Enzyme and high pressure assisted extraction of carotenoids from tomato waste

Enzyme (EA) and high pressure (HP) assisted extraction of carotenoids, especially lycopene, from tomato waste using various organic solvents was examined. Total carotenoid and lycopene extraction yields were increased by the use of pectinase and cellulase enzymes, when compared to the non enzyme treated solvent extraction process. The increase of extraction yield depended on the solvent. Maximum total carotenoid (127 mg/kg d.w.) and lycopene (89.4 mg/kg d.w.) extraction yields were obtained in enzyme treated samples extracted with ethyl lactate (solvent:solid = 10:1 mL:g), corresponding to almost 6-fold and 10-fold increase, respectively, with respect to non enzyme treated samples. HP assisted extraction led to higher extraction yields (from 2 to 64% increase depending on the solvent used) compared to conventional solvent extraction process performed at ambient pressure for 30 min. HP assisted solvent extraction was successfully performed at 700 MPa by using significantly (P < 0.05) lower ratios of solvent:solid (6:1 and 4:1 mL:g) and reduced processing time (10 min), compared to solvent extraction performed at ambient pressure, solvent:solid ratio 10:1 mL:g and 30 min extraction time.     

Statistical optimization of hydrolysis process for banana peels using cellulolytic and pectinolytic enzymes

Dried and ground banana peels (BP) were pretreated and hydrolyzed using a combination of cellulolytic and pectinolytic enzymes. Central composite design (CCD) was used to optimize cellulase, β-glucosidase and pectinase concentrations and hydrolysis time for production of glucose and reducing sugars. Design expert software was used to analyze and evaluate the data. The interactions between filter paper cellulase and β-glucosidase concentrations were statistically significant at a 95% confidence level in production of glucose and reducing sugars from BP. The validation experiment was carried out with cellulase, β-glucosidase and pectinase at 8 FPU/g cellulose, 15 IU/g cellulose and 66 IU/g pectin, respectively, for 15 h in a laboratory fermenter. The glucose and reducing sugars concentrations of 28.2 and 48 g/l, respectively, obtained through the validation experiment were higher than the theoretical values for glucose and reducing sugars predicted by the software. Glucose, galactose, arabinose, xylose and galacturonic acid concentrations increased with time, but a significant increase in fructose concentration was not observed. Process optimization also led to about 40% savings in hydrolysis time, indicating scale-up potential for the process.     

Pressurized liquid extraction and low-pressure solvent extraction of carotenoids from pressed palm fiber: Experimental and economical evaluation

In this work, a comparison of Soxhlet extraction (LPSE–SOX), percolation (LPSE–PE) and pressurized liquid extraction (PLE) for the recovery of carotenoid-rich extracts from pressed palm fiber (PPF) was carried out in terms of yield, carotenoid profile and economic viability to evaluate the methods’ industrial applicability. An optimization study was performed for each extraction technique with ethanol at a solvent/feed ratio of 20. The independent variables were temperature (35–55 °C), pressure (0.1–8 MPa) and flow rate (1.6, 2.4 g/min). The results showed that the global extraction yield obtained using LPSE–SOX (96 ± 4 mg extract/g PPF d.b.) after 6 h was higher than that obtained using LPSE–PE (74 ± 5 mg extract/g PPF d.b., 35 °C, 2.4 g/min) or PLE (44 ± 3 mg extract/g PPF d.b., 55 °C, 4 MPa, 2.4 g/min) after dynamic extraction time of 17 min under optimized conditions. On the other hand, the carotenoid yield obtained using PLE (305 ± 18 μg α-carotene/g extract and 713 ± 46 μg β-carotene/g extract) was higher than the obtained by LPSE–SOX (142 ± 13 μg α-carotene/g extract and 317 ± 46 μg β-carotene/g extract). PLE technique showed the highest selectivity for carotenoids than LPSE techniques. The lowest cost of manufacturing (COM) were obtained for LPSE–PE and PLE with values of US$13.4 and US$29.2/kg extract for a 0.5 m³ vessel capacity.     

Deterpenation of mandarin (Citrus reticulata) peel oils by means of countercurrent multistage extraction and adsorption/desorption with supercritical CO2

The mandarin (Citrus reticulata) peel oil consists of more than 98 wt.% terpenes and a small fraction of oxygenated components responsible for its distinct smell. The terpene fraction is composed mostly of limonene and the oxygenated aroma fractions are composed mainly of linalool and decanal. The removal of terpenes must be performed in order to increase the storage time of citrus oils. In this work, the deterpenation of two different cold-pressed mandarin peel oils employing countercurrent extraction and ad-/desorption with supercritical CO₂ and a combination of these processes were investigated. Countercurrent experiments were carried out at pressures ranging from 8.5 to 10.0 MPa and at 50 and 60 °C. At 10.0 MPa and 60 °C, a maximum selectivity of 12.8 between terpenes and aromas could be obtained at a folding ratio of 5.0, showing that the fractionation by means of countercurrent gas extraction could be employed. To investigate the complete removal of terpenes, ad-/desorption experiments were also performed and both the raffinate samples obtained through the countercurrent fractionation and the crude cold-pressed peel oils were used as feed material. The components evaluated were desorbed from silica-gel and the best fractionation results were obtained at 40 °C, 25 wt.% oil loading in two sequential pressure steps. Initially, terpenes were completely desorbed at 8.0 MPa. The second desorption step was carried out at 20.0 MPa and a selective fractionation of important aroma components was observed. Additionally, scale-up experiments were performed.     

Extraction of caffeine from natural matter using a bio-renewable agrochemical solvent

This paper reports experimental data on the pressurized liquid extraction of caffeine from green coffee beans and green tea leaves using ethyl lactate (ethyl 2-hydroxy-propanoate). This solvent is a new bio-renewable agrochemical solvent, naturally produced by fermentation from corn derived feedstock, which has been recently considered as a very suitable and environmental benign solvent for food industrial applications.Static extraction assays (one step during 10 min) were carried out in an Accelerated solvent extraction (ASE) system at three different extraction temperatures, namely 100, 150 and 200 °C. Extraction yield and caffeine recovery were determined and compared with those obtained when using other liquid solvents, such as ethyl acetate or ethanol. High recovery of caffeine (≈60%) was found in the extracts produced using ethyl lactate, which demonstrates the potential use of this green solvent for the extraction of caffeine from different vegetable sources.     

Use of micellar extraction and cloud point preconcentration for valorization of saponins from sisal (Agave sisalana) waste

Sisal (Agave sisalana) is the main hard fiber produced worldwide, with an estimated generation of 400 thousands t in 2011. From its leaves, only the hard fibers, which represent 3–5% of their weight, are removed. The remaining 95–97% is referred to as sisal waste and contains steroidal saponins that can be potentially used in foods, cosmetics and pharmaceuticals formulations, as well as for soil bioremediation. The present work aimed at to evaluate strategies for the extraction and concentration of saponins from sisal waste, focused on the use of clean solvents, such as water and ethanol. For this purpose, it was firstly performed a central composite rotatable design for the optimization of the extraction conditions followed by a comparison of this strategy with other methods (Soxhlet, ultrasound-assisted extraction and micellar extraction). Cloud point preconcentration was then tested, using several types and concentrations of salts. The use of orbital shaker extraction (200 rpm) with an ethanolic solution (30%, v/v) at 50 °C, a mass/volume ratio sisal/solvent of 0.17 (g/mL) for 4 h allowed a recovery of 38.6% of the saponins. When a micellar extraction strategy using 7.5% (v/v) of Triton X-100, under the above-mentioned conditions was performed, saponins recovery raised to 98.4%. In a subsequent step, the addition of 20% (m/v) sodium carbonate led to a preconcentration factor of 20.3. The best adsorbent for Triton removal from the preconcentrated solution was Amberlite FPX-66. The process strategy proposed in the present study showed to be efficient for saponins extraction and preconcentration from a low-cost, highly available agricultural waste.     

Extraction of phenolic compounds from pitanga (Eugenia uniflora L.) leaves by sequential extraction in fixed bed extractor using supercritical CO2, ethanol and water as solvents

With the goal of maximizing the extraction yield of phenolic compounds from pitanga leaves (Eugenia uniflora L.), a sequential extraction in fixed bed was carried out in three steps at 60 °C and 400 bar, using supercritical CO₂ (non-polar) as solvent in a first step, followed by ethanol (polarity: 5.2) and water (polarity: 9.0) in a second and third steps, respectively. All extracts were evaluated for global extraction yield, concentration and yield of both polyphenols and total flavonoids and antioxidant activity by DPPH method (in terms of EC₅₀). The nature of the solvent significantly influenced the process, since the extraction yield increased with solvent polarity. The aqueous extracts presented higher global extraction yield (22%), followed by ethanolic (16%) and supercritical extracts (5%). The study pointed out that the sequential extraction process is the most effective in terms of global extraction yield and yield of polyphenols and total flavonoids, because it produced the more concentrated extracts on phenolic compounds, since the supercritical ethanolic extract presented the highest phenolics content (240.5 mg GAE/g extract) and antioxidant capacity (EC₅₀ = 9.15 μg/mL). The most volatile fraction from the supercritical extract, which is similar to the essential oils obtained by steam distillation or hydrodistillation, presented as major compounds the germacrenos D and B + bicyclogermacrene (40.75%), selina-1,3,7(11)-trien-8-one + selina-1,3,7(11)-trien-8-one epoxide (27.7%) and trans-caryophyllene (14.18%).     

Supercritical CO2 extraction of omega-3 rich oil from Sacha inchi (Plukenetia volubilis L.) seeds

Supercritical carbon dioxide (SC-CO₂) was employed to extract omega-3 rich oil from Sacha inchi (Plukenetia volubilis L.) seeds and partially defatted cake. For ground seeds, the supercritical extraction was carried out at temperatures of 40, 50 and 60 °C and pressures of 300 and 400 bar, and for the cold pressed partially defatted cake, the extraction was carried out with 300 bar at 40 °C and with 400 bar at 60 °C. The global extraction yields (X₀), oil solubility, fatty acid composition of the oil and tocopherol content were determined. The seed samples used in this work contained 54.3% oil, of which 50.5% was linoleinc acid (ω-3). The maximum extraction recovery for the seeds as 92% at 400 bar and 60 °C, but on one occasion a recovery of 99.1% oil was obtained when cold pressed extraction was employed, followed by supercritical extraction at 400 bar and 60 °C. A high tocopherol content of about 2–3 g/kg of oil was obtained.     

Optimization of essential oil supercritical extraction from Algerian Myrtus communis L. leaves using response surface methodology

The present work deals with the application of the supercritical fluid extraction process to extract essential oils from the leaves of an Algerian myrtle plant (Myrtus communis L.). Using the surface response methodology, an optimization of the extraction recovery was carried out, varying the pressure in the range of [10–30 MPa], the temperature within [308–323 K], a solvent flow rate fixed at 0.42 kg h⁻¹ and a mean particle diameter equal to 0.5 mm or less than 0.315 mm. The maximum value of essential oil recovery relative to the initial mass of leaf powder was 4.89 wt%, and was obtained when the SC–CO₂ extraction was carried out under 313 K, 30 MPa and with a particle diameter less than 0.315 mm. A second-order polynomial expression was used to express the oil recovery. The calculated mass of recovered oil using the response surface methodology was very close to the experimental value, confirming the reliability of this technique.     

Flame atomic absorption spectrometric determination of Cd,Pb, and Cu in food samples after pre-concentration using 4-(2-thiazolylazo) resorcinol-modified activated carbon

This work aimed to develop a solid-phase extraction method using low-cost activated carbon produced from waste and modified with 4-(2-thiazolylazo) resorcinol for Cd(II), Pb(II), and Cu(II). The results showed that quantitative recovery of analytes was obtained at pH 6 with 3 M nitric acid as the eluent and a sample volume up to 1000 mL. The method was validated using certified reference material and addition-recovery tests. The limits of detection (LODs) for Pb(II), Cd(II), and Cu(II) were 2.03 μg L⁻¹, 0.15 μg L⁻¹, and 0.19 μg L⁻¹, respectively. The procedure was applied for determination of analytes in food samples.     

Characterization of pellets from industrial tomato residues

Large volumes of residual biomass (mainly peels and seeds) are generated by tomato industrial processing plants. After adequate drying and densification operations, those biomass wastes might be used for livestock food production, for lycopene extraction or even as fuel supply for thermal applications.The process described in the present paper is the manufacturing of 6 mm diameter pellets from tomato waste samples obtained from industrial processing plants. As a previous step, the samples were dehydrated to five different values of moisture content (20, 25, 29, 34 and 38 wt% w.b. approximately). Bulk and particle densities, hardness and durability of pellets were significantly influenced by the initial moisture content of the biomass raw materials, as well as by the subsequent reductions of such moisture content after pelletizing operations and storage periods. Increases of 21%, 41% and 67% in moisture content of the feeding biomass material – with respect to the lower value of the operating range, i.e. 20 wt% w.b. – were observed to yield the following percentage increments in a series of physical properties of pellets, respectively: 14%, 25% and 50% in bulk density; 6%, 16% and 18% in particle density; 225%, 1737% and 3575% in hardness; 8%, 44% and 88% in durability. Nevertheless, higher increments in moisture content of feeding material led to significantly lower values of the aforementioned properties – not to mention technical operating problems due to roller skidding in the pelletizing device.Pellets obtained from raw biomass (peels and seeds) with 34 wt% initial moisture content (9% final moisture content of pellets) were regarded as those with the most suitable configuration: durability 91.2%, hardness up to 88 N and energy density approaching 8 GJ/m³.     

Antioxidant protection of high-pressure processed minced chicken meat by industrial tomato products

Pressure-treatment at 300 MPa of minced chicken breast meat did not induce significant lipid oxidation during chill storage for up to 15 days, while pressure-treatment at 600 and 800 MPa enhanced formation of secondary lipid oxidation products measured as thiobarbituric acid reactive substances. However, a waste product from industrial tomato paste production was found to yield efficient protection against lipid oxidation in pressurized chicken meat. Addition of 0.30% tomato waste or of 0.10% final tomato paste to minced meat led to a lag phase of 6 days for formation of secondary oxidation products in meat pressure treated at 600 MPa. The waste product seemed special efficient in protecting chicken meat pressurized at 800 MPa, as a notably lower rate of formation of secondary oxidation products was found. Flavonoids washed out with the waste fraction may be more efficient as antioxidant than the other phenolics or carotenoids present in the other paste processing fractions. Addition of tomato paste fractions did not influence radical formation measured by electron spin resonance spectroscopy and the tomato waste is considered to be effective as antioxidant at subsequent reactions leading to secondary lipid oxidation products.     

Extraction of Epigallocatechin-3-gallate from green tea via supercritical fluid technology: Neural network modeling and response surface optimization

In this study the extraction of (−)-Epigallocatechin-3-gallate (EGCG) from Iranian green tea was investigated by supercritical CO₂ with ethanol as co-solvent. Design of experiments and modeling were carried out with response surface methodology by Minitab software. The HPLC analysis of the extracted samples was used in conjunction with response surface design to optimize four operating variables of supercritical CO₂ extraction (pressure, temperature, CO₂ flow rate and extraction dynamic time). Optimum recovery of EGCG (0.462 g/g) was obtained at 19.3 MPa, 43.7 °C, 106 min (dynamic) and 1.5 ml/min (CO₂ flow rate). Moreover, a three-layer artificial neural network was developed for modeling EGCG extraction from green tea. In this regard, different networks (by changing the number of neurons in the hidden layer and algorithm of network training) were compared with evaluation of networks accuracy in extraction recovery prediction. Finally, the Levenberg–Marquardt algorithm with the six neurons in the hidden layer has been found to be the most suitable network.     

Production of a lycopene-enriched fraction from tomato pomace using supercritical carbon dioxide

In recent years there has been a growing interest in functional foods because they may provide beneficial effects on human health. Moreover, the increasing interest of consumers in functional foods has brought about a rise in demand for ingredients obtained using technologies perceived to be natural and safe. In this study, supercritical fluid technology was used in order to obtain lycopene from an extract of dried tomato pomace using sunflower oil and ethanol. After the supercritical fluid fractionation, four fractions were collected, three separated fraction (SF) from the separator (after 30, 60 and 120 min of fractionation) and one residual fraction (RF) from the bottom of column (after 120 min). The concentration of lycopene was studied in the different fractions obtained under different pressures (10 and 30 MPa), CO₂ flow rates (5 and 15 kg h⁻¹), and heights of loading (top and bottom). The quantitative determination of lycopene was performed by HPLC coupled with a diode array detector. The effects of the different extraction parameters, as well as their interactions, were investigated using a full factorial design with three factors and two levels; the optimal conditions were calculated through response surface methodology. A statistically significant difference in lycopene content in the four fractions was obtained.     

Supercritical fluid extraction of Prunus persica leaves and utilization possibilities as a source of phenolic compounds

Mediterranean countries contribute highly on world peach production and tonnes of waste leaves are released due to pruning. The aim of this study was to investigate the utilization possibilities of the leaves by supercritical fluid extraction. A statistical design was used to evaluate the effect of temperature (40–80 °C), pressure (150–300 bar) and concentration of ethanol as co-solvent (6–20%) at a flow rate of 15 g/min and for a duration of 60 min. The most effective variables were found as pressure and co-solvent ratio (p < 0.005). Optimum extraction conditions were elicited as 60 °C, 150 bar and 6% co-solvent yielding a total phenol content of 79.92 mg GAE/g extract, EC₅₀ value of 232.20 μg/ml and a radical scavenging activity of 53.25% which was higher than the value obtained by conventional solvent extraction method (32.23%). Consequently, Prunus persica L. leaves were found as a potential phenolic source for industrial applications.     

Optimization of the supercritical fluid extraction of triterpenic acids from Eucalyptus globulus bark using experimental design

The supercritical CO₂ extraction of E. globulus deciduous bark was carried out at different temperatures (40–60 °C), pressures (100–200 bar), and ethanol contents (0.0–5.0 wt. %) to study triterpenic acids (TTAs) recovery. A factorial design of experiments and response surface methodology were implemented to analyze the influence of these variables upon extraction and perform its optimization. The best conditions were 200 bar, 40 °C and 5% ethanol, for which the statistically validated regression models provided: extraction yield of 1.2% (wt.), TTAs concentration of 50%, which corresponds to TTAs yield of 5.1 g/kg of bark and a recovery of 79.2% in comparison to the Soxhlet value. The trends of the free and acetylated TTAs were very different, due to their distinct CO₂-philic character caused by dissimilar polarities: the acetyl derivatives approached a plateau near 200 bar and 5% ethanol, while the free TTAs extraction always increased in the range of conditions studied.     

Extraction of mangiferin from Mahkota Dewa (Phaleria macrocarpa) using subcritical water

A pharmacological active component, mangiferin, was extracted from Mahkota Dewa using subcritical water extraction. The subcritical water extractions were carried out at temperatures ranging 323–423 K, pressures ranging 0.7–4.0 MPa, and extraction times ranging 1–7 h. Extraction yield of mangiferin was measured using high-performance liquid chromatography (HPLC). The extraction yield was strongly dependent on the temperature while weakly dependent on the extraction pressure. As the extraction temperature increased, the extraction mangiferin yield increased, possibly resulting from the decrease in polarity of subcritical water at higher temperature. At an optimal extraction condition of 373 K, 4.0 MPa and extraction time of 5 h, the extraction yield of mangiferin was 21.7 mg/g. This value was close to the extraction yield with methanol (25.0 mg/g) and higher than those with water (18.6 mg/g) or ethanol (13.2 mg/g) at their boiling points.     

Imprinted polymer-based extraction for speciation analysis of inorganic tin in food and water samples

In this study, an ion imprinted polymer (IIP), tin (IV)–4-(2-pyridylazo) resorcinol (PAR) complex (Sn(IV)–PAR–IIP) has been synthesized for speciation and selective solid-phase extraction (SPE) of tin species from food and water samples. For this purpose, copolymerization of Sn(IV)–4-(2-pyridylazo) resorcinol (PAR) complex was performed using methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), and 2,2′-Azobisisobutyronitrile (AIBN) as functional monomer, cross-linking agent, and initiator, respectively. The polymer particles were characterized by FT-IR, and thermogravimetric (TG) analyses. The effects of different variables such as solution pH, mass of the polymer, extraction and elution time, and type and volume of the eluent for elution of tin were evaluated by Box–Behnken design and response surface methodology. The significance of independent variables and their interactions were tested by the analysis of variance (ANOVA) with 95% confidence limits. The optimal conditions at extraction step were 8, 70 mg, and 25 min for solution pH, amount of polymer, and extraction time, respectively. Also, the optimal values for the elution step were 6.5 mL of HCl (4 M) as the eluent volume and type and elution time of 120 min. The detection limit of the proposed method was found to be 1.3 μg L^?1 and a linear dynamic range (LDR) in the range of 5–200 μg L^?1 was obtained. The influence of various cationic interferences on recovery percentage of Sn(IV) was studied. The method was applied to recovery and determination of tin species in different real samples.     

Fractionated extraction of saponins from Brazilian ginseng by sequential process using supercritical CO2, ethanol and water

Saponins are surfactants that reduce the surface tension of aqueous solutions, besides having pharmacological actions. In order to extract and fractionate saponins from Pfaffia glomerata roots and Hebanthe eriantha roots using supercritical technology, fractionated extracts were obtained from a sequential process in fixed bed using supercritical CO₂ (scCO₂), ethanol, and water as solvents. All extractions were carried out in four sequential steps, at 50 °C and 300 bar. In the first step, pure scCO₂ was used as solvent, while (a) scCO₂/etanol (70:30, w/w); (b) ethanol, and (c) ethanol/water (70:30, v/v) were used as solvents in the three subsequent steps. The extracts were analyzed by thin layer chromatography (TLC) and surface tension. The extraction yields of the four steps were 0.16, 0.55, 1.00, and 6.90% for P. glomerata roots, and 0.17, 0.58, 0.89, and 28% for H. eriantha roots, showing a predominance of high polarity compounds in these species. TLC analysis showed that the extraction process was selective according to the polarity of the solvent, and provided extracts containing different saponins, except for scCO₂ extraction. The extracts from the extraction using ethanol + scCO₂ (Step 2) showed the greatest ability to reduce the surface tension of water from 72 mN m⁻¹ (pure water) to 25 mN m⁻¹, suggesting that this step was the best for extraction of less polar saponins in the extracts. The critical micelle concentration (CMC) values were approximately 2 and 8 g L⁻¹ for P. glomerata and H. Eriantha, respectively. These results confirmed the efficacy of the extraction process under study.     

Optimization of microwave-assisted enzymatic extraction of polyphenols from waste peanut shells and evaluation of its antioxidant and antibacterial activities in vitro

A microwave-assisted enzymatic extraction (MAEE) method was developed and optimized to enhance the polyphenols extraction yield from waste peanut shells. The optimum conditions were as follows: irradiation time 2.6 min, amount of cellulase 0.81 wt.%, a pH of 5.5, and incubation at 66 °C for 2.0 h. Under these conditions, the extraction yield of total polyphenols could reach 1.75 ± 0.06%, which was higher than other extraction methods including heat-refluxing extraction, ultrasonic-assisted extraction and enzyme-assisted extraction. The structural changes of the plant material after different extractions observed by scanning electron microscopy provided visual evidence of the disruption effect. Moreover, the crude extract was then purified by NKA-9 resin, the polyphenols content in the purified extract increased to 62.73%. The antioxidant activities of the crude and purified polyphenols extract were evaluated by DPPH and hydroxyl radicals, reducing power and β-carotene bleaching test. The antibacterial activities of purified extract were also tested using Oxford cup method. The results indicated that the MAEE method was efficient and environment-friendly, and the polyphenols have significant antioxidant and antibacterial activities, which can be used as a source of potential antioxidant and preservative.