Current and New Insights in the Sustainable and Green Recovery of Nutritionally Valuable Compounds from Stevia rebaudiana Bertoni.

International audience; The South American plant Stevia rebaudiana Bertoni is a great source of noncaloric sweeteners (steviol glycosides), mainly concentrated in its leaves, but also has important antioxidant compounds (vitamin C, polyphenols, chlorophylls, and carotenoids) and other important macro- and micronutrients such as folic acid and all of the essential amino acids except tryptophan. Traditionally, conventional methods have been used to recover nutritionally valuable compounds from plant food matrices. However, nowadays, the need for obtaining greener, sustainable, and viable processes has led both food industries and food scientists to develop new processes in full correspondence…

Selective Extraction of Biocompounds from Stevia rebaudiana Bertoni Leaves Using Electrotechnologies

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…

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…

Experimental and theoretical investigations of lignin-urea-formaldehyde wood adhesive: Density functional theory analysis

Abstract In view of its chemical structure, lignin has recently become an interesting candidate for various applications. This work serves to optimize the isolation process of lignin from sugar industry by-product (bagasse can, molasses beet) applying alkali treatment. For this purpose, the effect of alkali and sulfuric acid concentrations have been studied ranging from 10% (w/v) to 20% (w/v) and 1.5 M–3 M, respectively. Moreover, the isolated lignins were characterized by different complementary analysis such as FT-IR and TGA/DTG. The aim behind this work is to reduce formaldehyde emissions and improving mechanical as well as physical properties of wood adhesive. Lignin was added with diff…

“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…

Valorization of Solanum Elaeagnifolium Cavanilles Weeds as a New Lignocellulosic Source for the Formulation of Lignin-Urea-Formaldehyde Wood Adhesive

Solanum Elaeagnifolium Cavanilles (SE-Cav) is an invasive plant that has been developed in Mediterranean basin countries especially in Morocco. This weeds which belongs to lignocellulosic biomass a...

Characteristics of cellulose fibers from Opuntia ficus indica cladodes and its use as reinforcement for PET based composites

With the aim of valorizing the unexplored Moroccan resources, Opuntia ficus indica (OFI) cladodes were proposed as a renewable source for the production of cellulose. In this work, cellulose microf...

Understanding the physicochemical properties of olive kernel to be used as a potential tool in the development of phenol-formaldehyde wood adhesive

Abstract During olive oil production process, a great number of by-products are generated, including olive kernel. These by-products can be used for the development of new products for use in many different industrial applications. The evaluation of the physicochemical properties of these by-products constitutes a key factor in evaluating the potential reutilization of olive oil by-products. In the present study, the physicochemical properties of olive kernel were analyzed. Fourier transform infrared spectroscopy (FT-IR), cross-polarization magic angle spinning 13 C nuclear magnetic resonance (CP/MAS 13 C NMR), Brunauer, Emmett and Teller (BET), scanning electron microscopy (SEM) and thermo…

Ultrasound as a Promising Tool for the Green Extraction of Specialized Metabolites from Some Culinary Spices

Spices are a popular food of plant origin, rich in various phytochemicals and recognized for their numerous properties. The aim of the study was to evaluate the antioxidant and antimicrobial activity, as well as the content of specialized metabolites, of aqueous extracts of three spice species––garlic (Allium sativum L.), ginger (Zingiber officinalle L.) and turmeric (Curcuma longa L.)––prepared by green extraction methods. Ultrasound treatment increased the chromaticity parameter b value of turmeric and ginger extracts, thus indicating a higher yellow color predominantly due to curcuminoids characteristic of these species. Ultrasound-assisted extraction significantly increased the content …

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…

Water-soluble polysaccharides from Opuntia stricta Haw. fruit peels: Recovery, identification and evaluation of their antioxidant activities

Abstract Opuntia stricta Haw. is considered as one of the most common cactus plant growing in Tunisia. Extracting valuable compounds from its fruit peel, considered as by-product, is drawing more and more attention, making it on the verge of commercialization. Water-soluble polysaccharides were extracted from Opuntia stricta Haw. peels, and their chemical composition assessed using thin layer chromatography. The antioxidant activities of the extracted polysaccharides were assessed using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, total antioxidant activity and reducing power capacity. The extraction yield of water-soluble polysaccharides was 7.53±0.86%. The chemical comp…

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 fields (PEF), pressurized liquid extraction (PLE) and combined PEF + PLE process evaluation: Effects on Spirulina microstructure, biomolecules recovery and Triple TOF-LC-MS-MS polyphenol composition

This study aims at evaluating the impact of different processes-pulsed electric fields (PEF), pressurized liquid extraction (PLE) and a multistep process combining PEF + PLE on the yield of antioxidant compounds (protein, polyphenols, chlorophyll a, chlorophyll b, and carotenoids) from Spirulina. Firstly, the effects of PEF or PLE treatment on the extraction yield of Spirulina biomolecules were evaluated. To further increase the extraction yield, PEF + PLE was used, as an innovative extraction approach. The results showed that PEF + PLE greatly improved the extraction yield compared with the PEF or PLE treatments alone. Compared with Folch extraction (conventional control technique), PEF + …

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…

Fruit juice sonication: Implications on food safety and physicochemical and nutritional properties

Abstract Over the last years, consumers are increasingly demanding for nutritious, healthy and fresh-like food products, with high organoleptic quality. Nowadays, emerging non-thermal technologies have raised great interest as a viable alternative to the conventional thermal methods, since they have minimal impact on sensorial and nutritional properties of fresh foods. Ultrasound (US) is one of these promising non-conventional processing technologies and it is especially suitable for preservation of fluid foods. US may be used alone or in combination with other preservation techniques, such as mild heat temperatures, high pressures and antimicrobials. Besides, data on inactivation of food m…

Emerging opportunities for the effective valorization of wastes and by-products generated during olive oil production process: Non-conventional methods for the recovery of high-added value compounds

Abstract Background A large amount of wastes and by-products are generated during olive oil production process. Traditionally, these products have been considered as a problem. However, they constitute a great source of high-added value compounds, which have the potential to be used as food additives and/or nutraceuticals. Therefore, valorization of wastes and by-products from food industry kills two birds with one stone and addresses both the use of waste and by-products and societal health, thus greatly contributing for a sustainable food chain from an environmental and economical point of view. Scope and approach In the present review, current and new insights in the recovery of high-add…

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…