Gabriela Clemente

Measuring and Improving Eco‐efficiency Using Data Envelopment Analysis

The concept of eco-efficiency can be defined with the “product value/environmental influence” ratio. Different models have been proposed to measure eco-efficiency. The main difference among them is the weighting system used to aggregate the environmental results. Data envelopment analysis (DEA) permits this aggregation without requiring a subjective judgment about the weights. In this study, we applied a DEA model to Spanish Mahon-Menorca cheese production to determine the most eco-efficient production techniques. To this end, 16 scenarios of Mahon-Menorca cheese production were built regarding technical (degree of automation) and cleaner production criteria. The environmental impacts were assessed by means of life cycle assessment. We carried out an economic assessment by determining the economic value added and the net income for each scenario. The results are referred to as 1 kilogram (kg) cheese ripened over 105 days. Through DEA, an eco-efficiency ratio between 0 and 1 was obtained. Three scenarios were found to be eco-efficient, with a high degree of automation (enclosed vat and molding and demolding machines) and accelerated cheese ripening. We used Monte Carlo simulation to carry out a sensitivity analysis to compare the influence of price changes on the eco-efficiency ratio. The results emphasize the consistency and stability of the eco-efficient scenarios.

Measuring and Improving Eco-efficiency Using Data Envelopment Analysis A Case Study of Mah´ on-Menorca Cheese

The concept of eco-efficiency can be defined with the “product value/environmental influence” ratio. Different models have been proposed to measure eco-efficiency. The main difference among them is the weighting system used to aggregate the environmental results. Data envelopment analysis (DEA) permits this aggregation without requiring a subjective judgment about the weights. In this study, we applied a DEA model to Spanish Mahon-Menorca cheese production to determine the most eco-efficient production techniques. To this end, 16 scenarios of Mahon-Menorca cheese production were built regarding technical (degree of automation) and cleaner production criteria. The environmental impacts were assessed by means of life cycle assessment. We carried out an economic assessment by determining the economic value added and the net income for each scenario. The results are referred to as 1 kilogram (kg) cheese ripened over 105 days. Through DEA, an eco-efficiency ratio between 0 and 1 was obtained. Three scenarios were found to be eco-efficient, with a high degree of automation (enclosed vat and molding and demolding machines) and accelerated cheese ripening. We used Monte Carlo simulation to carry out a sensitivity analysis to compare the influence of price changes on the eco-efficiency ratio. The results emphasize the consistency and stability of the eco-efficient scenarios.

The influence of blanching pretreatments on the quality of dehydrated broccoli stems/ Influencia del tipo de escaldado en la calidad de tallos de bróculi deshidratados

Different blanching treatments were applied to sliced broccoli stems prior to dehydration in order to improve product quality. The pretreatments used were a conventional blanching in water at 100°C, and a stepwise blanching using different temperatures for the first step (50, 55, 60, 65 and 70°C). Five rehydration temperatures were used (25, 40, 55, 65 and 80 °C). Rehydration rate, chlorophyll content and texture of the rehydrated product were evaluated. Rehydration was modeled based on Ficks diffusion equation. A good agreement between the model and the experimental data was obtained when D eff and W e values were identified for each temperature (average percent variation 99.3). Samples stepwise blanched at 60 °C showed, on average, the lowest W e and Ea values. Stepwise blanching at 60 and 65 °C and rehydration at 25, 40 and 55 °C were the combinations that gave the firmest product. Stepwise blanching at 50 °C and rehydration between 25 and 65 °C was the combination that preserved the highest chlorophyll content. From these results, it seems difficult to obtain firm samples with high chlorophyll content without any chemical additive.

Drying Kinetics of Grape Stalk

Grape stalk may be considered as an agro-food byproduct of the wine industry, being considered as a potential source of antioxidant compounds. Actually, before the extraction of antioxidants a previous stage of drying would be necessary. Stalks obtained from a red wine processing (Vitis vinifera var. Bobal) were characterized as a cylinder net with different size ending in spheres. The average diameters and mass fractions of the individual parts of the stalk were measured: spheres (4.4±0.7 mm and 0.352 mass fraction), large cylinders (3.3±0.6 mm and 0.204 mass fraction), intermediate cylinders (2.1±0.4 mm and 0.294 mass fraction) and small cylinders (1.1±0.3 mm and 0.150 mass fraction). Drying kinetics of each one of the parts of the stalk were carried out at 40 °C and 2 m/s using an initial mass load of 30 g. Furthermore, drying experiments of the whole stalk were conducted at the same experimental conditions. Different diffusion models were considered to predict the drying kinetics for each one of the individual parts of the stalk according to the geometry considered. A diffusion model for the whole stalk was developed by adding the individual diffusion models weighed by the corresponding mass fractions. The diffusion models considered fitted properly the drying kinetics of the individual parts considered on the stalk. The figures of the effective moisture diffusivity identified for the different kinds of cylinders were close (1.07-1.78 10-11 m2/s), however, the spheres showed a different behavior characterized by a significantly higher figure of effective moisture diffusivity (3.92 10-8 m2/s). Finally, the usefulness of the model considered to describe the drying kinetics of the whole stalks was shown.

In vitro interactions between calcium, zinc, copper and iron in milk- and soy-based infant formulas / Interacciones in vitro entre calcio, cinc, cobre e hierro en formulas de base láctea y de soja para lactantes

Interactions among calcium, zinc, copper and iron in milk- and soy-based infant formulas were as sessed in order to evaluate the influence of supplementation with one trace element on the bioavailability of the others. The criterion used to estimate the bioavailability is the percentage of dialysis, estimated by applying an in vitro method. Infant formulas were supplemented with CaCl2, ZnO, CuCO3 Cu(OH) 22H2O and FeSO4 7H2O at two levels (maximum (+) and minimum (-) allowed by the European Union). A factorial design at two levels with three factors (Zn, Cu and Fe addition) was carried out. The main effects and the second-order interactions of the studied factors on the bioavailability of a given element were estimated. The results obtained for milk-based formulas clearly indicated the negative influence of iron at the high addition level (+) on the dialysis percentage of calcium, and of zinc at the high addition level (+) on its own dialysis percentage, whereas in the same type of formulas, the addition of zinc had a positive effect on the copper dialysis percentage. In soy- based formulas a negative effect of added copper (+) on its own dialysis percentage was observed. The most important second order interaction found to be significant was the negative effect of (zinc x iron) on copper dialysis in milk-based formulas.

Potato Shrinkage During Hot Air Drying

Shrinkage is one of the most important physical changes that occur during the dehydration of foods. In this work, the effect of the temperature (35, 40, 50, 60 and 70 °C) and air velocity (7, 8, 9 and 10 m/s) on bulk volumetric shrinkage was investigated. Volume changes were evaluated by image analysis. It was found that neither temperature nor air velocity had any significant effects on bulk shrinkage in this system. The bulk shrinkage of the potato cubes was well correlated with the moisture content of the sample during drying (R2 = 97.28). Volume varied linearly with the moisture content changes under the studied conditions. The volume of lost water and the decrease in volume of the samples during dehydration were similar.

Influence of Management Practices on Economic and Environmental Performance of Crops. A Case Study in Spanish Horticulture

This article assesses the effect of management practices on the environmental and economic performance of tigernut production. Tigernut is a horticultural crop grown in a very limited and homogeneous area. Results show that the environmental variability among farms was greater than variability in costs. A selection of practices can reduce impacts per kilogram tigernut by factors 252.5 (abiotic depletion), 33 (aquatic ecotoxicity), or 6 (global warming) and costs by factors of between 2 and 3. The analysis shows a positive relationship between economic and environmental performance. Results highlight how proper management leads to both relatively low environmental impacts and costs.

Uncertainty analysis in the financial assessment of an integrated management system for restaurant and catering waste in Spain

PurposeThe goal of this study is to analyze the economic performance of an alternative system for waste management proposed by the European Integral-b project. Its aim is to treat both used cooking oil (UCO) and solid organic waste (SOW) from the hospitality sector by biodiesel production and anaerobic digestion, respectively. A cogeneration engine adapted to use glycerol as a fuel is implemented. These results complement others from a previous life cycle assessment (LCA).MethodsThe system proposed (scenario A) is compared to a system consisting of average waste management options (scenario B) by means of life cycle costing (LCC). The functional unit (FU) is the amount of UCO and SOW from hospitality produced per person and year in Spain. The profits generated by the FU under the two scenarios are calculated from a financial point of view. It is assumed that co-products from both scenarios translate into revenues for waste managers. Scenario analysis assesses different rates for the electricity output, subject to market regulations, and different levels of UCO availability. Monte Carlo simulations are carried out to analyze parameter and price uncertainty.Results and discussionThe profits in all the scenarios are negative, and those of scenario A are lower than those of scenario B under all the scenario formulations. Scenario A generates greater income than scenario B but also higher expenses, mainly due to SOW collection. The new electricity rates are detrimental for the financial performance of the Integral-b since the overall profits mostly depend on the sale of electricity. Readier UCO availability benefits both scenarios to a similar extent. The uncertainty analysis reinforces the comparative results, although there is some likelihood scenario A will generate greater profits. The sensitivity analysis allows for the key parameters to be identified in order to optimize the process further. Possible trade-offs between the LCC and LCA results have been evaluated.ConclusionsResults from the financial analysis show that the Integral-b process delivers greater losses as compared to a reference scenario. Both generate net costs, meaning that stakeholders have to finance the functions provided. Uncertainty in the electricity regulations constitutes an obstacle for such projects as these to be implemented. As in LCA, the definition of the system boundaries and FU is critical in LCC.