Renata Vardanega

Intensification of bioactive compounds extraction from medicinal plants using ultrasonic irradiation

Extraction processes are largely used in many chemical, biotechnological and pharmaceutical industries for recovery of bioactive compounds from medicinal plants. To replace the conventional extraction techniques, new techniques as high-pressure extraction processes that use environment friendly solvents have been developed. However, these techniques, sometimes, are associated with low extraction rate. The ultrasound can be effectively used to improve the extraction rate by the increasing the mass transfer and possible rupture of cell wall due the formation of microcavities leading to higher product yields with reduced processing time and solvent consumption. This review presents a brief survey about the mechanism and aspects that affecting the ultrasound assisted extraction focusing on the use of ultrasound irradiation for high-pressure extraction processes intensification.

Fast analysis of β-ecdysone in Brazilian ginseng (Pfaffia glomerata) extracts by high-performance liquid chromatography using a fused-core column

The recent development of fused-core technology in HPLC columns is enabling faster and highly efficient separations. This technology was evaluated for the development of a fast analysis method for β-ecdysone in extracts of Pfaffia glomerata. A step-by-step strategy was used to optimize temperature (30–55 °C), flow rate (1.0–2.0 mL min−1), mobile phase composition (mixtures of water and methanol or acetonitrile) and equilibration time (1–5 min). A gradient method has been developed using two solvents: 0.1% acetic acid in water and 0.1% acetic acid in acetonitrile. Optimized conditions provided a method for the separation of β-ecdysone in approximately 2 min with a total analysis time (sample-to-sample) of 9 min, including the return to initial conditions and the re-equilibration of the column. Evaluation of chromatographic performance revealed excellent intraday and interday reproducibility (>99.5%), resolution (2.78), selectivity (1.13), and peak symmetry (1.09) while presenting low limits of detection (0.20 mg L−1) and quantitation (0.67 mg L−1). The robustness of the method has also been calculated according to the concentration/dilution of the sample. Several sample solvents were evaluated and the best chromatographic results were obtained using 80% methanol in water. Finally, the developed method was validated with different extracts of Pfaffia glomerata samples.

Pressurized Liquid Extraction as a Promising and Economically Feasible Technique for Obtaining Beta-Ecdysone-Rich Extracts from Brazilian Ginseng (Pfaffia glomerata) Roots

Pressurized liquid extraction was used to obtain beta-ecdysone-rich extracts from Brazilian ginseng (Pfaffia glomerata) roots. The effects of temperature, pressure, and solvent on extraction yield, beta-ecdysone content, and antioxidant activity were determined. Extraction yield increased with temperature up to 25% (dry basis) while the selectivity decreased. The use of Ethanol:Water (80:20 v/v) as solvent produced extracts with the highest antioxidant activity. Beta-ecdysone recovery was maximized using pure ethanol. In the first hour of extraction, approximately 70% of the total yield and 74% of the total beta-ecdysone mass is obtained. The cost of manufacturing significantly decrease as the extractor capacity increased.

The study of model systems subjected to sub- and supercritical water hydrolysis for the production of fermentable sugars

Bioenergy obtained from lignocellulosic biomass is considered the most efficient way to achieve sustainable development in the future. However, there still are challenges in the cellulose conversion to hexoses, which could be used as raw material for the bioenergy production. Sub- and supercritical water hydrolysis have been researched as emergent technologies to obtain simple sugars from lignocellulosic biomass; however, the reaction pathways and kinetics of the hydrolysis of cellulose into oligomers and monomers, and their degradation under sub- and supercritical conditions, are not completely understood yet. Thus, this review provides an overview of the state-of-the-art on hydrolysis with sub- and supercritical water of model systems, cellulose and starch, in the context of elucidating the reaction pathways and kinetic behavior of the biomass hydrolysis to produce suitable fermentation substrates for the production of second generation bioethanol and other biofuels.

Energy Consumption Versus Antioxidant Activity of Pressurized Fluid Extracts from Pfaffia glomerata Roots

Conventional extraction techniques have been applied to obtain antioxidant extracts from Pfaffia glomerata roots, most of the times, using polar extracting solvents. Even if these techniques are able to provide extracts with antioxidant activities, more environmentally friendly techniques are nowadays preferred. Among them, supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) with green solvents have been widely applied to natural bioactive compounds extraction. The limitation of the use of pure supercritical CO2 for obtaining antioxidant extracts from Pfaffia glomerata roots was already demonstrated. When high amounts of modifier are added, the formation of a gas-expanded liquid is observed. This extracting solvent combines the advantages of the solvation properties of typical liquids and the transport properties of supercritical fluids, being an intermediate process between SFE and PLE, which can be called as pressurized fluid extraction (PFE). In this work, PFE of Brazilian ginseng (Pfaffia glomerata) roots were performed in order to obtain antioxidant extracts with potential applications in the pharmaceutical and food areas. Several CO2+ethanol mixtures (90:10 %, 50:50 % and 0:100 %, w/w) as extracting fluid were assayed. The effects of other two process parameters including pressure (10-20 MPa) and temperature (323-363 K) on the extraction yield, antioxidant activity and energy consumption per unit of manufactured product were investigated. PFE process was simulated using the SuperPro Designer simulation platform. The use of 10 % (w/w) of ethanol produced extracts with the highest antioxidant activity. On the other hand, higher temperature and ethanol percentage resulted in higher extraction yield and lower energy consumption per unit of manufactured product, while pressure did not affect any response variables. Copyright

Chapter 6 – Conventional extraction

Traditional extraction technologies, such as solvent extraction and steam distillation, have been used for the recovery of natural extracts from plant and animal sources for a long time. These extracts have mainly been used as food additives and medicines. Later, other more efficient and environmentally friendly methods like enzyme-, ultrasound-, and microwave-assisted extraction, and supercritical fluid extraction were developed. Following the tendency of modern society to decrease pollution, recovery of bioactive compounds from food wastes is an alternative option that adds value to such residues and at the same time decreases their environmental footprint. In this chapter, the use of well-established extraction technologies to recover bioactive compounds from food industry wastes is presented.

Obtaining functional powder tea from Brazilian ginseng roots: Effects of freeze and spray drying processes on chemical and nutritional quality, morphological and redispersion properties

In this work, the aqueous extract obtained from Brazilian ginseng (Pfaffia glomerata) roots (BGR), rich in beta-ecdysone and fructooligosaccharides (FOS), was powdered by spray drying and freeze drying techniques aiming to obtain a novel functional food product. The effects of these drying techniques on the chemical and nutritional quality, morphological and redispersion properties of the BGR powders were evaluated. The BGR powders obtained by both spray drying and freeze drying techniques maintained their beta-ecdysone and FOS contents after drying, demonstrating the stability of these functional compounds. It was found that the wettability of the powders obtained by different treatments was affected by the drying technique because freeze-dried particles reached the lower values (66 ± 5 s) while spray-dried particles showed a greater time for dispersion into water (150 ± 25 s). This behavior was mainly associated with differences between powder morphological properties since the freeze-dried particles presented a more porous structure, resulting in a greater water diffusivity into microstructure during the redispersion process. Drying process did not affect the storage stability of powders because the glass transition temperature (Tg) for both samples was approximately 160 °C at a relative humidity of 56%. Thus, both BGR powders presented adequate redispersion properties to constitute a new functional tea or even to be used as a functional ingredient in food products.

CHAPTER 11:Integration of Pressurized Fluid‐based Technologies for Natural Product Processing

Due to their characteristics, pressurized liquids and supercritical fluids have a great potential to improve the overall process for the production of natural products. If properly designed, processes using pressurized liquids and/or supercritical fluids can be highly efficient and reduce costs while providing environmental benefits. However, one of the keys for the successful production of natural products using these fluids as solvents is the integration of different processes in one single on‐line operation. There are several processes that can be performed on‐line using pressurized liquids and/or supercritical fluids, including extraction, fractionation, purification, solvent evaporation, particle formation and encapsulation of active ingredients. In several cases, the conventional processes used for the production of natural products can be replaced or improved by pressurized fluid techniques and thus the concept of process integration can be fully explored. Furthermore, the benefits involved are not only related to the manufacturing process and costs, but it is also possible to improve the quality of the final product. In this chapter, different aspects of the integration of pressurized fluids‐based technologies for the extraction, fractionation, purification and stabilization of extracts are discussed. Examples of successful applications of this concept are discussed and a case study dealing with the development of an integrated process for extraction and stabilization of bixin‐rich extract employing pressurized fluid in both processes is presented.