de Fraiture et al., 'Podium: Projecting water supply and demand for food production in 2025', Physics and Chemistry of the Earth (B), vol. 26(11-12), pp.869-876, 2001

Non-PR | IFPRI3 | EPTD

Water availability for agriculture - the major water user worldwide - is one of the most critical factors for food security in many regions of the world. The role of water withdrawals in irrigated agriculture and food security has been receiving substantial attention in recent years. This paper addresses key questions regarding water availability and food security, including: How will water availability and water demand evolve over the next three decades, taking into account availability and variability in water resources, the water supply infrastructure, and irrigation and nonagricultural water demands? What are the relationships among water scarcity, food production, and food security? How much of future food production will come from rainfed and irrigated areas? A global modeling framework, IMPACT-Water, is applied to explore answers to these questions using analysis.

Surveys of food intake in humans, following measurements of energy expenditures in free-living persons, obtained by the doubly-labeled water technique, have been severely questioned in recent years. The present article reviews studies performed in both adults and children, comparing energy intake and expenditures in the same individuals. In adults, reported intake is often insufficient to cover minimal energy needs. The typical level of "under-reporting" is about 20%, and it is even higher in obese subjects. Intake data obtained from children are more valid than data from adults. Different survey methods yield differing degrees of agreement between intake and expenditure measurements using the doubly labeled water technique: frequency questionnaires tend to induce over-reporting, whereas the classical 24 hours recall is very susceptible to large under-reporting. Even obese adults can provide accurate reports of their daily food intake if properly trained and motivated. The interpretation of data obtained with the doubly labeled water method should integrate the considerable day-to-day variations observed in human food intake. | Pesquisas de ingestão alimentar em seres humanos, seguindo medidas de gastos de energia, obtidas pela técnica da água duplamente marcada, têm sido amplamente questionadas nos últimos anos. Este artigo faz uma revisão de estudos realizados em adultos e crianças, comparando consumo e gastos de energia nos mesmos indivíduos. Em adultos, o consumo relatado é freqüentemente insuficiente para cobrir as necessidades mínimas de energia. O nível típico de sub notificação é de cerca de 20% e chega a percentuais maiores em indivíduos obesos. Dados de consumo obtidos de crianças são mais válidos que dados de adultos. Métodos diferentes de pesquisa produzem graus diferenciados de conformidade entre medidas de consumo e gasto usando a técnica da água duplamente marcada: questionários de freqüência tendem a induzir super estimados, enquanto o clássico recordatório de 24 horas é muito suscetível a grandes sub notificação. Até mesmo adultos obesos podem fornecer relatos precisos de seus consumos alimentares diários se apropriadamente treinados e motivados. A interpretação dos dados obtidos com o método da água duplamente marcada deveria integrar as consideráveis variações do dia-a-dia observadas na ingestão alimentar dos seres humanos.

Recently, several reports about sterilization effect of electrolyzed water have been published. The electrolyzed water is expected as one of attractive application for sanitation of fresh food, however, to install this electrolyzed water, we have to clear the potential of the microorganism control for real food. In this paper, we try to reveal the mechanism of the microorganism control, and also try to check the food quality change during the treatment. Therefore, to evaluate the effect of the electrolyzed water, we examined the several test for making sterilization mechanism clear and observed microorganism behavior on food surface. At first, for the purpose of making sterilization effects clear in vitro condition, we did microorganism test with several injection ratio and number. Then, we studied the effects of catalase on the enumeration of stressed Escherichia coli cells after acidic electrolyzed water treatment. Moreover, we studied sterilization effect of acidic electrolyzed water for E. coli on an agar block on the assumption as one of food model. In addition, we studied sterilization effects for sliced raw tuna as one sample of food surface treatment. The change in the quality of food surface was observed by scanning electron microscope, color meter and so on. Sterilization effects are dependent the condition of injection ratio and mixing numbers. These results suggest that it is important to keep available chlorine concentration for keeping the potential to the microorganisms' control. The increasing of E. coli number with the addition of catalase was suggested that the weak concentration of electrolyzed water gave the injured microbes. The Observation of cultivated E. coli behavior on agar block showed the microorganism behavior. Acidic electrolyzed water sterilizes microorganisms on sliced raw tuna, however, after treatment, the color change of surface of tuna and the protein denaturation were observed. These results suggest that when the electrolyzed water treatment is applied to control the microorganism on surface, the effect against food surface must be considered.

The effects of water and glass transition on the hydrolysis of sucrose by invertase in noncrystalline carbohydrate systems were investigated. Maltodextrin/sucrose (2:1) and maltodextrin/lactose/sucrose (1:1:1) were dissolved in distilled water. Invertase (10 mg/17.2 g) was added. Amorphous samples were produced by freeze-drying the solutions. Sorption isotherms were determined gravimetrically at 24 degrees C over the 0.113-0.763 aw, and over 0.239-0.764 aw, the glass transition, Tg was determined using differential scanning calorimetry (DSC). DSC and water sorption results suggested that samples remained noncrystalline. Sucrose inversion was analysed by monitoring glucose content during storage. Sucrose hydrolysis occurred at significant rates at 0.662 and 0.764 aw. The rate increase was not related to the apparent glass transition of the systems.

Gift

When a starchy food such as a rice grain or a strand of noodle is boiled, a high moisture region is generated at the surface spreading inward, producing a low moisture core. The characteristic features of the change of moisture profile were recently observed by nuclear magnetic resonance imaging (MRI). However, the profile cannot be described by any existing mathematical model based on the principle that water molecules are driven by the gradient of moisture content. In this paper, a new mathematical model is proposed using a new concept, water demand (WD). In this model, migration of water is driven by the gradient of WD, which is defined as the difference between the ceiling moisture content and the existing moisture content. This model is demonstrated to have a potential to describe the characteristic features of the change of moisture profile in starchy food during boiling.

Les économies d'eau dans les industries agro-alimentaires sont un enjeu qui conduit à une maîtrise des coûts directs et indirects (approvisionnement en eau et traitement des effluents). Si le renforcement de la réglementation conduit à une gestion raisonnée des ressources en eau soutenue par les incitations financières des Agences de l'Eau (redevance consommation et pollution), ces organismes encouragent également par l'attribution d'aides les initiatives dans ce domaine. Les démarches à suivre dans ce domaine doivent être raisonnées et favoriser les économies de la ressource notamment par la mise en place de technologies propres. Les résultats, directs ou indirects, obtenus sont généralement rapides et encourageants. Plus globalement, la recherche d'économies sur les consommations d'eau dans les industries agro-alimentaires, est très souvent le premier pas vers une maîtrise des coûts environnementaux qui s'inscrit en droite ligne dans l'optique de la mise en place d'un système de management de l'environnement