Evaluation of Pulsed Electric Field Polyphenol Extraction from Vitis vinifera, Sideritis scardica and Crocus sativus

This study exploited the application of pulsed electric field (PEF) on the recovery of polyphenols from aerial parts of Sideritis scardica, tepals of Crocus sativus, and fruits of Vitis vinifera. Short pulses of 10 μs in a period of 1 ms were applied to the plant material, while different electric field intensities, 1.2 to 2.0 kV/cm were tested to optimize the procedure. The content in total polyphenols and the polyphenolic profile of the plant extracts were evaluated. Along with PEF samples, control samples were prepared for comparison. PEF treatment enhanced the recovery in total polyphenols for all the three plants examined. A significant increase was noticed in each plant tested and PEF condition applied, though lower electric field intensities up to 1.4 kV/cm proved to be more effective. Under the optimum electric field intensities, 1.4 kV/cm for V. vinifera and 1.2 kV/cm for S. scardica and C. sativus, increases of 49.15%, 35.25%, and 44.36% in total polyphenol content, respectively, were achieved. Additionally, an 85% increase of quercetin 3-rutinoside for V. vinifera, a 56% of apigenin 7-O-glucoside for S. scardica, and a 64% increase for kaempferol 3-O-glucoside for C. sativus were obtained

Response Surface Optimization for the Enhancement of the Extraction of Bioactive Compounds from <i>Citrus limon</i> Peel

Citrus limon is among the species of the genus Citrus that dominates the world market. It is highly nutritious for humans as it contains twice the amount of the suggested daily intake of ascorbic acid and is also a good source of phenolic compounds, carotenoids, and other bioactive compounds. This study aimed to identify the optimal extraction procedures and parameters to obtain the maximum quantity of bioactive components from lemon peel by-products. Various extraction techniques, including stirring, ultrasound, and pulsed electric field, were evaluated, along with factors such as extraction time, temperature, and solvent composition. The results revealed that simple stirring for 150 min at 20 °C proved to be the most effective and practical method. The ideal solvent mixture consisted of 75% ethanol and 25% water, highlighting the crucial role of solvent composition in maximizing extraction efficiency. Among the extracted compounds were phenolics, ascorbic acid, and carotenoids. Under optimum extraction conditions, the extract was found to contain high total phenolic content (TPC) (51.2 mg of gallic acid equivalents, GAE/g dry weight), total flavonoid content (TFC) (7.1 mg of rutin equivalents, RtE/g dry weight), amounts of ascorbic acid (3.7 mg/g dry weight), and total carotenoids content (TCC) (64.9 μg of β-carotene equivalents, CtE/g). Notably, the extracts demonstrated potent antioxidant properties (128.9 μmol of ascorbic acid equivalents, AAE/g; and 30.3 μmol of AAE/g as evidenced by FRAP and DPPH assays, respectively), making it a promising ingredient for functional foods and cosmetics. The study’s implications lie in promoting sustainable practices by converting lemon peel into valuable resources and supporting human health and wellness through the consumption of natural antioxidants

Exploring the Antioxidant Properties of <i>Citrus limon</i> (Lemon) Peel Ultrasound Extract after the Cloud Point Extraction Method

Each year, a substantial amount of food is discarded around the globe. A significant portion of this waste consists of by-products derived from Citrus fruits such as lemons. The purpose of this research is to examine the polyphenol extraction and the antioxidant ability of lemon peel using cloud point extraction (CPE), a sustainable approach. CPE was conducted using three steps with a 20% w/v concentration of Span 20 as the surfactant, which has a critical micellar concentration of 6.13 × 10−5 mol/L. The pH was set at 7 and a salt concentration of 20% was maintained at 45 °C for 20 min. The subsequent outcomes of the analysis were obtained: total polyphenol content (TPC): 526.32 mg gallic acid equivalents per liter; total flavonoid content (TFC): 90.22 mg rutin equivalents per liter; FRAP, DPPH, and hydrogen peroxide assays: 2.40, 2.68 and 1.03 mmol ascorbic acid equivalents per liter, respectively, and 168.63 mg/L ascorbic acid content. The quantification of the polyphenolic compounds through High-Performance Liquid Chromatography showed that the most abundant compounds in the lemon peels are eriocitrin (159.43 mg/L) and hesperidin (135.21 mg/L). The results indicate that the proposed CPE technique is successful in extracting antioxidant compounds from lemon peels. The generated extracts have the potential to be exploited as dietary additives to enhance human health and can also be utilized for nutraceuticals or pharmaceutical purposes

Changes in Polyphenols and Anthocyanin Pigments during Ripening of <i>Vitis vinifera</i> cv Maratheftiko: A Two-Year Study

The vineyard of Cyprus is comprised largely of native Vitis vinifera varieties, which are rather underexploited with regard to wine production to date. Although empirical observations concur that several of these varieties may possess a high potential for the production of quality wines, analytical data pertaining to their polyphenolic composition are scarce. This study was undertaken with the aim of providing a detailed picture of the evolution patterns of several important polyphenolic constituents during the last stages of ripening of Maratheftiko, which is one of the major native grape varieties. This study included monitoring of representative simple phenolics, flavonoids and anthocyanin pigments for two consecutive years, 2021 and 2022, to obtain a more integrated portrayal of changes occurring during the critical period prior to harvest. It was revealed that there was a very high difference in the content of almost all polyphenols considered for the harvests in 2021 and 2022. The grapes harvested in 2022 had a much higher content in catechin, but most importantly, the content in total anthocyanins was 3.91-fold higher in 2022 compared to 2021. On the other hand, trans-resveratrol was the only polyphenolic metabolite whose difference was rather marginal. In seeds, the predominant substance was catechin, which displayed pronounced fluctuations during the period examined. It was concluded that the contents of major polyphenolic metabolites in Maratheftiko grapes might exhibit large variations during the period prior to harvest, most possibly reflecting differences in the average temperature and rainfall. Thus, tight monitoring of technologically important constituents, e.g., anthocyanins, is recommended to ensure the harvest of grapes with optimal maturity

Pulsed Electric Field Extraction and Antioxidant Activity Determination of Moringa oleifera Dry Leaves: A Comparative Study with Other Extraction Techniques

The scope of this work was to determine the possibility of the application of the pulsed electric field (PEF) technique to the production of extracts from Moringa oleifera plant material (freeze-dried leaves). Various PEF conditions (pulse duration&mdash;PD; and pulse interval&mdash;PI) were tested. A field strength of 7 kV/cm was used. The total phenols in the extracts were evaluated by the Folin&ndash;Ciocalteu method and the antioxidant activity was evaluated by the radical scavenging activity (DPPH&bull;), ferric reducing antioxidant power (FRAP) and Rancimat methods. The results were compared with those of the extracts obtained using other extraction techniques, namely microwave-assisted and ultrasound-assisted extractions, simple boiling water extraction, and plain maceration with water (as the control). The highest extraction of total phenols was achieved by the PEF procedure using 40 min treatment at a PD of 20 msec and a PI of 100 &mu;sec. Additionally, all methods for the determination of the antioxidant activity showed that the activity of the extracts was proportional to the total phenol content. Concerning the PEF procedure, a low pulse duration with a high pulse interval is proposed in order to achieve higher extraction efficiency

&beta;-Cyclodextrin-Aided Aqueous Extraction of Antioxidant Polyphenols from Peppermint (Mentha &times; piperita L.)

This study explored the use of &beta;-cyclodextrin (&beta;-CD) as an additive to improve the aqueous extraction of antioxidant polyphenols from peppermint (Mentha &times; piperita). For this purpose, an initial single-factor screening was performed to test the effect of &beta;-CD concentration on the yield of polyphenol extraction. In the following step, the extraction process was optimized through response surface methodology, considering &beta;-CD and temperature as the process variables. The experimental design included the yield in total polyphenols and total flavonoids, the ferric-reducing power and the antiradical activity as the responses. The optimization showed that each response was maximized at different levels of &beta;-CD concentration, but in all cases, 80 &deg;C was the optimum extraction temperature. The composition of the extracts produced was profiled by high-performance liquid chromatography (HPLC). A comparison of the &beta;-CD extract with the aqueous and hydroethanolic extracts revealed that the addition of &beta;-CD at a specified concentration might boost aqueous polyphenol extraction. On the other hand, the hydroethanolic extract exhibited the richest polyphenolic profile. It was also shown that the &beta;-CD extracts might possess improved antiradical activity. It was concluded that &beta;-CD-aided polyphenol extraction from M. piperita may provide extracts with enriched polyphenolic composition and improved antioxidant characteristics, and this technique may be considered an alternative to solvent extraction

Encapsulation of Moringa oleifera Extract in Ca-Alginate Chocolate Beads: Physical and Antioxidant Properties

The aim of the present study was to evaluate the physical and antioxidant properties of chocolate alginate beads containing Moringa oleifera leaf extract (MLE) produced with ecofriendly solvent extraction technology (Deep Eutectic Solvents). The concentration of MLE incorporated was 0, 2, 4, and 6% w/w, and hardening time for ionotropic gelation with CaCl2 solution was 2, 8, or 20 min. Freshly prepared beads were evaluated for their geometric (area, perimeter, ferret diameter, circularity, roundness), color (CIE L∗, a∗, and b∗ and chroma), and antioxidant properties (total phenolic content and percentage inhibition of DPPH• radical). Increasing the MLE concentration resulted in beads smaller in size and more spherical, whereas hardening time only affected their circularity. MLE concentration had also a profound effect on color and antioxidant properties of the beads. As the concentration of MLE increased, the beads appeared lighter and their chroma increased. The radical scavenging activity was ameliorated by the MLE concentration increase for samples hardened for 8 and 20 min, whereas it was unaffected for those at 2 min. The hardening time on the contrary did not affect the inhibition of DPPH• values, regardless of the amount of extract added

Optimization of Pulsed Electric Field-Based Extraction of Bioactive Compounds from <i>Cannabis sativa</i> Leaves

The current investigation examines the application of pulsed electric fields (PEFs) for isolating polyphenols from Cannabis sativa var. Futura 75 leaves. Firstly, the solvent composition, which included ethanol, water, and various mixtures of the two, was explored, along with the liquid-to-solid ratio. Subsequently, the primary parameters associated with PEFs (namely, pulse duration, pulse period, electric field intensity, and treatment duration) were optimized. The extracted samples were analyzed to determine their total polyphenol content (TPC), and individual polyphenols were also evaluated through high-performance liquid chromatography. In addition, the antioxidant activity of the extracts was assessed through ferric-reducing antioxidant power (FRAP) and DPPH assays. The extracts prepared utilizing PEFs were compared to the extracts obtained without PEFs in terms of their TPC, FRAP values, and DPPH activity. The results indicate that the most effective extraction parameters were a pulse duration of 10 μs, a pulse period of 1000 μs, and an electric field strength of 0.9 kV/cm after 25 min of extraction. The most efficient solvent was determined to be a 50% (v/v) mixture of ethanol and water in a 20:1 liquid-to-solid ratio. The extract obtained under the optimal conditions exhibited a ~75% increase in TPC compared to the extract obtained without any application of PEFs, while some individual polyphenols exhibited an increase of up to ~300%. Furthermore, significant increases of ~74% and ~71% were observed in FRAP and DPPH assays. From the information provided, it was observed that the tested variables had an impact on the recovery of polyphenols from C. sativa leaves

Optimization of the Extraction Parameters for the Isolation of Bioactive Compounds from Orange Peel Waste

More and more research is being focused on the production of value-adding products from waste materials. Food waste is not only a major global issue, but also an excellent source of bioactive compounds. In this study, the parameters that affect the extraction of the bioactive compounds (polyphenols, ascorbic acid, hesperidin, carotenoids) from orange peels, and their antioxidant properties, were optimized, using a response surface methodology (RSM) (examining the extraction temperature, time, and composition of the extraction solvent). In addition, the effect of two more techniques was examined [ultrasound (US) and pulsed electric field (PEF)], either separately or combined, so as to determine whether they can enhance the extraction of the compounds. From our results, it was apparent that orange peels are an excellent source of many bioactive compounds since the extracts contained hesperidin (16.26 mg/g dw), total polyphenols (34.71 mg GAE/g dw), ascorbic acid (1228.93 mg/100 g dw) and total carotenoids (52.98 μg CtE/g dw)

Evaluation of the Nutritional Value of <i>Prunus dulcis</i> Blossoms and the Antioxidant Compounds of Their Extracted Oil Using Green Extraction Method

Edible blossoms and extracted oils from various parts of plants have gained the interest of researchers in recent years due to their strong antioxidant activity and their high content of vitamins. In addition, they contain a plethora of polyphenols, and they do not have high caloric content. The blossoms of Prunus dulcis (i.e., almond tree) are edible; however, they have not been examined in terms of nutritional value. The present study aimed to examine the nutritional value of almond blossoms, as well as their extracted oil. The fat content of the blossoms was 1.75 g/100 g dry weight (dw), while the defatted blossoms were found to contain 1.34 g/100 g dw of crude protein and 29.97 g/100 g dw of carbohydrates. In addition, the blossom oil was tested for its composition of fatty acids, polyphenols, and total carotenoids. According to the results, several important fatty acids for human health were identified, such as oleic (25.17%), linoleic (15.64%), and linolenic (10.15%). Simultaneously, a low oxidation index (COX), i.e., 4.05, and many monounsaturated (25.17%) and unsaturated (67.56%) fats were detected, while both polyphenols (51.86 mg GAE/kg) and carotenoids were in abundance. Finally, the combination of simple stirring with ultrasound (a green extraction method) was found to be the most appropriate method to ensure maximum amounts of various antioxidant compounds in the blossom extracts (i.e., polyphenols and L-ascorbic acid). After optimization, the total polyphenol content increased by 23.98% and L-ascorbic acid content by 6.96%. In addition, antioxidant activity was tested by different antioxidant assays and specifically FRAP, DPPH, and H2O2, which showed a corresponding increase (14.46, 17.23, and 8.79%, respectively). Therefore, it can be concluded that Prunus dulcis blossoms, besides being edible, are also highly nutritious, and their oil has nutritional value and deserves further exploration