Analytical Chemistry, Environmental Chemistry, Biochemistry, Genetics and Molecular Biology, Electrochemistry
36
Scopus Publications
Scopus Publications
Mechanical and Thermal Properties of Poly (Butylene Adipate-co-Terephthalate) / Poly (Lactic Acid) Blend and Montmorillonite Functionalized by Ionic Liquids Composites Renata Dias, Fernando Scremin, Paulo Bittencourt, Douglas Dragunski, Alex Torquato, Oldair Leite Journal of the Brazilian Chemical Society, 2025 The composites of poly (butylene adipate co-terephthalate) / poly (lactic acid) (PBAT/PLA) blend and montmorillonites functionalized using imidazole-derived ionic liquids with different carbon chain sizes (butyl, octyl, and dodecyl) proved to be a promising alternative for improving the thermal and mechanical properties of the polymer blend. Functionalization of montmorillonites by ionic liquids was confirmed by increasing the basal spacing, and spectroscopical and thermal analysis evidence. The composite synthesis was carried out by casting technique generating homogeneous polymeric films. X-ray diffraction analyses suggested that montmorillonite functionalization with the ionic liquid of the butyl carbon chain fostered exfoliation and incorporation of the clay into the polymer. Furthermore, an increase in the thermal stability and mechanical properties of the material was observed. The other composites formed between the PBAT/PLA blend and the montmorillonite functionalized by ionic liquids of higher carbonic chain showed micro composites formation. Thus, their thermal and mechanical properties had no significant improvements.
Degradation of acid black 210 Na AZO dye through electro-oxidation with graphite electrodes Flavia Manente da Silva, Fábio Orssatto, Oldair Donizeti Leite, Mariana Lupo Falchi, Benedito Martins Gomes Desalination and Water Treatment, 2024 Dyes are widely used substances, however, if disposed of incorrectly in the environment, they can cause numerous problems. To degrade them, it is possible to use advanced oxidative processes (AOP) methods, such as electro-oxidation. This technique was used to degrade the azo dye Acid Black 210 Na. Four treatments were applied (A, B, C, and D) with electric current densities of 4, 12, 20, and 30 mA.cm −2 for 10 min, and the degradation was evaluated by molecular absorbance spectroscopy. Using ANOVA, it was verified that the most suitable condition for degradation corresponds to an electric current density of 20 mA.cm −2 (treatment C), obtaining degradation around 87 % for 459 nm and 95 % for 609 nm, since the degradation at 319 nm follows second-order kinetics, with a rate constant (K) of 0.561 and R² of 0.978. There was an increase in the toxicity of the samples, through the germination and growth of Lactuca sativa radicles and the test with Daphnia magna, after the treatments, possibly due to the presence of chlorine, since the absorbance analysis in the infrared region did not indicate the formation of toxic intermediates.
Influence of conventional and organic farming systems on brown sugar quality Raquel Roman Ros Doneda, Cristian Rafael Andriolli, Oldair Donizeti Leite, Deisy Alessandra Drunkler Semina Ciencias Agrarias, 2023 O açúcar mascavo é obtido a partir do caldo de cana-de-açúcar conservando suas propriedades quase inalteradas quando comparado à matéria-prima. O cultivo da cana-de-açúcar pode ser realizado por sistema de agricultura convencional ou por sistema de produção orgânica, o qual se destaca por sua crescente demanda ligada ao apelo à qualidade nutricional, segurança dos alimentos e questões ambientais. Este trabalho teve por objetivo analisar as influências dos sistemas de produção orgânico e convencional nas propriedades físico-químicas, sensoriais e na qualidade higiênico sanitária de açúcares mascavo comerciais. Para tal, onze amostras (05 convencionais e 06 orgânicas) foram analisadas. Os resultados foram tratados estatisticamente empregando análise de variância e, quando detectado diferença significativa ao nível de 5%, foram submetidos ao Teste de Tukey. As amostras, independente do tipo de cultivo, apresentaram resultados variáveis para os atributos umidade (0,80 a 3,24%), pH (6,03 a 8,71), cinzas (0,35 a 2,36%), cinzas condutimétricas (0,88 a 6,35%), glicídios redutores em glicose (3,09 a 7,91%), polaridade (80,19 a 92,95 °Z), sendo que para este atributo apenas cinco amostras encontraram-se de acordo com o único parâmetro exigido pela legislação (acima de 90,0 °Z); a cor apresentou luminosidade entre 44,05 a 61,72. Quanto aos minerais e metais, a amostra MO3 foi responsável pelas maiores concentrações de Ca (1.829,27 mg kg-1) e Mg (885,31 mg kg-1); na amostra MO1 o Mn esteve presente em maior quantidade (18,26 mg kg-1) e apresentou a menor concentração do elemento Al (1,02 mg kg-1); a MO4 obteve menor teor para o mineral Na (7,27 mg kg-1); a MO6 apresentou o teor mais baixo para o metal pesado Cu (3,06 mg kg-1) e mais elevado para o Zn com 6,43 mg kg-1; a concentração mais elevada de Fe esteve presente na amostra MC4, com 137,47 mg kg-1; o metal pesado Pb apenas não foi detectado nas amostras MC2, MC3 e MO3. As amostras apresentaram resultados satisfatórios e indicativos de práticas higiênico-sanitárias pela análise microscópica e microbiológica, com ausência de Coliformes a 45 ºC e Salmonella sp. e valores aceitáveis de mesófilos, bolores e leveduras. A análise sensorial não apresentou diferença estatística significativa (p > 0,05) entre os atributos avaliados: cor, granulosidade visual, sabor doce, aroma característico, solubilidade na boca e aceitação global. Em relação ao tipo de cultivo da cana-de-açúcar, os resultados em geral não permitiram afirmar a existência de vantagem na qualidade nutricional e higiênico sanitária do açúcar mascavo convencional ou orgânico.
Effect of ultrasound and chlorine dioxide on Salmonella Typhimurium and Escherichia coli inactivation in poultry chiller tank water Ana Paula Rossi, Daneysa Lahis Kalschne, Ana Paula Iglikowski Byler, Eder Lisandro de Moraes Flores, Oldair Donizeti Leite, Daniel dos Santos, Juliano Smanioto Barin, Cristiane Canan Ultrasonics Sonochemistry, 2021 This study evaluated the application of ultrasound alone or combined with chlorine dioxide (ClO2) for Salmonella Typhimurium and Escherichia coli inactivation in poultry processing chiller tank water. A Full Factorial Design (FFD) 22 was conducted for each microorganism to evaluate the effect of ultrasound exposure time (x1: 1 to 9 min; fixed: 37 kHz; 330 W; 25 °C) using a bath, and ClO2 concentration (x2: 1 to 17 mg L−1) on microorganism count expressed in log CFU mL−1 in distilled water. Variable x2 had a negative effect on Salmonella Typhimurium (-5.09) and Escherichia coli (-2.00) count, improving the inactivation; while a x1 increase present no inactivation improvement, explaining the use of x1 lower level (1 min) and x2 higher level (17 mg L−1). The best condition for microorganism inactivation based on FFD was evaluated in chiller tank water (with organic matter) at 25, 16, and 4 °C; x1 was kept (1 min), however x2 was adjusted to obtain the same residual free chlorine (2.38 mg L−1) considering the ClO2 consumption by organic matter, achieving the value of 30 mg L−1. An inactivation of 49% and 31% were observed for Salmonella Typhimurium and Escherichia coli. When ultrasound was replaced by a simple agitation in the presence of ClO2, there was no inactivation for both microorganisms. Moreover, at poultry carcass pre-chilling (16 °C) and chilling (4 °C) conditions, the synergism of ultrasound combined with ClO2 was more pronounced, with microorganisms’ reductions up to 100%.
Antioxidant effect of rice bran purified phytic acid on mechanically deboned chicken meat Cristiane Canan, Daneysa Lahis Kalschne, Gabriela Cavalca Ongaratto, Oldair Donizeti Leite, Ana Cristina Trindade Cursino, Eder Lisandro de Moraes Flores, Elza Iouko Ida Journal of Food Processing and Preservation, 2021 This study aimed to evaluate the antioxidant effect of rice bran purified phytic acid (PA; 78.2%) and compare it with the standard high purity rice PA (≥90%) after added to mechanically deboned chicken meat (MDCM) and stored at −18℃ for 120 days. Rice bran purified PA (RPA) and standard PA (SPA) were added to MDCM at 5 and 10 mmol/kg and MDCM samples were analyzed for lipid oxidation by thiobarbituric acid reactive substance (TBARS), warmed-over flavor (WOF), and estimated myoglobin content at 15 days intervals for up to 120 days. RPA addition to MDCM stored for 120 days at −18℃ inhibited lipid oxidation, reducing WOF, and heme pigment oxidation that maintains the characteristic MDCM color. The results suggested that RPA is a suitable and efficient natural antioxidant in MDCM. Practical applications Mechanically deboned chicken meat (MDCM) is a poultry deboned carcass by-product and an important raw material for cooked meat production. MDCM stability is affected by bone separation, grinding process, and bone marrow content (hemoglobin-rich). The meat industry demands quality and stability improvements for MDCM due to its rapid propensity for oxidation. Phytic acid (myo-inositol hexaphosphate) is a powerful antioxidant with potential use in foods. It is efficient, safe, and naturally sourced. It alters redox potential, keeping it in Fe3+ form, protecting it against oxidative damage, thus improving the MDCM quality. The present study results are expected to contribute to the meat industry in producing safe and quality products.
