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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Inhibiting thermo-oxidative degradation of oils during frying

Aladedunye, Adekunle Felix January 2011 (has links)
The present study sought for practical ways to improve the frying performance of oils without compromising the availability of the essential fatty acids and nutraceuticals. To this end, the influence of temperature, oxygen concentrations, and compositions of minor components on frying performance was investigated. A novel frying protocol, utilizing carbon dioxide blanketing, was developed and found to significantly improve the performance of the frying oil. Optimizing both the amounts and the compositions of endogenous minor components also improved the performance of the frying oil. Twenty one novel antioxidants were synthesized and evaluated under frying and storage conditions. Antioxidant formulations consisting of a combination of endogenous and synthesized antioxidants were developed and tested in an institutional frying operation. A rapid and effective frying test was developed to assess the frying performance of oils and applied antioxidants. Furthermore, a novel procedure for direct hydroxynonenal analysis in frying oil was developed. / xx, 249 leaves; 29 cm
22

Improving Fried Product and Frying Oil Quality Using Nitrogen Gas in A Pressure Frying System

Innawong, Bhundit 15 August 2001 (has links)
The commercial pressure frying has been limited to frying huge amount of products due to its dependence on the amount of moisture released from the food for generating the desired pressure. This study investigated the feasibility of using nitrogen gas as a substitute for steam in the pressure frying system. The effects of various process conditions (source of pressure, frying temperature and pressure) on fried product and frying oil qualities were evaluated. Frying experiments were performed on breaded/battered poultry products including chicken nuggets (homogenous) and chicken fillets (marinated, intact muscle). Efforts were also made to develop rapid methods to determine frying oil quality and discriminate among fresh, marginal and discarded oils using a chemosensory (also known as electronic nose) or Fourier transform infrared spectroscopy (FTIR-ATR). Frying temperature and pressure affected fried food quality. An increase in frying pressure resulted in tender, juicier products with less oil uptake due to high moisture retention. An increase in frying oil temperature resulted in an increased moisture loss, oil uptake resulting in less tender and juicier products. Compared with frying using steam released from food, using nitrogen provided similar or better quality fried products in terms of moisture retention, juiciness and texture. The reused oils from the fryer using nitrogen gas was better in quality than the system using steam as evidenced from the physical, chemical and chemosensory measurements. / Ph. D.
23

The correlation between color and oxidation status in high oleic deep-frying oils: impact of antioxidants

XU, HUI 23 August 2016 (has links)
Frying oil is a heat and mass transfer medium, which affects the quality of food. The reaction mechanisms in deep-frying oils are mainly thermal oxidation, hydrolysis, and polymerization, which result in lipid deterioration. Addition of synthetic or natural antioxidants can effectively slow down lipid deterioration during deep-frying. Total polar components, polymerized triglycerides, p-anisidine value, acid value and iodine value are reliable indicators for assessing oil degradation during frying. Color darkening of deep-frying oils is one of apparent changes during deep-frying and is closely associated with the levels of decomposition compounds in the frying oils. However, the evidence of the relationship between color and deep-frying oil quality indicators are scanty. The main objective of this thesis is to develop a model for rapid assessment of oil quality during 30-hour deep-frying processes using oil color and quality as indicators. Significant color changes (p < 0.05) were observed in soybean oil as compared to canola and sunflower oil during 30-hour deep-frying trials. Canolol-enriched frying oils showed the highest color values before deep-frying, but the final results showed the least color changes (p < 0.05) during the 30-hour deep-frying trials. The highest percentage of total polar components (15.55 %), polymeric triglycerides (9.3 %), and p-Anisidine value (62.34) were found in TBHQ-enriched deep-frying oil samples in soybean oil. The highest acid value (3.06 mg KOH/100g) was found in canolol-enriched frying oil samples in canola oil. Rosemary and canolol-enriched deep-frying oil samples showed significant effect (p < 0.05) on color changes while reducing formation of total polar components, polymeric triglycerides, and aldehydes during the 30-hour deep-frying study. Significant correlations (p < 0.05) were found between color and oil quality indicators in all of the deep-frying oil samples; significant regression (p < 0.05) models are expressing the level of oil deterioration from color (light-dark, red-green, yellow-blue) in deep-frying oils. Overall, this study established several models using color as an indicator aiming to rapidly assess deep-frying oil quality. / October 2016
24

Effect of fried lard and corn oil on blood cholesterol in hamsters.

January 2008 (has links)
Tan, Sijiao. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 118-136). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract (in English) --- p.iii / Abstract (in Chinese) --- p.vi / List of Abbreviations --- p.viii / Table of Contents --- p.x / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- Frying --- p.1 / Chapter 1.1.1 --- General introduction of frying --- p.1 / Chapter 1.1.2 --- Physical and chemical changes of oils during frying --- p.2 / Chapter 1.1.2.1 --- Physical changes --- p.2 / Chapter 1.1.2.2 --- Chemical changes --- p.5 / Chapter 1.1.2.2.1 --- Hydrolysis --- p.5 / Chapter 1.1.2.2.2 --- Oxidation --- p.5 / Chapter 1.1.2.2.3 --- Polymerization --- p.6 / Chapter 1.1.3 --- Frying oil selection --- p.11 / Chapter 1.1.4 --- Quality control of frying oil --- p.11 / Chapter 1.2 --- Selection of experiment oil --- p.13 / Chapter 1.2.1 --- Lard as a cholesterol-containing animal fat --- p.13 / Chapter 1.2.2 --- Corn oil as a healthy vegetable oil --- p.14 / Chapter 1.3 --- Current studies on frying oils --- p.18 / Chapter 1.4 --- Atherosclerosis and cholesterol metabolism --- p.19 / Chapter 1.4.1 --- Atherosclerosis --- p.19 / Chapter 1.4.2 --- Cholesterol metabolism and related regulating factor --- p.23 / Chapter 1.5 --- Animal model selection --- p.29 / Chapter CHAPTER 2 --- OBEJECTIVES --- p.30 / Chapter CHAPTER 3 --- MATERIALS AND METHODS / Chapter 3.1 --- Sample lard and corn oil preparation --- p.31 / Chapter 3.2 --- Diet preparation --- p.34 / Chapter 3.3 --- Animals --- p.36 / Chapter 3.4 --- Sample collection --- p.36 / Chapter 3.5 --- GC analysis of fatty acid composition in fresh and fried experiment oil samples --- p.37 / Chapter 3.6 --- Determination of plasma cholesterol and organ cholesterol --- p.41 / Chapter 3.7 --- "Determination of hamster fecal neutral and acidic sterols, corn oil phytosterol content" --- p.44 / Chapter 3.7.1 --- Determination of fecal neutral sterols --- p.44 / Chapter 3.7.2 --- Determination of fecal acidic sterols --- p.45 / Chapter 3.7.3 --- Determination of phytosterol content in corn oil --- p.46 / Chapter 3.8 --- "Determination of composition and concentration of liver triglycerides, total free fatty acids and phospholipids" --- p.51 / Chapter 3.9 --- Statistics --- p.54 / Chapter CHAPTER 4 --- RESULTS IN FRIED LARD EXPERIMENT / Chapter 4.1 --- Fatty acid composition and cholesterol content of experiment lard --- p.55 / Chapter 4.2 --- Body weight and food intake --- p.55 / Chapter 4.3 --- Relative organ weight --- p.55 / Chapter 4.4 --- "Plasma total cholesterol, triglycerides and HDL- cholesterol" --- p.60 / Chapter 4.5 --- Organ cholesterol --- p.60 / Chapter 4.6 --- Fecal neutral sterol output --- p.64 / Chapter 4.7 --- Fecal acidic sterol output --- p.64 / Chapter 4.8 --- Effect of fried lard on cholesterol balance in hamster --- p.64 / Chapter 4.9 --- "Effect of fried lard on hepatic triglycerides, free fatty acids and phospholipids concentration in hamster" --- p.68 / Chapter 4.10 --- Correlation between serum HDL cholesterol and liver cholesterol --- p.76 / Chapter 4.11 --- Correlation between serum HDL cholesterol and kidney cholesterol --- p.76 / Chapter 4.12 --- Correlation between serum TG and liver TG --- p.76 / Chapter CHAPTER 5 --- RESULTS OF FRIED CORN OIL EXPERIMENT / Chapter 5.1 --- Fatty acid composition and phytosterol content of experiment corn oil --- p.80 / Chapter 5.2 --- Body weight and food intake --- p.80 / Chapter 5.3 --- Relative organ weight --- p.84 / Chapter 5.4 --- Plasma total cholesterol,triglycerides and HDL- cholesterol --- p.84 / Chapter 5.5 --- Organ cholesterol --- p.87 / Chapter 5.6 --- Fecal neutral sterol and phytosterol output --- p.87 / Chapter 5.7 --- Fecal acidic sterol output --- p.92 / Chapter 5.8 --- Effect of fried corn oil on cholesterol balance and phytosterol balance in hamsters --- p.92 / Chapter 5.9 --- "Effect of fried corn oil on hepatic triglycerides, free fatty acids and phospholipids concentration in hamster" --- p.97 / Chapter 5.10 --- Correlation between serum HDL cholesterol and liver cholesterol --- p.105 / Chapter 5.11 --- Correlation between serum HDL cholesterol and kidney cholesterol --- p.105 / Chapter 5.12 --- Correlation between serum TG and liver TG --- p.105 / Chapter CHAPTER 6 --- DISCUSSION --- p.109 / Chapter CHAPTER 7 --- CONCLUSION --- p.117 / REFERENCE --- p.118
25

Heat and mass transfer analogy under turbulent conditions of frying

Farinu, Adefemi 20 November 2006
Sweetpotato (<i>Ipomoea batatas</i>) is a popular vegetable across the world. It is a staple food item of many countries in South America, Africa and Asia where the population depends on the crop as an important source of energy and essential nutrients like vitamins A and C, calcium, iron and copper. It is also a very popular crop in North America. Deep fat frying is one of the favourite processing methods for sweetpotato. The method is fast and the finished product is desired for its unique flavour and taste. <p>The main objective of this study was to establish analogy between convective heat and mass transfer during frying. The accurate estimation of the coefficients for both phenomena is challenging. During frying, the rate of heat transfer from the oil to the food surface is largely controlled by the convective heat transfer coefficient. This heat transfer coefficient is dependent on the interaction between the temperature gradient and the drying rate in a frying process. The temperature gradient and the drying rate in turn partly depend on the thermophysical properties of the product. In this study, thermophysical properties of sweetpotato were studied and modeled as a function of moisture content and temperature. The properties of interest are specific heat capacity, thermal conductivity, thermal diffusivity and density. A designed deep fat frying experiment of sweetpotato was carried out under four different oil temperatures (150, 160, 170 and 180°C) and using three different sample sizes (defined as ratio of diameter to thickness (D/L: 2.5, 3.5 and 4.0). Convective heat transfer coefficients under these frying conditions were estimated and computer simulation based on finite element modeling technique was used to determine convective mass transfer coefficients. Correlation between heat transfer coefficient and mass transfer coefficient were investigated with reliable statistical tool. Effects of sample size, oil temperature and frying time on heat and mass transfer were also studied. <p>Specific heat, thermal conductivity and thermal diffusivity of sweetpotato were all found to increase with increase in temperature and moisture content. Density decreased with increase in moisture content. Maximum heat transfer coefficient reached during sweetpotato frying was in the range of 700-850 W/m2.°C. Heat transfer coefficient of sample during frying increased with increase in frying oil temperature but decreased with increase in sample size. Same trend for heat transfer coefficient was observed for effects of oil temperature and sample size on mass transfer coefficient. Maximum mass transfer coefficient reached during sweetpotato frying was in the range of 4×10-6 to 7.2×10-6 kg/m2.s. No general relationship was established between heat transfer coefficient and mass transfer coefficient during frying but a relationship was established between maximum heat transfer coefficient and maximum mass transfer coefficient. A trend was also observed between maximum heat transfer coefficient and the corresponding mass transfer coefficient at that point.
26

Heat and mass transfer analogy under turbulent conditions of frying

Farinu, Adefemi 20 November 2006 (has links)
Sweetpotato (<i>Ipomoea batatas</i>) is a popular vegetable across the world. It is a staple food item of many countries in South America, Africa and Asia where the population depends on the crop as an important source of energy and essential nutrients like vitamins A and C, calcium, iron and copper. It is also a very popular crop in North America. Deep fat frying is one of the favourite processing methods for sweetpotato. The method is fast and the finished product is desired for its unique flavour and taste. <p>The main objective of this study was to establish analogy between convective heat and mass transfer during frying. The accurate estimation of the coefficients for both phenomena is challenging. During frying, the rate of heat transfer from the oil to the food surface is largely controlled by the convective heat transfer coefficient. This heat transfer coefficient is dependent on the interaction between the temperature gradient and the drying rate in a frying process. The temperature gradient and the drying rate in turn partly depend on the thermophysical properties of the product. In this study, thermophysical properties of sweetpotato were studied and modeled as a function of moisture content and temperature. The properties of interest are specific heat capacity, thermal conductivity, thermal diffusivity and density. A designed deep fat frying experiment of sweetpotato was carried out under four different oil temperatures (150, 160, 170 and 180°C) and using three different sample sizes (defined as ratio of diameter to thickness (D/L: 2.5, 3.5 and 4.0). Convective heat transfer coefficients under these frying conditions were estimated and computer simulation based on finite element modeling technique was used to determine convective mass transfer coefficients. Correlation between heat transfer coefficient and mass transfer coefficient were investigated with reliable statistical tool. Effects of sample size, oil temperature and frying time on heat and mass transfer were also studied. <p>Specific heat, thermal conductivity and thermal diffusivity of sweetpotato were all found to increase with increase in temperature and moisture content. Density decreased with increase in moisture content. Maximum heat transfer coefficient reached during sweetpotato frying was in the range of 700-850 W/m2.°C. Heat transfer coefficient of sample during frying increased with increase in frying oil temperature but decreased with increase in sample size. Same trend for heat transfer coefficient was observed for effects of oil temperature and sample size on mass transfer coefficient. Maximum mass transfer coefficient reached during sweetpotato frying was in the range of 4×10-6 to 7.2×10-6 kg/m2.s. No general relationship was established between heat transfer coefficient and mass transfer coefficient during frying but a relationship was established between maximum heat transfer coefficient and maximum mass transfer coefficient. A trend was also observed between maximum heat transfer coefficient and the corresponding mass transfer coefficient at that point.
27

Quality evaluation of frying oil and chicken nuggets using visiblenear-infrared hyper-spectral analysis

Kazemi Sangdehi, Samira January 2005 (has links)
The application of visible/near-infrared hyper-spectral analysis to monitor the quality of frying oil and fried breaded chicken nuggets was investigated. / Partial least squares (PLS) calibration models were developed to predict the acid value, total polar components and viscosity of heated oils with different ratios of hydrogenation. Coefficient of determination (R2) and root mean square error (RMSE) were calculated to assess the performance of each model. Results of the study demonstrated good prediction ability of the calibration models for the quality parameters with R2 values of over 0.92. / The second study was based on developing calibration models for prediction of moisture and fat contents of fried breaded chicken nuggets with different levels of moisture and fat contents. Performing the same procedure for evaluation of the PLS calibration models, results of the study demonstrated that moisture and fat contents of fried breaded chicken nuggets could be predicted with R2 values of 0.92.
28

Heat and mass transfer in deep fat frying of breaded chicken nuggets

Wang, Yunfeng, 1970- January 2005 (has links)
This study presents techniques that can be applied to optimize the quality of coated fried chicken nuggets. / Heat and mass transfer during deep fat frying of breaded chicken nugget was simultaneously modeled using the moving boundary concept. Numerical software FEMLABRTM 3.0 was used to solve the proposed model. To validate the model, experiments were conducted. Chicken nuggets were made with wheat flour based batter and breading. The samples were fried in a fryer using oil temperatures at 160, 170 and 180°C. Total frying times ranged from 90 to 300 s. A good agreement was obtained between predicted and observed results. / During the deep-frying process, the chicken nuggets samples shrank because of moisture loss and protein denaturation. Particle density and bulk volume shrinkage were analyzed at 3 different frying temperatures (160, 170 and 180°C). Particle density and shrinkage of the samples was measured using the liquid displacement technique with water. A linear relation was found for particle densities with moisture loss. The relationship between volumetric shrinkage and moisture loss was also found to be linear and the linear equation may be useful in predicting the volumetric shrinkage during frying. / In order to reduce the oil absorption of chicken nuggets during the frying process, the influence of pretreatment in microwave on the moisture and oil transfer in the coating and core layers of coated chicken nuggets were studied. Chicken nuggets pretreated in a microwave oven for 1 or 2 min were fried at 160°C for times ranging from 90 to 300 s to evaluate oil transfer. Microwave pretreatment had an important effect on moisture loss and oil uptake of chicken nuggets during deep-fat frying.
29

Evaluation of acrylamide in foods and development of some strategies for its reduction

Sansano Tomás, Mariola 17 July 2018 (has links)
Although the presence of acrylamide in foods was detected a decade ago, public concern about this issue, and in general about food health, seems to have increased in recent years. Acrylamide is a toxic human carcinogen present mainly in foods from plant origin and subjected to transformation processes in which temperatures above 120 °C are reached, such as frying and baking. Foods that mostly contribute to the intake of acrylamide are: French fries and chips, coffee and coffee substitute, biscuits, bread, pastries, battered and breaded products, breakfast cereals ..., being children and adolescents the most exposed population. From a chemical point of view, acrylamide is formed mainly from the reaction, during thermal processing, between asparagine and reducing sugars, as an intermediate product of the Maillard reaction. In the last decade, both health authorities and the scientific community have made great efforts in scientifically establishing limits of toxicity as well as exploring strategies aimed at reducing acrylamide formation. The purpose of this doctoral thesis is framed in this last sense. On the one hand, our work has been focused on searching new strategies for acrylamide mitigation, in two different types of food: fried potatoes and battered products. The effect of an emerging frying technique, named hot air frying, as well as pre-frying treatments, were studied in fried potatoes. In the case of batters however, the strategy consisted in modifying their composition by adding a hydrocolloid, chitosan, after having tested its potential in model systems. Furthermore, the effect of chitosan addition on the physical properties of the batter formulations and on the quality of the final product was evaluated. Finally, acrylamide bioaccessibility of the food products with the highest acrylamide content was addressed. These food products were subjected to an in vitro gastrointestinal simulation in order to study how acrylamide content progressed throughout the digestion process. Results showed that air fried potatoes as well as chitosan addition to batter formulations reduced the formation of acrylamide by about 90 and 60 %, respectively. The modification of the characteristics of chitosan (molecular weight and deacetylation degree) conditioned its ability to reduce the formation of acrylamide. Furthermore, the incorporation of chitosan to batters reduced the absorption of fat during frying. Chitosan increased viscosity and consistency of batters but, the color and texture of the fried products were not significantly altered. The total replacement of wheat flour by rice flour allowed to obtain gluten-free batters with similar viscosity, when adding chitosan. This new formulation could be adjusted to gluten-free battered products. The simulation of in vitro digestion showed a significant increment of acrylamide after the gastric stage in a wide range of foods. However, acrylamide bioaccessibility (after the intestinal stage) was reduced until pre-digestion levels or even lower in chips and French fries. / Si bien es verdad que la presencia de acrilamida en alimentos se detectó hace más de una década, la preocupación por parte del consumidor, no sólo por este tema si en la alimentación saludable en general, parece haberse incrementado en los últimos años. La acrilamida es un tóxico posible carcinógeno humano presente principalmente en alimentos derivados de materias primas de origen vegetal y sometidos a procesos de transformación en los que se alcanzan temperaturas por encima de 120 ºC como la fritura y horneado. Los alimentos que contribuyen mayoritariamente a la ingesta de acrilamida son: patatas fritas (tipo French fries y chips), café y substituto de café, galletas, pan, bollería, rebozados y empanados, cereales de desayuno¿, siendo la exposición al tóxico superior por parte de población infantil y adolescente. Desde un punto de vista químico, la acrilamida se forma principalmente a partir de la reacción entre la asparagina y azúcares reductores durante el procesado térmico, como producto intermedio de las reacciones de Maillard. En la última década, tanto las autoridades sanitarias como la comunidad científica han puesto un gran empeño en establecer científicamente los límites de toxicidad y en la búsqueda de estrategias orientadas a reducir su formación. El cometido de esta tesis doctoral se enmarca en este último sentido. Por un lado, se ha trabajado en la búsqueda de nuevas estrategias para la reducción de acrilamida, en dos tipos de alimentos distintos: patatas fritas y masas de productos rebozados. En patatas fritas se estudió el efecto de una técnica emergente de fritura, concretamente la fritura por aire caliente, junto con tratamientos previos a la fritura. En masas de rebozados, en cambio, se optó por modificar la composición de estos, adicionando un hidrocoloide, el quitosano, después de haber ensayado su potencial en sistemas modelo. Además, se evaluó el efecto de la incorporación de quitosano sobre las propiedades físicas de la masa de rebozado y sobre la calidad del producto final. Por último y no por ello menos importante, se abordó la problemática de la acrilamida sobre la salud humana desde el punto de vista de su bioaccesibilidad. Para ello, se seleccionaron los productos con mayor contenido en acrilamida dietética y se sometieron a una simulación gastrointestinal in vitro con el fin de conocer los cambios experimentados por el tóxico durante este proceso y determinar su bioaccesibilidad. Los resultados mostraron que la fritura de patatas por aire caliente, así como la incorporación de quitosano a las masas de rebozado reducían la formación de acrilamida alrededor de un 90 y 60 %, respectivamente. La modificación de las características del quitosano (en cuanto a masa molecular y grado de desacetilación) condicionó su capacidad de reducir la formación de acrilamida. La incorporación de quitosano redujo la absorción de grasa durante la fritura de las masas. Si bien aumentó la viscosidad y consistencia de éstas, no se vio alterado significativamente el color y la textura del producto final frito. La substitución total de harina de trigo por harina de arroz permitió obtener masas de rebozado sin gluten con semejante viscosidad, al adicionar quitosano. Esta nueva formulación podría ser adaptada a productos rebozados sin gluten. La simulación de digestión in vitro mostró aumentos significativos de acrilamida tras la fase gástrica en una amplia gama de alimentos. Sin embargo, la bioaccesibildad de acrilamida (tras la fase intestinal) se redujo hasta niveles previos a la digestión o incluso menores, en patatas fritas tipo chips y tipo French fries. / Si bé és veritat que la presència d'acrilamida en aliments es va detectar fa més d'una dècada, la preocupació per part del consumidor, no només per aquest tema si no en l'alimentació saludable en general, sembla haver-se incrementat en els últims anys. L'acrilamida és un tòxic possible carcinogen per a l'èsser humà present principalment en aliments derivats de matèries primeres d'origen vegetal i sotmesos a processos de transformació en els quals s'assoleixen temperatures majors a 120 ºC, com el procés de fregida o al forn. Els aliments que contribueixen majoritàriament a la ingesta d'acrilamida són: creïlles fregides (tipus French fries i chips), cafè i substitut de cafè, galetes, pa, brioixeria, arrebossats i empanats, cereals d'esmorzar ..., sent l'exposició al tòxic superior per part de població infantil i adolescent. Des d'un punt de vista químic, l'acrilamida es forma principalment a partir de la reacció entre l'asparagina i sucres reductors durant el processat tèrmic, com producte intermedi de les reaccions de Maillard. En l'última dècada, tant les autoritats sanitàries com la comunitat científica han posat un gran esforç a establir científicament els límits de toxicitat i en la recerca d'estratègies orientades a reduir la seva formació. La comesa d'aquesta tesi doctoral s'emmarca en aquest últim sentit. D'una banda, s'ha treballat en la recerca de noves estratègies per a la reducció d'acrilamida, en dos tipus d'aliments diferents: creïlles fregides i masses de productes arrebossats. En creïlles fregides es va estudiar l'efecte d'una tècnica emergent de fregit, concretament el fregit per aire calent, juntament amb tractaments previs al fregit. En masses d'arrebossats, en canvi, es va optar per modificar la composició d'aquests, addicionant un hidrocol·loide, el quitosà, després d'haver assajat el seu potencial en sistemes model. A més, es va avaluar l'efecte de la incorporació de quitosà sobre les propietats físiques de la massa d'arrebossat i sobre la qualitat del producte final. Finalment i no per això menys important, es va abordar la problemàtica de l'acrilamida sobre la salut humana des del punt de vista de la seva bioaccesibilidad. Per a això, es van seleccionar els productes amb major contingut en acrilamida dietètica i es van sotmetre a una simulació gastrointestinal in vitro per tal de conèixer els canvis experimentats pel tòxic durant aquest procés i determinar la seva bioaccesibilidad. Els resultats van mostrar que el fregit de creïlles per aire calent, així com la incorporació de quitosà a les masses d'arrebossat reduïen la formació d'acrilamida al voltant d'un 90 i 60%, respectivament. La modificació de les característiques del quitosà (quant a massa molecular i grau de desacetilación) va condicionar la seva capacitat de reduir la formació d'acrilamida. La incorporació de quitosà va reduir l'absorció de greix durant el fregit de les masses. Si bé va augmentar la viscositat i consistència d'aquestes, no es va veure alterat significativament el color i la textura del producte final fregit. La substitució total de farina de blat per farina d'arròs va permetre obtenir masses d'arrebossat sense gluten amb semblant viscositat, en addicionar quitosà. Aquesta nova formulació podria ser adaptada a productes arrebossats sense gluten. La simulació de digestió in vitro va mostrar augments significatius d'acrilamida després de la fase gàstrica en una àmplia gamma d'aliments. No obstant això, la bioaccesibildad d'acrilamida (després de la fase intestinal) es va reduir fins a nivells previs a la digestió o fins i tot menors, en creïlles fregides tipus chips i tipus French fries. / Sansano Tomás, M. (2017). Evaluation of acrylamide in foods and development of some strategies for its reduction [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86160 / TESIS
30

Quality evaluation of frying oil and chicken nuggets using visiblenear-infrared hyper-spectral analysis

Kazemi Sangdehi, Samira January 2005 (has links)
No description available.

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