid and polyphenol content), antioxidant activity and other general quality parameters (color, pH, °Brix, titratable acidity, reducing sugars and non-enzymatic browning index). In this case the UHPH treatments used consisted in combinations of two inlet temperatures (10 or 20ºC), three pressures (100, 200 or 300 MPa) and two holding times (≤ 0.7 or 30 seconds). Results were compared with two thermal pasteurization treatments (1 or 2 min at 90 ºC). UHPH treatments above 200 MPa were as effective as pasteurization to control both PME activity and spoilage bacteria in orange juice. Neither pectin methyl esterase activity nor microbial counts increased significantly after 50 days of storage at 4ºC. UHPH treated juices showed a better particle size distribution and cloudiness values than the pasteurized juices. In particular, the smallest particles were observed in samples treated at 300 MPa. L-ascorbic acid and carotenoid retention of orange juice depended on the high pressure used and more specifically on the maximum temperature achieved during the UHPH treatment. Content of flavonoids in orange juice increased after the UHPH treatments, achieving the maximum concentration in the samples treated at 200 and 300 MPa. Moreover, UHPH treated juices showed higher levels of trolox equivalent antioxidant capacity (TEAC) values than did fresh and heat-treated samples. Additionally, a preliminary sensorial test of preference and acceptability was made with the orange juice treated at 20ºC of inlet temperature and 300 MPa. Moreover with these samples a shelf-life test was carried out by 90 days at 6ºC and 20ºC. In the consumer acceptability study, the UHPH samples in term of color obtained the lowest score. Microbial counts of both UHPH treated and pasteurized samples kept below of the detection limit (1 Log CFU/ml) during the 90 days of storage at 6ºC.

Food industry is demanding for fast screening methodologies in order to guaranty food quality and safety. These methodologies should allow high throughput with sufficient accuracy and reproducibility. In this context, MS-Sensor is a challenging approach since it allows simultaneous determination of compounds in food matrices and complex mixtures with a high sample throughput. The basic working principle of MS-Sensor systems is based on the introduction of volatile components extracted from the headspace of a sample into the ionization chamber of a mass spectrometer. The mass spectra resulting from the ionization and fragmentation of this extract constitute a very complex ionization pattern that can be seen as a 'fingerprint' which is characteristic of the matrix being analyzed. These ionisation patterns are then processed by pattern recognition engines to perform tasks such as classification, recognition and, to a limited extent, quantification.This thesis is devoted to study the possibilities and capabilities of MS-Sensor approach to its application in several food quality related problems such as the determination rancidity levels in crisps; the detection of fungal spoilage in bakery products, the monitoring of sardines freshness under cold storage; the classification of virgin olive oils according its organoleptic properties and the discrimination of two Iberian ham qualities according pig's feeding. In each one of these applications it has been demonstrated the feasibility of using a MS-Sensor to solve the food quality problem under study. It has been widely demonstrated that the MS-Sensor profile can be considered as a useful fingerprint technique for characterization of the targeted quality property and, as in certain cases, even for quantification of several parameters correlated with this problem.Despite that feasibility of MS-Sensor has been widely demonstrated for the applications under study, this approach stills suffer from some weakness or drawbacks that may influence performance of MS-Sensor. Main drawbacks are the inherent high dimensionality of data response matrices and the low selectivity of m/z fragments pseudosensors used as variables in these matrices.These two drawbacks could be responsible for the lack of reproducibility showed by MS-Sensor systems in certain applications mentioned above. In order to success in the development of such applications it was necessary to figure out different strategies for overcoming this high dimensionality and the low selectivity. In order to handle the low selectivity of m/z fragments several new methodologies based on the use of multi-way algorithms has been implemented for the first time in the framework of this thesis. Besides, new variable selection algorithms has been developed and implemented in order to avoid high dimensionality modelling. It has been demonstrated that use of the developed algorithms leads to a simpler and more parsimonious models and consequently to a better performance and more reproducible results.In addition, several issues related to use of MS-Sensor in food analysis has been studied: the use of different headspace sampling techniques; the comparison of MS-Sensor systems performance against classical MOS based 'electronic noses'; the application of new algorithms for pre-processing MS-Sensor signals; the correlation of MS-Sensor response and the well-established methods to assess the quality property under study, etc.MS-Sensor is a powerful device set-up, capable of producing large amounts of highly selective information. Optimal use of this device implies both, a correct use of analytical techniques (sample handling and instrumental) and a rational use of subsequent data analysis. That can be only attained if analytical people in charge of experimental set-up work side by side with data analysis and software developers. This thesis aims to bring nearer this close collaboration. / La indústria alimentària exigeix el desenvolupament de mètodes analítics que puguin donar resposta immediata i que al mateix temps puguin garantir la qualitat i la seguretat dels productes de forma acurada i reproduïble. En aquests context, els mètodes que utilitzen un sistema MS-Sensor poden ser uns bons candidats ja que permeten fer l'anàlisi de volàtils de matrius complexes d'una manera ràpida i també permeten processar moltes mostres en poc temps. El funcionament d'un MS-Sensor es basa en la introducció dels compostos volàtils que s'extreuen de l'espai de cap d'una mostra en la font d'ionització d'un espectròmetre de masses sense prèvia separació cromatogràfica i sense necessitat d'una preparació de mostra prèvia. L'espectre de masses resultat de la ionització i fragmentació de tots els compostos volàtils presents en l'extracte es pot considerar com una empremta digital característica de la matriu que s'està analitzant. Els espectres de masses generats es processen a posteriori amb un sistema de reconeixement de patrons per tal de realitzar tasques associades a aquests sistemes com son la classificació i el reconeixement de noves mostres i dins de certs límits la quantificació d'aquestes.Aquesta tesi està dedicada a l'estudi de les capacitats i possibilitats d'aquests sistema a donar resposta a tot un seguit d'aplicacions relacionades amb l'anàlisi de la qualitat de diferents tipus d'aliments com son: la determinació del grau d'enranciment de patates fregides; la detecció del creixement fúngic en productes de brioxería industrial; la monitorització del grau de frescor de sardines guardades en fred; la classificació de diversos olis d'oliva en base a les seves propietats organolèptiques i la classificació del pernil ibèric en base a la seva qualitat determinada per l'alimentació del porc. Per cada una d'aquests aplicacions s'ha demostrat l'aplicabilitat i la fiabilitat del sistema MS-Sensor a l'hora de resoldre les diferents qüestions plantejades sobre qualitat alimentària. S'ha demostrat àmpliament que el perfil de volàtils que s'obté amb un MS-Sensor pot cosiderar-se com una empremta digital vàlida i molt útil en la caracterització del problema que es vol resoldre i fins i tot en alguns casos, s'ha demostrat que aquesta mateixa empremta es pot correlacionar amb el paràmetres d'anàlisi clàssics que s'usen més habitualment per tal de resoldre aquests problema o que inclús aquests sistema es pot fer servir per predir-los.Encara que la viabilitat del sistema MS-Sensor en les aplicacions plantejades ha estat demostrada àmpliament en el decurs d'aquesta tesis, aquests sistema té petits inconvenients o punts febles que resten per resoldre. Aquests inconvenients poden afectar de manera directa els resultants que se n'obtenen. Els principals punts febles del MS-Sensor son d'elevada dimensionalitat de les matrius de resposta que s'obtenen que és inherent al propi sistema i la baixa selectivitat del fragments m/z considerats com a variables en aquestes matrius.Aquests dos inconvenients poden ser els responsables de la falta de reproductibilitat que s'ha obtingut en algunes aplicacions. Per tal d'obtenir bons resultats en alguna d'aquestes aplicacions es van haver de plantejar noves estratègies que poguessin salvar les dificultat derivades de la baixa selectivitat de les variables i de la seva elevada dimensionalitat. Per primera vegada i dins del marc d'aquesta tesis s'ha plantejat l'ús d'algoritmes multi-way i la inclusió del temps de retenció com a variable que pugui reportar informació addicional en el processat de les respostes del MS-Sensor. A la vegada, s'ha desenvolupat i implementat nous algoritmes per a la selecció de variables per tal d'evitar en la mesura del possible l'elevada dimensionalitat en les matrius de resposta. S'ha demostrat que l'ús d'aquests nous algoritmes permet obtenir models més simples i robustos i per tant podem aconseguir un millor funcionament del sistema i resultats més reproduïbles.A més a més s'han estudiat diferents aspectes relacionats amb la utilització d'un sistema MS-Sensor per a l'anàlisi d'aliments com son: l'ús de diferents tècniques de mostreig d'espai de cap, la comparació del sistema MS-Sensor amb sistemes clàssics d'olfacte electrònic, l'aplicació i desenvolupament d'algoritmes de pre-processament dels espectres generats, la correlació de les respostes obtingudes amb un sistema MS-Sensor amb mètodes d'anàlisi d'aliments tradicionals, etc.El MS-Sensor es un dispositiu molt potent, capaç de produir una elevada quantitat de dades. L'ús òptim d'aquests sistema es composa d'una banda d'un ús correcte dels aspectes instrumentals com son el propi sistema en si i les tècniques de mostreig i per altra banda d'un ús racional de les tècniques d'anàlisi de dades. Això només s'aconsegueix si els analítics que treballen amb el set-up de l'experiment treballen colze a colze i en estreta col·laboració amb la gent encarregada de fer l'anàlisi de dades. Aquesta tesi, pretén fer més estret l'espai entre aquests dues disciplines i dóna les eines per ajuntat i promoure aquesta col·laboració.

A novel simulated food model (ascorbic acid, thiamine and a mixture of glucose and glycine) incorporating celite was developed. Basic kinetic parameters were established and the analysis of this data led to a reconsideration of the fundamental aspects relating the TDT and Arrhenius systems of evaluating kinetic parameters and their meaning. Heat penetration data was obtained for both conduction and convection systems, with the conduction system being characterized by parameters calculated from the heat penetration data. Stainless steel micro-capsules were used to isolate and obtain centerpoint nutrient destruction and compared it to the predictions of two computer models. Computer models were tested and verified for the conduction system and an optimization technique based on a multi-factor objective function evaluated. / Celite simulated a typical conduction system and the kinetics of quality factor degradation varied depending on composition. Centerpoint capsules worked well in evaluating nutrient destruction and provided a means for verifying computer simulations. Predictions from the Teixeira and Ball models indicated that the Teixeira model was a better process predictor. Multi-factor objective functions for maximizing nutrient retention were shown to work well in defining optimal conditions using the Teixeira program, while those based on the Ball model were indeterminate.

Aim: The aim of this research is to investigate factors which influence customer satisfaction in Asian restaurants.Method: Qualitative method and quantitative are used in this research. The data collected from both questionnaires and semi-structured interviews. Result and Conclusions: The research concludes that food quality and service quality are important factors of customer satisfaction towards Asian restaurants in Gävle. Meanwhile, environmental factors, the price of food and the authenticity of food also affect satisfaction of the Asian restaurant customers. Suggestions for future research: Future research could expand the diversity of samples to get a broader perspective of Customer satisfaction, or based on our research framework, a narrowed perspective of only one type of restaurant would be studied in the future. Contribution of the thesis: This thesis provides a new idea of studying customer satisfaction. Moreover, the research developed a model of customer satisfaction in the restaurant industry. Key words: Food Quality, Service Quality, Environmental Factors, Price and Authenticity Impression of Asian restaurants