Impact of PEF (Pulsed Electric Fields) on Olive Oil Yield and Quality

Olive oil holds significant importance in the European diet and is renowned globally for its sensory attributes and health benefits. The effectiveness of producing olive oil is greatly influenced by factors like the maturity and type of olives used, as well as the milling techniques employed. Generally, mechanical methods can extract approximately 80% of the oil contained in the olives. The rest 20% of the oil remains in the olive waste generated at the end of the process. Additionally, significant amounts of bioactive compounds like polyphenols are also lost in the olive pomace. Traditionally, heat treatment, enzymes, and other chemicals are used for the enhancement of oil extraction; however, this approach may impact the quality of olive oil. Therefore, new technology, such as pulsed electric field (PEF), is of great benefit for nonthermal yield and quality improvements

Meat substitutes : Resource demands and environmental footprints

FThe modern food system is characterized with high environmental impact, which is in many cases associated with increased rates of animal production and overconsumption. The adoption of alternatives to meat proteins (insects, plants, mycoprotein, microalgae, cultured meat, etc.) might potentially influence the environmental impact and human health in a positive or negative way but could also trigger indirect impacts with higher consumption rates. Current review provides a condensed analysis on potential environmental impacts, resource consumption rates and unintended trade-offs associated with integration of alternative proteins in complex global food system in the form of meat substitutes. We focus on emissions of greenhouse gases, land use, non-renewable energy use and water footprint highlighted for both ingredients used for meat substitutes and ready products. The benefits and limitations of meat substitution are highlighted in relation to a weight and protein content. The analysis of the recent research literature allowed us to define issues, that require the attention of future studies.Peer reviewe

Intensification of food freezing under the effect of pulsed electric fields

Ce travail de thèse porte sur l’étude de l’effet du traitement par champs électriques pulsés (CEP) sur l’amélioration de la congélation des tissus végétaux. Pour l’ensemble de notre étude, nous avons démontré que l’effet des champs électriques pulsés est complexe. Le prétraitement entraîne une électroperméabilisation des membranes. Les analyses calorimétriques ont mis en évidence que l’électroperméabilisation conduit à une augmentation de la teneur en eau liée. Les transferts de matière entre les milieux intra et extracellulaires sont intensifiés. Cela conduit à une modification dynamique de la composition des deux compartiments au cours de la congélation. En effet, les essais réalisés sur le cryo-pressage assisté par CEP démontrent que les températures de fusion sont plus basses et que le jus récupéré est beaucoup plus concentré. Il a été constaté que le temps de congélation d’un échantillon soumis préalablement à un prétraitement par champs électriques pulsés est sensiblement plus court que celui d’un échantillon sans prétraitement. D’autre part, l’électroperméabilisation facilite les transferts de matière avec le milieu extérieur. Le prétraitement par CEP accélère notamment l’imprégnation des tissus végétaux par des cryoprotectants, l’évaporation de l’eau libre et la sublimation de l’eau congelée. Finalement, le prétraitement par champs électriques pulsés induit des modifications de la structure des échantillons, de leur composition et influence favorablement les transferts couplés de masse et d’énergie.This work is focused on the study of the effects of pulsed electric fields (PEF) on the improvement of plant tissues freezing. These studies have demonstrated that the effects of the PEF are rather complex. The PEF treatment results in membrane electro-permeabilization. Calorimetric analyses showed that the electro-permeabilization leads to an increase in bound water content. It also results in acceleration of mass transfer processes between intra- and extracellular parts of a tissue. The dynamic modification of the composition of these two parts during the freezing was observed. Experimental tests using the PEF-assisted cryo-pressing demonstrated that the melting temperatures were lower and that the extracted juice was much more concentrated as compared to untreated tissues. Moreover, the PEF-treatment allowed significant decreasing of freezing time. Furthermore, the electro-permeabilization facilitates the mass transfer with the external medium. The PEF treatment accelerates the impregnation of plant tissues by cryoprotectants, evaporation of free water and sublimation of frozen water. Finally, the treatment by PEF induces changes in the structure of the samples, their composition and positively influences both the mass and energy transfers

Applicability of Pulsed Electric Field (PEF) Pre-Treatment for a Convective Two-Step Drying Process

Available literature and previous studies focus on the Pulsed Electric Field (PEF) parameters influencing the drying process of fruit and vegetable tissue. This study investigates the applicability of PEF pre-treatment considering the industrial-scale drying conditions of onions and related quality parameters of the final product. First, the influence of the PEF treatment (W = 4.0 kJ/kg, E = 1.07 kV/cm) on the convective drying was investigated for samples dried at constant temperatures (65, 75, and 85 °C) and drying profiles (85/55, 85/65, and 85/75 °C). These trials were performed along with the determination of the breakpoint to assure an industrial drying profile with varying temperatures. A reduction in drying time of 32% was achieved by applying PEF prior to drying at profile 85/65 °C (target moisture ≤7%). The effective water diffusion coefficient for the last drying section has been increased from 1.99 × 10−10 m2/s to 3.48 × 10−10 m2/s in the PEF-treated tissue. In case of the 85/65 °C drying profile, the PEF-treated sample showed the highest benefits in terms of process efficiency and quality compared to the untreated sample. A quality analysis was performed considering the colour, amount of blisters, pyruvic acid content, and the rehydration behavior comparing the untreated and PEF-treated sample. The PEF-treated sample showed practically no blisters and a 14.5% higher pyruvic acid content. Moreover, the rehydration coefficient was 47% higher when applying PEF prior to drying

Pulsed Electric Fields Assisted Extraction from Exotic Fruit Residues

International audienceThe production of exotic fruits (i.e., mango, papaya) is in continuous increase in the world. It reflects not only their appreciation by consumers and their decreasing prices, but it is also due to their increasing demand in food industry for the preparation of juices and beverages. Consequently, considerable amount of waste and by-products are generated during the processing of these fruits, which are generally modestly valorized as animal feed. Nevertheless, these residues represent a great source of valuable compounds that could be recovered and used for many purposes as food additives and/or nutraceuticals. The most common methods used for the recovery of these compounds are maceration and thermal extraction. These conventional methods, although efficient, are time and energy consuming, use generally toxic and expensive solvents, and may lead to the degradation and loss of thermosensitive molecules. In order to overcome these issues, numerous nonconventional technologies (i.e., pulsed electric fields) have been evaluated and introduced in many industries. These methods may allow recovering the target compounds selectively and in “green” manner. Reducing the energy consumption, the processing time, and downstream processing steps, along with the nonuse of toxic solvents and the preservation of the most thermo- labile compounds, are the major advantages of these technologies. In this chapter, an overview of mango and papaya fruits’ production, composition, and generated waste is provided. An emphasis is then given on the use of electro-technologies, especially pulsed electric fields (PEF) and high voltage electrical discharges (HVED), to recover high added value compounds from their fruit peels and seeds

Applicability of Pulsed Electric Field (PEF) Pre-Treatment for a Convective Two-Step Drying Process

Available literature and previous studies focus on the Pulsed Electric Field (PEF) parameters influencing the drying process of fruit and vegetable tissue. This study investigates the applicability of PEF pre-treatment considering the industrial-scale drying conditions of onions and related quality parameters of the final product. First, the influence of the PEF treatment (W = 4.0 kJ/kg, E = 1.07 kV/cm) on the convective drying was investigated for samples dried at constant temperatures (65, 75, and 85 °C) and drying profiles (85/55, 85/65, and 85/75 °C). These trials were performed along with the determination of the breakpoint to assure an industrial drying profile with varying temperatures. A reduction in drying time of 32% was achieved by applying PEF prior to drying at profile 85/65 °C (target moisture ≤7%). The effective water diffusion coefficient for the last drying section has been increased from 1.99 × 10−10 m2/s to 3.48 × 10−10 m2/s in the PEF-treated tissue. In case of the 85/65 °C drying profile, the PEF-treated sample showed the highest benefits in terms of process efficiency and quality compared to the untreated sample. A quality analysis was performed considering the colour, amount of blisters, pyruvic acid content, and the rehydration behavior comparing the untreated and PEF-treated sample. The PEF-treated sample showed practically no blisters and a 14.5% higher pyruvic acid content. Moreover, the rehydration coefficient was 47% higher when applying PEF prior to drying

Assessment of the effect of air humidity and temperature on convective drying of apple with pulsed electric field pretreatment

<p>This research aims at assessing the impact of pulsed electric field (PEF) pretreatment and various properties of drying agent (absolute humidity, temperature) on the course of convective drying (CD) of apples. Moreover, the selected quality indicators of obtained dried materials (dry matter content, water activity, hygroscopicity,<br>rehydration, color, total phenolic content, antioxidant activity) have been evaluated. As a result of increased permeabilization of cells, PEF reduced time of CD of apples even by 20%. However, lower total phenolic content and antioxidant activity in PEF-pretreated dried samples were observed. With the use of PEF, the release of phenolic compounds from the cellular structures of the apple tissue could occur, making them more susceptible to thermal degradation. After introducing the dehumidification system, an increase in the drying time of apples was observed. It could be so due to case hardening, which further deteriorated the reconstitution properties of the obtained dried materials.</p> <p>This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 817683 (acronym FOX).</p&gt

Valuable Compounds in Algae

In recent decades, the interest in algae species as a source of nutritive and valuable compounds has increased. This results from rising population growth, with serious effects in terms of land and water consumption, as well as greenhouse gases. Usually, extraction applications are focused on specific components, such as oil or pigments; however, conscious biorefinery of a broader spectrum of microalgal constituents would enable an increased economy. However, the technology for the production of microalgae is still within its early stages. The cultivation and downstreaming processes are highly energy- and cost-intensive, so the use of algae is limited to the production of high-value and low-volume products. Therefore, progression of environmentally friendly technologies is needed to realize an eco-friendly and economical usage of microalgae as a sustainable resource of the future. This chapter presents general overview of microalgae; moreover, origin and location of valuable compounds are discussed. Additionally, different conventional and novel (thermal and nonthermal) extraction techniques are reviewed

Energy Saving Food Processing

International audienceOne of the challenges to increase the profitability in food industry is to reduce the consumption of energy. Energy is mainly consumed by either increasing or decreasing the temperature during the different processes. A known strategy to recover a part of the consumed energy is to regenerate heat during product's cooling, to pre-heat the untreated products. To improve energy saving efficiency, many other techniques have been proposed either in the literature or already implemented in the processing chain of food products. These techniques, applied either alone or combined with existing ones, include electrotechnologies (i.e. pulsed electric fields), microwaves, ultrasounds, pulsed light processing, high-pressure processing, and some other technologies that are discussed herein. With regard to the diversity of unit operations in the food industry, this chapter is mainly dealing with analyzing the energy saving using these novel technologies in pasteurization and sterilization, extraction, evaporation and dehydration, chilling and freezing. The mechanisms of action of the described technologies as well as their advantages and disadvantages are discussed

The Effect of Traditional and Non-Thermal Treatments on the Bioactive Compounds and Sugars Content of Red Bell Pepper

The aim of the study was an investigation of the effect of traditional and non-thermal treatment on the bioactive compounds of red bell pepper. As a thermal process, blanching in water and in steam was studied, while for non-thermal the sonication, pulsed electric field treatment and their combination were used in this experiment. The red bell peppers were evaluated based on quality attributes such as: total carotenoids content; polyphenols; vitamin C; antioxidant activity and sugars content. Vitamin C and sugar content were analyzed using liquid chromatography and other measurements were determined based on the spectrophotometric method. Results showed that the blanching in water or in steam reduced bioactive compounds concentration; whereas non-thermal treatments as pulsed electric field (PEF) applied separately or in combination with ultrasound (US + PEF) let to obtain similar or slightly lower content of bioactive compounds in comparison to untreated peppers. When sonication (US) and combined treatment as PEF + US were applied; in most cases reduction of bioactive compounds concentration occurred. This effect was probably related to the effect of relatively long (30 min) ultrasound treatment. The application of appropriate parameters of non-thermal processing is crucial for the high quality of processed material