Environmental and economic sustainability of fresh-cut and pre-cooked vegetables.

Due to the growing awareness about the environmental and economic sustainability of food products, the present research aims to evaluate the sustainability of fresh-cut and pre-cooked vegetables, a niche market with growing demand. An analysis was carried out using a detailed material, energy, and economic inventory based on a commercial food processing plant located in northeast Spain. The environmental sustainability was determined using process-based environmental life cycle assessment (E-LCA), applying a cradle-to-market approach, and using the EF3.0 impact assessment methodology to quantify impacts on five midpoint categories (climate change, photochemical ozone formation, acidification, freshwater eutrophication, and fossil resource use) and an aggregated single score. Additionally, an environmental life cycle costing (E-LCC) was performed. The pre-cooked vegetable products showed a higher environmental footprint than the fresh-cut products in all the impact categories (between 14.0 % and 39.9 %) and involved higher life cycle costs (15.2 %), due to the increased demand for ingredients, packaging materials, and electricity consumption per FU (kg of product). The carbon footprint (CF) and the cost for the fresh-cut products were 0.72 kg CO2 eq/kg and 2.62 €/kg, respectively, compared to 0.86 kg CO2/kg and 3.02 €/kg for the pre-cooked vegetables. The environmental profiles of both products were rather similar, with a dominance of the Upstream stage (production of ingredients and packaging materials), followed by the Core stage (mainly due to electricity consumed during vegetable processing). The relevance of the Core stage is amplified in the economic analysis due to the incorporation of certain processes which were not included in the process-based E-LCA (e.g., labour, capital, insurance, maintenance costs, etc.). To integrate the economic and environmental analyses, an eco-efficiency index was calculated that describes the carbon emissions per unit of monetary cost, resulting in 0.27 kg CO2eq/€ for the fresh-cut and 0.28 kg CO2 eq/€ for the pre-cooked vegetables.

Optimizing the environmental sustainability of alternative post-harvest scenarios for fresh vegetables: A case study in Spain.

The aim of this research is to define different scenarios that optimize the environmental sustainability of the post-harvest stage of vegetable products (cauliflower and brassicas mix). These scenarios considered different packaging materials; energy generation technologies for the processing plant (standard electricity mix vs. renewable options); organic waste management (composting, anaerobic digestion, and animal feeding); and refrigerated transportation (local, national, and international, using diesel, natural gas, and hybrid trucks and railway). The analysis has been carried out based on a foreground inventory provided by a company that operating internationally, in accordance with the International Organization for Standardization (ISO) 14,040 methodological framework and following the latest Product Environmental Footprint (PEF) protocols. The analysis describes four midpoint categories, single score (SS) using EF3.0 life cycle impact assessment (LCIA) methodology and the Cumulative Energy Demand. The carbon footprint (CF) of the post-harvest stage for a base case scenario ranged between 0.24 and 0.29 kg CO2 eq/kg of vegetable, with a strong contribution associated to the production of packaging materials (57.8-65.2 %) and the transport stage (national range in conventional diesel vehicles) (31.5-38.0 %). Comparatively, lower emissions were associated with the energy consumed at the processing factory (up to 4.1 %) while the composting of organic waste management produced some impact savings (up to -3.5 %). Although certain differences were observed, the dominance of the transport stage and the packaging materials is sustained in all the other environmental impact and energy categories evaluated. The most effective measures to reduce the environmental footprint of the post-harvest stage involve: i) using reusable packaging materials; ii) reducing the transport range and using vehicles running on natural gas or hybrid technologies; iii) the incorporation of renewable energy to supply the factory; and iv) the utilization of the organic residues in higher value applications such as animal feeding. Implementing the measures proposed in this study would reduce the post-harvest CF of fresh vegetables by 90 %.

Valorization of biochars from pinewood gasification and municipal solid waste torrefaction as peat substitutes.

Gasification and torrefaction have both gained significant interest as bioenergy techniques. During biomass gasification together with fuel gas, carbon-rich solid substances are produced, whereas torrefaction process is mainly used to prepare a final product with higher calorific value and carbon content than the feedstock, through a low temperature pyrolysis. Both materials (carbon wastes from gasification and torrefied product) could be classified as alternatives to biochar obtained from slow pyrolysis of biomass. The use of biochar, typically from the slow pyrolysis of biomass, as soil amendment and, more recently, as growing media components has been widely researched. However, to our knowledge, no studies have compared the use of biochar from gasification and torrefaction as growing media component for growing media formulation. The objective of this work was to study the effect of two biochars on peat-based growing media: a pinewood gasification biochar (BG) and a biochar (BT) obtained by torrefaction of the organic fraction of municipal solid waste. Growing media mixing PT (peat) with 50%vol of BG or BT were prepared and characterized according to their chemical, thermal and hydrophysical properties. Phytotoxic experiments and growth of Lolium perenne were also performed. Results indicated that peat substitution in growing media by BG and BT at a 50%vol ratio improved their hydrophysical properties. Specifically, bulk density increased more than 50%, air space increased by 43%, the increment of the total porosity was 20%, and, finally, the water holding capacity increased by 18.3%. Significantly, a positive effect on plant biomass production (yield increment: 274%) was observed after addition of BT, whereas no significant differences were observed after addition of BG biochar. Therefore, it can be concluded that both BT and BG could be used as peat substitutes in growing media formulation.