1,354,124 research outputs found
Biorefinery strategy for winery waste: a multi-step process based on “green” pressurized fluids
No full textWinemaking generates a significant amount of waste. Grape marc, the main solid residue, constitutes 20-25% of the pressed grapes and approximately 8-9 million tons are produced globally each year1. The huge amounts, combined with the seasonal nature of the winemaking process, pose significant disposal, management, and environmental challenges.
In this context, the biorefinery concept for the sequential utilization of a biomass to obtain multiple products gained great interest. Generally, different chemical, physical and biological techniques are exploited and combined to maximize the biomass valorisation and economic profits. However, the integration and maintenance of multiple types of equipment make the economic feasibility of this approach challenging2.
A more feasible and effective approach could be the exploitation of a single versatile technology. A novel biorefinery strategy to sequentially extract multiple compounds using green pressurized fluids was investigated. The multi-step extraction process involved three sequential phases: a) lipids extraction using supercritical CO2 (SC-CO2); b) polyphenols extraction using a hydroalcoholic mixture at subcritical state; c) polysaccharides extraction using subcritical water (SCW). The solid residue from each step were used as the raw material for the subsequent step. All the extracts were quantified, chemically characterized, and compared with conventional ones.
The SC-CO2 achieved extraction yields comparable with conventional solvent extraction, with the advantages of ensuring a faster and free-solvent process3. The 50% ethanol-water mixture at subcritical state increased 1.5-fold the polyphenols content, and the kinetic curves pointed out a 4-fold decrease in extraction time4. Furthermore, the SCW led to a 4-fold increase of polysaccharides content compared to conventional extraction, with a remarkable 30-fold decrease in process time.
Appropriate scalability studies, based on mathematical modelling, and techno-economic evaluations are now necessary to effectively assess the potential transferability of this biorefinery strategy to an industrial scale
Ultrasound treatment of red wine: Effect on polyphenols, mathematical modeling, and scale-up considerations
No full textHigh-power ultrasound has recently been approved for the treatment of crushed grapes; it can be considered as a highly promising technology that can be adopted for several purposes in the winemaking process. The effect of ultrasound used at different amplitudes (30, 60, and 90%) and over different periods of time (2, 6, and 10 min) on the main polyphenols and other analytical indices relating to the sensory properties of red wines was studied. An increase in the amplitude and sonication time did not affect the initial polyphenol profile, and no degradative phenomena were revealed. A significant increase in the HCl index and a decrease in the astringency index and particle size were highlighted in all sonicated samples. The significant effects of ultrasounds were described well by the power law function, logistic, and Peleg's model, with good fitting results obtained (R2 > 0.94). Some scale-up considerations were reported with regard to the acoustic energy density (AED), as an intensive parameter of ultrasound treatments
Innovazioni con la tecnologia degli ultrasuoni
No full textGli ultrasuoni sono considerati come una delle tecnologie più promettenti da poter applicare per molteplici
scopi nel settore enologico (Plaza et al., 2019). Recentemente, l’Organizzazione Internazionale della Vigna
e del Vino ha ufficialmente riconosciuto e approvato il trattamento ad ultrasuoni del pigiato d’uva, per
incrementare e favorire l’estrazione dei composti presenti nelle bucce d’uva (OIV, 2019). Gli ultrasuoni
sono delle onde elettromagnetiche ad alta intensità e bassa frequenza, che possono indurre effetti fisici e
meccanici sulle strutture molecolari e biologiche, ma anche effetti chimici mediante la formazione di specie
chimiche radicaliche altamente reattive (Bhargava et al., 2021).
Nel settore enologico, gli ultrasuoni sono stati studiati per molteplici scopi, come ad esempio: estrazione
dei composti fenolici durante la fase di macerazione (Bautista-Ortin et al., 2017), estrazione dei precursori
d’aromi (Roman et al., 2020), sostituzione e/o riduzione degli additivi enologici (Clodoveo et al., 2016),
gestione dei microrganismi di interesse enologico (Jiranek et al., 2008) e valorizzazione dei sottoprodotti
(Natolino et al., 2020, Romero-Diez et al., 2019). Inoltre, gli ultrasuoni sono stati considerati come una
tecnologia molto promettente finalizzata a favorire e incrementare i processi chimici che avvengono
durante le fasi di affinamento e invecchiamento (Tao et al., 2014; Garcìa-Martin et al., 2013). Sono stati
evidenziati effetti positivi sul cambiamento del colore e delle proprietà chimico-fisiche dei polifenoli nei vini
rossi (Tiwari et al., 2010; Celotti et al., 2016; Ferraretto et al., 2016). Nonostante i numerosi studi scientifici
inerenti agli ultrasuoni, nessuna delle applicazioni appena menzionate è stata oggetto di scale-up a livello
produttivo-industriale. Dopo le opportune fasi di ricerca scientifica e di ottimizzazione in laboratorio,
generalmente è auspicabile che il processo possa essere direttamente trasferibile a livello produttivo su
scala industriale. Per far ciò è necessario assicurarsi che le condizioni di processo ottimizzate e definite in
laboratorio siano mantenute anche su scala industriale, in modo da assicurare che la qualità del prodotto
finito sia la stessa e che nel contempo la capacità produttiva sia incrementata (Peshkovsky, 2017). Un
adeguato processo di scale-up può essere ottenuto mediante l’utilizzo di diversi approcci. Uno di questi
prevede l’utilizzo di cosiddetti impianti pilota che permettono di provare le condizioni operative definite in
laboratorio e valutarne pertanto l’efficienza produttiva su scale industriale
Kinetic models for conventional and ultrasound assistant extraction of polyphenols from defatted fresh and distilled grape marc and its main components skins and seeds
No full textKinetic modeling is essential for industrial applications. The applicability of six mathematical models (parabolic diffusion, power law, Weibull's equation, Elovich's equation, second order rate, two- site kinetic models) to describe the kinetics of the conventional (CSLE) and ultrasound assistant extraction (UAE) of polyphenols (TPC) from fresh and distilled grape marc and its components, seeds and skins, after removal of non-polar compounds was studied. The best extraction yield of TPC for all the samples was obtained using UAE with ethanol-water mixture (57:43 v/v) as solvent, 200 W and 26 kHz after 30 min. The two-site kinetic model showed (R2 0.9965–1.000, NRMSD (%) 0.21–2.29) the best agreement with the experimental results. Important proanthocyanidins concentrations and significant antioxidant activity were observed both for fresh and distilled grape marc and its components. Fresh grape skins resulted particularly rich of oligomeric proanthocyanidins and the distilled ones of polymeric proanthocyanidins. These extracts could be used for different healthy purposes
Microwave pretreatment of Moringa oleifera seed: Effect on oil obtained by pilot-scale supercritical carbon dioxide extraction and Soxhlet apparatus
No full textThe effect of microwave radiation (MW) at three levels of power (100, 200 and 400 W) and for three radiation time (30, 60 and 90 s) on Moringa oleifera seeds was studied as a pretreatment process prior to oil extraction by pilot-scale supercritical carbon dioxide (SC-CO2) extraction and Soxhlet apparatus. Extraction oil yield by Soxhlet increased with MW pretreatments at 100 W for 30, 60 and 90 s with respect to untreated seeds. Therefore, these MW conditions were selected for SC-CO2 extraction of oil, carried out at 40 °C and 300 bar. Combining MW pretreatment at 100 W for 30 s with SC-CO2 extraction, the maximum oil yield of 35.28% w/w was obtained. The chemical quality of oil extracted by SC-CO2 was higher than Soxhlet oil
Policosanols from grape marc: A new step towards a sustainable biorefinery for the wine industry by SC-CO2 extraction
No full textSupercritical carbon dioxide (SC-CO2) extraction of policosanol (PC) from grape marc was investigated for the
first time. Employing the broken plus intact cells (BIC) model (Sovov ́a’s model) the investigation focused on
analyzing the SC-CO2 process to extract the nonpolar fraction from grape marc efficiently. Operating conditions
for SC-CO2 extraction—280 bar pressure, 70 ◦C temperature, and a flow rate of 10 kgCO2/h—yielded the highest
policosanol content. The extracted policosanol ranged between 3922 and 4083 mg/kgDM, constituting approximately
8 % of the total extraction yield. Surprisingly, this amount of PC was of the same order of magnitude
found in beeswax yellow, a well-known rich natural source of PC. The primary aliphatic alcohols found in the PC
from grape marc were hexacosanol, octacosanol, and triacontanol. These findings were consistent with grape
marc samples from other Italian regions. Furthermore, a comparative analysis between SC-CO2 and Soxhlet
extraction methods for PC was carried out
Ultrasound-assisted extraction of proanthocyanidins from vine-shoots of Vitis vinifera.
No full textProanthocyanidins are high added value polyphenols which have received considerable attention for their health-protective activities. An alternative vine-shoots exploitation as a cheap source of proanthocyanidins obtained by ultrasound-assisted extraction was studied. Amplitude (50–100%), liquid-to-solid ratio (L/S) (50–100 mL/ g) and extraction time (10–30 min) were the variables studied by Box–Behnken design to maximize extraction of oligomeric proanthocyanidins (OPCs) and polymeric proanthocyanidins (PPCs) extracted from vine shoots at 80°C. Under the optimal conditions found and validated the OPCs resulted 89.18 ± 0.08 mg catechin/100 g DM and the PPCs 95.46 ± 0.65 mg catechin /100 g DM. The total proanthocyanidins content found in vine shoots was 1.82 mg/g DM and resulted higher than those reported for barley, whole grain rice and stored vine shoots
Abecarnil, a beta-carboline derivative, does not exhibit anticonvulsant tolerance or withdrawal in mice.
No full textDevelopment of tolerance and dependence has been reported to occur upon chronic administration of traditional benzodiazepines (BZDs). We compared the effect of chronic treatment with abecarnil, a beta-carboline derivative with high affinity for central BDZ receptors, and diazepam, the BDZ prototype, in mice. After acute administration, abecarnil was as potent and effective as diazepam in protecting from bicuculline-induced convulsion. The time-course analysis of two peak equieffective doses of abecarnil (1.9 mg/kg p.o.) and diazepam (2.7 mg/kg p.o.) showed a similar duration of action. The anticonvulsant potency of diazepam was reduced in mice given chronic diazepam (25 mg/kg p.o., 2 times a day for 17 days). No tolerance to abecarnil was apparent when the drug was administered for the same period using a comparable dose (20 mg/kg p.o.). Severe symptoms of precipitated withdrawal were observed upon administration of the BDZ partial inverse agonist Ro 15-3505 in mice treated chronically with diazepam but not abecarnil. In mice made tolerant to diazepam, maximum [3H]-flumazenil binding sites were reduced in both cerebral cortex (-50%) and cerebellum (-55.2%). No changes in [3H]-flumazenil binding were measured in chronic abecarnil-treated mice. These data indicate that abecarnil possesses a very low tolerance/dependence liability and does not affect BZD receptor density after chronic administration
Broken and Intact Cell Model for supercritical carbon dioxide extraction of tea Camellia sinensis (L) seed oil
No full textThe model of broken and intact cells was used to fit the experimental data, and it was proved to be able to describe the extraction process of tea seed oil. The extraction rate, observed through the overall extraction curves (OEC), resulted in being faster the higher the pressure whereas the temperature had less influence on the extraction kinetics. The volume mass transfer coefficients in the fluid phase (kfa0) and solid phase (ksas) were used as fitting parameters. The maximum average deviation between measured and calculated oil yield was 4.1%. Mass transfer coefficients in the fluid phase and solid phase varied between 2.40·10−2–2.75·10−2 s−1 and 4.32·10−5–6.90·10−5 s−1, respectively. The outcomes of work showed the highest extraction yield (50.03 ± 0.68% w/w) obtained at 300 bar and 40 °C. Tea seed oil extracted using SC-CO2 presented higher antioxidant capacity and lower UV indices than oil extracted with n-hexane
Application of Supercritical Fluids Technology on winery by-products
No full textWinemaking process produces a large amount of solid wastes, including grape marc and wine lees. In 2014, the Italian production of grapes was estimated to be 6 million tons, which corresponds to about 1.5 million tons of grape marc. The new European regulations about the organization of winery sector and waste management (EC 479/2008 and EC 555/2008) have revoked the compulsory distillation of the by–products of winemaking, creating a great problem on winery waste handling and disposal. Grape marc has a heavy environmental impact for the high content of phenols that considerably increase chemical and biochemical oxygen demands. This biomass could be disposed and valorised first by extraction of added-value bioactive compounds and then by production of biopolymers and bio-fuels. One of the higher value options is the recovery of polyphenols, which could be used in pharmaceutical, cosmetic and food industry.
In this regard, this PhD thesis aimed to study the application of Supercritical Fluid Extraction (SFE) and Supercritical Anti-Solvent (SAS) process to recover bioactive compounds of high-added value from grape marc, in particular polyphenols, which show beneficial effects on human health against several diseases.
SFE with supercritical carbon dioxide (SC-CO2) has been widely used for the extraction from natural products. It is an environment-friendly technology, which represents an alternative to conventional extraction techniques and offers several advantages over classical solvent extraction methods. For the extraction of polar compounds, such as polyphenols, a co-solvent/modifier is necessary to add to SC-CO2.
Three different “green” SC-CO2 co-solvents were investigated: ethanol, water and an ethanol aqueous mixture with 57%(v/v) ethanol concentration. The effect of pressure, temperature, CO2 flow rate and percentage of co-solvent, which are the main process parameter of a SFE process, were studied for each co-solvent used. The results indicated that SFE process carried out using the ethanol aqueous mixture (57% v/v) as co-solvent at 8 MPa, 40°C, 6.0 kg/h of CO2 flow rate added with 10% of co-solvent, showed the best results for Total Polyphenol Content (TPC), Antioxidant activity and Proanthocyanidins.
A combination of ultrasound assisted extraction (UAE) and supercritical carbon dioxide (SC-CO2) extraction to maximize polyphenols recovery from grape marc was studied.
It is well known that ultrasounds waves can improve the extraction processes with their cavitational effect. The effect of temperature and time of UAE on polyphenols compounds was investigated by 22 full factorial design. The highest concentration of polyphenols was obtained at 80°C and 4 minutes of ultrasound extraction. The obtained UAE-Raffinates were extracted by supercritical carbon dioxide. The overall extraction curves (OECs) of the UAE-Raffinates extracted by SC-CO2 were described and evaluated. The performance of the combined process has been checked by comparison of total polyphenol content, proanthocyanidin fractions and antioxidant activity with both UAE and SC-CO2 extraction.
Supercritical Fluids can be used not only for extraction methods, but also for other purposes. The peculiar properties of supercritical fluids can be exploited in micronization processes. The precipitation of pharmaceutical and natural products has attracted great attention in recent years. The conventional techniques, including spry-drying, freeze-drying, liquid antisolvent crystallization or milling processes, show several disadvantages: (1) production of coarse particles, (2) mechanical or thermal degradation of the products, and (3) final products with low purity.
For these reasons, a micronization process with supercritical carbon dioxide (SC-CO2), namely supercritical anti-solvent (SAS) process, was applied to recover polyphenol compounds from grape marc extract. A 23 factorial design was applied to study the effect of the main SAS process parameters (pressure, temperature and CO2 molar fraction) on recovered particles, total polyphenol compound (TPC) and antioxidant activity. The precipitates with high quality was obtained at 12 MPa, 45°C and 0.99 of CO2 mole fraction. Fractionation of proanthocyanidins, as well as HPLC-DAD analysis of polyphenols and scanning electronic microscopy (SEM) analysis were performed on the best products obtained by SAS.
Economic considerations, based on the literature data, and future perspectives regarding the application of supercritical fluids processes were discussedIl processo di vinificazione genera una grande quantità di residui solidi, costituiti principalmente da vinacce e fecce. Nel 2014 la produzione italiana di uva ammontava a 6 milioni di tonnellate, che corrispondono a una produzione di circa 1.5 milioni di tonnellate di vinaccia. La nuova regolamentazione della Comunità Europea riguardante il settore vitivinicolo e la gestione dei rifiuti (CE 479/2008 e CE 555/2008) ha introdotto una progressiva diminuzione, fino alla totale scomparsa, della distillazione obbligatoria dei sottoprodotti dell’industria enologica. Tutto ciò ha comportato enormi problemi e disagi nella gestione e nell’utilizzo di questi sottoprodotti. La vinaccia ha un enorme impatto dal punto di vista ambientale e a causa del suo alto contenuto in sostanze polifenoliche determina un aumento dei valori di COD e BOD dell’ambiente. Questo sottoprodotto può essere sfruttato e valorizzato mediante l’estrazione di composti bioattivi ad alto valore aggiunto e successivamente per la produzione di biopolimeri, energia e/o biocarburanti. Una delle opzioni di maggior interesse è il recupero di polifenoli, che possono essere utilizzati in campo farmaceutico, cosmetico e alimentare.
In questo contesto, questa tesi di dottorato ha come obiettivo lo studio dell’estrazione con fluidi supercritici (SFE) e il recupero mediante la tecnologia SAS (Supercritical Anti-Solvent) di composti bioattivi ad alto valore aggiunto da vinacce d’uva, in particolare le sostanze polifenoliche che possiedono effetti benefici sulla salute umana.
L’estrazione SFE, con il diossido di carbonio allo stato supercritico (SC-CO2), è ampiamente utilizzata per l’estrazione di matrici naturali. È una tecnologia eco-compatibile ed eco-sostenibile, che rappresenta un’alternativa alle tecniche di estrazione convenzionali e offre diversi vantaggi rispetto all’estrazione classica con solventi. Per l’estrazione di composti polari, come sono i polifenoli, è necessaria l’aggiunta di un co-solvente al diossido di carbonio allo stato supercritico.
Tre diversi tipi di co-solvente sono stati studiati: etanolo, acqua e una miscela etanolo/acqua, con una concentrazione in etanolo del 57% (v/v). Per ciascun co-solvente utilizzato, sono stati valutati gli effetti dei principali parametri operativi dell’estrazione con fluidi supercritici: pressione, temperatura, flusso di CO2 e percentuale di co-solvente utilizzato. I risultati ottenuti indicano che l’estrazione con CO2 supercritico addizionato con la miscela etanolo/acqua (57% v/v) come co-solvente a 8 MPa, 40°C, 6.0 kg/h di flusso di CO2 e 10% di co-solvente, ha permesso di ottenere i risultati migliori per quanto riguarda il contenuto di polifenoli totali, l’attività antiossidante e il contenuto di proantocianidine.
L’accoppiamento dell’estrazione assistita con ultrasuoni (UAE) e dell’estrazione con CO2 supercritico è stato studiato, con l’obiettivo di massimizzare il recupero di polifenoli da vinacce d’uva.
È noto che gli ultrasuoni permettono di migliorare i processi estrattivi grazie al fenomeno della cavitazione. Un disegno sperimentale fattoriale completo (22) è stato applicato per lo studio dell’effetto della temperatura e del tempo del processo UAE. La più alta concentrazione di polifenoli è stata ottenuta nell’estrazione con ultrasuoni condotta a 80°C per 4 minuti. Successivamente, i residui solidi ottenuti dalle prove di estrazione con ultrasuoni sono stati estratti ulteriormente con l’SFE. Le cinetiche di estrazione (OECs) delle prove con CO2 supercritico sono state considerate e studiate. La combinazione dei due processi estrattivi è stata valutata considerando il contenuto totale di polifenoli, l’attività antiossidante e il contenuto di proantocianidine degli estratti ottenuti con UAE e SFE.
I fluidi supercritici posso essere utilizzati non solamente nei processi estrattivi, ma anche per altri scopi ed applicazioni. Le proprietà caratteristiche dei fluidi supercritici possono essere sfruttate nei processi di micronizzazione. Negli ultimi anni i processi di precipitazione dei composti farmaceutici e naturali hanno ricevuto un enorme interesse. I processi convenzionali, come lo spry-drying, freeze-drying e i processi di macinazione, presentano diversi svantaggi: (1) produzione di particelle grossolane, (2) degradazione termica e meccanica del prodotto finito, (3) prodotto finito impuro, contenente tracce di solventi e interferenti tossici. Per queste ragioni, è stato applicato un processo di micronizzazione con fluidi supercritici, definito come SAS (Supercritical Anti-Solvent), per il recupero di polifenoli da estratti di vinaccia. Un disegno sperimentale fattoriale completo (23) è stato applicato per lo studio dell’effetto dei principali parametri di processo (pressione, temperatura e frazione molare del CO2) sulla quantità di particelle recuperate, il contenuto di polifenoli totali e l’attività antiossidante. I campioni con i migliori risultati sono stati ottenuti a 12 MPa, 45°C e 0.99 di frazione molare del CO2. I campioni migliori ottenuti nelle prove sperimentali sono stati inoltre caratterizzati mediante il frazionamento delle proantocianidine, l’analisi HPLC-DAD dei polifenoli e l’analisi al microscopio a scansione elettronica (SEM).
Sulla base dei dati di letteratura sono state effettuate considerazioni economiche, e discusse le prospettive future delle possibili applicazioni dei fluidi supercritici nei processi industrial
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