Editorial | The main challenge faced by agriculture is to produce enough food for a continued increase in population, however in the context of ever-growing competition for water and land, climate change, droughts and anthropic water scarcity, and less-participatory water governance. Such a context implies innovative issues in agricultural water management and practices, at both the field and the system or the basin scales, mainly in irrigation to cope with water scarcity, environmental friendliness, and rural society welfare. Therefore, this special issue was set to present and discuss recent achievements in water, agriculture, and food nexus at di erent scales, thus to promote sustainable development of irrigated agriculture and to develop integrated approaches to water and food. Papers cover various domains including: (a) evapotranspiration and crop water use; (b) improving water management in irrigated agriculture, particularly irrigation scheduling; (c) adaptation of agricultural systems to enhance water use and water productivity to face water scarcity and climate change; (d) improving irrigation systems design and management adopting multi-criteria and risk approaches; (e) ensuring sustainable management for anthropic ecosystems favoring safe and high-quality food production, as well as the conservation of natural ecosystems; (f) assessing the impact of water scarcity and, mainly, droughts; (g) conservation of water quality resources, namely by preventing contamination with nitrates; (h) use of modern mapping technologies and remote sensing information; and (i) fostering a participative and inclusive governance of water for food security and population welfare | info:eu-repo/semantics/publishedVersion

O sucesso no desenvolvimento de novos produtos alimentares, por substituição total ou parcial de determinados lípidos por congéneres de origem vegetal e seus subprodutos (ex. polímeros), baseiase na garantia da manutenção ou melhoria das características sensoriais dos produtos tradicionais, relativamente aos quais se quer inovar, bem como da estabilidade do produto durante um prazo tido por suficiente. Os cremes de barrar são basicamente emulsões de água-em-óleo (a/o), assemelham-se à manteiga na sua aparência, consistência e composição. A fase lipídica normalmente é uma mistura de óleos vegetais e/ou óleos e gorduras de origem animal contendo corantes naturais (-caroteno), estabilizantes, emulsionantes, aromatizantes, antioxidantes, lecitinas e vitaminas lipossolúveis. A fase aquosa contém proteínas, leite desnatado, onde podem ser incorporadas pequenas quantidades de outros ingredientes, tais como o sal, conservantes, espessantes e vitaminas hidrossolúveis. Presentemente, existe uma enorme quantidade de estudos de caracterização de emulsões alimentares de óleo-em-água (o/a) e esta abundância contrasta com a enorme escassez de estudos análogos sobre emulsões água-em-óleo (a/o). | info:eu-repo/semantics/publishedVersion

[resumo] | [abstract]

As emulsões a/o, neste caso margarinas, são sistemas multifásicos complexos, constituídos por uma fase líquida dispersa (aquosa), uma fase líquida contínua (lipídica) onde estão embebidos cristais de gordura cuja função é estabilizar a fase dispersa.O teor lipídico e emulsionante têm efeitos directos nas propriedades reológicas. O mimetismo lipídico destas emulsões envolve o controlo de mecanismos a nível microscópico no que diz respeito ao controlo da cristalização de gorduras, influenciando fortemente a microestrutura e as propriedades reológicas da emulsão. Sugere-se que a microscopia óptica e a reologia podem ser utilizadas no seguimento e controlo dos processos de formação e estabilização de emulsões. Objectivos:Observar, fotografar e filmar as emulsões. Comprovar, ou não, se as diferentes formulações das emulsões, apresentavam microestruturas diferentes. Determinar a composição das fases de cada emulsão utilizando um programa de tratamento de imagem. Determinar o tamanho médio de gota e a distribuição do tamanho de gota. Considerações finais: No caso dos resultados de tratamento de imagem verifica-se que há três emulsões com tamanho médio de gota semelhante (A, D e E) e as outras duas (B e C) são significativamente diferentes, tendo sido possível determinar as composições globais das fases aquosa e lipídica com valores muito próximos do esperado. Verifica-se que o escoamento altera a microestrutura da emulsão de água/óleo. Essas modificações são quantificadas em função das condições de escoamento consideradas e comparadas com as funções materiais reológicas medidas experimentalmente num espectrómetro mecânico Rheometrics RMS-800. Os resultados experimentais obtidos foram comparados com os modelos matemáticos preditivos, verificando-se uma boa aproximação com os resultados experimentais.

[Resumo] | [Abstract]

The crucial challenge for smallholder farmers in sub-Saharan Africa is feeding a growing population while preserving the natural resource base of the agricultural system. In future, this challenge will be exacerbated by soil degradation and climate change. Conservation Agriculture (CA) has been promoted as a strategy that can improve yields, soils and effective water use. CA thus has potential to increase the resilience of farming systems facing the mentioned challenges. However, CA since its introduction in sub-Sahara Africa has not moved from the invention to the innovation stage: the CA innovation seen as a package is not meeting the farmers’ needs, capabilities and opportunities. Overall, the attempt to transfer this innovation in a conventional linear way from science to farm has been disappointing. The INCAA project is designed as an action research process aimed at targeting the challenging (and often missing) interfaces of science-driven technology and local realities in innovation systems. The overall objective of INCAA is to mentor and analyse a learning process that supports the innovation of CA in sub-Saharan Africa. The case studies of the project are Laikipia County, Kenya and Koumbia District, Burkina Faso. Building on the experiences of past projects, INCAA will (1) map benefits and adaptations of CA in innovation systems around the partner projects; (2) foster joined learning of stakeholders to test and validate CA tools; and (3) develop learning strategies for an innovation process towards CA including institutional and individual dimensions. This project will start from those who take the final decision on the fate of CA - the farmers. By assessing how farmers have actually adapted and implemented CA, we can derive lessons on the benefits and losses related to such CA modes for all stakeholders involved in the agricultural system. This contribution will 1) introduce the overall conceptual, methodological and structural design of the project and 2) highlight its first preliminary results which so far show high influence of gender aspects towards the adoption decision process. Differing roles of and expectations towards men and women within the farming communities are often an invisible obstacle for further adoption of CA.

Using a top-down modelling approach, a balanced trophic food web model of a water reservoir of the Ria Formosa lagoonal system was constructed. Few adjustments of input data were necessary to run the model since most of the parameters were estimated at the study site and the characteristics of the water reservoir allowed a high degree of control and precision in terms of sampling and data collection. Trophic levels of the 14 compartments included in the model varied between 1.0 for primary producers and detritus to 3.4 for carnivorous fish and the 14 groups were aggregated in a food chain with six trophic levels. The water reservoir has a detritus based food chain, with the majority of the biomass concentrated in the first two levels, the producers level and the herbivore/detritivore level (97.6%). The transfer efficiencies were low, and decreased with increasing level number, varying between 6.0 and 0.2%. The degree of "ecosystem maturity" was difficult to establish, but several parameters indicate that it could be high. The water reservoir studied, which has similar environmental and ecological characteristics as the Ria Formosa lagoon. is near its carrying capacity. (C) 2004, Elsevier B.V. All rights reserved.

The feeding habits of several fish species in a water reservoir of the Ria Formosa, Portugal, that has similar ecological characteristics to the outside tidal channels, were studied and compared with food availability. The gilthead seabream (Sparus aurata), the most abundant fish species, mainly selected gastropods and bivalves, although occasionally fish and small crustaceans such as tanaids, ostracods, and cumaceans were also selected. Polychaetes, although abundant in the environment, were not particularly selected by any of the fish species studied. The diets of all the species studied were characterized by a large variety of prey, allowing them to survive in environments of low diversity and poor stability, such as coastal lagoons. These fish are largely benthic feeders, essentially eating the epimacroinvertebrates and endomacroinvertebrates and, occasionally, fish. Diplodus vulgaris and Diplodus annularis preferentially selected gastropods and small crustaceans. Spondyliosoma cantharus generally preyed on crustaceans, including the highly mobile epifauna, the mysids, and decapods. Halobatrachus didactylus and Anguilla anguilla, had very diversified diets that included fish. Mullus barbatus were found to have selected all groups of crustaceans and also bivalves. Wrasses, gobies, and Diplodus sargus, all small-sized fish, singled out small crustaceans, gastropods, and bivalves. The Sparids were the least specialized predators, with broader niches than the other species. They preferentially selected molluscs, which were abundant in the environment. A large overlap of diets was observed and competition may be important when fish biomass is high.

Vegetable proteins proved to be good emulsifiers for food emulsions with dietetic advantages. The use of these emulsions as car- riers for healthy ingredients, such as colourings, with antioxidant and other beneficial properties, is an interesting subject. In this work, the capacity of the biomass of the microalga Chlorella vulgaris (which has been widely used as a food supplement) as a fat mimetic, and its emulsifier ability, was evaluated. Pea protein emulsions with C. vulgaris addition (both green and orange – carotenogenic) were prepared at different protein and oil contents. The rheological properties of the respective food emulsions were measured in terms of the viscoelastic properties and steady state flow behaviour and texture properties. It was observed that the two microalgal forms evidenced a fat mimetic capacity in these emulsions, the performance of the green stage of this C. vulgaris organism was significantly (p < 0.05) better than the orange stage.