Avaliou-se o efeito de tratamentos químicos, revestimentos comestíveis e irradiação na conservação de mamões processados minimamente. Após seleção, lavagem e sanitização, os mamões foram descascados e cortados em meias rodelas, as quais foram submetidas a diferentes tratamentos, embaladas e armazenadas a 5±1°C e 90±2%UR. Os mamões PM foram avaliados após 1, 3, 6, 9, 12 e 15 dias. As análises microbiológicas foram fundamentadas na quantificação de coliformes totais e termotolerantes, bactérias psicrotróficas, bolores e leveduras, assim como na verificação da presença de Salmonella. As avaliações físico-químicas basearam-se na determinação da concentração de CO2 no interior das embalagens, perda de massa, cor, firmeza, sólidos solúv eis, acidez titulável, ratio e pH. As características sensoriais aparência, aroma, sabor e textura foram avaliad as por meio de testes com escala hedônica. No primeiro experimento os tratamentos foram: controle, aldeído cinâmico a 0,1%, cloreto de cálcio a 0,75% e combinação de aldeído cinâmico a 0,1% com cloreto de cálcio a 0,75%. O uso de tratamentos químicos em mamões PM resultou em: maior controle de coliformes totais para os mamões PM tratados com aldeído cinâmico e com a combinação de aldeído cinâmico e cloreto de cálcio; menor concentração de CO2 e maior manutenção da firmeza para mamões PM tratados com a combinação de aldeído cinâmico e cloreto de cálcio; e maior concentração de CO2 para os mamões PM tratados apenas com aldeído cinâmico. A imersão nos tratamentos químicos resultou em maior descoloração da polpa dos mamões PM e redução do teor de sólidos solúveis ao longo do armazenamento. No segundo experimento foram utilizados os tr atamentos: controle, amido de arroz a 3%, alginato de sódio a 0,5% e carboximetilcelulose a 0,25%. O uso desses três tipos de revestimento resultou em maior controle de coliformes totais do que o observado no controle. Mamões PM revestidos com amido de arroz e carboximetilcelulose apresentaram redução e aumento da concentração de CO2, respectivamente. Os mamões PM revestidos apresentaram menores teores de sólidos solúveis e seus valores de pH se tornaram menores após 9 dias de armazenamento refrigerado. O r evestimento com carboximetilcelulose proporcionou maior firmeza da polpa no 15° dia. No terceiro experimento foram utilizados os tratamentos: controle, radiação nas doses de 2kGy e 4kGy. O uso de radiação gama em mamões PM resultou em: maior controle de coliformes totais; menor concentração de CO2 nos mamões PM tratados com 2kGy; maior concentração de CO2 e maior descoloração da polpa nos mamões PM tratados com 4kGy; redução da firmeza nos mamões PM tratados com 2kGy e 4kGy; ligeira redução do teor de sólidos solúveis e pequenas variações da acidez titulável em todos os tratamentos. As características sensoriais dos mamões PM tratados com radiação gama não diferiram significativamente do controle durante os 15 dias de armazenamento / The effect of chemical treatments, edible coatings , and irradiation on fresh-cut papaya conservation was evaluated. After selection, washing, and sanitation the papayas were peeled and cut into half slices, which were submitted to different treatments, packed, and stored at 5±1°C and 90±2%RU. The fresh-cut papayas were evaluated after 1, 3, 6, 9, 12, and 15 days. The microbiological analyses were based on the count of total coliform, thermotolerant and psychrotrophic bacteria, molds and yeasts, as well as on the presence of Salmonella. The physicochemical evaluations were based on the determination of CO2 concentration inside the package, weight loss, color, firmness, soluble solids, titratable acidity, ratio, and pH. The sensory characteristics appearance, aroma, flavor, and texture were evaluated using a hedonic scale. In the first experiment, the treatments tested we re: control, cinnamic aldehyde 0.1%, calcium chloride 0.75%, and the combination of cinnamic aldehyde 0.1% and calcium chloride 0.75%. Using chemical treatments to preserve fresh cut papaya resulted in: higher control of total coliforms in fresh-cut papayas treated with cinnamic aldehyde and with the combination of cinnamic aldehyde and calcium chloride; lower CO2 concentration and increased maintenance of firmness in freshcut papayas treated with the combination of cinnamic aldehyde and calcium chloride; and increased in the CO2 concentration in fresh-cut papayas treated only with cinnamic aldehyde. Immersion in chemical treatments caused higher pulp discoloration and reduction in solu ble solids during storage. In the second experiment, the treatments tested were: control, rice starch 3%, sodium alginate 0.5%, and carboxymethylcellulose 0.25%. The use of these three coatings resulted in higher control of total coliforms compared to the control treatment. The fresh-cut papayas coated with rice starch and carboxymethylcellulose presented reduction and increase in the CO2 concentration, respectively. Coated fresh-cut papayas presented lower soluble solids and pH values were lower after 9 days of cold storage. Carboxymethylcellulose coating increased firmness maintenance at day 15. In the third experiment, the following treatments were used: control, radiation at the doses of 2kGy and 4kGy. The use of Gamma radiation in fresh-cut papaya resulted in: higher control of total coliforms; lower CO2 concentration in fresh-cut treated with 2kGy; increased CO2 concentration and increased pulp discoloration in fresh-cut papayas treated with 4kGy; reduction in firmness in fresh-cut papayas treated with 2kGy and 4kGy; slight reduction in soluble solids and small changes in titratable acidity in all treatments. The sensory characteristics of fresh-cut papayas treated with gamma radiation did not significantly differ from the control during the 15 days of storage

This study investigated pressure-induced starch gelatinisation in water and milk suspensions. A rheological method, termed ‘pasting curves’, provided an objective and analytical means to determine the degree of pressure-induced starch gelatinisation. In addition, a polarised light microscope was used to observe birefringence of the starch granules and the degree of starch swelling was measured. The preliminary investigation into pressure-induced gelatinisation of six different starches showed that potato starch was the most pressure resistant and was not gelatinised after a pressure treatment of 600 MPa for 30 min at 20 °C. Waxy rice, waxy corn and tapioca starches showed complete gelatinisation after the same treatment while normal rice and normal corn starches were only partially gelatinised despite the disappearance of birefringence. Based on the preliminary study, two starches (normal and waxy rice starches) were selected for more detailed studies. The effects of treatment conditions (pressure, temperature and duration) on the gelatinisation were investigated with these selected starches. The degree of gelatinisation was dependent on the type of starch and the treatment conditions. The results also indicated that different combinations of the treatment conditions (e.g. high treatment pressure for a short time and low treatment pressure for a longer time) could result in the same degree of gelatinisation. Both starch types exhibited sigmoidal-shaped pressure-induced gelatinisation curves and there was a linear correlation between the degree of swelling and the apparent viscosity of the starch suspension. After treatments at =500 MPa for 30 min at 20 °C, both starches lost all birefringence although the apparent viscosity and the degree of swelling of normal rice starch did not increase to the same extent as observed in waxy rice starch. Pressure-induced gelatinisation of starch was retarded when starch was suspended in skim milk. This was attributed to the effect of soluble milk minerals and lactose present in the milk whereas milk proteins (casein and whey) did not affect the degree of gelatinisation at the levels present in 10% total solids skim milk. The presence of soluble milk and/or lactose may lead to less effective plasticising of starch chains by the suspension medium. Interactions between milk components and starch molecules may also play a role in retarding gelatinisation by reducing the mobility of starch chains. The functionality of starch in a dairy application was tested using acid milk gels as a model system. Skim milk with added starch (waxy rice or potato starch) was either pressure treated (500 MPa, 20°C, 30 min) or heat treated (80°C, 30 min) and subsequently acidified to form acid milk gels. The addition of waxy rice starch resulted in firmer acid milk gels, and increasing the amount of starch caused an increase in the firmness of both pressure-treated and heat-treated samples. However, pressure-treated samples with added potato starch did not show significant changes in the firmness whereas the heat-treated counterparts showed a marked increase in the firmness as the level of potato starch increased. The difference between the effects of the two different starches can be explained by the extent of starch gelatinisation in skim milk. Starch granules absorb water during gelatinisation whether induced by pressure or heat which effectively increases milk protein concentration in the aqueous phase to form a denser protein gel network on acidification. The firmness of acid milk gels can be increased by adjusting the pH at pressure or heat treatment to higher than the natural pH of milk. The effect of pH at pressure or heat treatment and addition of starch on the acid milk gel firmness was additive and independent of each other up to a starch addition level of 1%. This study provided an insight into pressure-induced gelatinisation of starch by showing gelatinisation properties of starches of different botanical origins and the effects of the treatment conditions (treatment pressure, treatment temperature and duration) on the degree of gelatinisation. Furthermore, the results from the pressure treatments of starch in dairy-based suspensions showed that pressure-induced gelatinisation was affected by other components in the system. These results demonstrate the importance of understanding the gelatinisation properties of starch in complicated food systems in which a number of other components are present. In terms of the application of starch in dairy systems, when starch was added to milk and gelatinised by pressure treatment, the acid milk gel produced by subsequent acidification was firmer than the acid milk gel made from skim milk alone.

This study investigated pressure-induced starch gelatinisation in water and milk suspensions. A rheological method, termed ‘pasting curves’, provided an objective and analytical means to determine the degree of pressure-induced starch gelatinisation. In addition, a polarised light microscope was used to observe birefringence of the starch granules and the degree of starch swelling was measured. The preliminary investigation into pressure-induced gelatinisation of six different starches showed that potato starch was the most pressure resistant and was not gelatinised after a pressure treatment of 600 MPa for 30 min at 20 °C. Waxy rice, waxy corn and tapioca starches showed complete gelatinisation after the same treatment while normal rice and normal corn starches were only partially gelatinised despite the disappearance of birefringence. Based on the preliminary study, two starches (normal and waxy rice starches) were selected for more detailed studies. The effects of treatment conditions (pressure, temperature and duration) on the gelatinisation were investigated with these selected starches. The degree of gelatinisation was dependent on the type of starch and the treatment conditions. The results also indicated that different combinations of the treatment conditions (e.g. high treatment pressure for a short time and low treatment pressure for a longer time) could result in the same degree of gelatinisation. Both starch types exhibited sigmoidal-shaped pressure-induced gelatinisation curves and there was a linear correlation between the degree of swelling and the apparent viscosity of the starch suspension. After treatments at =500 MPa for 30 min at 20 °C, both starches lost all birefringence although the apparent viscosity and the degree of swelling of normal rice starch did not increase to the same extent as observed in waxy rice starch. Pressure-induced gelatinisation of starch was retarded when starch was suspended in skim milk. This was attributed to the effect of soluble milk minerals and lactose present in the milk whereas milk proteins (casein and whey) did not affect the degree of gelatinisation at the levels present in 10% total solids skim milk. The presence of soluble milk and/or lactose may lead to less effective plasticising of starch chains by the suspension medium. Interactions between milk components and starch molecules may also play a role in retarding gelatinisation by reducing the mobility of starch chains. The functionality of starch in a dairy application was tested using acid milk gels as a model system. Skim milk with added starch (waxy rice or potato starch) was either pressure treated (500 MPa, 20°C, 30 min) or heat treated (80°C, 30 min) and subsequently acidified to form acid milk gels. The addition of waxy rice starch resulted in firmer acid milk gels, and increasing the amount of starch caused an increase in the firmness of both pressure-treated and heat-treated samples. However, pressure-treated samples with added potato starch did not show significant changes in the firmness whereas the heat-treated counterparts showed a marked increase in the firmness as the level of potato starch increased. The difference between the effects of the two different starches can be explained by the extent of starch gelatinisation in skim milk. Starch granules absorb water during gelatinisation whether induced by pressure or heat which effectively increases milk protein concentration in the aqueous phase to form a denser protein gel network on acidification. The firmness of acid milk gels can be increased by adjusting the pH at pressure or heat treatment to higher than the natural pH of milk. The effect of pH at pressure or heat treatment and addition of starch on the acid milk gel firmness was additive and independent of each other up to a starch addition level of 1%. This study provided an insight into pressure-induced gelatinisation of starch by showing gelatinisation properties of starches of different botanical origins and the effects of the treatment conditions (treatment pressure, treatment temperature and duration) on the degree of gelatinisation. Furthermore, the results from the pressure treatments of starch in dairy-based suspensions showed that pressure-induced gelatinisation was affected by other components in the system. These results demonstrate the importance of understanding the gelatinisation properties of starch in complicated food systems in which a number of other components are present. In terms of the application of starch in dairy systems, when starch was added to milk and gelatinised by pressure treatment, the acid milk gel produced by subsequent acidification was firmer than the acid milk gel made from skim milk alone.

This study investigated pressure-induced starch gelatinisation in water and milk suspensions. A rheological method, termed ‘pasting curves’, provided an objective and analytical means to determine the degree of pressure-induced starch gelatinisation. In addition, a polarised light microscope was used to observe birefringence of the starch granules and the degree of starch swelling was measured. The preliminary investigation into pressure-induced gelatinisation of six different starches showed that potato starch was the most pressure resistant and was not gelatinised after a pressure treatment of 600 MPa for 30 min at 20 °C. Waxy rice, waxy corn and tapioca starches showed complete gelatinisation after the same treatment while normal rice and normal corn starches were only partially gelatinised despite the disappearance of birefringence. Based on the preliminary study, two starches (normal and waxy rice starches) were selected for more detailed studies. The effects of treatment conditions (pressure, temperature and duration) on the gelatinisation were investigated with these selected starches. The degree of gelatinisation was dependent on the type of starch and the treatment conditions. The results also indicated that different combinations of the treatment conditions (e.g. high treatment pressure for a short time and low treatment pressure for a longer time) could result in the same degree of gelatinisation. Both starch types exhibited sigmoidal-shaped pressure-induced gelatinisation curves and there was a linear correlation between the degree of swelling and the apparent viscosity of the starch suspension. After treatments at =500 MPa for 30 min at 20 °C, both starches lost all birefringence although the apparent viscosity and the degree of swelling of normal rice starch did not increase to the same extent as observed in waxy rice starch. Pressure-induced gelatinisation of starch was retarded when starch was suspended in skim milk. This was attributed to the effect of soluble milk minerals and lactose present in the milk whereas milk proteins (casein and whey) did not affect the degree of gelatinisation at the levels present in 10% total solids skim milk. The presence of soluble milk and/or lactose may lead to less effective plasticising of starch chains by the suspension medium. Interactions between milk components and starch molecules may also play a role in retarding gelatinisation by reducing the mobility of starch chains. The functionality of starch in a dairy application was tested using acid milk gels as a model system. Skim milk with added starch (waxy rice or potato starch) was either pressure treated (500 MPa, 20°C, 30 min) or heat treated (80°C, 30 min) and subsequently acidified to form acid milk gels. The addition of waxy rice starch resulted in firmer acid milk gels, and increasing the amount of starch caused an increase in the firmness of both pressure-treated and heat-treated samples. However, pressure-treated samples with added potato starch did not show significant changes in the firmness whereas the heat-treated counterparts showed a marked increase in the firmness as the level of potato starch increased. The difference between the effects of the two different starches can be explained by the extent of starch gelatinisation in skim milk. Starch granules absorb water during gelatinisation whether induced by pressure or heat which effectively increases milk protein concentration in the aqueous phase to form a denser protein gel network on acidification. The firmness of acid milk gels can be increased by adjusting the pH at pressure or heat treatment to higher than the natural pH of milk. The effect of pH at pressure or heat treatment and addition of starch on the acid milk gel firmness was additive and independent of each other up to a starch addition level of 1%. This study provided an insight into pressure-induced gelatinisation of starch by showing gelatinisation properties of starches of different botanical origins and the effects of the treatment conditions (treatment pressure, treatment temperature and duration) on the degree of gelatinisation. Furthermore, the results from the pressure treatments of starch in dairy-based suspensions showed that pressure-induced gelatinisation was affected by other components in the system. These results demonstrate the importance of understanding the gelatinisation properties of starch in complicated food systems in which a number of other components are present. In terms of the application of starch in dairy systems, when starch was added to milk and gelatinised by pressure treatment, the acid milk gel produced by subsequent acidification was firmer than the acid milk gel made from skim milk alone.

Avaliou-se o efeito de tratamentos químicos, revestimentos comestíveis e irradiação na conservação de mamões processados minimamente. Após seleção, lavagem e sanitização, os mamões foram descascados e cortados em meias rodelas, as quais foram submetidas a diferentes tratamentos, embaladas e armazenadas a 5±1°C e 90±2%UR. Os mamões PM foram avaliados após 1, 3, 6, 9, 12 e 15 dias. As análises microbiológicas foram fundamentadas na quantificação de coliformes totais e termotolerantes, bactérias psicrotróficas, bolores e leveduras, assim como na verificação da presença de Salmonella. As avaliações físico-químicas basearam-se na determinação da concentração de CO2 no interior das embalagens, perda de massa, cor, firmeza, sólidos solúv eis, acidez titulável, ratio e pH. As características sensoriais aparência, aroma, sabor e textura foram avaliad as por meio de testes com escala hedônica. No primeiro experimento os tratamentos foram: controle, aldeído cinâmico a 0,1%, cloreto de cálcio a 0,75% e combinação de aldeído cinâmico a 0,1% com cloreto de cálcio a 0,75%. O uso de tratamentos químicos em mamões PM resultou em: maior controle de coliformes totais para os mamões PM tratados com aldeído cinâmico e com a combinação de aldeído cinâmico e cloreto de cálcio; menor concentração de CO2 e maior manutenção da firmeza para mamões PM tratados com a combinação de aldeído cinâmico e cloreto de cálcio; e maior concentração de CO2 para os mamões PM tratados apenas com aldeído cinâmico. A imersão nos tratamentos químicos resultou em maior descoloração da polpa dos mamões PM e redução do teor de sólidos solúveis ao longo do armazenamento. No segundo experimento foram utilizados os tr atamentos: controle, amido de arroz a 3%, alginato de sódio a 0,5% e carboximetilcelulose a 0,25%. O uso desses três tipos de revestimento resultou em maior controle de coliformes totais do que o observado no controle. Mamões PM revestidos com amido de arroz e carboximetilcelulose apresentaram redução e aumento da concentração de CO2, respectivamente. Os mamões PM revestidos apresentaram menores teores de sólidos solúveis e seus valores de pH se tornaram menores após 9 dias de armazenamento refrigerado. O r evestimento com carboximetilcelulose proporcionou maior firmeza da polpa no 15° dia. No terceiro experimento foram utilizados os tratamentos: controle, radiação nas doses de 2kGy e 4kGy. O uso de radiação gama em mamões PM resultou em: maior controle de coliformes totais; menor concentração de CO2 nos mamões PM tratados com 2kGy; maior concentração de CO2 e maior descoloração da polpa nos mamões PM tratados com 4kGy; redução da firmeza nos mamões PM tratados com 2kGy e 4kGy; ligeira redução do teor de sólidos solúveis e pequenas variações da acidez titulável em todos os tratamentos. As características sensoriais dos mamões PM tratados com radiação gama não diferiram significativamente do controle durante os 15 dias de armazenamento / The effect of chemical treatments, edible coatings , and irradiation on fresh-cut papaya conservation was evaluated. After selection, washing, and sanitation the papayas were peeled and cut into half slices, which were submitted to different treatments, packed, and stored at 5±1°C and 90±2%RU. The fresh-cut papayas were evaluated after 1, 3, 6, 9, 12, and 15 days. The microbiological analyses were based on the count of total coliform, thermotolerant and psychrotrophic bacteria, molds and yeasts, as well as on the presence of Salmonella. The physicochemical evaluations were based on the determination of CO2 concentration inside the package, weight loss, color, firmness, soluble solids, titratable acidity, ratio, and pH. The sensory characteristics appearance, aroma, flavor, and texture were evaluated using a hedonic scale. In the first experiment, the treatments tested we re: control, cinnamic aldehyde 0.1%, calcium chloride 0.75%, and the combination of cinnamic aldehyde 0.1% and calcium chloride 0.75%. Using chemical treatments to preserve fresh cut papaya resulted in: higher control of total coliforms in fresh-cut papayas treated with cinnamic aldehyde and with the combination of cinnamic aldehyde and calcium chloride; lower CO2 concentration and increased maintenance of firmness in freshcut papayas treated with the combination of cinnamic aldehyde and calcium chloride; and increased in the CO2 concentration in fresh-cut papayas treated only with cinnamic aldehyde. Immersion in chemical treatments caused higher pulp discoloration and reduction in solu ble solids during storage. In the second experiment, the treatments tested were: control, rice starch 3%, sodium alginate 0.5%, and carboxymethylcellulose 0.25%. The use of these three coatings resulted in higher control of total coliforms compared to the control treatment. The fresh-cut papayas coated with rice starch and carboxymethylcellulose presented reduction and increase in the CO2 concentration, respectively. Coated fresh-cut papayas presented lower soluble solids and pH values were lower after 9 days of cold storage. Carboxymethylcellulose coating increased firmness maintenance at day 15. In the third experiment, the following treatments were used: control, radiation at the doses of 2kGy and 4kGy. The use of Gamma radiation in fresh-cut papaya resulted in: higher control of total coliforms; lower CO2 concentration in fresh-cut treated with 2kGy; increased CO2 concentration and increased pulp discoloration in fresh-cut papayas treated with 4kGy; reduction in firmness in fresh-cut papayas treated with 2kGy and 4kGy; slight reduction in soluble solids and small changes in titratable acidity in all treatments. The sensory characteristics of fresh-cut papayas treated with gamma radiation did not significantly differ from the control during the 15 days of storage

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2019-02-27T11:49:16Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Gustavo Antoniacomi de Carvalho.pdf: 6310308 bytes, checksum: 8e1efd9d86bc5a1adf80b45bba2a3985 (MD5) / Made available in DSpace on 2019-02-27T11:49:16Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Gustavo Antoniacomi de Carvalho.pdf: 6310308 bytes, checksum: 8e1efd9d86bc5a1adf80b45bba2a3985 (MD5) Previous issue date: 2018-01-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Cerâmicas porosas vêm ganhando visibilidade devido a algumas aplicações tecnológicas interessantes, tais como a utilização em eletrólitos sólidos, ânodos de células a combustível, filtros cerâmicos e reposição óssea e dental. Dentre elas, há especial atenção ao estudo de materiais porosos com porosidade graduada, nos quais a quantidade de poros e a morfologia dos mesmos se alteram pelo volume do material. Nesse trabalho foi realizado o processamento e caracterização de materiais cerâmicos de alumina com porosidade graduada a partir das técnicas de freeze casting e colagem de barbotina, utilizando hidróxido de alumínio e amido de arroz como fases de sacrifício. Após a conformação das amostras por esses métodos, a porosidade foi caracterizada por microscopia eletrônica de varredura, pelas medidas de porosidade aparente feita pelo Princípio de Arquimedes e pela distribuição de tamanho de poros feita pela técnica de porosimetria de mercúrio. Foi avaliada também a resistência mecânica das amostras a partir de ensaio de compressão. Foi confirmada a relação entre as amostras processados isoladamente e suas respectivas camadas nas amostras graduadas. Foi observada também uma boa interação interfacial entre cada uma das camadas das amostras graduadas. A porosidade das amostras com porosidade graduada se manteve próxima do esperado, o valor esperado foi determinado a partir da média das amostras processadas isoladamente em relação às camadas do material com porosidade graduada. O ensaio mecânico demonstrou que não houve influência das interfaces dos materiais graduados na sua resistência à compressão. / Porous ceramics have been gaining visibility due to some interesting technological applications, such as its use as solid electrolytes, fuel cell anodes, ceramic filters and bone and dental reposition. Among them, there is special care in studying graded porosity materials, where the quantity of pores and pore morphology changes through the material volume. In this work the processing and characterization of alumina ceramic materials with functionally graded porosity by freeze casting and slip casting techniques using aluminum hydroxide and rice starch as sacrificial template was performed. After conformation, the porosity was characterized through electron scanning microscopy, apparent porosity through Archimedes method and median pore size through mercury porosimetry. The mechanical resistance was also obtained by compression testing. The analysis allowed to confirm the relation between each of the isolated samples’ microstructure and its respective layer in each of the graded materials, also, the graded materials shown good interfacial interaction between each of the layers. The porosity in graded materials kept close to the expected value, which was determined by the medium value of the porosities of the isolated samples respective to the graded material. Mechanical testing shown that there was no influence of the graded material interfaces in its compressive strength.

Tesis por compendio / [ES] El arroz, es uno de los cereales más consumidos a nivel mundial y debido a su alto valor nutricional, forma parte de la dieta básica de la población en general. Su elevado contenido de almidón, sin modificar o tras su modificación, lo convierte en un alimento atractivo para la industria alimentaria. No obstante, este mismo componente favorece el desarrollo del Bacillus cereus después de su cocción. Este microorganismo forma esporas resistentes al calor, lo que supone un riesgo para el consumidor, especialmente si el arroz cocinado no se almacena a temperatura adecuada. En la presente tesis doctoral, se han propuesto algunas estrategias tecnológicas para mejorar el procesado y garantizar la inocuidad alimentaria del arroz y sus derivados. Estas estrategias consisten en la aplicación de plasma frío y en el uso de quitosano de insecto (Tenebrio molitor) como antimicrobiano. Desde el punto de vista tecnológico, se ha visto que la tecnología de plasma es capaz de modificar determinadas propiedades tecnológicas del almidón que dependen de la variedad del arroz. Estos resultados abren la puerta a un uso más amplio de este componente en la industria alimentaria y en la formulación de alimentos a la carta. En cuanto a la inocuidad del arroz, el plasma frío reduce los niveles de células vegetativas y de esporas de B. cereus, convirtiéndolo en una tecnología alternativa de desinfección de materias primas como el arroz, antes de su procesado posterior. El nivel de inactivación tanto de células vegetativas como de esporas, estuvo determinado por el tiempo y potencia de tratamiento, así como la matriz que lo contenía en el caso de las esporas. El quitosano de insectos redujo la termorresistencia del B. cereus y resultó ser bacteriostático o bactericida en función de la concentración y la temperatura de almacenamiento. Estos efectos lo convierten en una buena estrategia de control de dicho microorganismo en arroz y sus derivados. A través de un modelo de evaluación a la exposición se ha podido corroborar los resultados sobre el efecto del quitosano en el B. cereus, a la vez que se pone de manifiesto la importancia que tienen cambios accidentales en las condiciones de procesado sobre el nivel final de microorganismos en el alimento y del número inicial de microorganismos sobre el porcentaje de unidades infectas después del tratamiento. Los resultados de la presente tesis ponen de manifiesto estrategias más sostenibles que son capaces de mejorar el procesado y la inocuidad del arroz y productos derivados del mismo. / [CA] L'arròs és un dels cereals més consumits a nivell mundial i, a causa del seu alt valor nutricional, forma part de la dieta bàsica de la població en general. El seu alt contingut d'almidó, sense modificar o després de la seva modificació, el converteix en un aliment atractiu per a la indústria alimentària. No obstant això, aquest mateix component afavoreix el desenvolupament del Bacillus cereus després de la seva cocció. Aquest microorganisme forma espores resistents al calor, la qual cosa suposa un risc per al consumidor, especialment si l'arròs cuinat no es conserva a una temperatura adequada. En la present tesi doctoral, s'han proposat algunes estratègies tecnològiques per millorar el processament i garantir la innocuïtat alimentària de l'arròs i els seus derivats. Aquestes estratègies consisteixen en l'aplicació de plasma fred i en l'ús de quitosà d'insecte (Tenebrio molitor) com a antimicrobià. Des del punt de vista tecnològic, s'ha vist que la tecnologia de plasma és capaç de modificar certes propietats tecnològiques de l'almidó que depenen de la varietat de l'arròs. Aquests resultats obren la porta a un ús més ampli d'aquest component en la indústria alimentària i en la formulació d'aliments a la carta. Quant a la innocuïtat de l'arròs, el plasma fred redueix els nivells de cèl·lules vegetatives i d'espores de B. cereus, convertint-lo en una tecnologia alternativa de desinfecció de matèries primeres com l'arròs, abans del seu processament posterior. El nivell d'inactivació tant de cèl·lules vegetatives com d'espores va estar determinat pel temps i potència de tractament, així com la matriu que les contenia en el cas de les espores. El quitosà d'insectes va reduir la termoresistència del B. cereus i va resultar ser bacteriostàtic o bactericida en funció de la concentració i la temperatura d'emmagatzematge. Aquests efectes el converteixen en una bona estratègia de control d'aquest microorganisme en l'arròs i els seus derivats. A través d'un model d'avaluació a l'exposició s'ha pogut corroborar els resultats sobre l'efecte del quitosà en el B. cereus, alhora que es posa de manifest la importància que tenen accidentals canvis en les condicions de processat sobre el nivell final de microorganismes en l'aliment i del nombre inicial de microorganismes sobre el percentatge d'unitats infectades després del tractament. Els resultats de la present tesi posen de manifest estratègies més sostenibles que són capaces de millorar el processament i la innocuïtat de l'arròs i productes derivats del mateix. / [EN] Rice is one of the most widely consumed cereals worldwide, due to its high nutritional value, it is part of the population basic diet. Its high starch content, unmodified or modified, makes it an attractive ingredient for the food industry. However, this same component promotes the development of Bacillus cereus after cooking. This microorganism forms heat-resistant spores, which poses a risk to consumers, especially if the cooked rice is not stored at the correct temperature. In this doctoral thesis, some technological strategies have been proposed to improve the processing and ensure the food safety of rice and its derivatives. These strategies include the application of cold plasma and the use of insect chitosan from Tenebrio molitor as an antimicrobial. From a technological perspective, plasma technology has demonstrated its ability to modify technological properties of starch, which vary based on the type of rice. These results open the door to a broader use of this component in the food industry and in customized food formulation. Regarding the safety of rice, cold plasma reduces the levels of vegetative cells and spores of B. cereus, making it an alternative technology for disinfecting raw materials such as rice before further processing. The level of inactivation of both vegetative cells and spores was determined by the time and power of the treatment, as well as the matrix containing them in the case of the spores. Insect chitosan reduced the thermo-resistance of B. cereus and was found to be bacteriostatic or bactericidal depending on the concentration and storage temperature. These effects make it a good control strategy for this microorganism in rice and its derivatives. Through an exposure assessment model, the results on the effect of chitosan on B. cereus have been corroborated, while also highlighting the importance of accidental changes in processing conditions on the final level of microorganisms in the food and the initial number of microorganisms on the percentage of infected units after treatment. The results of this thesis demonstrate more sustainable strategies that are capable of improving the processing and safety of rice and its derivatives. / La presente tesis doctoral se enmarca dentro del Programa de Doctorado Ciencia, Tecnología y Gestión Alimentaria de la Universidad Politécnica de Valencia. Para el desarrollo de la presente tesis doctoral, María Inés Valdez Narváez, ha disfrutado de una beca concedida por la Generalitat Valenciana para la contratación de personal investigador predoctoral (ACIF/2021/424) llevada a cabo en el Instituto de Agroquímica y Tecnología de Alimentos de Valencia, Centro de Excelencia Severo Ochoa, así como una beca BEFPI concedida por la Generalitat Valenciana para Estancias de contratados predoctorales en centros de investigación fuera de la comunidad Valenciana (CIBEFP/2022/56) desarrollada en The Agriculture and Food Development Authority- TEAGASC (Dublin-Irlanda). Este trabajo ha sido cofinanciado además por los proyectos: fondos del Ministerio de Ciencia e Innovación Ref. PID2020- 116318RB-C31 y proyecto TRACE-RICE Ref. AMD-1934-1 / Valdez Narváez, MI. (2024). Estrategias tecnológicas para mejorar la desinfeccion y procesado de derivados de arroz [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/210721 / Compendio