Master of Science / Department of Grain Science and Industry / Bhadriraju Subramanyam / Organic, hard red winter wheat of 11% moisture was tempered with distilled water to moisture levels of 16 and 18% and held for 8, 16, and 24 h. At each moisture and holding time wheat was unexposed (control) or exposed to infrared radiation for 1, 1.5, and 2 min using a bench-top flameless catalytic infrared emitter. The mean external grain temperatures for 16% mc wheat measured with thermocouples during infrared exposure of 1, 1.5, and 2 min ranged from 77.4-83.1, 93.7-101.2, and 91.2-98.3°C, respectively; corresponding mean internal temperatures were 67.3-76.4, 80.0-85.6, and 81.3-93.2°C. Minor differences in kernel moisture, hardness, and weight were observed among treatments. Tempered wheat after infrared exposure among treatments lost 1.5-2% moisture. Infrared exposure of wheat reduced initial bacterial loads (6.7×10[superscript]4 CFU/g) by 98.7% and fungal loads (4.3×10[superscript]3 CFU/g) by 97.8% when compared with those on untreated wheat. Wheat tempered to 18% and exposed for 2 min to infrared radiation lost 2% moisture, and this wheat when milled had a yield of 73.5%. The color of flour from infrared- exposed wheat was slightly dark (color change, ΔE = 0.31) when compared with untreated flour. Differential scanning calorimetry showed that flours from infrared exposed wheat had lower enthalpy (3.0 J/g) than those unexposed to infrared (3.3 J/g). These flours were adversely affected because they had longer mixing times (7-15 min) at all infrared exposures due to the presence of insoluble polymeric proteins (up to 60%). Microbial loads in flour from wheat tempered to 18% and exposed for 1-2 min had 0.6-2.4 log reduction compared to flour from untreated wheat. Wheat tempered to 18% moisture with electrolyzed-oxidizing (EO) water reduced bacterial and fungal loads up to 66%. EO water tempered wheat exposed for 1, 1.5, and 2 min to infrared radiation showed microbial reductions of 99.5% when compared with control wheat. Infrared treatment of tempered wheat cannot be recommended as it adversely affected flour functionality. The use of EO water for tempering as opposed to potable water that is generally used in mills slightly enhances microbial safety of hard red winter wheat.

O objetivo desse trabalho foi desenvolver um aparelho experimental de baixo custo para produção de água eletrolisada ácida (AEA) e verificar sua eficácia na desinfecção de resina acrílica termo polimerizável (RA). Além disso, verificou-se a influência da AEA nas seguintes propriedades da RA. Sorção, Solubilidade, Resistência Flexural, Microdureza Knoop e Rugosidade Superficial. A AEA foi produzida através do processo de eletrólise de uma solução de NaCl a 5% numa célula eletrolítica de dois compartimentos separados por uma membrana semipermeável. Foram utilizados eletrodos de grafite e a diferença de potencial aplicada entre eles foi de 30 V, gerada por um alimentador com capacidade máxima de corrente de 2 A. Após 20 minutos de eletrólise a solução anódica (AEA) apresentou os seguintes parâmetros: pH 3,0 e potencial de óxi-redução de 1150 mV. O tempo de imersão na solução para o ensaios de desinfecção bem como os de propriedades características da RA foi de 10 minutos. A AEA foi eficaz na desinfecção da RA pois os corpos desinfectados não provocaram a turvação dos meios de cultura. A imersão em AEA aumentou estatisticamente (p<0,05) a sorção e a solubilidade da resina acrílica, porém os valores permaneceram dentro dos parâmetros estabelecidos pela ISO 1567. As demais propriedades da resina ficaram inalteradas (p>0,05). / The aim of this research was to develop a low cost experimental apparatus able to produce Electrolyzed Acidic Water (EAW) and verify its efficacy for disinfection of a denture base acrylic resin (AR). It was also verified the influence of EAW on the following properties of AR: Sorption, Solubility, Flexural Strength, Knoop Hardness and Superficial Rugosity. EAW was produced through an electrolysis process of an aqueous NaCl solution (5%) in an electrolytic two chambers cell with a separation membrane between the chambers. Graphite electrodes were used and the potential difference between them was 30 V, provided by a power supply with maximum amperage capacity of 2 A. 20 minutes after the begging of the electrolysis process the anodic solution (EAW) showed the following parameters: pH 3.0 and oxidation-reduction potential (ORP) of 1150 mV. The immersion time in the solution for the disinfection test and also for the evaluation of AR properties was 10 min. EAW was able to disinfect AR as the infected specimens did not cause turbidity of the culture medium. Immersion in EAW increased the sorption and decreased the solubility of the AR in a statistically significant way (p<0.05) but it was within the range required by ISO 1567. All the other AR properties suffered no changes (p<0.05)

O objetivo desse trabalho foi desenvolver um aparelho experimental de baixo custo para produção de água eletrolisada ácida (AEA) e verificar sua eficácia na desinfecção de resina acrílica termo polimerizável (RA). Além disso, verificou-se a influência da AEA nas seguintes propriedades da RA. Sorção, Solubilidade, Resistência Flexural, Microdureza Knoop e Rugosidade Superficial. A AEA foi produzida através do processo de eletrólise de uma solução de NaCl a 5% numa célula eletrolítica de dois compartimentos separados por uma membrana semipermeável. Foram utilizados eletrodos de grafite e a diferença de potencial aplicada entre eles foi de 30 V, gerada por um alimentador com capacidade máxima de corrente de 2 A. Após 20 minutos de eletrólise a solução anódica (AEA) apresentou os seguintes parâmetros: pH 3,0 e potencial de óxi-redução de 1150 mV. O tempo de imersão na solução para o ensaios de desinfecção bem como os de propriedades características da RA foi de 10 minutos. A AEA foi eficaz na desinfecção da RA pois os corpos desinfectados não provocaram a turvação dos meios de cultura. A imersão em AEA aumentou estatisticamente (p<0,05) a sorção e a solubilidade da resina acrílica, porém os valores permaneceram dentro dos parâmetros estabelecidos pela ISO 1567. As demais propriedades da resina ficaram inalteradas (p>0,05). / The aim of this research was to develop a low cost experimental apparatus able to produce Electrolyzed Acidic Water (EAW) and verify its efficacy for disinfection of a denture base acrylic resin (AR). It was also verified the influence of EAW on the following properties of AR: Sorption, Solubility, Flexural Strength, Knoop Hardness and Superficial Rugosity. EAW was produced through an electrolysis process of an aqueous NaCl solution (5%) in an electrolytic two chambers cell with a separation membrane between the chambers. Graphite electrodes were used and the potential difference between them was 30 V, provided by a power supply with maximum amperage capacity of 2 A. 20 minutes after the begging of the electrolysis process the anodic solution (EAW) showed the following parameters: pH 3.0 and oxidation-reduction potential (ORP) of 1150 mV. The immersion time in the solution for the disinfection test and also for the evaluation of AR properties was 10 min. EAW was able to disinfect AR as the infected specimens did not cause turbidity of the culture medium. Immersion in EAW increased the sorption and decreased the solubility of the AR in a statistically significant way (p<0.05) but it was within the range required by ISO 1567. All the other AR properties suffered no changes (p<0.05)

O objetivo desse trabalho foi desenvolver um aparelho experimental de baixo custo para produção de água eletrolisada ácida (AEA) e verificar sua eficácia na desinfecção de resina acrílica termo polimerizável (RA). Além disso, verificou-se a influência da AEA nas seguintes propriedades da RA. Sorção, Solubilidade, Resistência Flexural, Microdureza Knoop e Rugosidade Superficial. A AEA foi produzida através do processo de eletrólise de uma solução de NaCl a 5% numa célula eletrolítica de dois compartimentos separados por uma membrana semipermeável. Foram utilizados eletrodos de grafite e a diferença de potencial aplicada entre eles foi de 30 V, gerada por um alimentador com capacidade máxima de corrente de 2 A. Após 20 minutos de eletrólise a solução anódica (AEA) apresentou os seguintes parâmetros: pH 3,0 e potencial de óxi-redução de 1150 mV. O tempo de imersão na solução para o ensaios de desinfecção bem como os de propriedades características da RA foi de 10 minutos. A AEA foi eficaz na desinfecção da RA pois os corpos desinfectados não provocaram a turvação dos meios de cultura. A imersão em AEA aumentou estatisticamente (p<0,05) a sorção e a solubilidade da resina acrílica, porém os valores permaneceram dentro dos parâmetros estabelecidos pela ISO 1567. As demais propriedades da resina ficaram inalteradas (p>0,05). / The aim of this research was to develop a low cost experimental apparatus able to produce Electrolyzed Acidic Water (EAW) and verify its efficacy for disinfection of a denture base acrylic resin (AR). It was also verified the influence of EAW on the following properties of AR: Sorption, Solubility, Flexural Strength, Knoop Hardness and Superficial Rugosity. EAW was produced through an electrolysis process of an aqueous NaCl solution (5%) in an electrolytic two chambers cell with a separation membrane between the chambers. Graphite electrodes were used and the potential difference between them was 30 V, provided by a power supply with maximum amperage capacity of 2 A. 20 minutes after the begging of the electrolysis process the anodic solution (EAW) showed the following parameters: pH 3.0 and oxidation-reduction potential (ORP) of 1150 mV. The immersion time in the solution for the disinfection test and also for the evaluation of AR properties was 10 min. EAW was able to disinfect AR as the infected specimens did not cause turbidity of the culture medium. Immersion in EAW increased the sorption and decreased the solubility of the AR in a statistically significant way (p<0.05) but it was within the range required by ISO 1567. All the other AR properties suffered no changes (p<0.05)

No description available.

The objectives of this project were to evaluate the efficacies of electrolyzed oxidizing (EO) and ozonated waters as antimicrobial agents for enhancing the microbiological safety of fresh strawberries (Fragaria x ananassa). The influence of sodium chloride (NaCl) concentrations used for preparing EO water was evaluated on their bactericidal activities against naturally occurring aerobic mesophiles on strawberries with a contact time of 5, 10, or 15 min. EO water and ozonated water containing about 1.90 ppm ozone were evaluated and compared with sodium hypochlorite (NaOCl) solution on their capabilities to inactivate and control the growth of Listeria monocytogenes and Escherichia coli O157:H7 inoculated onto strawberries stored at 4 ± 1 °C for up to 15 d, respectively. Post-treatment neutralization of fruit surfaces by washing was also investigated. More than 2 log₁₀ CFU/g reduction of mesophilic aerobic bacteria was achieved in samples washed for 10 or 15 min in EO water prepared from 0.10% (w/v) NaCl solution. Bactericidal activity of treatment solutions against L. monocytogenes and E. coli O157:H7 was not affected by post-treatment neutralization, and their effectiveness against both pathogens in whole fruit tissues did not significantly increase with increasing exposure time. The EO water had an equivalent antibacterial effect as compare with NaOCl in eliminating L. monocytogenes and E. coli O157:H7 on whole strawberry tissues. Fruit surfaces washing with distilled water resulted in 1.90 and 1.27 log₁₀ CFU/ml of rinse fluid reduction of L. monocytogenes and E. coli O157:H7, respectively, whereas ≥ 2.60 log₁₀ CFU/ml of rinse fluid reduction of L. monocytogenes and up to 2.35 and 3.12 log reduction of E. coli O157:H7 were observed on fruit surfaces washed with EO water and NaOCl solution, respectively. However, EO water and NaOCl solution treatments did not exhibit a higher microbicidal activity than water treatment during refrigeration storage. The ozone treatment on inoculated strawberries was not remarkably effective in removing and eliminating pathogens on the whole fruit tissues, but the populations of L. monocytogenes and E. coli O157:H7 were significantly decreased after ozone treatment regardless of the exposure time. The number of L. monocytogenes and E. coli O157:H7 on fruit surfaces was decreased by 2.17 and 2.02 log₁₀ CFU/ml of rinse fluid, respectively, after washing with ozonated water for 10 min. / Graduation date: 2008

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The chicken meat has characteristics that has currently attracted the consumer, leading to increased industrial production, which seeks better production conditions. Ultrasound (US) and the electrolyzed water (EW) are technologies that enable improvements in traditional processes employed by slaughter houses. Its features allow it to have a reduction in water consumption and improvements in features such as the microbiological safety and tenderness. However, further studies are briefly describing possible oxidative effects on meat, especially chicken. Descriptions of the application of US pre-chilling showed improvements compared to applications without this technology. US demonstrated assist heat transfer, resulting in a more homogeneous and rapid cooling, especially in frequencies of 130 kHz. Combinations with EW and US have shown an intensification of cooling. These applications have a limit of time, and observed a reduction in the ability to cool the parts analyzed when this limit is exceeded. The US and EW applications also reported reductions in the initial microbial load, without that there was the initiation of oxidative processes, changes in glycolysis and the beginning of the muscle of the conversion process in the meat. In this pieces were not analyzed changes in its tenderness. Characterizing a prospective use of both technologies in larger and industrial scales. / A carne de frango possui características que atualmente tem atraído o consumidor, acarretando em uma crescente produção industrial, que busca melhores condições produtivas. O ultrassom (US) e a água eletrolisada (AE) são tecnologias que possibilitam melhorias em processos tradicionais empregados por indústrias frigoríficas. Suas características permitem que haja uma redução do consumo de água e melhorias em atributos como a segurança microbiológica e a maciez. No entanto, ainda são poucos os estudos que descrevam possíveis efeitos oxidativos na carne, especialmente na de frango. As descrições da aplicação de US no pré-resfriamento demonstraram melhorias em comparação com aplicações sem esta tecnologia. O US demonstrou auxiliar as transferências de calor, resultando em um resfriamento homogêneo e mais rápido, principalmente em frequências de 130 kHz. As combinações com AE e US demonstraram uma intensificação do resfriamento. Essas aplicações possuem um limiar de tempo, sendo observada uma redução na capacidade de resfriar as peças analisadas quando este limite é ultrapassado. As aplicações de US e AE também apresentaram reduções na carga microbiológica inicial, sem que houvesse a iniciação de processos oxidativos, alterações na glicólise e no início do processo de conversão do músculo em carne. Contudo, os pedaços analisados não tiveram alterações na sua maciez. Caracteriza-se uma prospectiva utilização de ambas as tecnologias em escalas industriais.

No description available.