Factores de decisão de compra de produtos alimentares biológicos

Mestrado em MarketingNos últimos anos, temos assistido a alterações no paradigma de consumo alimentar. Tem-se verificado a nível mundial uma crescente preocupação e interesse em relação aos produtos biológicos, sejam eles alimentares ou não. O impacto que os métodos de cultivo convencionais podem ter na saúde e no meio ambiente levam o consumidor a procurar alternativas mais seguras e mais sustentáveis. Este fenómeno contribui para a dinamização do sector, tornando o mercado de produtos biológicos mais apelativos, gerando mais procura. Ao longo deste estudo são abordados aspetos importantes relativos às características dos consumidores, averiguando as suas atitudes e as suas intenções de compra de produtos biológicos. Os resultados demonstram que a preocupação com a saúde e bem-estar não têm um impacto positivo quer na atitude quer na intenção de compra de produtos alimentares biológicos. Por outro lado, ao longo desta investigação é provado que a preocupação com a ética e com o ambiente tem um impacto positivo na intenção de compra destes produtos. O atributo com maior peso neste estudo foi a preocupação com a segurança alimentar que foi provado estatisticamente que tem um impacto positivo tanto na atitude como na intenção de produtos biológicos. A consciência da qualidade apenas tem impacto na atitude em relação aos produtos alimentares biológicos, bem como a consciência do preço. Por fim, foi provado que a atitude em relação aos produtos alimentares biológicos afeta positivamente a sua intenção de compra.In recent years, we have witnessed changes in the food consumption paradigm. There has been a growing worldwide concern and interest regarding organic products, whether it is food or not. The impact that conventional cultivation methods can have on health and the environment, leads consumers to look for safer and more sustainable alternatives. This phenomenon contributes to the dynamism of the sector, making the organic products market more attractive generating more demand. Important aspects of consumer characteristics are addressed throughout this study by examining their attitudes and intentions whe purchasing organic products. The results demonstrated that the concern for health and well-being does not have a positive impact on either attitude or purchase intent for organic food. On the other hand, throughout this research, it is proven that concern with ethics and the environment has a positive impact on the purchase intention of these products. The most significant attribute in this study was the concern for food safety, which has been statistically proven to have a positive impact on the attitude and intent of biological products. Both quality and price awareness only impact the attitude towards organic food. Finally, it has been proved that the attitude towards organic food positively affects the respective buying intentioninfo:eu-repo/semantics/publishedVersio

Experimental and in-silico investigation of population heterogeneity in continuous Sachharomyces cerevisiae scale-down fermentation in a novel two-compartment setup.

BACKGROUND: In large-scale bioreactors, microbes often encounter fluctuating conditions of nutrient and oxygen supply, resulting in different microbial behavior at the different scales. The underlying reason is spatial heterogeneity, caused by limited mixing capabilities at production scale. Consequently, scale-up of processes is challenging and there is a need for laboratory-scale reactor setups that can mimic large-scale conditions to enhance the understanding of how fluctuating environmental conditions affect microbial physiology. RESULTS: A two-compartment, scale-down setup, consisting of two interconnected stirred tank reactors was used in combination with mathematical modeling, to mimic large-scale continuous cultivations. One reactor represents the feeding zone with high glucose concentration and low oxygen, whereas the other one represents the remaining reactor volume. An earlier developed population balance model coupled to an unstructured model was used to describe the development of bulk concentrations and cell size distributions at varying dilution rate, glucose feed concentration as well as recirculation times between the two compartments. The concentration profiles of biomass and glucose were successfully validated experimentally. Single cell properties of two fluorescent reporter strains that were applied for deeper investigation of cell robustness characteristics and ethanol growth distributions were quantified compartment-wise revealing differences in cell population distributions related to environmental conditions and also compared with the one-compartment, conventional chemostat. CONCLUSION: Results underline the utility for the proposed combined approach as well as the use of continuous scale-down reactors for process investigations as insights concerning single-cell characteristics of the process are revealed, which are normally hidden

Physiological heterogeneities in microbial populations and implications for physical stress tolerance

<p>Abstract</p> <p>Background</p> <p>Traditionally average values of the whole population are considered when analysing microbial cell cultivations. However, a typical microbial population in a bioreactor is heterogeneous in most phenotypes measurable at a single-cell level. There are indications that such heterogeneity may be unfavourable on the one hand (reduces yields and productivities), but also beneficial on the other hand (facilitates quick adaptation to new conditions - i.e. increases the robustness of the fermentation process). Understanding and control of microbial population heterogeneity is thus of major importance for improving microbial cell factory processes.</p> <p>Results</p> <p>In this work, a dual reporter system was developed and applied to map growth and cell fitness heterogeneities within budding yeast populations during aerobic cultivation in well-mixed bioreactors. The reporter strain, which was based on the expression of green fluorescent protein (GFP) under the control of the ribosomal protein RPL22a promoter, made it possible to distinguish cell growth phases by the level of fluorescence intensity. Furthermore, by exploiting the strong correlation of intracellular GFP level and cell membrane integrity it was possible to distinguish subpopulations with high and low cell membrane robustness and hence ability to withstand freeze-thaw stress. A strong inverse correlation between growth and cell membrane robustness was observed, which further supports the hypothesis that cellular resources are limited and need to be distributed as a trade-off between two functions: growth and robustness. In addition, the trade-off was shown to vary within the population, and the occurrence of two distinct subpopulations shifting between these two antagonistic modes of cell operation could be distinguished.</p> <p>Conclusions</p> <p>The reporter strain enabled mapping of population heterogeneities in growth and cell membrane robustness towards freeze-thaw stress at different phases of cell cultivation. The described reporter system is a valuable tool for understanding the effect of environmental conditions on population heterogeneity of microbial cells and thereby to understand cell responses during industrial process-like conditions. It may be applied to identify more robust subpopulations, and for developing novel strategies for strain improvement and process design for more effective bioprocessing.</p