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1.
Molecules ; 27(21)2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36364260

RESUMO

Membrane-based processes are increasingly used to clarify and concentrate thermo-sensitive fruit juices and plant extracts as alternatives to conventional processes. This work aimed to evaluate the quality of red fruit juices clarified and concentrated by an integrated membrane process with special regard to the preservation of valuable compounds. A red fruit juice obtained from a blend of pomegranate, cactus pear, and red orange juices of Sicilian origin was clarified by microfiltration (MF) and then pre-concentrated up to 33 °Brix by nanofiltration (NF). The pre-concentrated juice was finally concentrated by osmotic distillation (OD) up to 50 and 60 °Brix. Samples of clarified, pre-concentrated, and concentrated juice were analyzed for their physico-chemical composition and in terms of the antioxidant activity and inhibitory activity against α-amylase and lipase. The results clearly confirmed the assumption of a mild fruit juice processing method, allowing us to preserve the original nutritional and functional properties of the fresh juice. In particular, the OD retentate at 60 °Brix resulted the most active sample against pancreatic lipase and α-amylase inhibitory activity with IC50 values of 44.36 and 214.65 µg/mL, respectively.


Assuntos
Sucos de Frutas e Vegetais , Frutas , Frutas/química , Destilação/métodos , alfa-Amilases , Lipase/análise
2.
Crit Rev Food Sci Nutr ; 61(13): 2152-2174, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32496876

RESUMO

Steviol glycosides (SGs), as natural sweeteners from Stevia rebaudiana, are currently employed for replacing sugar and its derivatives in several food products and formulations. Such compounds play an essential role in human health. Their usage provides a positive effect on preventing diseases related to sugar consumption, including diabetes mellitus, cancer, and lipid metabolism disorders. The traditional extraction of SGs is performed by means of solvent extraction, which limits their application since the removal of residual solvents is a challenging task requiring further downstream purification steps. In addition, the presence of residual solvents negatively affects the quality of such compounds. Today, food technicians are looking for innovative and improved techniques for the extraction, recovery and purification of SGs. Membrane-based technologies, including microfiltration, ultrafiltration, and nanofiltration, have long been proven to be a valid alternative for efficient extraction and purification of several high added-value molecules from natural sources. Such processes and their possible coupling in integrated membrane systems have been successfully involved in recovery protocols of several compounds, such as metabolites, polyphenols, anthocyanins, natural pigments, proteins, from different sources (e.g., agro-food wastes, plant extracts, fruits, fermentation broths, among others). Herein, we aim to review the current progresses and developments about the extraction of SGs with membrane operations. Our attention has been paid to the latest insights in the field. Furthermore, key process parameters influencing the extraction and purification of SGs are also discussed in detail.


Assuntos
Diterpenos do Tipo Caurano , Stevia , Antocianinas , Glucosídeos , Glicosídeos , Humanos , Folhas de Planta
3.
Molecules ; 26(7)2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33916021

RESUMO

Wastewaters and by-products generated in the winemaking process are important and inexpensive sources of value-added compounds that can be potentially reused for the development of new products of commercial interest (i.e., functional foods). This research was undertaken in order to evaluate the potential of nanofiltration (NF) membranes in the recovery of anthocyanins and monosaccharides from a clarified Carménère grape marc obtained through a combination of ultrasound-assisted extraction and microfiltration. Three different flat-sheet nanofiltration (NF) membranes, covering the range of molecular weight cut-off (MWCO) from 150 to 800 Da, were evaluated for their productivity as well as for their rejection towards anthocyanins (malvidin-3-O-glucoside, malvidin 3-(acetyl)-glucoside, and malvidin 3-(coumaroyl)-glucoside) and sugars (glucose and fructose) in selected operating conditions. The selected membranes showed differences in their performance in terms of permeate flux and rejection of target compounds. The NFX membrane, with the lowest MWCO (150-300 Da), showed a lower flux decay in comparison to the other investigated membranes. All the membranes showed rejection higher than 99.42% for the quantified anthocyanins. Regarding sugars rejection, the NFX membrane showed the highest rejection for glucose and fructose (100 and 92.60%, respectively), whereas the NFW membrane (MWCO 300-500 Da) was the one with the lowest rejection for these compounds (80.57 and 71.62%, respectively). As a general trend, the tested membranes did not show a preferential rejection of anthocyanins over sugars. Therefore, all tested membranes were suitable for concentration purposes.


Assuntos
Antocianinas/isolamento & purificação , Membranas Artificiais , Monossacarídeos/isolamento & purificação , Extratos Vegetais/química , Ultrafiltração , Vitis/química , Antocianinas/análise , Antocianinas/química , Fenômenos Químicos , Peso Molecular , Monossacarídeos/análise , Monossacarídeos/química , Nanoporos , Compostos Fitoquímicos , Reprodutibilidade dos Testes , Açúcares/análise , Açúcares/química
4.
Molecules ; 26(6)2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33806935

RESUMO

Olive mill wastewater (OMW), generated as a by-product of olive oil production, is considered one of the most polluting effluents produced by the agro-food industry, due to its high concentration of organic matter and nutrients. However, OMW is rich in several polyphenols, representing compounds with remarkable biological properties. This study aimed to analyze the chemical profile as well as the antioxidant and anti-obesity properties of concentrated fractions obtained from microfiltered OMW treated by direct contact membrane distillation (DCMD). Ultra-high performance liquid chromatography (UHPLC) analyses were applied to quantify some phenols selected as phytochemical markers. Moreover, α-Amylase, α-glucosidase, and lipase inhibitory activity were investigated together with the antioxidant activity by means of assays, namely ß-carotene bleaching, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS) diammonium salts, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and Ferric Reducing Activity Power (FRAP) tests. MD retentate-which has content of about five times greater of hydroxytyrosol and verbascoside and about 7 times greater of oleuropein than the feed-was more active as an antioxidant in all applied assays. Of interest is the result obtained in the DPPH test (an inhibitory concentration 50% (IC50) of 9.8 µg/mL in comparison to the feed (IC50 of 97.2 µg/mL)) and in the ABTS assay (an IC50 of 0.4 µg/mL in comparison to the feed (IC50 of 1.2 µg/mL)).


Assuntos
Destilação , Olea/química , Fenóis , Compostos Fitoquímicos , Águas Residuárias/química , Fenóis/química , Fenóis/isolamento & purificação , Compostos Fitoquímicos/química , Compostos Fitoquímicos/isolamento & purificação
5.
Molecules ; 25(16)2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32824751

RESUMO

In this work, a membrane-based process for the purification and concentration of antioxidant compounds from aqueous Goji (Lycium barbarum L.) berry extracts was investigated. The aqueous extract was previously clarified with hollow fiber ultrafiltration (UF) membranes in order to remove suspended solids and ß-carotene and to produce a clarified extract enriched in phenolic compounds. Then, three UF flat sheet polyamide membranes with a molecular weight cut-off (MWCO) in the range 1000-3500 Da were tested to purify and concentrate phenolic compounds from the clarified extract. The effect of MWCO and transmembrane pressure (TMP) on the performance of selected membranes in terms of productivity and selectivity towards total dissolved solids (TDS), total phenolic compounds (TPC), total carbohydrates (TC) and total antioxidant activity (TAA) was evaluated. Experimental results indicated that the 2500 Da membrane exhibited a lower fouling index, higher cleaning efficiency, lower rejection towards carbohydrates (lower than 30%) and higher rejection towards phenolic compounds (higher than 50%) in comparison to the other investigated membranes. The inclusion of a diafiltration process in the treatment of the clarified extract with this membrane in a spiral-wound configuration improved the concentration of sugar compounds in the permeate stream and increased the purification of phenolic compounds in the retentate fraction.


Assuntos
Lycium/química , Membranas Artificiais , Fenóis/análise , Fenóis/isolamento & purificação , Extratos Vegetais/química , Ultrafiltração/métodos
6.
Crit Rev Food Sci Nutr ; 59(18): 2927-2948, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-29787307

RESUMO

To date, according to the latest literature inputs, membranes-based technologies (microfiltration, ultrafiltration and nanofiltration) have demonstrated to meet the recovery of biologically active compounds, mainly phenolic compounds and their derivatives, from agro-food products and by-products. The goal of this paper is to provide a critical overview of the on ongoing development works aimed at improving the separation, fractionation and concentration of phenolic compounds and their derivatives from their original sources. The literature data are analyzed and discussed in relation to separation processes, molecule properties, membrane characteristics and key factors affecting the performance of such technologies. Technological advances and improvements over conventional technologies, as well as critical aspects to be further investigated are highlighted and discussed. Finally, a critical outlook about the current status for a large-scale application and the role of these processes from an environmental viewpoint is provided.


Assuntos
Tecnologia de Alimentos , Membranas Artificiais , Fenóis , Ultrafiltração , Fracionamento Químico , Análise de Alimentos , Tecnologia de Alimentos/métodos , Tecnologia de Alimentos/tendências , Fenóis/isolamento & purificação
7.
Molecules ; 24(12)2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31248174

RESUMO

In this work, the use of polymeric ultrafiltration and nanofiltration membranes was investigated in order to recover glycyrrhizin and phenolic compounds from licorice wastewaters. Filtration experiments were performed on a laboratory scale using four polyamide thin-film composite membranes (GK, GH, GE, and DK, from GE Osmonics) with different molecular weight cut-offs (from 150 to 3500 Da). The permeate flux and retention values of glycyrrhizin, the total polyphenols, the caffeic acid, the total carbohydrate, and the total antioxidant activity as a function of the transmembrane pressure (TMP) and weight reduction factor (WRF) were evaluated. In selected operating conditions, the membrane productivity decreased in the order of GK > DK > GH > GE, with a similar trend to that of water permeability. Glycyrrhizin was totally rejected by selected membranes, independently of TMP and WRF. For the other antioxidant compounds, the retention values increased by increasing both of the parameters. According to the experimental results, a combination of membranes in a sequential design was proposed as a viable approach to produce concentrated fractions enriched in bioactive compounds and purified water from licorice wastewater.


Assuntos
Glycyrrhiza/química , Ácido Glicirrízico/isolamento & purificação , Membranas Artificiais , Fenóis/isolamento & purificação , Águas Residuárias/química , Ácido Glicirrízico/análise , Fenóis/análise , Ultrafiltração , Fluxo de Trabalho
8.
Molecules ; 24(19)2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31557931

RESUMO

Olive tree (Olea europaea L.) leaf, a waste by-product of the olive oil industry, is an inexpensive and abundant source of biophenols of great interest for various industrial applications in the food supplement, cosmetic, and pharmaceutical industries. In this work, the aqueous extraction of high-added value compounds from olive leaves by using microfiltered (MF), ultrapure (U), and osmosis-treated (O) water was investigated. The extraction of target compounds, including oleuropein (Olp), hydroxytyrosol (HyTyr), tyrosol (Tyr), verbascoside (Ver), lutein (Lut), and rutin (Rut), was significantly affected by the characteristics of the water used. Indeed, according to the results of liquid chromatography tandem mass spectrometry, the extracting power of microfiltered water towards rutin resulted very poor, while a moderate extraction was observed for oleuropein, verbascoside, and lutein. On the other hand, high concentrations of hydroxytyrosol were detected in the aqueous extracts produced with microfiltered water. The extraction power of ultrapure and osmosis-treated water proved to be very similar for the bio-active compounds oleuropein, verbascoside, lutein, and rutin. The results clearly provide evidence of the possibility of devising new eco-friendly strategies based on the use of green solvents which can be applied to recover bioactive compounds from olive leaves.


Assuntos
Suplementos Nutricionais/análise , Olea/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Fracionamento Químico , Cromatografia Líquida , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem
9.
Int J Mol Sci ; 19(2)2018 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-29364859

RESUMO

Pressure-driven membrane-based technologies represent a valid approach to reduce the environmental pollution of several agro-food by-products. Recently, in relation to the major interest for natural compounds with biological activities, their use has been also addressed to the recovery, separation and fractionation of phenolic compounds from such by-products. In particular, tight ultrafiltration (UF) and nanolfiltration (NF) membranes have been recognized for their capability to recover phenolic compounds from several types of agro-food by-products. The separation capability of these membranes, as well as their productivity, depends on multiple factors such as membrane material, molecular weight cut-off (MWCO) and operating conditions (e.g., pressure, temperature, feed flow rate, volume reduction factor, etc.). This paper aims at providing a critical overview of the influence of these parameters on the recovery of phenolic compounds from agro-food by-products by using tight UF and NF membranes. The literature data are analyzed and discussed in relation to separation processes, molecule properties, membrane characteristics and other phenomena occurring in the process. Current extraction methodologies of phenolic compounds from raw materials are also introduced in order to drive the implementation of integrated systems for the production of actractive phenolic formulations of potential interest as food antioxidants.


Assuntos
Membranas Artificiais , Nanotecnologia , Polifenóis , Ultrafiltração , Alimentos , Análise de Alimentos , Estrutura Molecular , Polifenóis/análise , Polifenóis/química , Ultrafiltração/métodos
10.
Plant Foods Hum Nutr ; 73(4): 336-343, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30090973

RESUMO

For the first time the chemical profile, physico-chemical parameters, inhibition of carbohydrate hydrolysing enzymes associated with type 2 diabetes, and radical scavenging properties of Sambucus nigra L. (elderberry) juice treated by nanofiltration (NF) were investigated. Three commercial NF membranes with different molecular weight cut-off (MWCO) (400 and 1000 Da) and polymeric material (composite fluoro-polymer and polyethersulphone) were tested. According to HPLC analyses, most part of bioactive compounds were retained by the NF membranes producing a retentate fraction of interest for the production of functional foods. The NP030 membrane, a polyethersulphone membrane with a MWCO of 400 Da, exhibited the highest rejection towards phenolic compounds when compared with the other selected membranes. Accordingly, the produced retentate fractions exhibited the highest radical scavenging activity.


Assuntos
Filtração/instrumentação , Manipulação de Alimentos/métodos , Sucos de Frutas e Vegetais , Membranas Artificiais , Sambucus nigra/química , Antioxidantes/farmacologia , Cromatografia Líquida de Alta Pressão , Filtração/métodos , Manipulação de Alimentos/instrumentação , Sucos de Frutas e Vegetais/análise , Inibidores de Glicosídeo Hidrolases/farmacologia , Peso Molecular , Permeabilidade , Polímeros/química , Sulfonas/química , alfa-Amilases/antagonistas & inibidores
11.
Int J Mol Sci ; 16(4): 8968-87, 2015 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-25913377

RESUMO

Commercial nanofiltration (NF) membranes in spiral-wound configuration (NP030 from Microdyn Nadir and Desal DK from GE Water & Process Technologies) were used in a sequential design in order to produce a separated fraction of phenolic and sugar compounds from an aqueous artichoke extract. For both membranes, the effect of transmembrane pressure (TMP) on the permeation flux was evaluated. In optimized conditions of TMP, the NP030 membrane exhibited high rejections of apigenin, cynarin and chlorogenic acid (higher than 85%); on the other hand, very low rejections of fructose, glucose and sucrose (lower than 4%) were measured. Starting from an extract with a total antioxidant activity (TAA) of 5.28 mM trolox a retentate fraction with a TAA of 47.75 mM trolox was obtained. The NF permeate from the NP030 membrane was processed with the Desal DK membrane in optimized conditions of TMP producing a permeate stream free of phenolic and sugar compounds. Accordingly, as most part of phenolic compounds was removed in the first NF step, the concentration of sugar compounds in the NF retentate had much higher results than that of phenolic compounds.


Assuntos
Antioxidantes/isolamento & purificação , Cynara scolymus/química , Fenóis/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Antioxidantes/química , Membranas Artificiais , Fenóis/química , Extratos Vegetais/química , Soluções , Ultrafiltração
12.
J Sci Food Agric ; 94(14): 2935-42, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24591090

RESUMO

BACKGROUND: Up to now, the management of olive mill wastewaters, a three-phase mill by-product, remains an unsolved problem, in particular for those regions where huge quantities of vegetable water are produced. Olive mill wastewaters were therefore treated to evaluate the characteristics of permeate and retentate fractions produced by an integrated membrane system working at two different volume concentration factors. RESULTS: The effect of two membrane-based filtration steps (microfiltration and nanofiltration) on the content of chemical oxygen demand, dry matter, sensory quality, phenolic compounds and antioxidant activity of permeate and retentate samples was evaluated. Furthermore, the effect of two different volume concentration factors (VCF), in the nanofiltration step, were investigated. At high VCF values, the total phenolic content in the retentate fraction was found to be 3.7-fold higher than the starting one, while the reduction of chemical oxygen demand in the permeate fraction was greater than 97% also at lower VCF values. CONCLUSION: Each filtration step has provided useful information concerning the utility and appropriateness of the processes chosen, suggesting a sustainable hypothesis of 'normal industrial practice' that can be included in current processes of oil extraction, in order to purify water and recover phenolic compounds with high added value.


Assuntos
Resíduos Industriais/análise , Membranas Artificiais , Olea/química , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Filtração/instrumentação , Filtração/métodos , Indústria Alimentícia
13.
Membranes (Basel) ; 14(2)2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38392665

RESUMO

A combination of straw filtration and nanofiltration was investigated for the first time as a sustainable approach aimed at valorizing olive mill wastewaters (OMWs) within a circular economy strategy. Ground straw filters with different granulometry (120, 250 and 500 µm) were tested in the first step to clarify the raw wastewater. The 500 µm filter offered the best performance due to a lower exposed surface of the filtering fibers and a shorter filtering time, allowing us to reduce about 70% of the chemical oxygen demand (COD) of the raw wastewater. Three different commercial membranes in a flat-sheet configuration with a molecular weight cut-off (MWCO) in the range 150-500 Da were tested to fractionate the clarified wastewater according to a dead-end configuration. Among the investigated membranes, a polymeric membrane of 500 Da (NFA-12A) exhibited the highest productivity in selected operating conditions (steady-state values of 11.4 L/m2 h at 20 bar and 24 ± 2 °C). In addition, flux decays for this membrane were lower than the other two tested membranes, indicating a lower propensity to fouling phenomena. Higher rejections towards total polyphenols and total antioxidant activity (TAA) (76.6% and 73.2%, respectively) were also observed for this membrane. Flavanols and hydroxycinnamic acids were retained by more than 99%. The combination of straw filtration and NF with the NFA-12A membrane allowed us to reduce the COD of raw OMWs up to 97.6%. The retentate fraction of this membrane exhibited a TAA of 18.9 ± 0.7 mM Trolox, supporting its propensity for the development of innovative formulations of interest in food and nutraceutical applications.

14.
Membranes (Basel) ; 13(5)2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37233557

RESUMO

Osmotic distillation (OD) was implemented at laboratory scale to concentrate a red fruit juice produced from a blend of blood orange, prickly pear, and pomegranate juice. The raw juice was clarified by microfiltration and then concentrated by using an OD plant equipped with a hollow fiber membrane contactor. The clarified juice was recirculated on the shell side of the membrane module, while calcium chloride dehydrate solutions, used as extraction brine, were recirculated on the lumen side in a counter-current mode. The influence of different process parameters, such as brine concentration (20, 40, and 60% w/w), juice flow rate (0.3, 2.0, and 3.7 L min-1), and brine flow rate (0.3, 2.0, and 3.7 L min-1) on the performance of the OD process in terms of evaporation flux and increase in juice concentration, was investigated according to the response surface methodology (RSM). From the regression analysis, the evaporation flux and juice concentration rate were expressed with quadratic equations of juice and brine flow rates, as well as the brine concentration. The desirability function approach was applied to analyse the regression model equations in order to maximize the evaporation flux and juice concentration rate. The optimal operating conditions were found to be 3.32 L min-1 brine flow rate, 3.32 L min-1 juice flow rate, and an initial brine concentration of 60% w/w. Under these conditions, the average evaporation flux and the increase in the soluble solid content of the juice resulted in 0.41 kg m-2 h-1 and 12.0 °Brix, respectively. Experimental data on evaporation flux and juice concentration, obtained in optimized operating conditions, resulted in good agreement with the predicted values of the regression model.

15.
Foods ; 13(1)2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38201048

RESUMO

The recovery of valuable compounds like phenolic compounds and sugars from grape marc extracts implies different steps, including clarification. In this study, a response surface methodology (RSM) was used as a statistical tool to study the effects of operating conditions such as transmembrane pressure (TMP), temperature and feed flow rate on the performance of a microfiltration (MF) monotubular ceramic membrane with a pore size of 0.14 µm in the clarification of grape marc extract from the Carménère variety, as well to optimize the process conditions by implementing the Box-Behnken statistical design. The desirability function approach was applied to analyze the regression model equations in order to maximize the permeate flux and concentration of malvidin-3-O-glucoside, glucose and fructose in the clarified extract. The optimal operating conditions were found to be 1 bar, 29.01 °C and 5.64 L/min. Under these conditions, the permeate flux and concentration of malvidin-3-O-glucoside, glucose and fructose resulted in 65.78 L/m2h, 43.73 mg/L, 305.89 mg/L, and 274.85 mg/L, respectively.

16.
Membranes (Basel) ; 12(7)2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35877915

RESUMO

Partial removal of sugars in fruit juices without compromising their biofunctional properties represents a significant technological challenge. The current study was aimed at evaluating the separation of sugars from phenolic compounds in apple juice by using three different spiral-wound nanofiltration (NF) membranes with a molecular weight cut-off (MWCO) in the range of 200-500 Da. A combination of diafiltration and batch concentration processes was investigated to produce apple juice with reduced sugar content and improved health properties thanks to the preservation and concentration of phenolic compounds. For all selected membranes, permeate flux and recovery rate of glucose, fructose, and phenolic compounds, in both diafiltration and concentration processes, were evaluated. The concentration factor of target compounds as a function of the volume reduction factor (VRF) as well as the amount of adsorbed compound on the membrane surface from mass balance analysis were also evaluated. Among the investigated membranes a thin-film composite membrane with an MWCO of 200-300 Da provided the best results in terms of the preservation of phenolic compounds in the selected operating conditions. More than 70% of phenolic compounds were recovered in the retentate stream while the content of sugars was reduced by about 60%.

17.
Antioxidants (Basel) ; 12(1)2022 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-36670864

RESUMO

Tacle is a citrus variety which recently gained further interest due to its antioxidant and biological properties. This study suggests using Nuclear Magnetic Resonance (NMR) imaging to characterize Tacle juice's metabolic composition as it is intimately linked to its quality. First, polar and apolar solvent systems were used to identify a significant fraction of the Tacle metabolome. Furthermore, the antioxidant capacity and the total content of flavonoids, polyphenols and ß-carotene in the juice were investigated with UV-Visible spectroscopy. Tacle juice was clarified and fractionated by ultrafiltration (UF) and nanofiltration (NF) membranes in order to recover and purify its bioactive principles. Finally, the second part of this work sheds light on the spectrophotometric assays and 1H-NMR spectra of fractions coming from membrane operations coupled with a multivariate data analysis technique, PCA, to explore the impact of UF and NF processes on the metabolic profile of the juice.

18.
Microorganisms ; 10(2)2022 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-35208763

RESUMO

The purification of phycocyanin (PC) from Spirulina generally involves a combination of different techniques. Here, we report the results on PC yields from a combined aqueous extraction-ultrafiltration (UF) process of a strain of Arthrospira maxima cultivated in a farm devoted to producing PC with food-grade purity. Samples optimized from different biomass/solvent ratios were purified by using a polyethersulphone (PES) membrane with a molecular weight cut-off (MWCO) of 20 kDa. The UF system was operated at 2.0 ± 0.1 bar and at 24 ± 2 °C up to a volume concentration factor (VCF) of 5. A diafiltration (DF) process was conducted after UF in order to increase the PC recovery in the retentate. Samples were collected during both UF and DF processes in order to evaluate membrane productivity and PC purity. The average permeate fluxes of about 14.4 L/m2h were measured in the selected operating conditions and more than 96% of PC was rejected by the UF membrane independently ofthe extraction yields and times. The concentration of PC in the final retentate was 1.17 mg/mL; this confirmed the observed rejection and the final VCF of the process (about 5-fold when compared to the concentration of PC in the crude extract). In addition, the combination of UF and diafiltration allowed the removal of about 91.7% of the DNA from the crude extract, thereby improving the purity of the phycocyanin in the retentate fraction.

19.
Crit Rev Food Sci Nutr ; 51(6): 524-46, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21929330

RESUMO

The lay press often heralds polyphenols as panacea for all sorts of diseases. The rationale is that their antioxidant activity would prevent free radical damage to macromolecules. However, basic and clinical science is showing that the reality is much more complex than this and that several issues, notably content in foodstuff, bioavailability, or in vivo antioxidant activity are yet to be resolved. We summarize the recent findings concerning the effects of polyphenols on human health, analyze the current limitations at pitfalls, and propose future directions for research.


Assuntos
Antioxidantes/farmacologia , Polifenóis/farmacologia , Animais , Antioxidantes/farmacocinética , Disponibilidade Biológica , Biomarcadores/análise , Curcumina/química , Dieta , Análise de Alimentos , Radicais Livres , Humanos , Lythraceae/química , Metabolômica/métodos , Mitocôndrias/metabolismo , Polifenóis/farmacocinética , Vinho/análise
20.
Membranes (Basel) ; 11(5)2021 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-34070146

RESUMO

In any membrane filtration, the prediction of permeate flux is critical to calculate the membrane surface required, which is an essential parameter for scaling-up, equipment sizing, and cost determination. For this reason, several models based on phenomenological or theoretical derivation (such as gel-polarization, osmotic pressure, resistance-in-series, and fouling models) and non-phenomenological models have been developed and widely used to describe the limiting phenomena as well as to predict the permeate flux. In general, the development of models or their modifications is done for a particular synthetic model solution and membrane system that shows a good capacity of prediction. However, in more complex matrices, such as fruit juices, those models might not have the same performance. In this context, the present work shows a review of different phenomenological and non-phenomenological models for permeate flux prediction in UF, and a comparison, between selected models, of the permeate flux predictive capacity. Selected models were tested with data from our previous work reported for three fruit juices (bergamot, kiwi, and pomegranate) processed in a cross-flow system for 10 h. The validation of each selected model's capacity of prediction was performed through a robust statistical examination, including a residual analysis. The results obtained, within the statistically validated models, showed that phenomenological models present a high variability of prediction (values of R-square in the range of 75.91-99.78%), Mean Absolute Percentage Error (MAPE) in the range of 3.14-51.69, and Root Mean Square Error (RMSE) in the range of 0.22-2.01 among the investigated juices. The non-phenomenological models showed a great capacity to predict permeate flux with R-squares higher than 97% and lower MAPE (0.25-2.03) and RMSE (3.74-28.91). Even though the estimated parameters have no physical meaning and do not shed light into the fundamental mechanistic principles that govern these processes, these results suggest that non-phenomenological models are a useful tool from a practical point of view to predict the permeate flux, under defined operating conditions, in membrane separation processes. However, the phenomenological models are still a proper tool for scaling-up and for an understanding the UF process.

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