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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.
31

Application of Infrared Spectroscopy and Chemometrics to the Cocoa Industry for Fast Composition Analysis and Fraud Detection

Quelal Vásconez, Maribel Alexandra 20 January 2020 (has links)
[ES] El cacao es un producto de alto valor, no únicamente por sus características sensoriales, sino porque también presenta un alto contenido en antioxidantes y alcaloides estimulantes con efectos saludables. Debido a la alta demanda, la industria del cacao en polvo tiene el desafío de asegurar la calidad de grandes volúmenes de producción de una manera rápida y precisa, evitando la presencia de contaminantes o adulterantes en la materia prima, ofreciendo productos donde se preserven las propiedades saludables. La espectroscopia del infrarrojo cercano (NIR) es una tecnología rápida y no destructiva útil en el análisis de productos alimentarios. La presente tesis doctoral se centra en evaluar el potencial uso del NIR como una herramienta de control de calidad con el fin de poder resolver problemas que se presentan en la industria del cacao en polvo. Los problemas a resolver incluyen la detección de materiales no deseados o adulterantes en el cacao en polvo, y la monitorización rápida y precisa del contenido de flavanoles y metilxantinas del cacao en polvo durante el proceso de alcalinización. El primer capítulo evalúa la viabilidad del NIR, en combinación con análisis quimiométricos, en la detección de la presencia de materiales no deseados o adulterantes como son cascarilla de cacao o harina de algarroba. Para ello, diferentes muestras de cacao en polvo natural y con diferentes niveles de alcalinización (suave, medio y fuerte) fueron mezcladas con distintas proporciones de cascarilla de cacao (con cacao natural) o harina de algarroba (con cacao natural y alcalinizado). Los resultados obtenidos indican que el NIR, combinado con modelos estadísticos tales como el análisis discriminante por mínimos cuadrados parciales (PLS-DA) y la regresión parcial de mínimos cuadrados (PLS), es un método rápido y eficaz para identificar cualitativa y cuantitativamente materiales no deseados o adulterantes como la cascarilla y la algarroba en cacao en polvo, independientemente del grado de alcalinización o el nivel de tostado de la harina de algarroba. En el segundo capítulo, el análisis composicional del cacao en polvo se orientó al control de los cambios producidos en el contenido de flavanoles y metilxantinas debidos al proceso de alcalinización al que se somete el caco en polvo. Se determinó el contenido de catequina, epicatequina, cafeína y teobromina mediante cromatografía líquida de alta resolución (HPLC), correlacionándose los contenidos obtenidos para cada uno de estos compuestos con las determinaciones NIR. Se obtuvieron buenos modelos para la predicción de los compuestos mediante regresión PLS con valores superiores a 3 para la relación entre el rendimiento y la desviación (RDP), lo cual demuestra que los modelos obtenidos pueden ser utilizados para la rápida y fiable predicción del contenido de flavanoles y metilxantinas en cacaos naturales y con diferentes niveles de alcalinización. / [CAT] El cacau és un producte d'alt valor, no sols per les seues característiques sensorials, sinó perquè també presenta un elevat contingut en antioxidants i alcaloids estimulants amb efectes saludables. A conseqüència a l'alta demanda, l'industria del cacau en pols té el desafiament d'assegurar la qualitat de grans volums de producció d'una manera ràpida i precisa, evitant la presència de contaminants o adulterants en la matèria cosina, oferint productes a on se preserven les propietats saludables. L'espectroscòpia de l'infrarroig proper (NIR) és una tecnologia ràpida i no destructiva útil en l'anàlisi de productes alimentaris. La present tesis doctoral se centra en avaluar el potencial ús del NIR com una eina de control de qualitat amb l'objectiu de poder resoldre problemes que es presenten en l'industria del cacau en pols. Els problemes a resoldre inclouen la detecció de materials no desitjats o adulterants en el cacau en pols, i la monitorització ràpida i precisa del contingut de flavanols i metilxantines del cacau en pols durant el procés d'alcalinització. El primer capítol avalua la viabilitat del NIR, en combinació amb anàlisis quimiométrics, en la detecció de la presència de materials no desitjats o adulterants com són pellofa de cacau o farina de garrofa. Per a això, diferents mostres de cacau en pols natural i amb diferents nivells d'alcalinització (suau, mig i fort) foren barrejades en distintes proporcions de pellofa de cacau (en cacau natural) o farina de garrofa (en cacau natural i alcalinisat). Els resultats obtinguts per a NIR, combinats amb models estadístics com l'anàlisi discriminant per mínims quadrats parcials (PLS-DA) i la regressió parcial de mínims quadrats (PLS), és un mètode ràpid i eficaç per identificar materials no desitjats o adulterants com la pellofa de cacau o la farina de garrofa, amb independència del grau d'alcalinització del cacau o de torrat de la farina de garrofa. En el segon capítol, l'anàlisi composicional del cacau en pols s'orientà al control dels canvis produïts en el contingut de flavanols i metilxantines a causa del procés d'alcalinització al que se sotmet el cacau en pols. Es va determinar el contingut de catequina, epicatequina, cafeïna i teobromina mitjançant cromatografia líquida d'alta resolució (HPLC), i es van correlacionar els continguts obtinguts per a cadascun d'estos composts amb les determinacions NIR. Es van obtindré bons models per a la predicció dels composts mitjançant regressió PLS amb valors superiors a 3 per a la relació entre el rendiment i la desviació (RDP), la qual cosa demostra que els models obtinguts poden ser emprats per a la ràpida i fiable predicció del contingut de flavanols i metilxantines en cacaus naturals o amb diferents nivells d'alcalinització. / [EN] Cocoa is a product of high value, not only because of its sensory characteristics, but also because it has a high content of antioxidants and stimulating alkaloids with health effects. Due to the high demand, the cocoa powder industry has the challenge of ensuring the quality of large volumes of production in a fast and accurate way, avoiding the presence of contaminants or adulterants in the raw material, offering products where the healthy properties are preserved. The near infrared spectroscopy (NIR) is a rapid and non-destructive technology useful in the analysis of food products. The present doctoral thesis focuses on evaluating the potential use of NIR as a quality control tool in order to solve problems that arise in the cocoa industry powdered. The problems to solve include the detection of unwanted materials or adulterants in the cocoa powder, and the rapid and accurate monitorization of the flavanols and methylxanthines content in the cocoa powder during the alkalization process. The first chapter evaluates the viability of the NIR, in combination with chemometric analysis, in the detection of presence of unwanted materials or adulterants such as cocoa shell or carob flour. For this, different samples of natural cocoa powder and with different levels of alkalization (light, medium and strong) were mixed with different proportions of cocoa shell (with natural cocoa) or carob flour (with natural and alkalized cocoa). The results obtained indicate that the NIR combined with statistical models such as the partial least squares discriminant analysis (PLS-DA) and the partial least squares regression (PLS), is a fast and efficient method to identify qualitative and quantitative unwanted materials or adulterants such as shell and carob in cocoa powder, regardless of the degree of alkalization or level of roasting of carob flour. In the second chapter, the compositional analysis of cocoa powder was oriented to the control of the changes produced in the content of flavanols and methylxanthines due to the process of alkalization to which the cocoa powder is subjected. The content of catechin, epicatechin, caffeine and theobromine were determined by high performance liquid chromatography (HPLC), correlating the contents obtained for each of these compounds with the NIR determinations. Good models were obtained for the prediction of compounds by regression PLS with values above 3 for the ratio of performance to deviation (RDP), which shows that the obtained models can be used for the quick and reliable prediction of flavanol content and methylxanthines in natural cocoas and with different alkalization levels. / This Doctoral Thesis has been carried out thanks to a doctoral studies scholarship granted by the Ministry of Higher Education, Science, Technology and Innovation (SENESCYT) of the Republic of Ecuador / Quelal Vásconez, MA. (2019). Application of Infrared Spectroscopy and Chemometrics to the Cocoa Industry for Fast Composition Analysis and Fraud Detection [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/135258 / TESIS
32

Food Defense Among Meat Processing and Food Service Establishments in Kentucky

Webb-Yeates, Morgan 01 May 2013 (has links)
Agroterrorism is the deliberate introduction of a plant or animal disease with thegoal of causing fear, economic instability, illness, or death. After the 2002 terroristattacks on the World Trade Center, the security of the food supply is of increasingconcern to the United States. A major incidence of agroterrorism or food tampering would have far reaching impacts on the economy and public health. The first objective of this project was to determine knowledge and concern of agroterrorism in meat processing facilities in Kentucky, and to determine knowledge and concern of food tampering and food defense in food service establishments in Warren County, Kentucky. The second objective was to determine security strategies that were being implemented by these facilities. Two separate surveys, one for meat processors and the other for food service establishments, were designed to meet these objectives. An observational study was conducted for meat processing facilities. It was found that these facilities were generally unconcerned with agroterrorism, although a reasonable amount of security implementations were in place at these facilities. A statistical comparison between restaurants and non-restaurant food service establishments, such as schools, hospitals, and hotels, was performed. Both types of food service establishments expressed little concern about a food tampering event. Non- restaurant food service establishments were slightly more concerned than restaurants about both food tampering and food defense.
33

關於中國內地食品安全法律制度若干問題的研究: 由安徽阜陽劣質奶粉事件引發的幾點思考 / 由安徽阜陽劣質奶粉事件引發的幾點思考

侯米蘭 January 2006 (has links)
University of Macau / Faculty of Law
34

中國食品安全管理中政府監管的缺失分析 : 以三鹿事件為例 / 以三鹿事件為例

王欣 January 2010 (has links)
University of Macau / Faculty of Social Sciences and Humanities / Department of Government and Public Administration
35

The privatization of food and environmental hygiene services in Hong Kong: an evaluation and future prospects

Siu, Wing-ho, Joseph., 蕭永豪. January 2001 (has links)
published_or_final_version / Public Administration / Master / Master of Public Administration
36

Quality of deep fried chip cooking oil at fast food outlets in the South Central Operational Entity within Ethekwini Municipality.

Padayachee, Theresa. January 2006 (has links)
The demand for deep fried chips by public and the number of people entering the fast food industry in the form of fast food outlets has increased tremendously. Frying oils are very expensive and are the most important ingredient used in the preparation of fried foods. Due to high oil costs and lack of knowledge, frying oils are used to their maximum. This has resulted in the abuse of deep fried chip cooking oils. The overall quality of the deep fried chip cooking oil used in the South Central Operational Entity of the eThekwini Municipality is not known but abused cooking oils have been identified by Environmental Health Practitioners (EHP's) during routine inspections of fast food outlets. Considering all of the above, the objectives of the proposed research were: (l) Determine the overall prevalence of the use of abused deep fried chip cooking oils at fast food outlets in the South Central Operational Entity of the eThekwini Municipality. (2) Determine in which supervision areas in the South Central Operational Entity the use of abused cooking oil is most prevalent. (3) Determine current/reported practices in preserving the quality of chip oil. (4) Make appropriate recommendations to owner/managers of the fast food outlets and to Environmental Health Practitioners. The study design was observational utilizing a Rapid Epidemiological Assessment (REA) technique, with both a descriptive and analytical component. All fast food outlets making deep fried chips in the South Central Operational Entity registered with the eThekwini Health Department at the time of the study were included in the study population. The Lot Quality Assurance Sampling (LQAS) method was used to determine the overall prevalence of the use of abused oil and to determine supervision areas reached the predetermined service target. A total of 100 fast food outlets were sampled. An oil sample from each fast food outlet, which was taken and sent to a laboratory where an Oxifrit Test was done on every oil sample taken. The Oxifrit Test was the benchmark in this study. EHP's of eThekwini Municipality collected further data by means of an observational checklist and a closed-ended questionnaire, which aimed to establish cooking oil preservation practices. The study revealed that 60 of the outlets had oil that was acceptable whereas 40 had oil that was unacceptable (abused oil). In the multivariate analysis the only factors significantly associated with abused oil were the condition of the fryer and frequency of oil change. Supervision Areas 6, and 4 had more abused deep fried chip cooking oil than average in the South Central Operational Entity. For further prioritization, Supervision Areas 6 and 4 fell below the decision rule for majority of acceptable oil preservation practices, thus Supervision Areas 6 and 4 will be targeted for intervention. Intervention will include education, monitoring and ultimately enforcing the law by EHP's to ensure safe use of deep fried chip cooking oil in the South Central Operational Entity within eThekwini Municipality. / Thesis (M.P.H.)-University of KwaZulu-Natal, 2006.
37

Stanovení autenticity potravin rostlinného původu pomocí molekulárních metod / Determination of athenticity of plant foods by molecular techniques

Plášková, Anna January 2020 (has links)
The aim of presented diploma thesis was to determination of authenticity of fruit baby foods for early infant feeding using molecular methods. In the experimental part, isolation kit was used for isolation of plant DNA from fruits (strawberry, apricot, raspberry, apple) and from six commercial fruit products for children. Isolated DNA was characterized and verified using PCR methods with primers specific for plant rDNA (ITS2). Specific primer pairs were designed to amplify DNA for the detection of one fruit species. Primer specificity was assessed with four fruit species. A mixture of fruit puree from the two fruits was used to determine the sensitivity of the multiplex PCR assay. Six commercial fruit products were evaluated to verify the applicability of the multiplex PCR assay. The methodology of molecular detection of fruit DNA by qPCR and multiplex qPCR (duplex) includes approaches, which enable to detect two fruits (strawberry-raspberry, apricot-apple) in one reaction and thus reduces time and money requirements.
38

Combining Systems Methodologies to Reduce Allergen-Related Food Recalls

Sweney, Jill Marie 14 May 2015 (has links)
The risk of poor food safety is a major focus for managers in the food manufacturing industry. Despite industry-led and regulatory efforts to improve the overall food safety of US packaged consumer foods, product recalls and market withdrawals are increasing. This is especially true for the most frequent cause for food recall: the undeclared allergen. With industry trends leaning toward adoption of third-party food safety management certifications, a popular food safety code from the Safe Quality Foods Institute is evaluated using Systems Analysis. Three changes to the food safety code are proposed to address three of the top causes for an allergen-related recall in the United States. In practice, the SQF code should make better use of control theory to reduce delays in production monitoring activities, should make better use of purposeful action in the implementation of a HACCP plan to ensure continuing validity of the plan, and SQFI needs to consider adding an organizational assessment for food safety culture.

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