Increasing the yield of extraction of bioactive compounds from plants is of high importance. Grape stems are widely discarded during the wine-making process, despite their high content in many valuable compounds. The aim of this work was to examine whether the use of pulsed electric field (PEF) treatment of the stems could increase the yield of polyphenol and volatile compounds in the extracts. For this reason, a relatively low-energy consuming PEF process was employed (low-electric field strength, 1 kV/cm) for a short time (30 min) at the grape stems. In addition, the effect of different solvents during this pretreatment step was examined. With the use of Folin–Ciocalteu assay, the extracts were compared with the respective control samples (not pretreated with PEF). Moreover, extracts were prepared to assess whether changes occur to the volatile profile of the extracts. The results were conclusive that not only PEF can increase the yield of polyphenols (up to 35% increase recorded), but also that the solvent used during PEF pretreatment can affect the process. Furthermore, a 234% increase in the total content of volatile compounds was recorded, when PEF was used as a pretreatment step. Therefore, the combination of PEF and ultrasound-assisted extraction is highly promising to obtain grape stem extracts with a higher content of bioactive compounds.

The canned fruits industry utilizes high amounts of water and energy, which results in the generation of vast quantities of wastewater and solid waste. The main scope of this study was to compare the environmental footprint of a canned fruits industry (alternative scenario) equipped with appropriate processes (pulsed electric fields, anaerobic digestion, composting, membrane bioreactors, and ultraviolet treatment) that sufficiently save energy and valorize production wastes to a typical setup that uses conventional waste methods (conventional scenario) via conducting a life cycle assessment study. Based on the results, the life cycle assessment confirmed the fact that the incorporation of the proposed methods, as described in the alternative scenario, dramatically reduced the environmental footprint of the industry, with certain environmental impact categories reaching a decrease of up to 90.00%. More specifically, according to the obtained results, a decrease of 11.81, 64.56, and 89.79% in regards to climate change, freshwater ecotoxicity, and freshwater consumption, respectively, was achieved in the alternative scenario compared to the conventional method. The study verified the environmental advantages of integrating such energy saving and waste treatment/valorization technologies across the canned fruits industry’s processing chain, contributing to environmental sustainability and safety.

Wood-related procedures, such as lumberjacking and pruning, inevitably result in big piles of leaves, which are considered a major by-product. Extracting valuable compounds from natural by-products is an ongoing trend. In this work, the use of Pulsed Electric Field (PEF) was evaluated as a pretreatment step, prior to the ultrasound-assisted extraction of phenolic compounds from Aesculus carnea leaves. In addition, various solvent systems were examined, as well as the time of pretreatment with PEF. According to the results, up to 33% more phenolic compounds can be extracted, under optimum conditions (30% ethanol in water as solvent and PEF pretreatment for 30 min, compared to the same solvent, without PEF). Moreover, PEF treatment time was not (i.e., 30 and 60 min) and no differences were recorded, suggesting that a lower treatment time can yield the same extraction of phenolic compounds. As such, the use of PEF is highly recommended in combination with ultrasound extraction, to maximize the yield of phenolic compounds extracted from the leaves of Aesculus carnea.