Recovery Of Phenolic Compounds Research Articles

Recovery of ascorbic acid, phenolic compounds and carotenoids from acerola by-products: An opportunity for their valorization

Ascorbic acid, phenolic compounds and carotenoids were extracted from acerola (Malpighia emarginata DC.) by-products using gas-expanded liquids (GXLs) based on carbon dioxide expanded ethanol at 40 °C and 7 MPa. The by-products generated in the processing of acerola: bagasse (seed and peel) and non-pomace (from the juice clarification step), were studied separately. The overall extraction yields obtained were 3.8 and 12.9 g/100 g for bagasse and non-pomace, respectively. Ascorbic acid was not detected in the bagasse extract, while 158.2 mg/gextract was found in non-pomace extract, and 193.7 mg/g was found in the acerola juice powder. The higher the concentration of ascorbic acid, the higher the antioxidant activity of the extracts. The phytochemical profile obtained by LC-Q-TOF-MS/MS showed a higher number of phenolic compounds (hydroxycinnamic acids and flavonoids) in the bagasse and non-pomace extracts when compared to acerola juice. In addition, GXL promoted the extraction of a pool of carotenoids (lutein and β-carotene), pheophytin and chlorophyll derivatives detected by LC-APCI-MS/MS. The obtained extracts, rich in bioactive compounds, open an opportunity for the valorization of acerola by-products, meeting the current demand for natural nutraceuticals rich in vitamin C and polyphenols.

Comparison of Ultrasound Assisted Extraction and Conventional Extraction Technique on Recovery of Phenolic and Flavonoid Compounds from Aloe barbadensis Miller

Aloe barbadensis Miller (Aloe vera) is useful for skin care and its bioactive compounds could replace the insecure chemical compounds that used in cosmeceutical application. This study was designed to evaluate the effect of solvents and ultrasound assisted extraction (UAE) parameters such as duty cycle and sonication time on the concentration of phenolic and flavonoid compounds from Aloe vera. The extraction efficiencies of the best condition of UAE were compared with that of conventional extraction technique. The Aloe vera gel sample was used in this study. The total phenolic and flavonoid compounds were determined by using UV-Vis spectrophotometer. The result shows that extraction solvents significantly affect extraction yield of phenolic and flavonoid compounds, and it was found that ethanol to be the most suitable solvent. The best condition of UAE was duty cycle of 50% and 40 min of sonication time. The sonication time with the UAE was 40 min, which was six-times shorter than with the conventional extraction technique. The highest concentrations of total phenolic and flavonoid compounds using UAE were found to be 11.41±0.04 and 6.76±0.05 mg/mL, respectively. The UAE was found to be more efficient in extraction of phenolic and flavonoid in comparison with conventional extraction technique.

Recovery and antioxidant activity of phenolic compounds extracted from walnut press-cake using various methods and conditions

Walnut (Juglans regia L.) press-cake is a residue of oil processing from which the phenolic compounds were extracted using ethanol 60 % by batch and semi-continuous operations, or by ultrasound-assisted maceration in the case of de-oiled cake, with particular attention to the variables time and solid-solvent ratio. For batch extraction, the conditions maximizing total phenolic yield (TPC) and radical scavenging activity evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay were 60 °C without the addition of phospholipids, provided however for phenolic yield, that an extraction time of 60 min and a ratio of 25 mL of solvent per g of cake were applied. Values of up to 14.8 mg gallic acid equivalent (GAE)/gcake and 136.9 μmol Trolox equivalent/gcake were obtained. The semi-continuous variant gave a TPC of 19.8 mg GAE/gcake and an overall extract containing 8% phenolic compounds and 46 % oil. After de-oiling, the cake was subjected to ultrasound-assisted extraction. The TPC and DPPH varied slightly with the applied conditions, between 10.4 and 13.3 mg GAE/gcake and 83–107 μmol Trolox Equiv./gcake respectively, unless the solid/solvent ratio increased to 1/200 (TPC of 29 mg GAE/gcake). It was also shown that the oxidative stability of Camelina sativa L. Crantz oil increased from 24 to 72 h by enrichment with walnut extract.

Enhanced Recovery of Phenolic and Tocopherolic Compounds from Walnut (Juglans Regia L.) Male Flowers Based on Process Optimization of Ultrasonic Assisted-Extraction: Phytochemical Profile and Biological Activities.

The extraction of bioactive compounds present in walnut (Juglans regia L.) male flowers (WMFs) was performed based on an experimental design using ultrasonic-assisted extraction. Solvent nature, extraction time, and water content were selected as experimental variables, and phenolic, flavonoidic, and condensed tannins contents and antioxidant properties were evaluated. Acetone was the solvent with the highest extraction performance, with the extracts obtained using this solvent displaying an increased concentration of bioactive compounds and increased antioxidant activities. For several extracts with high bioactive content, individual polyphenolic and tocopherolic compounds were evaluated by means of LC-MS and LC-MS/MS. The best extraction conditions for polyphenolic (2.86 mg gallic acid equivalents/g WMF) and tocopherolic compounds (29.4 µg/g WMF) were acetone with 40% water content (N20) and acetone with 20% water content (N15), respectively. Although the total tocopherol concentrations were lower than in other Juglans regia parts, most of the total tocopherol quantity was provided by the highly biologically active δ-tocopherol (84%). Significant quantities of quercetin (101.9 µg/g), hyperoside (2662.9 µg/g), quercitrin (405.7 µg/g), and isoquercitrin (1293.7 µg/g) were determined in WMF (N20). Both extracts inhibited the enzymatic activity of α-glucosidase and tyrosinase; however, an increased inhibition was observed for N20, the extract with the higher polyphenolic content. Conversely, N15 had higher anticancerous activity on the cell lines used, with a moderate selectivity towards the cancerous phenotype being observed for both extracts. At non-cytotoxic concentrations, both extracts displayed good antioxidant activities in cellular cultures, decreasing basal and H2O2-induced oxidative stress. This is the first characterization of both hydrophilic and lipophilic phytochemicals in WMF extracts. The outcomes of our study reveal that walnut male flowers have strong biological activities, thus justifying further research to demonstrate their usefulness in the food, pharmaceutical, and/or cosmetic industries.

Pressurized Liquid Extraction Optimization from Supercritical Defatted Olive Pomace: A Green and Selective Phenolic Extraction Process

Olive pomace (OP) is the main by-product of the olive oil industry produced in large quantities. Its valorization as a source of phenolic bioactive compounds is paramount for the sustainable growth of related industries. This work proposes an intensified process to maximize the recovery of phenolic compounds in dry extracts using hydroalcoholic mixtures. Supercritical carbon dioxide defatting pre-treatment was performed. Following this, pressurized liquid extraction was optimized through a circumscribed central composite design. The factors consisted of temperature (65.0–185.0 °C), ethanol percentage (8.0–92.0%), and solid/liquid ratio (0.2–0.8 gOP/mLSOLVENT). Besides the total phenolic content (TPC) and the total flavonoid content (TFC), the major phenolic compounds of OP [hydroxytyrosol (HT), tyrosol (TY), and oleuropein (OL)] were evaluated. Further, decarboxymethyl OL aglycone dialdehyde (3,4-DHPEA-DEDA) was identified by HPLC-DAD-MS/MS as the most abundant polyphenol and was studied for the first time for OP. Different conditions were found to optimize each key compound. In 67% shorter extraction time and 38% less solvent consumption compared to conventional extraction, an increase of 475% for OL, 428% for HT, 194% for TY, 373% for 3,4-DHPEA-DEDA, 89% for TPC, and 158% for TFC was observed. The antioxidant activity by oxygen radical absorbance capacity (ORAC) assay increased 89% (optimal conditions) and correlated with TPC, 3,4-DHPEA-DEDA, and TFC. Thus, an efficient, selective, scalable, and green extraction process was established.

Microwave-assisted extraction of phenolic compounds from Carica papaya leaves: An optimization study and LC-QTOF-MS analysis

Carica papaya is a well-known plant with diverse importance to human beings. The efficacy of microwave-assisted extraction (MAE) in the recovery of phenolic compounds from C. papaya leaf was investigated in this study. The MAE process variables were optimized using response surface method; at the optimized conditions, the embedded phenolic compounds in the extract were identified through LC-QTOF-MS analysis. The results showed that the best MAE conditions were: time of irradiation at 3 min; microwave power of 420 W; feed-to-solvent ratio of 1:12 g/mL; and solvent concentration of 56% ethanol/water to achieve 102.59 mg GAE/g d.w. of total phenolic content (TPC). At these conditions, an aggregate of 72 phenolic compounds was tentatively identified. These results infer that MAE as a technique can recover phenolic compounds from C. papaya leaf. Hence, the identified compounds can further be quantified with their respective pharmacological properties in future studies.

Ultrasonic-Assisted Extraction and Natural Deep Eutectic Solvents Combination: A Green Strategy to Improve the Recovery of Phenolic Compounds from Lavandula pedunculata subsp. lusitanica (Chaytor) Franco.

The present study aimed at evaluating the effectiveness of different natural deep eutectic solvents (NADES) on the extraction of phenolic compounds from Lavandula pedunculata subsp. lusitanica (Chaytor) Franco, on the antioxidant activity, and acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase (Tyr) inhibitory capacities. Ten different NADES were used in this research and compared with conventional solvents. Ultrasound-assisted extraction (UAE) for 60 min proved to be the best extraction condition, and proline:lactic acid (1:1) and choline chloride:urea (1:2) extracts showed the highest total phenolic contents (56.00 ± 0.77 mgGAE/gdw) and antioxidant activity [64.35 ± 1.74 mgTE/gdw and 72.13 ± 0.97 mgTE/gdw in 2.2-diphenyl-1-picrylhydrazyl (DPPH) and 2.2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods, respectively]. These extracts also exhibited enzymes inhibitory capacity particularly against Tyr and AChE. Even so, organic acid-based NADES showed to be the best extractants producing extracts with considerable ability to inhibit enzymes. Twenty-four phenolic compounds were identified by HPLC-HRMS, being rosmarinic acid, ferulic acid and salvianolic acid B the major compounds. The results confirmed that the combination of UAE and NADES provide an excellent alternative to organic solvents for sustainable and green extraction, and have huge potential for use in industrial applications involving the extraction of bioactive compounds from plants.

Recovery of phenolic compounds from agro-industrial by-products: Evaluating antiradical activities and immunomodulatory properties

Grape pomace (GP), spent coffee grounds (SCG), tomato pomace (TP) and red corn cobs (RCC) were collected and polyphenols were extracted by optimizing ethanol solvent extractions. Subsequently, extracted phenolic acids, flavonoids and anthocyanins were completely characterized by HPLC, HPLC-DAD and LC-ES-MS. Antiradical activity (DPPH) and anti-inflammatory assays (IL-8 cytokine gene expression in the Caco-2 cell line) were then investigated.Results indicated a total polyphenol content for the by-products in the range: 4.64±0.31–22.77±0.65mg gallic acid equivalent g−1 dry weight, and an antiradical activity in the range: 21.47±0.09–89.76±0.24μM Trolox equivalent g−1 dry weight. The best anti-inflammatory performances were reported for SCG and GP and they were due to the high flavonoid contents, playing phenolic compounds a minor role.Taking into consideration the results above reported and the information related to the by-products studied, i.e. geographical provenience, daily availability and biomass potential preservation, the agro-industrial wastes were ranked for their suitability to be potentially upgraded to industrial level in the following order: spent coffee grounds≫grape pomace>red corn cobs≫tomato pomace.

Effect of drying methods on biorefinery process to obtain capsanthin and phenolic compounds from Capsicum annuum L.

Red peppers (Capsicum annuum L.) that are eliminated as waste due to its low quality for commercialization were used as raw material to recover bioactive compounds in a biorefinery approach. The effect of temperature (40, 60 °C) and pressure (15, 25, 35 MPa) was evaluated on the oleoresin extraction yield and carotenoids composition obtained by supercritical fluid extraction (SFE). The effect of drying technique (solar drying, conventional oven, and freeze-drying) was evaluated. Sequentially, the effect of solvent type (100% ethanol and 75% (vol/vol) ethanol) using pressurized liquid extraction (PLE) was evaluated on the recovery of phenolic compounds and antioxidant activity. The best SFE condition was 60 °C and 25 MPa. The drying methods did not significantly affect carotenoids recovery by SFE. For PLE, the composition of the solvent influenced the extraction yield and composition. The highest values for total phenolic compounds and antioxidant activity were obtained using 100% ethanol as solvent.

Comparison of different ultrafiltration membranes as first step for the recovery of phenolic compounds from olive-oil washing wastewater

The production of olive oil generates wastewater with a high organic load and toxicity due to the high concentration of phenolic compounds. In recent years, the study on the treatments of these waters has been intensified together with the search for a process to recover these phenolic compounds due to their great antioxidant potential. All this with the aim of implementing the concept of circular economy. In this study, four different organic ultrafiltration membranes were evaluated in order to recover the phenolic compounds present in olive oil washing wastewater (OOWW) from an oil mill in the Valencian Community (Spain). The tested membranes differ in materials and molecular weight cut-off (MWCO): two permanently hydrophilic polyethersulfone (PESH) membranes with MWCO of 4 and 50 kDa, respectively, one polyethersulfone (PES) membrane with a MWCO of 5 kDa and a regenerated cellulose acetate (RCA) membrane with a MWCO of 10 kDa. Transmembrane pressure (TMP) and crossflow velocity (CFV) were varied from 1 to 3 bar and from 1.5 to 3.4 m·s−1, respectively. The effectiveness of the different membranes and operating conditions were evaluated comparing the permeate flux and the rejection of chemical oxygen demand (COD) and total phenolic compounds (TPhs). The membranes with lower MWCO showed stable permeate fluxes without significant changes over time, while the 50 kDa membrane showed a gradual decrease, without achieving a stable flux. Low rejection of phenolic compounds was observed in all cases, while the rejection of COD varied between 19.5 % and 62.9 % depending on the membrane and operating conditions tested. Except for the 50 kDa PESH membrane, initial permeability recovery greater than 95 % was achieved with a 35 °C water rinse, indicating that membrane fouling was not severe. Since the aim was to recover the TPhs in the permeate stream and separate them from the organic matter, the 5 kDa PES membrane at 2 bar and 2.5 m·s−1 was considered to be the best option. At those conditions a stable permeate flux of 40 L·h−1·m−2 was obtained, while the lowest TPhs rejection was observed (8.01 %) with a high COD rejection (61.18 %).

Revalorization of Coffee Husk: Modeling and Optimizing the Green Sustainable Extraction of Phenolic Compounds.

This study aimed to model and optimize a green sustainable extraction method of phenolic compounds from the coffee husk. Response surface methodology (RSM) and artificial neural networks (ANNs) were used to model the impact of extraction variables (temperature, time, acidity, and solid-to-liquid ratio) on the recovery of phenolic compounds. All responses were fitted to the RSM and ANN model, which revealed high estimation capabilities. The main factors affecting phenolic extraction were temperature, followed by solid-to-liquid ratio, and acidity. The optimal extraction conditions were 100 °C, 90 min, 0% citric acid, and 0.02 g coffee husk mL−1. Under these conditions, experimental values for total phenolic compounds, flavonoids, flavanols, proanthocyanidins, phenolic acids, o-diphenols, and in vitro antioxidant capacity matched with predicted ones, therefore, validating the model. The presence of chlorogenic, protocatechuic, caffeic, and gallic acids and kaemferol-3-O-galactoside was confirmed by UPLC-ESI-MS/MS. The phenolic aqueous extracts from the coffee husk could be used as sustainable food ingredients and nutraceutical products.

Overall evaluation of artichoke leftovers: Agricultural measurement and bioactive properties assessed after green and low-cost extraction methods

Globe artichoke is rich in nutrients and phenolic compounds. However, nearly 85% of its biomass is discarded following harvest. To propose a scalable and economically attractive process for the revalorization of this material, a holistic analysis of the leftovers (bracts, stems and leaves) of three Argentine cultivars (Sampedrino, Gallego and Gringo) was proposed. Agricultural studies revealed differences for the crop yield of each variety and that bracts accounted for 65% of the overall waste biomass. Differences were also found for morphological features (aspect evaluation and color in the L*, a* and b* values). For the recovery of phenolic compounds, low-cost, green, and industrially applicable extraction methods were proposed and regardless of the water-based variations employed, stems extracts showed the highest values for biological activity. Among varieties, Sampedrino had the highest phenolic compounds concentration and antioxidant capacity for stems extracts (4.3 ± 0.2 mgGA/gFW for total phenolic compounds, 1.21 ± 0.01 mgGA/gFW for ABTS.+ scavenging capacity and 0.73 ± 0.02 mgGA/gFW for Ferric reducing antioxidant power). HPLC-MS confirmed the presence of 5-O-caffeoylquinic acid and dicaffeoylquinic acids in all samples, and a flavonoid with medical applications, kaempferol-3-O-glucoside, in leaves of all varieties. High concentrations of anthocyanins were also found in stems of all varieties. Here we propose friendly extractions using aqueous solvents for the recovery of health-promoting phenolic bioactive compounds that present great feasibility and transferability to the food industry for added-value products.

Profile of phenolic compounds and antimicrobial potential of hydroalcoholic extracts from cashew-apple coproducts

Phytochemicals from tropical fruits and their by-products have shown the potential to use as antimicrobial natural. This study aimed to optimize the recovery of phenolic compounds (total polyphenols and flavonoids) from cashew apple using ultrasound-assisted extraction to promote the functional attributes to its coproducts and to evaluate their antioxidant and antimicrobial potential. An experimental design applying a response surface methodology was used for the extraction process. The ethanol concentration (13.76 % to 56.21 %) and the ultrasonic bath time (21.71 to 78.28 min.) were considered as independent variables, and the polyphenols content, total flavonoids as dependent variables. The phenolic profile of optimized hydroalcoholic extracts (UPLC-QToF-MSE) and their antimicrobial potential against foodborne pathogenic bacteria was assessed. The optimized conditions for a total phenolic extract of 750 mg GAE 100 g-1 were 42.16 % ethanol and 37.34 min in an ultrasonic bath, and for total flavonoids of 479.07 mg of quercetin per 100 g-1 were 37.15 % ethanol and 25.13 min. A total of 15 compounds including quercetin and myricetin derivatives, gallic acid, and anacardic acid were identified. The extracts displayed effective action against Staphylococcus aureus and Listeria monocytogenes. The extracts were effective against foodborne pathogenic bacteria thus demonstrating their potential to be a good natural alternative to synthetic additives in the food industry.

A review on sources and extraction of phenolic compounds as precursors for bio-based phenolic resins

Residues from biomass processing/harvesting (e.g., straw, saw chips, bark) contain value-added chemicals for multiple applications. Biomass residues can be converted to chemicals and fuels, unlike other renewable sources such as wind and hydro, with the added benefit of reducing economic and environmental costs associated with residue disposal. Pyrolysis, the thermal degradation of the biomass, can convert these low-value residues to high-value energy or chemicals. The pyrolysis oils derived from lignocellulosic biomass are of particular interest as potential sources of bio-phenols. This review is focused on the extraction and recovery of phenolic compounds from bio-oil produced during the pyrolysis of various biomass residues with a particular focus on the potential of hemp residues (hurds and straw) as a source of phenolic compounds. Considerable progress has been made toward producing cost-effective renewable phenolic resins. New and advance technologies and materials are being used for the production of bio-based resins. However, further investigation is required on the optimization of pre-treatment, extraction, and analytical techniques to meet the challenges of satisfactory quality and low cost of renewable resins.

Optimization of microwave extraction method of phenolic compounds from red onion using response surface methodology and inhibition of lipoprotein low-density oxidation

In the present study, we have optimized by surface response methodology (BBD model) phenolic compounds recovery using microwave-assisted extraction (MAE) as an innovative technique. The extraction was carried out under different experimental conditions: ethanol/water (x1, 30–80 %), time (x2, 30–180 s), microwave power (x3, 500–900 W) and solvent to sample ratio (x4, 20:1 40:1, v/w). Total phenolics content (TPC) and antioxidant activities (AA) of onion extract were investigated on 2,2−9-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS+), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), oxygen radical absorbance capacity (ORAC) tests, and on biological model oxidation, human low-density lipoprotein (LDL). The maximum predicted TPC under the optimal MAE conditions (70 % ethanol), 700 W microwave power, 65 s extraction time and 25 mL g–1 solvent to solid ratio), was 10.90 ± 0.88 mg GAE g–1 DW. The AA of MAE or conventional extraction (CE) extract showed similar activities to neutralize DPPH, ABTS or AAPH derived radicals. The modified Gompertz model has been successfully used to describe CDs production kinetic in LDL Cu2+-mediated oxidation. This allowed the estimation of the lag time (Tlag) and the oxidation propagation rate (Rp) with precision. LDL oxidation assay showed that red onion extract increased significantly Tlag and giving an increased protection ratio at higher concentration (2.95 μmol L−1) of 180 % and 172 % for MAE and CE methods, respectively. However, Rp and CDs production remained constant. Results showed that microwave used for extraction does not affect the composition and antioxidant properties of onion sample. Red onion may be an important source of bioactive compounds and could promote health consumers.

The effect of Pulsed Electric Field as a pre-treatment step in Ultrasound Assisted Extraction of phenolic compounds from fresh rosemary and thyme by-products

Emerging extraction techniques, including pulsed electric field (PEF) and ultrasound (US), are attracting considerable interest in the recovery of bioactives. Though, limited work has focused on PEF application as pre-treatment for US assisted extraction to enhance the release of phenolics from herbs. Hence, the present study investigated the use of an optimized PEF pre-treatment to enhance the recovery of phenolics from fresh rosemary and thyme by-products in a subsequent US assisted extraction step. Total phenolic content (TPC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) were assessed as an index of extraction efficacy. Qualitative and quantitative analyses were performed through liquid chromatography-mass spectrometry analyses to evaluate the influence of the methods on individual phenolic compounds and the formation of potential derivatives. The results indicated that in a number of cases PEF pre-treatment enhanced (p < 0.05) the recovery of phenolic compounds and antioxidant capacity compared to US individually.

Infusions prepared with Stevia rebaudiana: application of a simplex centroid mixture design for the study of natural sweeteners and phenolic compounds.

The online version of this article (10.1007/s13197-021-04979-9).

Improving the Recovery of Phenolic Compounds from Spent Coffee Grounds (SCG) by Environmentally Friendly Extraction Techniques.

The aim of this study was to investigate and compare the effects of different extraction techniques (high hydrostatic pressure-assisted extraction (HHPE), ultrasound-assisted extraction (UAE), and classical solvent extraction (CSE)) on phenolic compounds from spent coffee grounds (SCG). Different HHPE parameters (300, 400 and 500 MPa at 25 °C for 5, 10 and 15 min) and UAE parameters (40%, 50%, and 60% amplitude at 25 °C for 5, 10 and 15 min) were used. These techniques were compared with CSE (at 50 °C for 30 min) according to total phenolic content (TPC), antioxidant activity (AA), high-performance liquid chromatography (HPLC), scanning electron microscopy (SEM), and infrared (IR) spectroscopy. The results showed that eco-friendly techniques increased the TPC and AA compared to CSE and morphological changes were verified by SEM results. Furthermore, chlorogenic and caffeic acid were also quantified by using HPLC. Chlorogenic acid was found as the main phenolic compound in spent coffee grounds (SCG). The highest chlorogenic acid was detected as 85.0 ± 0.6 mg/kg FW with UAE at 60% amplitude for 15 min. In brief, for the extraction of phenolic compounds from waste SCG eco-friendly techniques such as HHPE and/or UAE were more convenient than CSE.

A short time bioactive compounds extraction from Cucurbita pepo seed using continuous ultrasound‐assisted extraction

This study aimed to investigate the effect of acoustic cavitation on phenolic compounds recovery from Cucurbita pepo seed using continuous ultrasound-assisted extraction (CUAE) as a green extraction process. A Box–Behnken response surface design was carried out to investigate and optimize the CUAE independent variables, including concentration of hydroethanolic solvent, biomass to solvent ratio, and sonication time on the total extractable phenols (TEP). The optimized conditions were 70.98% v/v concentration of hydroethanolic solvent, 1:26.49 g/mL ratio of biomass to solvent, and 55.38 min sonication time, under which the predicted TEP was 14.01 mg GAE/g. The determination of DPPH and HO free radical scavenging abilities revealed that the extract had a good ability to scavenge these free radicals and polyphenol concentration was positively correlated with antiradical capacity (AC). The gas chromatography–mass spectrophotometer (GC/MS) analysis revealed that C. pepo seed extract is a potential source of essential fatty acids (39% of total fatty acids). From the results, the phenolic compounds and essential fatty acids from C. pepo seeds could be obtained using the cavitation phenomenon during short time extraction. The AC of product was considerably influenced by the CUAE process mode, while the fatty acid composition was almost constant. The microstructure of cells was investigated using scanning electron microscope (SEM), which confirmed the cell disruption by acoustic cavitation technology.

Influence of Free and Encapsulated Olive Leaf Phenolic Extract on the Storage Stability of Single and Double Emulsion Salad Dressings

Valorization of wastes has become an unavoidable goal in the olive oil industry. A possible approach is the recovery of leaf phenolic compounds, which have a great interest for food industries, due to their antioxidant and antimicrobial activities. Thus, this study aims at comparing the effects of encapsulated (e-OLE) and free olive leaf extract (f-OLE) on storage stability of salad dressings prepared as single and double emulsion systems. Creaming, rheological properties, double emulsion yield, pH, total phenol content (TPC), antioxidant activity, and peroxide value (PV) of the dressings were monitored over 90 days at 4 °C. Microstructure examination showed a more homogeneous distribution of the droplet size with the inclusion of OLE. No creaming and very little variations in rheological parameters (< 10%) were observed. OLE enrichment and double emulsion systems significantly (P < 0.05) improved the rheological behavior, with a higher effect of e-OLE due to the alginate-pectin beads. OLE enrichment extended the oxidation induction period from 15–20 days to 50 days. In conclusion, the work demonstrated that OLE encapsulation by emulsification-internal gelation technique was effective in gradually releasing polyphenols during salad dressing storage, thus increasing product protection toward oxidation phenomena.