Selective Extraction of Biocompounds from Stevia rebaudiana Bertoni Leaves Using Electrotechnologies

Pulsed Electric Fields and High-Voltage Electrical Discharges-Assisted Extraction of Valuable Biocompounds and Biopolymers from Rapeseed By-Products

Oilseed treatment by ultrasounds and microwaves to improve oil yield and quality: An overview.

International audience; Efficiency is a key point to ensure the profitability in the production of vegetable oils from oilseeds. To maximize the recovery yields of seed oils, the traditional process involves mechanical expression followed by subsequent chemical extraction using organic solvents (e.g. hexane). Besides health, environmental, and economic related issues to the use of organic solvents, thermal treatment of seeds during conventional oil extraction process inevitably leads to chemical changes (e.g. changes in macronutrients such as protein denaturation/degradation in the meal, oil oxidation, and changes in minor constituents such as fatty acids, sterols, phenolic compounds and to…

New approaches for the effective valorization of papaya seeds: Extraction of proteins, phenolic compounds, carbohydrates, and isothiocyanates assisted by pulsed electric energy

Abstract The study compares the efficiency of common aqueous extraction (CE) at different pH (2.5–11) and temperatures (20–60 °C) and extraction assisted by pulsed electric energy (pulsed electric fields, PEF or high voltage electrical discharges, HVED) of nutritionally valuable and antioxidant compounds from papaya seeds. The exponential decay pulses with initial electric field strengths of ≈ 13.3 kV/cm and ≈ 40 kV/cm for PEF and HVED treatments, respectively, were used. The number of pulses n was changed within 1–2000. The impacts of temperature and pH on extraction efficiency of different components (proteins, total phenolic compounds, carbohydrates, isothiocyanates) and antioxidant capa…

Recovery of colorants from red prickly pear peels and pulps enhanced by pulsed electric field and ultrasound

Abstract The aim of this work was to evaluate the potential of the non-conventional pre-treatments; pulsed electric fields (PEFs) and ultrasounds (USNs), to enhance the extraction of red colorants from red prickly pear ( Opuntia stricta Haw.) peels and pulps. The overall goal was to valorize the thick part of the fruit, being discarded for fruit's consumption. PEF and USN treatments were first optimized using fruit slices, followed by a supplementary aqueous extraction (+ SAE) up to 1 h. The optimal conditions were then applied for peels and pulps, separately. Results showed that PEF + SAE and USN + SAE enhanced significantly the extraction of red colorants (betanin/isobetanin), compared to…

Seed oil extraction from red prickly pear using hexane and supercritical CO2: assessment of phenolic compound composition, antioxidant and antibacterial activities

Investigating Opuntia species for their seed oil content is of much importance owing to their potential use for food and in cosmetic applications. These oils have an important content in unsaturated fatty acids as well as antioxidant compounds (e.g. polyphenols, vitamin E), which have been associated with the prevention of some chronic diseases. Moreover, Opuntia stricta oils possess important antimicrobial activities. For instance, the main focus of this study was to compare the effectiveness of conventional (hexane extraction) and novel (supercritical (SC)-CO2 ) extraction methods for the recovery of oil and phenolic compounds from O. stricta seeds. The oil yield of both extracts was then…

Ultrasound-assisted green solvent extraction of high-added value compounds from microalgae Nannochloropsis spp.

Abstract The aim of this work was to investigate ultrasound (US)-assisted green solvent extraction of valuable compounds from the microalgae Nannochloropsis spp. Individual green solvents (water, ethanol (EtOH), dimethyl sulfoxide (DMSO)) and binary mixture of solvents (water-DMSO and water-EtOH) were used for the extraction procedures. Maximum total phenolic compounds yield ( Y p  ≈ 0.33) was obtained after US pre-treatment ( W  = 400 W, 15 min), being almost 5-folds higher compared to that found for the untreated samples and aqueous extraction ( Y p  ≈ 0.06). The highest yield of total chlorophylls ( Y c  ≈ 0.043) was obtained after US ( W  = 400 W, 7.5 min), being more than 9-folds highe…

Pulsed electric field and pH assisted selective extraction of intracellular components from microalgae Nannochloropsis

Abstract The study was aimed at investigation of the potential of pulsed electric field (PEF) pre-treatment as a preliminary step of pH-assisted aqueous extraction of algae components from microalgae Nannochloropsis suspensions. The PEF and sonication (S) were compared as pretreatment methods. They were applied at normal (pH = 8.5) and basic (pH = 11) conditions, and supplementary basic extraction (at pH = 11) was done. The extracts were analyzed for content of pigments, proteins, carbohydrates, total phenolic compounds and antioxidant capacity. The colloidal stability of PEF- and S-pretreated suspensions was also evaluated. The data evidence that PEF technique allows selective extraction o…

Potential use of pulsed electric technologies and ultrasounds to improve the recovery of high-added value compounds from blackberries

Abstract A better knowledge of the effect of non-conventional extraction technologies, which can avoid the use of high temperatures and toxic solvents, on the antioxidant compounds recovery from blackberries, is necessary. Thus, high voltage electrical discharges (HVED), pulsed electric fields (PEF), and ultrasounds (USN) treatments were applied in order to evaluate the effects of processing on protein, total phenolics and anthocyanins extraction from blackberries. Moreover, two-stage extraction involving the use of HVED, PEF and USN as pre-treatments and supplementary extraction during 5 h with hot water at mild temperature (50 °C) or an hydroalcoholic solution (30% ethanol, w/w) was evalu…

“Ice” juice from apples obtained by pressing at subzero temperatures of apples pretreated by pulsed electric fields

Abstract The impact of apple pretreatment by pulsed electric field (PEF) on juice extraction using the freezing-assisted pressing was studied. Apple discs were PEF pretreated at electric field strength of E  = 800 V/cm and then air blast frozen inside the freezer (− 40 °C). Then, pressing experiments in a laboratory-pressing chamber (2–5 bars) were started at sub-zero temperature (− 5 °C). Time evolution of juice yield and its nutritional qualities were compared for PEF and untreated apple samples. High improvements of juice yield were obtained for freeze-thawed (FT) and PEF + FT samples. The combination of PEF + pressing (5 bar) at sub-zero temperature gave optimum results for juice extrac…

Impact of pulsed electric fields and high voltage electrical discharges on extraction of high-added value compounds from papaya peels

Abstract Extraction of the nutritionally valuable and antioxidant compounds from papaya peels using conventional aqueous extraction (E) (at 20 °C, 50 °C, and 60 °C) and extraction assisted by pulsed electric field (PEF) or by high voltage electrical discharges (HVED) was studied. Increase of extraction temperature or extraction in basic media (pH = 11) not always resulted in an increase of the yields or TEAC values. E.g., the concentration of proteins and TEAC values at pH = 7 and pH = 11 were noticeably smaller at 60 °C as compared to those measured at 50 °C. HVED-assisted technique showed a higher extraction efficiency of high-added value compounds compared to PEF-assisted extraction. E.g…

Optimization of microwave-assisted extraction of polyphenols from Quercus bark

Abstract Box–Behnken response surface methodology was used to investigate and optimize microwave assisted extraction (MAE) (treatment power and time) of antioxidant compounds, especially polyphenols, from bark extracts. Moreover, the effects of solvent composition (methanol and ethanol) particle size, and pH conditions were evaluated and optimized. In addition, the effects of MAE were compared to conventional solvent extraction at room temperature and reflux extraction (at 100 °C). The results indicated that all process variables had a significant effect on polyphenol and antioxidant recovery, except for methanol (p > 0.05). For instance, TPC and antioxidant activity were increased when hig…

Recent insights for the green recovery of inulin from plant food materials using non-conventional extraction technologies: A review

Abstract Inulin constitutes an important food ingredient, widely used for its fiber content, and its ability to substitute fat and sugar ingredients. Traditionally, industrial inulin production from chicory roots requires high extraction temperature (70–80 °C) and long extraction time (1–2 h). This conventional extraction is generally accompanied with the presence of a large amount of impurities in the extracted juice, mainly due to the application of high temperature, requiring thus further purification steps. To overcome these issues, developing novel extraction technologies, consuming less energy, faster, and providing high yield and purity, is of paramount importance to meet the require…

Gas assisted mechanical expression (GAME) as a promising technology for oil and phenolic compound recovery from tiger nuts

Abstract The aim of this work was to investigate the potential of gas assisted mechanical expression (GAME) process as an innovative technology for oil extraction and polyphenol recovery from tiger nuts. GAME process was first studied by varying the supercritical carbon dioxide (SC-CO2) and the mechanical expression (ME) pressures (10–30 MPa), then was compared to separate processes applied alone, using either SC-CO2 or ME. The results showed that the better conditions for GAME were found using 20 MPa for SC-CO2 and 30 MPa for ME. Under these conditions, 50% of oil was released from tiger nuts after 10 min extraction, compared to only 10% and 20% when using SC-CO2 and ME separately at 20 an…

Pulsed electric field assisted extraction of nutritionally valuable compounds from microalgae Nannochloropsis spp. using the binary mixture of organic solvents and water

Abstract This work studies the potential of the pulsed electric field (PEF) assisted extraction of nutritionally valuable compounds from microalgae Nannochloropsis spp. using the binary mixture of organic solvents (dimethyl sulfoxide, DMSO and ethanol, EtOH) and water. The one-stage (E I ) and two stage (E II ) extraction procedures were compared. The procedure E I included the common extraction using the binary mixtures. Two stage (E II ) extraction procedure involved PEF-treatment (20 kV/cm) of microalgae suspension (1% wt.) and extraction in water as the first step. The second step included the common extraction using the binary mixtures. The effects of extraction procedure and concentra…

Current applications and new opportunities for the use of pulsed electric fields in food science and industry

ABSTRACT Several studies have demonstrated the feasibility of pulsed electric fields (PEF) for different applications in food industry. PEF technology is therefore a valuable tool that can improve functionality, extractability, and recovery of nutritionally valuable compounds as well as the bioavailability of micronutrients and components in a diverse variety of foods. Additionally, other studies have shown the potential of PEF treatments to reduce food processing contaminants and pesticides. This opens the doors to new PEF applications in the food industry. This review focused on some of the most renowned traditional and emerging PEF applications for improvement of osmotic dehydration, ext…

Gas assisted mechanical expression (GAME) for the selective recovery of lipophilic and hydrophilic compounds from olive kernel

Abstract This work is devoted to valorize olive kernel; a by-product produced during olive oil extraction process. For this purpose, aqueous liquid solid extraction (LSE), mechanical expression (ME), supercritical CO2 (SC-CO2) and gas assisted mechanical expression (GAME), processes were compared when applied separately or consequently (ME + GAME), in terms of total phenolic compound (TPC) and oil recovery yields. Results showed that although the high extraction yields of TPC using LSE (61.4 ± 1.3%), the extraction process is economically not viable. However, it was demonstrated that applying ME (1 h at 30 MPa) followed by GAME (1 h at 30 MPa ME and 10 MPa SC-CO2 pressures) allowed recoveri…

Electro-biorefinery as a Potential Tool for Valorization of Mango and Papaya By-products

During exotic fruits processing, a large amount of by-products, especially seeds and peels, are produced and discarded into the environment causing organic pollution. However, it is recognized that these by-products are a good source of high-added value compounds, which can be used for different purposes (i.e. food additives and/or nutraceuticals). At this stage of development, there is a lack of information about the different extraction methods that can be used for the recovery of high-added value compounds from papaya and mango by-products. In this line, the extraction assisted by pulsed electric technologies seems to be rather promising. In this research study, the exponential decay pul…

Evaluating the potential of cell disruption technologies for green selective extraction of antioxidant compounds from Stevia rebaudiana Bertoni leaves

Abstract An increased interest has been shown by both food technologists and food industry regarding Stevia rebaudiana Bertoni leaves ( Stevia ) for their high content of bioactive components (phenolic compounds, vitamin C, carotenoids). The aim of this work was to study the effect of emerging technologies such as high voltage electrical discharges (HVED) and pulsed electric fields (PEF) and ultrasounds (US) on the intensification of the extraction of valuable compounds from Stevia leaves. The proposed processes combined pretreatment (HVED, PEF and US) and extraction of intracellular compounds using water as solvent at ambient temperature. The energy inputs of the treatments varied from 24 …

Electrotechnologies, microwaves, and ultrasounds combined with binary mixtures of ethanol and water to extract steviol glycosides and antioxidant compounds from Stevia rebaudiana leaves

The aim of this work was to investigate the potential use of non-conventional technologies (microwaves, ultrasounds, pulsed electric fields, and high voltage electrical discharges) to enhance the extraction of high-added value compounds (mainly stevioside and rebaudioside A), and antioxidants (total phenolic compounds, flavonoids, chlorophylls, and carotenoids), from Stevia rebaudiana leaves. After treatment at equivalent energy, a supplementary diffusion was performed until 1 h. Results demonstrated that when water (100%) was used as solvent, the maximum recovery of stevioside (50.8 ± 0.1 mg/g) was obtained after ultrasound-assisted extraction, while microwave allowed the highest yields of…