O consumo de couve-manteiga (Brassica oleracea cv. acephala) e brócolis (Brassica oleracea L. var. italica) tem sido inversamente associado à morbidade e mortalidade causadas por doenças degenerativas. Estas espécies são altamente consumidas no Brasil, o que viabiliza o seu uso como minimamente processado (MP). A crescente preocupação mundial com a estocagem, qualidade nutricional e segurança microbiológica dos alimentos tem levado a muitos estudos visando à análise microbiológica, vitamínica e tempo de vida de prateleira. No intuito de melhorar a qualidade destes produtos, o processamento por radiação em baixas doses é eficiente na manutenção da qualidade do produto, em alguns casos não comprometendo seus valores nutricionais e sensoriais. O objetivo deste estudo foi avaliar a eficácia da radiação gama de 60Co com doses de 0, 1,0 e 1,5 kGy na redução da microbiota presente nestes vegetais, assim como analisar suas características nutricionais e sensoriais. A metodologia empregada neste trabalho foram as análises microbiológicas, análise colorimétrica, análise dos compostos fenólicos, análise antioxidante e análise sensorial. A análise microbiológica mostrou uma diminuição no desenvolvimento de populações de microrganismos aeróbios, psicrotróficos e bolores e leveduras com doses de radiação crescentes. A análise sensorial não mostrou diferença significativa entre os diferentes tempos de cocção analisados. Quanto à análise de fenólicos totais, houve diferença significativa entre as amostras, sugerindo que com o aumento da dose de irradiação houve um aumento na quantidade de fenólicos totais encontrado em couve e brócolis MP. Pode-se observar que a amostra de couve controle apresentou alta atividade antioxidante e para as amostras tratadas por irradiação houve um decréscimo de percentual. Em contrapartida as amostras de brócolis apresentam um aumento na percentagem de sequestro de DPPH proporcional ao aumento da dose de radiação. As análises colorimétricas revelaram que para as amostras de couve MP e floretes de brócolis não houve diferenças significativas, entretanto para as amostras de talos de brócolis houve diferença significativa quanto ao amarelecimento durante a estocagem. Concluise que o processamento de couve-manteiga e brócolis por radiação gama pode ser uma alternativa viável para as indústrias, uma vez que houve redução da população de microrganismos, sem alterações nas qualidades sensoriais e com mínimas alterações nas características que conferem poder antioxidante. / The consumption of collard greens (Brassica oleracea cv. acephala) and broccoli (Brassica oleracea L. var. italica) has been inversely associated with morbidity and mortality caused by degenerative diseases. These species are highly consumed in Brazil, which enables its use as minimally processed (MP). The growing worldwide concern with the storage, nutritional quality and microbiological safety of food has led to many studies aimed at microbiological analysis, vitamin and shelf life. To improve the quality of these products, radiation processing can be effective in maintaining the quality of the product, rather compromising their nutritional values and sensory. The aim of this study was to evaluate the effectiveness of gamma radiation from 60Co at doses of 0, 1.0 and 1.5 kGy on the reduction of microbiota in these plants, and analyze their nutritional and sensory characteristics. The methodology used in this study was microbiological analysis, colorimetric analysis, analysis of phenolic compounds, antioxidant analysis and sensory analysis. The microbiological analysis showed a decrease in the development of populations of aerobic microorganisms, psychrotrophic and yeast and mold with increasing doses of radiation. The sensory analysis showed no significant difference between different times of cooking analyzed. The analysis of phenolic compounds, significant differences between the samples, suggesting that with increasing dose of irradiation was an increase in the amount of phenolic compounds found in broccoli and collard greens MP. It can be observed that the sample of control collard greens showed high antioxidant activity and for the samples treated by irradiation was a decrease of percentage. In contrast the samples of broccoli show an increase in the rate of scavenging DPPH with increase of the dose of radiation. The colorimetric analysis revealed that for samples of MP collard greens and broccoli foil of no significant differences, but for samples of stems of broccoli significant difference on the yellowing during storage. It is concluded that the processing of collard greens and broccoli butter by gamma radiation may be a viable alternative to the industry, since there was a reduction of the population of microorganisms, without changes in the sensory qualities and with minimum changes in the characteristics that confer antioxidant power.

Canola and juncea meals can be used in poultry diets instead of soybean meal. The meals were fed to broilers and turkeys in digestibility trials to measure the apparent metabolizable energy (AMEn). Throughout growth trials, canola and juncea meals were fed at four levels (0, 10, 20 and 30 %) with and without a dietary enzyme cocktail (DEC). This study investigated higher inclusion levels than previously recommended for use in broilers diets. The carcass compositions, fatty acid analysis and liver parameters were measured to investigate the effects of diets on birds. The AMEn of the meals were used in formulating broiler and turkey diets. Growth trials found positive effects of DEC on performance, allowed higher inclusion levels of the meals. No negative effects of diets were observed for liver parameters and carcass compositions. The fatty acid profiles of carcass tissues were improved by increasing levels of canola oil in diets.

No description available.

O consumo de couve-manteiga (Brassica oleracea cv. acephala) e brócolis (Brassica oleracea L. var. italica) tem sido inversamente associado à morbidade e mortalidade causadas por doenças degenerativas. Estas espécies são altamente consumidas no Brasil, o que viabiliza o seu uso como minimamente processado (MP). A crescente preocupação mundial com a estocagem, qualidade nutricional e segurança microbiológica dos alimentos tem levado a muitos estudos visando à análise microbiológica, vitamínica e tempo de vida de prateleira. No intuito de melhorar a qualidade destes produtos, o processamento por radiação em baixas doses é eficiente na manutenção da qualidade do produto, em alguns casos não comprometendo seus valores nutricionais e sensoriais. O objetivo deste estudo foi avaliar a eficácia da radiação gama de 60Co com doses de 0, 1,0 e 1,5 kGy na redução da microbiota presente nestes vegetais, assim como analisar suas características nutricionais e sensoriais. A metodologia empregada neste trabalho foram as análises microbiológicas, análise colorimétrica, análise dos compostos fenólicos, análise antioxidante e análise sensorial. A análise microbiológica mostrou uma diminuição no desenvolvimento de populações de microrganismos aeróbios, psicrotróficos e bolores e leveduras com doses de radiação crescentes. A análise sensorial não mostrou diferença significativa entre os diferentes tempos de cocção analisados. Quanto à análise de fenólicos totais, houve diferença significativa entre as amostras, sugerindo que com o aumento da dose de irradiação houve um aumento na quantidade de fenólicos totais encontrado em couve e brócolis MP. Pode-se observar que a amostra de couve controle apresentou alta atividade antioxidante e para as amostras tratadas por irradiação houve um decréscimo de percentual. Em contrapartida as amostras de brócolis apresentam um aumento na percentagem de sequestro de DPPH proporcional ao aumento da dose de radiação. As análises colorimétricas revelaram que para as amostras de couve MP e floretes de brócolis não houve diferenças significativas, entretanto para as amostras de talos de brócolis houve diferença significativa quanto ao amarelecimento durante a estocagem. Concluise que o processamento de couve-manteiga e brócolis por radiação gama pode ser uma alternativa viável para as indústrias, uma vez que houve redução da população de microrganismos, sem alterações nas qualidades sensoriais e com mínimas alterações nas características que conferem poder antioxidante. / The consumption of collard greens (Brassica oleracea cv. acephala) and broccoli (Brassica oleracea L. var. italica) has been inversely associated with morbidity and mortality caused by degenerative diseases. These species are highly consumed in Brazil, which enables its use as minimally processed (MP). The growing worldwide concern with the storage, nutritional quality and microbiological safety of food has led to many studies aimed at microbiological analysis, vitamin and shelf life. To improve the quality of these products, radiation processing can be effective in maintaining the quality of the product, rather compromising their nutritional values and sensory. The aim of this study was to evaluate the effectiveness of gamma radiation from 60Co at doses of 0, 1.0 and 1.5 kGy on the reduction of microbiota in these plants, and analyze their nutritional and sensory characteristics. The methodology used in this study was microbiological analysis, colorimetric analysis, analysis of phenolic compounds, antioxidant analysis and sensory analysis. The microbiological analysis showed a decrease in the development of populations of aerobic microorganisms, psychrotrophic and yeast and mold with increasing doses of radiation. The sensory analysis showed no significant difference between different times of cooking analyzed. The analysis of phenolic compounds, significant differences between the samples, suggesting that with increasing dose of irradiation was an increase in the amount of phenolic compounds found in broccoli and collard greens MP. It can be observed that the sample of control collard greens showed high antioxidant activity and for the samples treated by irradiation was a decrease of percentage. In contrast the samples of broccoli show an increase in the rate of scavenging DPPH with increase of the dose of radiation. The colorimetric analysis revealed that for samples of MP collard greens and broccoli foil of no significant differences, but for samples of stems of broccoli significant difference on the yellowing during storage. It is concluded that the processing of collard greens and broccoli butter by gamma radiation may be a viable alternative to the industry, since there was a reduction of the population of microorganisms, without changes in the sensory qualities and with minimum changes in the characteristics that confer antioxidant power.

No description available.

No description available.

sn-Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the acylation of sn-1 position of sn-glycerol-3-phosphate to produce lysophosphatidic acid and Coenzyme A. GPATs are involved in several lipid synthetic pathways and play important physiological roles in plant development. The present doctoral thesis includes three related studies, which aim to molecularly and functionally characterize several plant GPAT genes and the encoded enzymes. The first study characterized three endoplasmic reticulum-bound GPAT4s encoded by three homologous GPAT4 genes of Brassica napus (oilseed rape), focusing primarily on their functional divergence and physiological roles in plant development and lipid biosynthesis. The three homologous GPAT4 genes exhibited different expression patterns and altered epigenetic features. Phenotypic rescue of a gpat4 gpat8 Arabidopsis double mutant and analysis of the gpat4 RNAi B. napus lines suggested physiological roles for the GPAT4s in cuticle formation of the rosette leaves, early flower development, pollen development and storage lipid biosynthesis. The second study investigated stable internal reference genes for gene expression studies in B. napus. This project identified four reliable reference genes to be used in gene expression analysis of BnGPAT4 homologues in both vegetative tissues and developing seeds. The third study focused on molecular cloning and biochemical characterization of a soluble plastidial GPAT isolated from a chilling-tolerant plant, western wallflower (Erysimum asperum). A truncated form of recombinant EaGPAT, with the putative transit peptide deleted, was functionally expressed in yeast. A series of enzymatic assays were performed in order to determine the optimum in vitro reaction conditions for the recombinant EaGPAT. The recombinant EaGPAT was further assayed with different acyl-CoAs and exhibited a substrate preference for 18 carbon unsaturated acyl-CoAs. With this substrate preference, the EaGPAT could potentially be used as a biotechnological tool for improving plant chilling-tolerance or increasing unsaturated fatty acid content of seed oil. Overall, the present doctoral studies revealed the functional divergence and important physiological roles of the GPAT4s in B. napus, and biochemically characterized a plastidial GPAT from E. asperum. The knowledge obtained from these studies provides new insights into the role of GPAT in plants and will be useful for further development of biotechnological approaches to modify seed oil biosynthesis in oleaginous crops. / Plant Science

Oilseed and oilseed meal extracted from members of <i>Brassicaceae</i> release broadspectrum biocidal isothiocyanate when ground and exposed to moisture. The compounds are released when the seed enzyme myrosinase catalyzes the hydrolysis of glucosinolates producing glucose, sulfate, and pesticidal isothiocyanates. Allylisothiocyanate (AITC), the predominant isothiocyanate of <i>Brassica juncea</i>, has broad-spectrum biological activities against plants, animals and fungi. Knowledge of the concentration of AITC arising from a treatment with mustard and AITC toxicity to many target and non-target species is not known. Therefore, factors affecting AITC release and assays of mustard toxicity were conducted. The rate of AITC release from mustard meal was affected by temperature and pH. Current isothiocyanate extraction and quantification methods measure a change in the concentration of glucose (a predominant product of myrosinase-catalysed glucosinolate hydrolysis) to determine myrosinase activity. The objectives of this work were to study: 1) factors affecting myrosinase activity in mustard (<i>Brassica juncea</i>), 2) the effects of AITC on seed germination and 3) the toxicity of AITC and mustard meal.<p> Attempts were made to improve the Herb and Spice Method, the only available industrial method to measure total isothiocyanate production in mustard meal. The effects of a wide range of reaction temperatures (7 to 97°C) and incubation times (0 min to 2 h) on myrosinase-catalyzed conversion of sinigrin (a glucosinolate) to allyl isothiocynate (AITC) were studied. Significant inhibition of enzyme activity was observed at all temperatures over 57°C, and at 97°C no myrosinase activity was found. It was concluded that myrosinase-catalyzed conversion of sinigrin to AITC was a rapid process and detectable amounts of AITC could be found in samples in two min, and that higher temperatures inhibited myrosinase activity. The pH of the reaction mixture significantly affected myrosinase-catalyzed conversion of sinigrin to AITC. A change in pH did not affect the substrate, but severely affected the activity of myrosinase. Furthermore, other compounds viz., boric acid (H3BO3), succinic acid (C2H4(COOH)2),calcium chloride (CaCl2) and ethanol (C2H5OH), were explored for their ability to inhibit myrosinase activity. Calcium chloride and ethanol were particularly effective.<p> It was hypothesized that AITC might act as a plant growth promoter/regulator based on the fact that AITC and ethylene, a plant growth regulator, exhibit structural similarity (R-CH=CH2, where R is -CH2SCN and -H in AITC and ethylene, respectively). Therefore, AITC might act as an ethylene analogue. Ethylene is known to promote seed germination and overcome seed dormancy in a dose- and species-dependent manner.Flax and tomato seeds were used as model systems to test the germination enhancing properties of AITC. It was concluded that AITC promoted flax and tomato seed germination and thus might be used for this application in agricultural practice.<p> An assay was developed for testing AITC toxicity in ground seed by exploring HSP70 expression in <i>Caenorhabditis elegans</i> as a marker of toxicity. <i>C.elegans</i> strain N2 was exposed to different concentrations (0 to 10 ìM) of AITC for 2 h at room temperature. Western blotting with anti-<i>HSP70</i> antibody showed a marked increase in the expression of <i>HSP70</i> protein in a dose-dependent manner. Assays of the expression of <i>HSP70A</i> mRNA by quantitative real time reverse transcriptase (RT) PCR revealed no significant change in the expression of <i>HSP70A</i> mRNA at low concentrations of AITC (< 0.1 ìM). However, treatment with higher concentrations (>1ìM) resulted in four- to five - fold increase in expression of <i>HSP70A</i> mRNA over the control. To understand if mustard toxicity was due to AITC alone, or if other compounds in mustard ground seed affected <i>HSP70</i> transcript production, <i>C. elegans</i> was exposed to AITC or <i>Brassica juncea</i> cv. Arrid ground seed (Arrid is a mustard variety with a lower level of sinigrin (<3 ìM per gram of seed), or both. ELISA revealed increased expression of HSP70 protein in C. elegans treated with AITC + ground seed, but the level of protein was less than that observed with AITC alone. These results indicated that mustard ground seed toxicity was contributed primarily by AITC, and that some ground seed components antagonized AITC toxicity in <i>C. elegans</i>.

Oilseed and oilseed meal extracted from members of <i>Brassicaceae</i> release broadspectrum biocidal isothiocyanate when ground and exposed to moisture. The compounds are released when the seed enzyme myrosinase catalyzes the hydrolysis of glucosinolates producing glucose, sulfate, and pesticidal isothiocyanates. Allylisothiocyanate (AITC), the predominant isothiocyanate of <i>Brassica juncea</i>, has broad-spectrum biological activities against plants, animals and fungi. Knowledge of the concentration of AITC arising from a treatment with mustard and AITC toxicity to many target and non-target species is not known. Therefore, factors affecting AITC release and assays of mustard toxicity were conducted. The rate of AITC release from mustard meal was affected by temperature and pH. Current isothiocyanate extraction and quantification methods measure a change in the concentration of glucose (a predominant product of myrosinase-catalysed glucosinolate hydrolysis) to determine myrosinase activity. The objectives of this work were to study: 1) factors affecting myrosinase activity in mustard (<i>Brassica juncea</i>), 2) the effects of AITC on seed germination and 3) the toxicity of AITC and mustard meal.<p> Attempts were made to improve the Herb and Spice Method, the only available industrial method to measure total isothiocyanate production in mustard meal. The effects of a wide range of reaction temperatures (7 to 97°C) and incubation times (0 min to 2 h) on myrosinase-catalyzed conversion of sinigrin (a glucosinolate) to allyl isothiocynate (AITC) were studied. Significant inhibition of enzyme activity was observed at all temperatures over 57°C, and at 97°C no myrosinase activity was found. It was concluded that myrosinase-catalyzed conversion of sinigrin to AITC was a rapid process and detectable amounts of AITC could be found in samples in two min, and that higher temperatures inhibited myrosinase activity. The pH of the reaction mixture significantly affected myrosinase-catalyzed conversion of sinigrin to AITC. A change in pH did not affect the substrate, but severely affected the activity of myrosinase. Furthermore, other compounds viz., boric acid (H3BO3), succinic acid (C2H4(COOH)2),calcium chloride (CaCl2) and ethanol (C2H5OH), were explored for their ability to inhibit myrosinase activity. Calcium chloride and ethanol were particularly effective.<p> It was hypothesized that AITC might act as a plant growth promoter/regulator based on the fact that AITC and ethylene, a plant growth regulator, exhibit structural similarity (R-CH=CH2, where R is -CH2SCN and -H in AITC and ethylene, respectively). Therefore, AITC might act as an ethylene analogue. Ethylene is known to promote seed germination and overcome seed dormancy in a dose- and species-dependent manner.Flax and tomato seeds were used as model systems to test the germination enhancing properties of AITC. It was concluded that AITC promoted flax and tomato seed germination and thus might be used for this application in agricultural practice.<p> An assay was developed for testing AITC toxicity in ground seed by exploring HSP70 expression in <i>Caenorhabditis elegans</i> as a marker of toxicity. <i>C.elegans</i> strain N2 was exposed to different concentrations (0 to 10 ìM) of AITC for 2 h at room temperature. Western blotting with anti-<i>HSP70</i> antibody showed a marked increase in the expression of <i>HSP70</i> protein in a dose-dependent manner. Assays of the expression of <i>HSP70A</i> mRNA by quantitative real time reverse transcriptase (RT) PCR revealed no significant change in the expression of <i>HSP70A</i> mRNA at low concentrations of AITC (< 0.1 ìM). However, treatment with higher concentrations (>1ìM) resulted in four- to five - fold increase in expression of <i>HSP70A</i> mRNA over the control. To understand if mustard toxicity was due to AITC alone, or if other compounds in mustard ground seed affected <i>HSP70</i> transcript production, <i>C. elegans</i> was exposed to AITC or <i>Brassica juncea</i> cv. Arrid ground seed (Arrid is a mustard variety with a lower level of sinigrin (<3 ìM per gram of seed), or both. ELISA revealed increased expression of HSP70 protein in C. elegans treated with AITC + ground seed, but the level of protein was less than that observed with AITC alone. These results indicated that mustard ground seed toxicity was contributed primarily by AITC, and that some ground seed components antagonized AITC toxicity in <i>C. elegans</i>.

No description available.