Application of an integrative system (2D PLE×HPLC-PDA) for bioactive compound extraction and online quantification: Advantages, validation, and considerations.

Analyzing compounds such as polyphenols in solid samples frequently uses a solid-liquid extraction step. The solid-liquid extraction and analysis integration in a single equipment is not commercially available since several challenges are inherent to this hybridization. In the context of developing more sustainable analytical procedures, innovative techniques are demanded. Given that, this work proposes a new integrative system (2D PLE × HPLC-PDA) and presents its validation for bioactive compound extraction and online quantification, discussing the main advantages and cares that need to be taken. Two food byproducts - passion fruit bagasse and coffee husks - were chosen as solid model samples. The system was configured to perform pressurized liquid extraction (PLE) with periodical automated extract injection in the HPLC, consequently obtaining the online quantification of target compounds from the solid samples. In parallel with the online injections, extract fractions were collected and submitted to offline analysis in which the extraction yield of piceatannol and chlorogenic acid and caffeine were evaluated, respectively, for passion fruit bagasse and coffee husks. The extraction yields obtained by online and offline injections were compared and were significantly equal (p > 0.05). Thus, the 2D PLE × HPLC-PDA system represents a feasible tool to integrate solid sample preparation and chemical analysis of biocompounds in a single and online step.

Pressurized liquid extraction coupled in-line with SPE and on-line with HPLC (PLE-SPExHPLC) for the recovery and purification of anthocyanins from SC-CO2 semi-defatted Açaí (Euterpe oleracea).

This study aimed to extract anthocyanins from dried and semi-defatted açaí pulp using green technologies based on the coupling of pressurized liquid extraction (PLE) with in-line purification through solid-phase extraction (SPE) and on-line analysis by high-performance liquid chromatography (HPLC). Critical parameters that affect the extraction efficiency and purification were investigated and optimized by response surface methodology (RSM). PLE was performed with acidified water at different pH (2.0, 4.5, and 7.0) and temperatures (40, 80, and 120 °C) at 15 MPa, 2 mL/min, and solvent-to-feed mass ratio equal to 40. SPE was optimized in a column packed with the adsorbent PoraPak™ Rxn. Different ethanol concentrations (50, 75, and 100 %) and temperatures (30, 40, and 50 °C) were evaluated for the anthocyanin's elution. The optimal conditions of the two experimental designs were determined by the RSM, firstly for PLE: 71 °C and pH 2; then using this PLE condition, the optimization of the SPE was obtained: 30 °C and 50 % ethanol. The developed PLE method provided similar anthocyanin yield to other techniques, and the coupling with SPE in-line produced an extract 5-fold more concentrated than PLE alone. Therefore, the system (PLE-SPE × HPLC-PDA) proved to be a powerful tool for monitoring the extraction process in real-time.

Insights on the Extraction and Analysis of Phenolic Compounds from Citrus Fruits: Green Perspectives and Current Status.

Citrus fruits (CF) are highly consumed worldwide, fresh, processed, or prepared as juices and pies. To illustrate the high economic importance of CF, the global production of these commodities in 2021 was around 98 million tons. CF's composition is considered an excellent source of phenolic compounds (PC) as they have a large amount and variety. Since ancient times, PC has been highlighted to promote several benefits related to oxidative stress disorders, such as chronic diseases and cancer. Recent studies suggest that consuming citrus fruits can prevent some of these diseases. However, due to the complexity of citrus matrices, extracting compounds of interest from these types of samples, and identifying and quantifying them effectively, is not a simple task. In this context, several extractive and analytical proposals have been used. This review discusses current research involving CF, focusing mainly on PC extraction and analysis methods, regarding advantages and disadvantages from the perspective of Green Chemistry.

Extraction of potential bioactive compounds from industrial Tahiti lime (Citrus latifólia Tan.) by-product using pressurized liquids and ultrasound-assisted extraction.

This work evaluated two emerging techniques in extracting phenolic compounds from Tahiti lime pomace - pressurized liquid extraction (PLE) and ultrasound-assisted extraction (UAE). PLE was performed at different temperatures (60 - 110 °C) and times (5 - 40 min), and UAE was carried out varying ultrasound power (160 - 792 W), time (2 - 10 min), and solvent to feed mass ratio (20 - 40 kg solvent/kg dried pomace). Both used ethanol and water (3:1, wt.) as the solvent. The effects of these variables were evaluated on global extraction yield, polyphenols, hesperidin, narirutin yields, and antioxidant capacity. PLE was strongly affected by temperature and extraction time, and the highest temperature (110 °C) provided the best results for global yield, total phenolic, and ORAC, except for hesperidin and narirutin, which were not significative affected by temperature. UAE revealed a weak dependency on power, S/F, and time; however, the lowest power level significantly increased the yields compared to no power application. Thus, P = 480 W, t = 6 min, and S/F = 30 was chosen as the best condition in the UAE in terms of overall extraction yield, total phenolics, specific phenolics, antioxidant capacities, and solvent and energy expenditures. UAE mechanisms were investigated by comparing with heated and stirred maceration, and scanning electron microscopy suggested that total phenolic yield was influenced by mechanisms that only ultrasound can provide. Micrographics confirmed the cavitation effect on Tahiti lime pomace particles' surface. To sum up, PLE resulted in the highest yields and antioxidant capacity, followed by UAE.

Recovery of sugars and amino acids from brewers' spent grains using subcritical water hydrolysis in a single and two sequential semi-continuous flow-through reactors.

This study evaluated the subcritical water hydrolysis (SWH) of brewer's spent grains (BSG) to obtain sugars and amino acids. The experimental conditions investigated the hydrolysis of BSG in a single flow-through reactor and in two sequential reactors operated in semi-continuous mode. The hydrolysis experiments were carried out for 120 min at 15 MPa, 5 mL water min-1, at different temperatures (80 - 180 °C) and using an S/F of 20 and 10 g solvent g-1 BSG, for the single and two sequential reactors, respectively. The highest monosaccharide yields were obtained at 180 °C in a single reactor (47.76 mg g-1 carbohydrates). With these operational conditions, the hydrolysate presented xylose (0.477 mg mL-1) and arabinose (1.039 mg mL-1) as main sugars, while low contents of furfural (310.7 µg mL-1), 5-hydroxymethylfurfural (<1 mg L-1), and organic acids (0.343 mg mL-1) were obtained. The yield of proteins at 180 °C in a process with a single reactor was 43.62 mg amino acids g-1 proteins, where tryptophan (215.55 µg mL-1), aspartic acid (123.35 µg mL-1), valine (64.35 µg mL-1), lysine (16.55 µg mL-1), and glycine (16.1 µg mL-1) were the main amino acids recovered in the hydrolysate. In conclusion, SWH pretreatment is a promising technology to recover bio-based compounds from BSG; however, further studies are still needed to increase the yield of bioproducts from lignocellulosic biomass to explore two sequential reactors.

Systemic antioxidant and anti-inflammatory effects of yellow passion fruit bagasse extract during prostate cancer progression.

We evaluated the impact of yellow passion fruit (Passiflora edulis sp.) bagasse extract (PFBE) administration in systemic oxidative and inflammatory parameters in vivo, considering prostate cancer progression in transgenic mice (TRAMP). Piceatannol, scirpusin-B, dicaffeoylquinic acid, citric acid, and (+)-catechin were identified in PFBE, and the extract showed high in vitro antioxidant capacity. Some alterations in systemic parameters were verified during prostate cancer progression, as the increase in ALT and MDA levels, and SOD and GPx activities in the plasma. In the liver, higher MDA, TNF-α, and NF-κB levels, and GR and GPx activities were verified. Compared to their respective controls, the short- and long-term PFBE administration reduced MDA levels in the liver and plasma. The long-term treatment increased the catalase activity in the plasma, while the short-term treatment increased the hepatic SOD and catalase activities. Still, a reduction in hepatic TNF-α and NF-κB levels was verified after long-term treatment. PRACTICAL APPLICATIONS: Prostate cancer progression is associated with changes in systemic redox status and inflammation markers. Moreover, the intake of polyphenols with antioxidant properties, besides delaying prostate carcinogenesis, may improve the systemic antioxidant defenses and inflammatory response. In vitro studies pointed to a promising antioxidant and anti-inflammatory potential of yellow passion fruit bagasse. However, in vivo studies are scarce. Our results provided information about in vivo impacts of PFBE oral consumption on antioxidant defense and inflammation, indicating its potential as an adjuvant during the initial steps of prostate cancer.

Recent advances and trends in extraction techniques to recover polyphenols compounds from apple by-products.

Apple is one of the most consumed fruits worldwide and has recognized nutritional properties. Besides being consumed fresh, it is the raw material for several food products, whose production chain generates a considerable amount of by-products that currently have an underestimated use. These by-products are a rich source of chemical compounds with several potential applications. Therefore, new ambitious platforms focused on reusing are needed, targeting a process chain that achieves well-defined products and mitigates waste generation. This review covers an essential part of the apple by-products reuse chain. The apple composition regarding phenolic compounds subclasses is addressed and related to biological activities. The extraction processes to recover apple biocompounds have been revised, and an up-to-date overview of the scientific literature on conventional and emerging extraction techniques adopted over the past decade is reported. Finally, gaps and future trends related to the management of apple by-products are critically presented.

Selective Extraction of Piceatannol from Passiflora edulis by-Products: Application of HSPs Strategy and Inhibition of Neurodegenerative Enzymes.

Passiflora edulis by-products (PFBP) are a rich source of polyphenols, of which piceatannol has gained special attention recently. However, there are few studies involving environmentally safe methods for obtaining extracts rich in piceatannol. This work aimed to concentrate piceatannol from defatted PFBP (d-PFBP) by means of pressurized liquid extraction (PLE) and conventional extraction, using the bio-based solvents selected with the Hansen solubility parameters approach. The relative energy distance (Ra) between solvent and solute was: Benzyl Alcohol (BnOH) < Ethyl Acetate (EtOAc) < Ethanol (EtOH) < EtOH:H2O. Nonetheless, EtOH presented the best selectivity for piceatannol. Multi-cycle PLE at 110 °C was able to concentrate piceatannol 2.4 times more than conventional extraction. PLE exhibited a dependence on kinetic parameters and temperature, which could be associated with hydrogen bonding forces and the dielectric constant of the solvents. The acetylcholinesterase (AChE) and lipoxygenase (LOX) IC50 were 29.420 µg/mL and 27.682 µg/mL, respectively. The results reinforce the demand for processes to concentrate natural extracts from food by-products.

Impregnation of passion fruit bagasse extract in alginate aerogel microparticles.

Passion fruit bagasse extract (PFBE) is a rich source of polyphenols, including piceatannol. This work produced alginate (1, 2, 3 wt%) aerogel and investigated the impregnation of gallic acid (GA) and PFBE in alginate aerogel microparticles. The microparticles of ca. 100 µm in diameter were obtained by emulsion-gelation method, submitted to solvent exchange, wet impregnation (WI) and supercritical drying. Alginate aerogels derived from 1 wt% solution led to a higher GA loading and, therefore, this formulation was used to impregnate PFBE. The loading of PFBE, total phenolic, and piceatannol contents based on grams of raw aerogel were 0.62 g, 10.77 mg, and 741.85 µg, respectively, which means a loading efficiency of total phenolics and piceatannol of 47.1% and 34.7%. DSC analysis and X-ray diffraction showed that particles behave as amorphous materials and ORAC assay revealed that impregnated aerogel microparticles presented antioxidant capacity. Alginate aerogel microparticles presented as an appropriated material for drug loading, whereas WI and supercritical drying demonstrated to be useful techniques to load PBBE in aerogels.