A new model of water sorption isotherm is developed on the basis of Raoult's law. It is assumed that water present in food occurs in two states, as free water with properties of the bulk water and as water of hydration. Hydrated molecules are considered as new entities with molecular weights larger than those of non-hydrated molecules. Hydration reduces the free concentration of water and thus affects water activity in solution. Application of the developed equation to food sorption data showed that it gives approximation of sorption isotherms much better than that offered by the GAB model. Moreover, it predicts infinite adsorption at a(w)=1, the property which is not offered by the GAB equation. The new equation makes it possible to interpolate isotherms at high water activities close to one. The probability that the new equation will fit the food isotherm with small RMS is higher than 90% and substantially exceeds that found for the GAB model. As a two-parameter model it makes substantial improvement over the three-parameter GAB equation.

Water, energy, and food are essential for human well-being and for sustainable development. Water is required in almost all types of electricity generation and it is highly consumed in food production. Cities, industry, and crop production have increased their needs for water, energy and land resources, and at the same time, they are facing problems associated with the environmental degradation and, in some regions, resource scarcity. This paper proposes a multiobjective optimization model for the design of a water distribution network from a water–energy–food nexus point of view. Additionally, crop production and cost relationships are integrated to account for the water and energy requirements in the agricultural sector. The economic objective is the maximization of annual gross profit, which accounts for the water, energy and food production; the environmental objective establishes the minimization of overall greenhouse gas emissions, and the social objective is the maximization of the number of jobs. In this paper, because the objectives are opposites, a multistakeholder assessment is proposed in order to analyze and quantify the relationship of the water–energy–food nexus to assess synergies that improve the decision-making process. The mathematical model was applied to a case study located in the Sonoran Desert in Mexico, in which, a series of scenarios were solved to illustrate the capabilities of the proposed optimization approach. The results show strong trade-offs between the considered objectives as well as the quantification of the water–energy–food nexus.

Uzbekistan, being historically one of the most populated and agriculture-based republics in the former Soviet Union, still features quite high annual population growth rates and great dependence on agriculture as a backbone for the rest of the economic reforms. With water playing an extremely important role in producing a sufficient food base for the country's growing population and earning much needed foreign exchange for the government to ensure overall economic development, the pressures on this scarce resource will obviously and inevitably grow, putting it much at risk over a long-term perspective. So would available water be enough to meet ever-increasing demands from major economic uses in the foreseeable future, and what can be the options for meeting such demands - these are the key questions raised and researched in this article. As such the research concentrates on the two major country-specific scenarios with water and its multiple uses for Uzbekistan - the business as usual and the best case. Both scenarios discuss possible future implications for the next quarter-century given certain assumptions. Finally when summarizing the findings, the paper provides conclusions and recommendations as to how the model and further scenarios can be better optimized given the trans-boundary nature of most water resources in Central Asia where Uzbekistan geographically belongs.

This study evaluates the strategic importance of gray water, which is a component of virtual water, defined as “the water embedded in key water-intensive commodities such as wheat” or “the water required for the production of commodities.” Estimation of gray water plays a role in ensuring water and water-dependent food security for both importing and exporting countries. Methodologies towards reducing virtual water for strategic crops in the Tunisian semi-arid region include irrigation techniques and the control of runoff. Resources management practices that improve family income especially for women and children, all contribute to food security.

Water activity and glass transition temperature concepts were used to investigate the connection between the two distinct criteria of food stability. The data on sorption isotherms and glass transition temperatures were obtained from the literature. Two most commonly used models i.e. GAB and Gordon-Taylor equations were used to model water activity/moisture content and glass transition temperatures/solids content relationships. The models' (GAB and Gordon-Taylor) parameters were used to estimate water activity and glass transition temperature at given moisture/solids content. Results indicate that there is a considerable discrepancy in the temperature-related stability criteria predicted by the concepts of water activity (aw) and the glass phenomenon (Tg). A greater understanding of water sorption properties and Tg is required to establish a sound processing and storage stability criteria.

To foster their competitive advantage, food firms pay an increasing attention to strategies that tend to distinguish their products from the ones supplied by their competitors, dedicating to this task most of their resources, knowledge and creativity. In such a framework, also the resource water, often seen as an homogenous product, is more and more utilized in the advertisement as an element that increases the quality of the final good. This paper aims at building a model that can explain the observed behaviour in the different food industries and that can give some insights about the future perspectives of the utilization of the water as a differentiation factor. To reach this goal, first we present a survey of the commercials of specific food industries (beverages, pasta, bread, fresh produce), in which the contribute of water to the product is shown. On the basis of empirical evidence, we argue that the propensity to use water as an element of differentiation is greater when greater are the degrees of technological knowledge, the consumers' perceptions, and the importance of the differentiation strategy in that specific industry. Since we expect that these three factors will increase over time, we also conclude that it is rational to experiment a generalized increase of the utilization of water in the commercials of food products. We also recommend to extend the analysis testing the results using a quantitative approach | Per effetto dell'aumento della competizione sui mercati nazionali e internazionali, l'industria alimentare è spinta a dedicare una crescente attenzione alle strategie di differenziazione. A tal fine, essa impiega gran parte delle risorse, delle conoscenze e della creatività a disposizione. In un tale contesto, anche l'acqua, una risorsa spesso interpretata come bene altamente omogeneo, risulta sempre più utilizzata nelle campagne promozionali dei prodotti alimentari per spiegare la maggiore qualità degli stessi. Il presente contributo ha l'intento di costruire un modello esplicativo di questi comportamenti tale da offrire, al contempo, indicazioni prospettiche circa il ruolo dell'acqua come elemento di differenziazione. Analizzando le pubblicità di alcuni specifici prodotti (bevande, pasta, pane, ortofrutta fresca), si argomenta che la propensione all'utilizzo dell'acqua come fattore di differenziazione in un determinato comparto alimentare è direttamente proporzionale al livello delle conoscenze tecnologiche, alla percezione del consumatore e alla rilevanza della strategia di differenziazione in quello stesso comparto. Considerando che, nel tempo, ciascuna delle tre determinanti è destinata a sperimentare un trend positivo, è lecito attendersi anche un crescente riferimento al contributo della risorsa acqua all'interno dei messaggi pubblicitari. L'impostazione prevalentemente teorica del presente contributo induce a considerare particolarmente interessante l'ipotesi di testare i risultati mediante un approccio prettamente quantitativo

Many countries are exposed to malnutrition within their population, either in the form of undernutrition or obesity leading to dire affects for human health. As a consequence, a ‘Decade of Action’ was certified by the UN in 2016 to promote the need to end all types of malnutrition. Within food security objectives, this study evaluates the possibility to maximise the nutritional value of agricultural output through the optimal allocation of water and energy resources. Using a hypothetical case study in Qatar, two complementary multi-objective mathematical models are developed to solve various scenarios. Firstly, the goal programming minimises the expected value of negative deviation from the desired target in food groups and nutrients. Secondly, the linear programming model increases the expected value of self-sufficiency percentage in food groups and nutrients. The results indicate the specific dependency of increasing the self-sufficiency of different nutrients on the increased production of dates group and fish group, implying that dates and fish can be considered strategic crops in terms of their contribution towards food security, owing to the fact that they require the least quantity of water and energy resources for production. As poultry and meat groups require the largest quantities of water and energy resources, optimal results do not favour their production. The optimal production mix that increases the satisfaction of nutrients at 40% of the food groups self-sufficiency satisfaction with the same amount of energy and water are as follows: 52378, 47085, 111303 tonnes of dates, milk and dairy products and fish groups respectively. This production mix will achieve 29.18%, 100%, 90.8%, and 2.5% satisfaction percentage of carbohydrates, protein, fats, and fibres respectively.

Water-adsorption data and glass transition temperatures (Tg) of maltodextrins with dextrose equivalent (DE) values ranging from 4 to 38, horseradish roots, and strawberries were used to establish relationships between water activity (aw), water content (m), and Tg. Critical m values were considered as those depressing Tg to 25C. Corresponding values of critical aw were obtained from GAB isotherms that were used to model water adsorption. The use of BET isotherms was tested, but the model showed poor correlation with experimental data at high aw values, especially for low DE maltodextrins. Critical m and aw values were lowest for strawberries (1.5 g H2O/g solids; 0.07 aw). The values increased with decreasing DE, ranging from 72 (0.44 aw) to 11.2 g H2O/g solids (0.70 aw). Understanding of water-sorption properties and Tg is valuable in controlling processability and stability, and for determining of food-packaging requirements.

La prediccion de actividad de agua (aw) mediante modelos matematicos, por lo general, esta limitada a disoluciones acuosas de electrolitos y no electrolitos. El efecto de componentes alimenticios tales como las grasas, las proteinas y la fibra no se considera cuando estos modelos se aplican a los alimentos. El valor estimado de aw en alimentos reales, generalmente, es mayor que el valor medido debido a que tanto las proteinas como las grasas ligan moleculas de agua. Por tal motivo, se desarrollo un programa para ordenadores que permite evaluar con buena precision el valor de actividad de agua, y que ademas es capaz de lo siguiente: (1) Predecir la aw a partir de modelos matematicos tales como Pitzer, Bromley, Norrish, Ross, Ferro-Chirife-Boquet y Ferro-Bermengui-Chirife. (2) Establecer un nivel de similitud entre alimentos de aw y composicion conocidos frente a alimentos a los que solo se conoce la composicion. (3) Definir un factor de desviacion en funcion del nivel de similitud anteriormente descrito en el que se considera la presencia de grasas, proteinas y fibra. El analisis de productos embutidos, para la primera iteraccion, dio un factor de desviacion de 1,07. En el caso de algunos productos azucarados, que incluyen gomas y pectinas, se encontro que el factor fue de 1,12. Una vez incrementado el numero de datos almacenados, los cuales dan apoyo al proceso iterativo de la prediccion de actividad de agua, el factor de desviacion converge rapidamente a uno.

A mathematical relationship based on freezing point depression (FPD) was developed for determining the water activity (WA) of foods, and was applied to WA determinations in various liquid foods and for glycerol. WA values calculated from FPD data showed excellent agreement with published WA values for different foods (within 0.01 WA units). It is concluded that the mathematical relationship reported is useful for determining AW values in frozen foods stored at temperatures between 0 to -40 degrees C.(wz)