Pre-treatment and digestion of plant proteins - The quinoa case

The growing global population will place increased pressure on the world&rsquo;s resources to provide more proteins. It is expected that we need to switch at least partly from animals as sources of protein, to plant-based proteins, to ensure sufficient and sustainable production of proteins for everyone. Animal protein is nutritionally of very high quality, since it contains all essential amino acids, whereas vegetable sources generally lack one or more of the essential amino acids. However, this thesis shows that the image that plant proteins have an inferior amino acid profile and poor digestibility is not accurate. For instance, quinoa contains protein with an almost ideal amino acid profile. Especially the essential amino acids profile is considered to be well-balanced for human nutrition. Besides, quinoa contains almost twice as much dietary fibre as most other grains and is high in phosphorus,&nbsp;magnesium and iron. In addition, the quinoa is a good source of calcium, which is useful for vegans and lactose intolerant people. The gluten-free nature of quinoa, being a non-cereal, is considered safe for celiac patients. Next to the amino acid profile including the essential amino acids, the digestibility is another important factor in determining the quality of a protein source. Generally, the potential use of plant proteins and thus also quinoa protein as a food ingredient is limited by their relatively lower digestibility as compared with animal proteins. However, this thesis shows that the reformulate digestibility can be improved by choosing a proper pre-treatment. This thesis starts with a study on the effect of pre-treatment on in vitro gastric digestion of quinoa obtained via wet and dry fractionation (Chapter 2).&nbsp; Quinoa protein was isolated (QPI) from quinoa seeds using a wet fractionation method with a purity of 87% (w/dw) and concentrated (QPC) via a dry fractionation method with a purity of 28% (w/dw). The dry fractionation process only involved milling and sieving and kept the protein in its natural, native state. The wet fractionation method affected the protein digestibility negatively in comparison to the dry fractionation method. In turn, heating decreased the protein digestibility of both types of quinoa. However, the effect of the temperature was lower in the QPC than in the QPI. The better digestibility of the QPC was attributed to the prevention of the formation of large aggregates during the heating of the protein. The influence of heating on the denaturation and the digestibility properties of QPI obtained from a sweet quinoa variety at various extraction pH values was analysed in Chapter 3. Heating the quinoa protein suspensions led to protein denaturation and aggregation, which was stronger at higher treatment temperatures. The protein digestibility was also lower when the protein dispersions had been heated at 90 and 120 &deg;C instead of 60 &deg;C, while the digestibility decreased with increasing extraction pH. Both the effects of high temperature and of the extraction pH on the protein digestibility were ascribed to protein aggregation. Chapter 4 extended the study from protein dispersions, towards protein gels. The type protein source (soy, pea, whey and albumin) and the temperature at which the protein is gelled into a semi-solid product, has great influence on the in vitro gastric protein digestibility. Gels formed at 140 &deg;C digest faster as compared to gels induced at 90 and 120 &deg;C. It is thus clear that by adapting the gel morphology, one can also adapt the gastric digestibility of food products, which is not just a function of the source of the protein, but also very much on the structure of the food products, and on its processing history. Dry milling and subsequent sieving of quinoa sweet varieties (Riobamba and Atlas) produced fractions that were enriched in protein and in starch (Chapter 5). This new dry fractionation method is a more resource efficient alternative to the conventional wet extraction of quinoa proteins and starch. The quinoa protein could be concentrated to a purity of around 32% (32 g/100 g dry solids) for both quinoa varieties analysed, while starch could be isolated to a fraction with a purity of 86-89 % (86-89 g/100 g dry solids). The protein yield and protein separation efficiency were higher for the Riobamba variety. The protein-enriched fraction is rich in oil and fibre as well. The proteins concentrated via the dry fractionation method proposed retained their native properties and showed a high water retention capacity and solubility when unheated. The gelatinization temperature of the starch-rich fraction was influenced by the residual presence of proteins. The starch isolation method had a pronounced effect on the pasting and textural properties. The protein-enriched fractions can be of relevance as functional food ingredients, with a high potential for application in gluten-free products. The influence of starch and fibre on the in vitro gastric digestion of unheated and heated quinoa protein suspensions was studied in Chapter 6. The presence of either starch or fibre reduced the protein digestibility, which is explained by the lower accessibility of pepsin to hydrolyse the proteins, due to the swelling of these components. However, it was found that when fibre was added to a protein-starch system, the presence of fibre partially counteracted the reducing effect of starch on the protein digestibility. Therefore, there is a synergistic effect between the two that merits further study. The quinoa protein systems that had been heated at 120 &deg;C showed reduced protein digestibility, which is due to the formation of large aggregates during pre-heating of the suspensions, as was also found in Chapter 2. In Chapter 7, it was found that heating does not affect the in vitro protein digestibility of SPI dispersions, while heating of PPC dispersions at 120 &deg;C increased its protein digestibility, even though both protein types became partially insoluble. The soy protein isolate (SPI) and pea protein concentrate (PPC) dispersions were then separated into a soluble and an insoluble fraction to study the effect of heat-induced aggregation on protein digestibility. The insoluble fractions contained heat-induced aggregates and were less digestible than their soluble counterparts, which became more digestible with heating. This compensated for the relatively low digestibility of the insoluble fractions. Thus, the solubility of proteins is not always a prerequisite for protein digestion. Finally, the main findings of this thesis were discussed and an outlook for further research was given around the major themes of this thesis (Chapter 8). The developments of a new separation process of plant proteins was discussed as well as the implications of the separation process on the protein functionality. A dry fractionation process for protein concentration of amaranth was presented. The possible effects of the protein isolation or concentration process were mentioned. Overall, three main conclusions could be drawn from this thesis. Quinoa protein can be well isolated using conventional wet processes, yielding a QPI with good purity, but can also be concentrated using the new dry fractionation process. Both types of quinoa protein are well digestible according to the in vitro gastric assay that was used. The conditions during processing of the raw materials into protein isolate or concentrate strongly influence the gastric digestibility: the thermal load, but also the pH applied during the isolation change the gastric digestion perhaps even stronger than the original differences between different protein sources. The digestion of dissolved protein is relatively fast, while that of gelled protein is significantly slower; the presence of other components such as starch or fibre slows the gastric digestion significantly down. This may be due to the lower amount of gastric fluid that is available for the protein, the lower swelling of the protein, and the subsequent slower of pepsin into the protein matrix. </ol

Los medios comunitarios alternativos de la localidad de Engativá como herramienta para la construcción de la memoria colectiva, la identidad local y el sentido de pertenencia del barrio Ciudadela Colsubsidio

Los medios de comunicación comunitarios nacen a mediados del siglo pasado como forma alternativa de transmisión informativa a los ya tradicionales y hegemónicos medios masivos de comunicación. Circulan en pequeñas comunidades, las cuales gestionan de manera autónoma los procesos de creación y distribución de los productos informativos. Este proceso contrasta con el utilizado por los medios comerciales de comunicación masiva, gracias a su independencia informativa con respecto de los grupos económicos, la generación de contenido pertinente a una comunidad específica y la autonomía en el desarrollo de los productos informativos. En Colombia, de forma indirecta a los procesos de paz con las guerrillas izquierdistas, el gobierno nacional ha incentivado el desarrollo de políticas públicas que han impulsado el surgimiento de Medios Comunitarios Alternativos a lo largo y ancho del país. Aunque estaban destinados para funcionar en zonas apartadas de la geografía nacional afectadas por la violencia, este fenómeno informativo fue adoptado en las grandes urbes. En el caso del Distrito Capital, Bogotá está dividida en localidades, una de las cuales hace parte de la unidad de observación de la presente investigación. Esta localidad es Engativá. Ubicada al noroccidente de la capital colombiana y con más de un millón trescientos mil habitantes, cuenta con una gran variedad de Medios Comunitarios Alternativos, que son distribuidos en varios formatos. La presente investigación busca identificar si tres de los Medios Comunitarios Alternativos de mayor circulación en la localidad son consultados en uno de sus barrios: la Ciudadela Colsubsidio. Y, de igual forma, identificar si los contenidos de estos Medios Comunitarios Alternativos tienen, o no, pertinencia con las problemáticas del barrio y si contribuyen al desarrollo de la identidad local, el sentido de pertenencia y la construcción de la memoria colectiva del barrio.The Community Mass Media was born in the middle of the last century, as an alternative way of informative transmission from the traditional and hegemonic massive media that already existed. This community media circulates in small communities and develops independently the creation and distribution process of the informative products. This process is a contrast to the one normally used by the mass commercial media, thanks to its informative independence from the big economic groups, the generation of its contents appropriate to a specific community and the autonomy in the development of the informative products. In Colombia, in a non-direct way towards the process of peace with the guerrilla groups, the national government has stimulated the development of public policies promoting the growth of the Community Alternative Media Communication all around the country. Although it was expected to operate in isolated zones of the country affected by the violence, this informative phenomenon was adopted by major cities. In the Case of the Capital District, Bogota is divided into localities, and one of them is the main subject of observation for the present investigation. The name of this locality is Engativa. Located in the north-west of Colombia s capital city, and with more than one million three hundred thousand inhabitants, there is a big variety of Community Alternative Media Communication available that is distributed in many different formats. The present investigation seeks to identify if the three major Community Alternative Media Communications that circulate in the locality are consulted in one of the neighborhoods: Ciudadela Colsubsidio, and also identify if the contents of this Community Alternative Media Communication have or do not have relevance with the Problem areas of the neighborhood , if it contributes to the development of the local identity, sense of ownership and the construction of the collective memory of the neighborhood.Magíster en ComunicaciónMaestrí

The Combined Effect of Cold and Copper Stresses on the Proliferation and Transcriptional Response of Listeria monocytogenes

Listeria monocytogenes is a foodborne pathogen that can cause severe disease in susceptible humans. This microorganism has the ability to adapt to hostile environmental conditions such as the low temperatures used by the food industry for controlling microorganisms. Bacteria are able to adjust their transcriptional response to adapt to stressful conditions in order to maintain cell homeostasis. Understanding the transcriptional response of L. monocytogenes to stressing conditions could be relevant to develop new strategies to control the pathogen. A possible alternative for controlling microorganisms in the food industry could be to use copper as an antimicrobial agent. The present study characterized three L. monocytogenes strains (List2-2, Apa13-2, and Al152-2A) adapted to low temperature and challenged with different copper concentrations. Similar MIC-Cu values were observed among studied strains, but growth kinetic parameters revealed that strain List2-2 was the least affected by the presence of copper at 8°C. This strain was selected for a global transcriptional response study after a 1 h exposition to 0.5 mM of CuSO4 × 5H2O at 8 and 37°C. The results showed that L. monocytogenes apparently decreases its metabolism in response to copper, and this reduction is greater at 8°C than at 37°C. The most affected metabolic pathways were carbohydrates, lipids and nucleotides synthesis. Finally, 15 genes were selected to evaluate the conservation of the transcriptional response in the other two strains. Results indicated that only genes related to copper homeostasis showed a high degree of conservation between the strains studied, suggesting that a low number of genes is implicated in the response to copper stress in L. monocytogenes. These results contribute to the understanding of the molecular mechanisms used by bacteria to overcome a combination of stresses. This study concluded that the application of copper in low concentrations in cold environments may help to control foodborne pathogens as L. monocytogenes in the industry

Seasonal induction of cluster roots in Embothrium coccineum J.R. Forst. & G. Forst. in the field: factors that regulate their development

Embothrium coccineum J.R. Forst. & G. Forst. (Proteaceae) is a tree that grows successfully in nutrient poor soils of southern Chile at full sunlight. Under these conditions it develops cluster roots (CR). However, the induction of CR on this species has not been studied completely. The aim of this work was to study the effect of seasonality, soil and weeds in the development of CR in E. coccineum . The present study was performed in Los Lagos Region (41º72’ S lat), Chile. Plants of E. coccineum were grown in sandy soils in presence or absence of weeds, using two concentrations of organic matter. The number of CR per plant, CR mass and P concentration in leaves was measured during the four seasons in E. coccineum plants. The CR development in the soil with high organic matter concentration and without weeds was observed in autumn, spring and summer, and in the soil with low organic matter concentration was observed in autumn, winter and spring. Not found related of this result with the foliar P concentration in E. coccineum. The results suggest a strong seasonal and weeds effect on CR development in E. coccineum under field conditions

Protección de heridas de poda mediante fungicidas contra Diaporthe australafricana y Neofusicoccum parvum en kiwis cv. Hayward

45 p.Chile, es considerado actualmente como el tercer mayor exportador de kiwis frescos (Actinidia deliciosa) a nivel mundial. Las plantas de kiwis son una de las especies más importantes en nuestro país con una superficie de 10.569 hectáreas, siendo el cultivar Hayward la más plantada, abarcando un 84,5% de superficie de kiwis. Debido a la expansión de este frutal de hoja caduca y a la intensificación en su producción, se han generado ciertos problemas que afectan a la producción nacional. Dentro de éstos, se encuentran las enfermedades asociadas a especies de hongos fitopatógenos. Una de las enfermedades más importantes hoy en día que afectan a los huertos de kiwi cv. Hayward, es la cancrosis de la madera y muerte regresiva de brazos. Este síndrome está asociado a un complejo de hongos fitopatógenos que ocasionan daños económicos importantes al cultivo. Los hongos fitopatógenos Diaporthe australafricana y Neofusicoccum parvum, son uno de los hongos que están descritos y asociados a las enfermedades muerte regresiva de brazos y/o cargadores de kiwi. El objetivo de este estudio consistió en determinar la efectividad de cinco ingredientes activos (i.a) de fungicidas y dos mezclas de ingredientes de fungicidas en la protección de herida de poda en kiwi contra la infección artificial de D. australafricana y N. parvum en plantas cv. Hayward. Los fungicidas comerciales utilizados en este estudio fueron Pasta Poda Full (i.a. Tebuconazol y Kresoxim metil), Podexal (i.a. Piraclostrobin), Apolo 25 EW (i.a. Tebuconazol), Krexim 50 SC (i.a. Kresoxim metil), Polyben 50 WP (i.a. Benomilo), una aplicación de Pasta Poda Full (i.a. Tebuconazol y Kresoxim metilo) reforzada (pasta + aspersión) con Apolo 25 EW (i.a. Tebuconazol) y otro tratamiento de Pasta Poda Full (i.a. Teboconazol y Kresoxim metil) con Polyben 50 WP (i.a. Benomilo). La efectividad de los productos se evaluó en virtud de la longitud de las lesiones necróticas en los cargadores, luego de 9 meses desde la protección de heridas e inoculación con micelio de D. australafricana y N. parvum. En base a la condiciones del presente trabajo, este estudio demuestra que los productos aplicados para la protección de heridas de poda en cargadores, reducen efectivamente el avance de D. australafricana y N. parvum. En el caso de D. australafricana, el producto comercial Pasta Poda Full (i.a. Tebuconazol y Kresoxim metil) redujo significativamente las lesiones necróticas logrando una efectividad de la enfermedad del 75%, y en el caso de N. parvum, los productos comerciales Podexal (i.a. Piraclostrobin), Pasta Poda Full (i.a. Tebuconazol y Kresoxim metil) más Polyben 50 WP (i.a. Benomilo) redujeron significativamente las lesiones necróticas logrando una efectividad de la enfermedad del 80%. Sin embargo, ningún producto evito el ingreso de D. australafricana y N. parvum en los haces vasculares de los cargadores en una condición de alta presión de inóculo en kiwi cv. Hayward Palabras claves: Diaporthe australafricana, Neofusicoccum parvum, fungicidas, heridas de poda, enfermedades de la madera, cancrosis, kiwi./ABSTRACT:Chile is currently considered the third largest of exporter of fresh kiwifruit (Actinidia deliciosa) worldwide. The kiwifruit are one of the most important species in our country with 10.569 hectares, where the cultivar Hayward is the most planted, and covering 84.5% of planted area of kiwifruits. Due to the expansion of this deciduous fruit and to the intensification in this production, several problem have been describe as example postharvest disorder, quality of fruits and diseases. The diseases caused by fungi are important problems that affect to kiwifruits in the orchard as during cold storage of kiwifruits in Chile. One of the most important diseases today that affect the orchards of kiwifruit cv. Hayward is the wood canker, and arms and cordon dieback. The arms and cordons dieback is a disease caused by a complex of phytopathogenic fungi that cause important economic damage to the crop. The fungal trunk pathogens Diaporthe australafricana and Neofusicoccum parvum are some of the fungi that are being described and associated to arm and cordon dieback in kiwifruits in Chile. The objective of this study was to determine the effectiveness of five active ingredients (a.i) of fungicides and two mixes of a.i in the protection of pruning wounds in cane against infection associated to D. australafricana and N. parvum in kiwifruit cv. Hayward. The commercial fungicides used in this study were Pasta Poda Full (a.i. Tebuconazole and Kresoxim methyl), Podexal (a.i. Pyraclostrobin), Apolo 25 EW (a.i. Tebuconazole), Krexim 50 SC (a.i. Kresoxim methyl), Polyben 50 WP (a.i. Benomyl), a blend of Pasta Poda full (a.i. Tebuconazole and Kresoxim methyl) (paste + spray) with Apolo 25 EW (a.i. Tebuconazole) and another treatment of Pasta Poda Full (a.i. Tebuconazole and Kresoxim methyl) with Polyben 50 WP (a.i. Benomyl). The effectiveness of the products was evaluated according to the length of the necrotic lesions in the canes, after 9 months from wound protection and mycelial inoculation of D. australafricana and N. parvum. Based on the conditions of the present study shows that the fungicide treatment applied for the protection of pruning wounds in canes, effectively reduce the internal progression of D. australafricana and N.parvum. In the case of D. australafricana, the commercial product Pasta Poda Full (a.i.Tebuconazole and Kresoxim methyl) significantly reduced necrotic lesions achieving a 75% of efficacy, and in the case of N. parvum the commercial products Podexal (a.i. Pyraclostrobin),Pasta Poda Full (a.i. Tebuconazole and Kresoxim methyl) with Polyben 50 WP (a.i. Benomyl) significantly reduced necrotic lesions reaching 80% efficacy. However, none of the fungicide treatments avoids the entrance of D. australafricana and N. parvum, when a high inoculum pressure was used (mycelium) on protected canes of kiwifruits. Keywords: Diaporthe australafricana, Neofusicoccum parvum, fungicides, pruning wounds, cordon dieback, canker, kiwifruit

Deshidratacion prematura en bayas de Vitis vinifera cv. Merlot : Efecto de la disminucion del area foliar y aplicacion de un antitranspirante.

Resumen (Spanish, English)49 p.Con el objetivo de determinar el efecto de la relación copa/raíz sobre la deshidratación prematura de bayas, se realizó un ensayo durante la temporada 2002-2003 en la localidad de Apalta VI región. El cultivar utilizado fue Merlot de 4 años de edad, plantado a una densidad de 1,5 x 1,0 m, regado por goteo y conducido en espaldera vertical simple (orientación norte-sur). El ensayo se condujo como un diseño en bloques al azar con cinco repeticiones. Los tratamientos consistieron en la aplicación de un antitranspirante Vapor Gard (di-1-p menthene) y la reducción del área foliar a un 40% en los cuales se midieron las siguientes variables: diámetro y peso de bayas, potencial hídrico del xilema, humedad del suelo, área foliar, incidencia y severidad en plantas y racimos, distribución de raíces, peso de poda y composición química del mosto (sólidos solubles, pH, acidez total), además se determinó la relación copa/raíz. El antitranspirante utilizado no fue efectivo para disminuir la deshidratación prematura de las bayas lo que se reflejó en un mayor porcentaje de racimos afectados y menor peso de las bayas al ser comparado con plantas en que se redujo el área foliar donde el problema fue menor. La reducción del área foliar a un 40% mediante chapoda fue efectiva para disminuir la deshidratación de las bayas. La distribución y cantidad de raíces fue similar en plantas en que se redujo el área foliar y se aplicó el antitranspirante, además los resultados encontrados no determinaron diferencias significativas para la relación copa/raíz, diámetro de bayas, potencial hídrico del xilema, humedad del suelo. Donde si se encontraron diferencias fue en el peso de bayas y de poda, también en el área foliar de brotes, % de racimos y plantas afectadas y grado de severidad

Evaluacion de dosis y tiempo de aplicacion de nuevos fungicidas sobre el control de Venturia inaequalis y Podosphaera leucotricha en manzano.

Resumen (Spanish, English)51 p.Las dos más importantes enfermedades del manzano, tanto en Chile como en las distintas zonas productoras del mundo, son venturia y oidio, causadas por los hongos Venturia inaequalis y Podosphaera leucotricha respectivamente. En los últimos años se han comenzado a utilizar fungicidas que presentan efecto retroactivo o erradicante sobre ambas enfermedades ya que permiten retrasar las aplicaciones, aún después de presentadas las condiciones de temperatura y humedad para el desarrollo de estas enfermedades, lo que se traduce finalmente en ahorro de recursos. En 1996 en la Comuna de Río Claro, VII Región, a 3 km al oeste de la localidad de Cumpeo (35º16’ latitud sur, 71º15’ longitud oeste) se realizaron ensayos sobre hojas y frutos de manzanos cultivar Starkimson para determinar la dosis óptima y tiempo óptimo de aplicación post infección de los fungicidas kresoxim metil (grupo de las estrobirulinas) y tebuconazole (fungicida IBE), en el control de Venturia inaequalis en manzano, mediante mediciones de incidencia y severidad de la enfermedad. Por otra parte, el mismo año en la Estación Experimental Panguilemo de la Universidad de Talca, ubicada a 4 Km al norte de esta ciudad a un costado de la carretera panamericana, 35º25’ latitud sur, 71º37’ longitud oeste, se realizaron ensayos sobre hojas y frutos de manzano de la variedad Royal Gala para establecer la dosis óptima de tebuconazole para el control de Podosphaera leucotricha en manzano y para determinar el fungicida más efectivo entre tebuconazole y miclobutanil en el control de esta enfermedad, también midiendo incidencia y severidad. El fenómeno de la Niña se presentó el año de estudio arrojando una alta sequía con un déficit de precipitaciones de 46,8% y sólo dos períodos infectivos para Venturia inaequalis en contraste con los 7 a 10 que se registran en una temporada normal (Latorre, 1992). Esta situación no permitió determinar la eficiencia ni la retroactividad de los fungicidas Kresoxim metil y Tebuconazole en el control de Venturia inaequalis, sin embargo, se determinó que para estas condiciones, Tebuconazole presentó un efecto retroactivo en el control de la enfermedad de 72 horas en hojas de manzano, no determinándose su retroactividad en frutos. Respecto a Podosphaera leucotricha, tampoco fue posible determinar la eficiencia ni la retroactividad de los fungicidas Tebuconazole y Miclobutanil en su control, debido principalmente a las condiciones climáticas de la temporada de estudio, que se tradujeron en una muy baja incidencia de esta enfermedad. En un año de sequía alta o severa, la incidencia de venturia y oidio en manzano es muy baja, alcanzando niveles de infección de promedio en hojas y frutos de sólo 3,2% para la primera enfermedad y 8,0% para la segunda. Se recomienda repetir los ensayos en años de condiciones climáticas normales, especialmente respecto a precipitaciones, de forma tal de contar con una incidencia que permita detectar diferencias en la eficacia de los fungicidas estudiados

El desarrollo organizacional en las instituciones educativas particulares.

Las instituciones de educación particulares en el Ecuador registran varios problemas en su gestión administrativa debido principalmente al limitado desarrollo organizacional, la investigación permitió determinar de qué manera se relaciona el desarrollo organizacional con el cliente interno. La metodología empleada se detalla a continuación: el enfoque utilizado fue cuantitativo debido que para el desarrollo se empleó modelos estadísticos para la comprobación de hipótesis, las modalidades de investigación: bibliografía y de campo con un nivel correlacional, la población de estudio fue de 87 clientes internos de las diferentes instituciones de la provincia de Morona Santiago. Los resultados más relevantes calculados R (coeficiente de relación de Pearson) fueron: de 0,979 entre tecnología y la innovación y 0,973 entre asignación de tareas y su cumplimiento, con lo que se denoto que existe una correlación positiva entre los factores de la variable independiente y dependiente. Por lo cual se sugiere diseñar un manual de procesos para la asignación de funciones