Total Phenolic Content Yield Research Articles

New insights of phenolic compounds from optimized fruit extract of Ficus auriculata

In this study, the extraction conditions extracted maximize amounts of phenolic and bioactive compounds from the fruit extract of Ficus auriculata by using optimized response surface methodology. The antioxidant capacity was evaluated through the assay of radical scavenging ability on DPPH and ABTS as well as reducing power assays on total phenolic content (TPC). For the extraction purpose, the ultrasonic assisted extraction technique was employed. A second-order polynomial model satisfactorily fitted to the experimental findings concerning antioxidant activity (R2 = 0.968, P < 0.0001) and total phenolic content (R2 = 0.961, P < 0.0001), indicating a significant correlation between the experimental and expected value. The highest DPPH radical scavenging activity was achieved 85.20 ± 0.96% at the optimum extraction parameters of 52.5% ethanol (v/v), 40.0 °C temperature, and 22 min extraction time. Alternatively, the highest yield of total phenolic content was found 31.65 ± 0.94 mg GAE/g DF at the optimum extraction conditions. From the LC–ESI–MS profiling of the optimized extract, 18 bioactive compounds were tentatively identified, which may regulate the antioxidant activity of fruits of F. auriculata.

Deep eutectic solvent‐based microwave‐assisted extraction of phytochemical compounds from black jamun pulp

AbstractMicrowave‐assisted extraction of black jamun fruit pulp was conducted under different processing conditions and the phytochemical compounds of the extract were accessed. The extraction method was modeled by an artificial neural network (ANN) by varying microwave power, extraction time, liquid–solid ratio, and water percentage in deep eutectic solvent (DES) in the range of 200–400 W, 240–300 s, 20–50 ml g−1, and 10–40%, respectively. The ANN result showed that microwave power had the highest effect on total phenolic content (TPC) followed by microwave heating duration, water contents in DES, and the solid‐to‐liquid ratio. The water content in DES significantly affected the yield of TPC and TAC and had a positive effect on both the responses. The optimum values obtained from the integrated ANN and genetic algorithm (ANN‐GA) approach for TPC and total anthocyanin content (TAC) were 44.483 mg gallic acid equivalent (GAE) g−1 and 9.682 mg C3G g−1, respectively. The optimum values were attained at a microwave power of 400 W, the water content in DES of 40%, the liquid–solid ratio of 48 ml g−1, and extraction time of 240 s. Integrated ANN‐GA modeling of extraction is vital for selecting the correct extraction method and the industrial scale‐up of the technique.Practical ApplicationsThe research uses a hybrid artificial neural network and genetic algorithm approach to obtain the optimum condition for the extraction of black jamun pulp. The application of deep eutectic solvents (DES) in bioactive compound extraction is an innovative approach for reducing pollution, lowering costs, and enhancing extraction efficiency. The water content of the DES had a positive impact on total phenolic content and anthocyanin content yield. Therefore, the suggested optimization of the extraction process by applying DES would provide increased extract yield within a shorter extraction time with lesser solvents consumption. The anthocyanin compounds extracted can be used in various industries, including food, pharmaceuticals, and chemicals.

Green Extraction of Phenolic Compounds from Lotus Seedpod (Receptaculum Nelumbinis) Assisted by Ultrasound Coupled with Glycerol.

Lotus Receptaculum Nelumbinis has been sparking wide research interests due to its rich phenolic compounds. In the present work, ultrasonic-assisted extraction coupled with glycerol was employed to extract phenolic compounds from Receptaculum Nelumbinis and the process was optimized using a response surface methodology with Box-Behnken design (BBD). The optimal conditions for the total phenolic content (TPC) extract were obtained: glycerol concentration of 40%, an extraction temperature of 66 °C, ultrasonic time of 44 min, and the solvent-to-solid ratio of 55 mL/g. Under these optimum extraction conditions, the extraction yield of TPC was 92.84 ± 2.13 mg gallic acid equivalents (GAE) /g. Besides, the antioxidant activities demonstrated the ability of free radical scavenging by four different methods that included 2,2-Diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and reducing activity (RA) were 459.73 ± 7.07, 529.97 ± 7.30, 907.61 ± 20.28, and 983.66 ± 11.80 μmol TE/g, respectively. Six phenolic compounds were identified by ultra-high pressure liquid chromatography combined with triple-time-of-flight mass spectrophotometry (UPLC-Triple-TOF/MS) from the extracts. Meanwhile, Fourier transform infrared (FTIR) was conducted to identify the characteristic functional groups of the extracts and thus reflected the presence of polyphenols and flavonoids. Scanning electron microscopy (SEM) illustrated the microstructure difference of four treatments, which might explain the relationships between antioxidant activities and the structures of phenolic compounds.

Maximising phenolic compounds and antioxidant capacity from Laurencia intermedia using ultrasound-assisted extraction

<i>Laurencia intermedia</i>, which belongs to red algae (Rhodophyta), has been found in tropical shore areas. Recently, it has been reported to be a rich source of bioactive compounds; however, there have been limited studies on extraction techniques for recovering bioactive compounds from <i>L. intermedia</i>. Hence, this study was conducted to optimise the ultrasound extraction conditions for maximising recovery yield of total phenolic content (TPC) and antioxidants from <i>L. intermedia</i> using response surface methodology. The results showed that the ratio of sample to solvent had the strongest effect on TPC, while extraction temperature, extraction time, ethanol concentration and ratio of sample to solvent had significant influence on antioxidant power. The yield of TPC, DPPH scavenging ability and ferric reducing antioxidant power were 161.79 ± 3.52 mg GAE/100 g, 32.30 ± 1.20 mg TE/100 g and 87.77 ± 3.17 mg TE/100 g, respectively at the optimum extraction conditions (50 ℃, 60 min, 30% ethanol and sample to solvent ratio of 2 g/100 mL). These conditions were employed to prepare <i>L. intermedia</i> extract for subsequent fractionation step, which generated <i>n</i>-hexane, ethyl acetate and aqueous fractions. Among these fractions, ethyl acetate fraction was found to possess the highest yield of TPC and the greatest antioxidant capacity that could be used for further isolation and purification of individual compounds.

“Intensification of Vaporization by Decompression to the Vacuum” (IVDV), a novel technology applied as a pretreatment to improve polyphenols extraction from olive leaves

Impact of the “Intensification of Vaporization by Decompression to the Vacuum” (IVDV) on extraction of polyphenols from olive leaves was investigated. Using Response Surface Methodology, the effect of three variables were studied: initial water content of leaves, processing time and steam pressure on total phenolic content (TPC). Extractions of TPC from leaves were achieved either using 100% water as a solvent (w100), or 50% (v/v) aqueous ethanol (w50). Following IVDV pretreatment, TPC yields were enhanced with both solvents by approximately 3 times compared to the negative controls. Furthermore, oleuropein and hydroxytyrosol were intensified by up to 600% and 238% respectively. Antioxidant-antiradical assays revealed higher activities, up to 3.5 times, in extracts from IVDV-treated leaves. Calculation of the extraction indices Zp, reflecting cellular damage, confirmed the beneficial effect of IVDV on the extraction yield. Finally, Scanning Electron Microscopy (SEM) permitted the morphological observation of IVDV-treated as compared to untreated leaves.

Extraction Kinetics of Phenolic Antioxidants from the Hydro Distillation Residues of Rosemary and Effect of Pretreatment and Extraction Parameters.

Rosemary residue, remaining after the distillation of essential oil, is currently unexploited, while it is a source of phenolic antioxidant components. This raw material was used for the extraction of phenolic compounds by aqueous ethanol or acetone in a continuously stirred reactor. The experimental results were fitted with a two-stage diffusion model. The highest extraction rates, total phenolic content (TPC) recovery, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity were obtained by acetone 60% and ethanol 60%. Grinding of the raw material enhanced the extraction rate and increased TPC yield and antioxidant capacity as the particle size decreased. Pre-treatment by maceration in water (4 h) dissolved a high amount of TPC and shortened the extraction time, while the combination with the pulsed electric field process did not provide further improvement. The use of ultrasound increased the efficiency of the extraction.

Bee Bread: Physicochemical Characterization and Phenolic Content Extraction Optimization.

Beebread or ambrosia is a unique product for humans and bees, which is the result of lactic fermentation on pollen in honeycombs. Bee bread is a rich source of nutrients (proteins, vitamins) and polyphenols (such as flavonoids, flavonols, phenolic acids). This study aimed to characterize bee bread in terms of physicochemical properties: pH, free acidity, glucose, fructose, sucrose, raffinose and melesitose content, total phenolic content (TPC), total flavones content (TFC), fatty acids and individual phenolics (gallic acid, protocatechiuc acid, p-hydroxybenzoic acid, caffeic acid, vanillic acid, chlorogenic acid, p-coumaric acid, rosmarinic acid, myricetin, luteolin, quercetin and kaempferol). The main phenolic compound identified in the bee bread was kaempferol, followed by myricetin and luteolin. The TPC, TFC and extraction yield were optimized in function of ultrasonic amplitude, temperature and time and the suitable conditions for achieving the maximum level were 87.20% amplitude of ultrasonic treatment, 64.70 °C and 23.10 min, respectively for reaching 146.2 mg GAE/L of TPC, 1231.5 mg QE/g of TFC and a 5.72% extraction yield. The most abundant fatty acids were C18:3 (all-cis-9,12,15) octadeca-6,9,15-trienoic acid, followed by C16:1 (9Z)-hexadec-9-enoic acid, C21:0 heneicosanoic acid and C18:2 (all-cis-9,12) (9Z,12Z)-octadeca-9,12-dienoic acid, respectively.

Subcritical water extraction of phenolics, antioxidants and dietary fibres from waste date pits

The growing demand for dates, as food, has enhanced its production and increased the total amount of date pits waste. Subcritical water extraction (SCWE) can be used to effectively extract valuable products from date pits. This study was to extract phenolic compounds, total flavonoid content, antioxidants, and dietary fibres from the date seeds using SCWE. The effects of process variables such as feed mixture concentration (x), extraction temperature (T), and extraction time (t) on the yields of total phenolic content (TPC), total flavonoid content (TFC), antioxidants, and dietary fibres were investigated for process optimisation using desirability approach. The results showed that extraction temperature could significantly increase TPC, TFC, and dietary fibres extraction yields, but has less effect on the antioxidant extraction. The feed mixture concentration has shown a significant effect on antioxidant extraction but was insignificant on TPC, TFC, and dietary fibres extractions. The desirability approach of process optimisation validated the feasibility of using SCWE for valuable products extraction from date pits.

Optimization of microwave-assisted extraction of phenolic compounds from Ocimum gratissimum leaves and its LC–ESI–MS/MS profiling, antioxidant and antimicrobial activities

Phenolic compounds are essential for growth, pigmentation, resistance to pathogens, reproduction, and among others. This study focused on the optimization of microwave-assisted extraction process variables, i.e., solvent/sample ratio (X1), irradiation time (X2) and microwave power (X3), based on the yields of total phenolic content (TPC) and total flavonoid content (TFC) from Ocimum gratissimum leaf using Box Behnken Design. Furthermore, the chemical compounds in the extract under optimized MAE conditions were identified using LC–ESI–MS/MS analysis; its antioxidant and antibacterial properties were evaluated as well, and optimal MAE conditions, i.e., X1 = 10:1 mL/g, X2 = 3 min and X3 = 553 W, were obtained with TPC and TFC yields of 184.99 ± 3.05 (mg GAE/g extract) and 68.78 ± 2.07 (mg QE/g extract), respectively. The results indicated that the leaf extract of O. gratissimum possesses antioxidant and antibacterial properties. Aside from these, the LC–ESI–MS/MS analysis provided tentative identification of 131 phenolic and other phytochemical compounds in the leaf extract at optimized conditions. The extract showed higher inhibitory activities against all the considered bacteria organisms (at least the concentration of 15 mg/mL). Thus, O. gratissimum leaf can be employed as an industrial crop with potential usage in the nutraceutical and food products.

Optimization of pulsed-mode ultrasound assisted extraction of bioactive compounds from pomegranate peel using response surface methodology

In this study, a pulsed mode ultrasound assisted extraction was performed for the extraction of bioactive compounds from Pomegranate (Punica granatum L.) peel. Box-Behnken experimental design combined with response surface methodology, was applied for the optimization of process conditions. The independent variables investigated were ultrasound amplitude (50–80%), sonication time (5–15 min), duty cycle (0.2–0.8), and methanol concentration (30–70%) to maximize the yield of total phenolic content, flavonoid content, total condensed and hydrolysable tannin (TCT and THT respectively), and antioxidant activity (DPPH and FRAP). The experimental results were fitted to quadratic models, and statistical analysis in terms of multiple regression, and analysis of variation was carried out for each response variable. The optimum predicted values of the response variables were obtained at 70% methanol concentration, 12.8 min of sonication treatment at a duty cycle of 0.58, and 80% ultrasound amplitude. A comparative analysis at optimized condition showed better recovery of bioactive compounds in pulsed mode, compared to continuous mode of sonication. Correlation analysis of the response variables was done to find the associations among the variables. Multivariate analysis using principal component analysis, and hierarchical cluster analysis was done for better understanding of interactions among experimental treatments and responses.

Plum ( Prunus domestica L.) leaves extract as a natural antioxidant: Extraction process optimization and sunflower oil oxidative stability evaluation

The current work aimed to maximize the yield of total phenolic content (TPC) and associated antioxidant activity of plum leaf extract. The feasibility of using the optimal extract as a natural antioxidant for retarding the oxidation process in sunflower oil using rancimat method was also investigated. One-factor-at-a-time (OFAT) method and 32 full factorial design were implemented in sequence to optimize the studied factors (extraction time [ET] (10–60 min) and ethanol percentage [EtOH%] (0%–75%)). DPPH scavenging ability of the obtained extracts were positively (r ≥ 0.7493) and significantly (p < .0001) correlated to TPC yield. The optimal conditions for extraction plum leaves were 64.37% EtOH% and 60 min with desirability of 0.856. The optimal plum leaves extract was subjected to HPLC analysis. At the same concentration (200 ppm), the protection factor of BHT and optimal plum leaves extract against sunflower oxidation were insignificantly (p > .05) differed. Practical applications Plum (Prunus domestica L.) leaves are characterized by a high content of phenolic compounds which varied between 66.50 to 143.7 mg GAE/g powder. Plum leaf extracts exhibited high scavenging activity against DPPH radicals. The protection factor of the freeze-dried optimal leaves extract was insignificantly differed than that of BHT at the concentration of 200 ppm. These findings indicate that plum leaves extract could efficiently retard the oxidation process of edible oils; and consequently, improve their quality and extend their shelf life.

STATISTICAL OPTIMIZATION AND CHARACTERIZATION OF ACOUSTICALLY EXTRACTED ANANAS COMOSUS PEEL POWDER WITH ENHANCED ANTIOXIDANT CAPACITY

Ananas comosus (L.) Merr is one of many commercially popular fruits in the cannery food industry that contributes to the increasingly mounting agro-industrial waste. In this study, a four−factor−three−level Box−Behnken design (BBD) that comprised of sonication time (A), solvent ratio (B), amplitude (C) and liquid−solid ratio (D) for the ultrasound−assisted extraction (UAE) of pineapple peels (PP) was utilized to optimize the yield of total phenolic content (TPC). Under an optimized UAE condition [5 min; 50 % of ethanol: water; 65 % of amplitude; 35:1 mL/g of liquid−solid ratio], the highest TPC from PP of 708.10 mg gallic acid equivalent (GAE)/g DW was achieved. Antioxidant capacity analysis of PP revealed a high total flavonoid content (TFC) with the IC50 for 2,2−diphenyl−1−picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) of 1146.86 ± 11.83 mg QE/g, 11.83 mg/mL and 1578.07 ± 25.96 µM Fe (II)/100g, respectively. High-performance liquid chromatography (HPLC) analysis revealed that the major flavonoid in the phenolic profile of PP extracts being catechin followed by quercetin and gallic acid. The UAE of PP extracts exhibited higher TPC than known conventional extraction techniques, thus indicating its efficacy to recover satisfactory quantities of phenolics in PP under optimized conditions.

A novel, green environment-friendly cloud point extraction of polyphenols from pomegranate peels: a comparative assessment with ultrasound and microwave-assisted extraction

ABSTRACT Pomegranate peel is a potential source of polyphenols, antioxidants, pectin, organic acids. Cloud point extraction (CPE) process parameters were optimized for efficient separation of polyphenols. Maximum extraction was obtained at 1:70 solid: solvent ratio, 8% (v/v) Triton X-114 at 55°C, pH 4.5 with 14% NaCl for 30 minutes. Ultrasound assisted CPE showed maximum yield of total phenolic content (TPC; 96.28 mg GAE/g) and total flavonoids content (TFC; 12.27 mg QE/g) with 94.48% antioxidant activity (AA) to that of conventional, ultrasound and microwave-assisted CPE. These extractives can be labeled as green and may be used in food or dietary applications. Abbreviations: CPE: Cloud point extraction; AA: Antioxidant activity; TPC: Total polyphenol content; TFC: Total flavonoid content; CPT: Cloud point temperature; CMC: Critical micellar concentration; OVAT: One variable at a time; GAE: Gallic acid equivalent; QE: Quercetin equivalent; HLB: Hydrophilic lipophilic balance

Total phenolic content and antioxidant activity of Pandanus amaryllifolius by soaking and microwave-assisted extraction

Many studies have reported on the limitation of conventional extraction methods. Therefore, this work aims to compare the effects of conventional soaking extraction and microwave-assisted extraction (MAE) on the total phenolic content (TPC) and antioxidant activity of Pandanus amaryllifolius leaves. For soaking method, the pandan leaves were soaked in various ethanol-water mixture (50, 75 and 100%) at different temperatures (40, 50, 60, 70°C) for 10 minutes. Meanwhile for MAE method, the pandan leaves were extracted in the same concentrations of ethanol-water and subjected to different microwave power level (100, 180, 300, 450, 600 and 850W) for 10 minutes. It was found that MAE resulted in higher yield of TPC (1.557 mg/g gallic acid equivalent) compared to conventional soaking method (0.979 mg/g gallic acid equivalent). MAE could remarkably retain bioactive total phenolic content and antioxidant activity and has huge potential and application in the food industry.

Modeling and Optimizing of Microwave-Assisted Extraction of Antioxidants and Phenolics from Wormwood (Artemisia absinthium L.) Using Response Surface Methodology

In this study, modelling and optimizing microwave-assisted extraction (MAE) of antioxidants and phenolics from wormwood (Artemisia absinthium L.) was performed by using response surface methodology with face-centered composite design as factors of temperature, extraction time, solvent concentration, and solid-to-solvent ratio. The MAE process factors were optimized so that cupric reducing antioxidant capacity (CUPRAC) and total phenolic content (TPC) of the wormwood extract are maximized. All of the models calculated for the two responses (CUPRAC and TPC) were found significant (p&amp;lt;0.0001) to show the relationship between the response and independent parameters. Extraction temperature was found as the most significant operational factor in MAE. Extraction time was found is the most insignificant parameter in MAE. The data obtained by the experimental model and the predicted by the model were found to be strongly accordance. It shows the suitability of the model and its success in optimization. The CUPRAC and TPC yields were obtained as 1.22 and 1.42 mmol TR/g-dried sample under the optimum operational conditions of MAE. According to the CUPRAC and TPC values, under the same operational conditions, MAE method was found to be approximately two times more efficient than classical heat extraction. As a result, the modeled methodology can be applied to the extraction of antioxidant and phenolics from the wormwood in the natural product industry.

Encapsulation of phenolic-rich extract from banana (Musa cavendish) peel.

Banana peel, a by-product rich in phenolics and other bioactive compounds, has great potentials as a natural preservative or healthy food ingredient. However, the instability of bioactive compounds derived from banana peel limits their applications, and as such encapsulation is necessary to improve their stability and widen their applications. This study investigated the impact of spray drying conditions and coating materials on the physical, phytochemical, and antioxidant properties of the peel extract to identify the most suitable encapsulation process. The results showed that inlet temperature (ranging from 140 to 180°C) and feeding rate (3-15mL/min) did not significantly affect the total phenolic content (TPC) and antioxidant capacity but influenced the moisture content and recovery yield of the powder. The ratio of dry matter in fresh extract-to-coating material (DM-to-CM) (1:1-1:7 (w/w)) did not affect the moisture content. However, it affected the TPC, antioxidant properties, and recovery yield of the powder. Finally, the type of coating materials did not significantly affect TPC and antioxidant properties, but other physical properties, dopamine levels and recovery yield. The most suitable encapsulation conditions were identified as an inlet drying temperature of 150°C, a feeding rate of 9mL/min, a ratio of DM-to-CM of 1:1 (w/w), and coating with a combination of maltodextrin M100 and gum acacia. Powder prepared under the most suitable conditions had a spherical shape with a rough surface and had stable TPC under storage conditions of 40°C for 4weeks. It also has ideal physical, phytochemical and antioxidant properties and is suitable for further applications.

Application of the Folin-Ciocalteu method to the evaluation of Salvia sclarea extracts

Polyphenols are valuable group of phytoconstituents due to their high antioxidant activity and healing properties. Antioxidant properties of sages are attributed mainly to a high level of phenolic compounds. The aim of the present study was to elaborate an analytical procedure for the evaluation of the content of secondary metabolites of the polyphenol nature in the herb of Clary Sage (Salvia sclarea L.). Four crude extracts of Salvia sclarea herb obtained with different technologies were used to develop an analytical procedure for the total phenolic content (TPC) assay by spectrophotometric method. The optimum conditions for the analysis (time of the reaction, wavelength, and reference substances) were chosen and experimentally justified (60–80 min, 760 nm, gallic acid and rutin, respectively). Under these conditions, the developed analytical procedure is robust in the indicated time and easy for performing in phytochemical or technological laboratories. The yield of TPC from the herb of Salvia sclarea was the highest in the extracts prepared by heating at a temperature of 36–46 °C and with using the ultrasonic bath. TPC was the highest in the extract in which solvent-to-herb ratio was the least (10:1) and particle size was in the range of 2–5 mm. As a result of the studies, the analytical procedure of the determination of TPC was developed and its parameters were justified. This methodology complies with the requirements for pharmaceutical analysis to ensure the reliability of results during pharmaceutical development and routine control of Salvia sclarea extracts.

Improving the quality of Vernonia amygdalina extract by ultrasound‐assisted extraction coupled with gas bubble flotation

AbstractVernonia amygdalina is an herb commonly used in folk medicine; It possesses various compounds with therapeutic capabilities. Traditional extraction approaches applied to this plant may destroy its bioactive compounds and inherently contaminate them with toxic organic solvents. In this study, ultrasound‐assisted extraction combined with gas‐bubble flotation was applied to increase V. amygdalina extraction yield. The efficiency of water maceration was increased by 200%, without the drawbacks of the conventional extraction methods. The total phenolic content yield was 189 ± 12.7 (mg GAE/g dry weight) with a condensation efficiency of 115 ± 5.7%; and the total flavonoid content was 6.44 ± 1.68 (mg QE/g dry weight). Additionally, the antioxidant activity of the condensed foam was enhanced up to 120%. Analysis of the extract by FTIR revealed the presence of extractable chemical families: sesquiterpene lactones, saponins and flavonoids, and that the chemical characteristics of the extract were also preserved due to mild extracting conditions. Overall, this method is effective for extracting bioactive compounds from herbs with appealing advantages: no thermal degradation, organic solvent free extraction, and low energy consumption.Practical ApplicationsThe utilization of ultrasound‐assisted extraction and gas bubble flotation has been proven to be effective in condensing the aqueous extract of Vernonia amygdalina. Gas bubble flotation was shown to condense the herb extract by 120%, which is considered efficient given the simplicity and energy consumption of the process.

Phenolic Acids in Jerusalem Artichoke (Helianthus tuberosus L.): Plant Organ Dependent Antioxidant Activity and Optimized Extraction from Leaves.

Phenolic acids including chlorogenic acids are major polyphenolic compounds found in Jerusalem artichoke (Helianthus tuberosus L.). The plant itself is an emerging biorefinery crop due to the inulin-rich tubers, a bioethanol feedstock, but the aerial parts represent a rich source of bioactive compounds. We have determined the level of major phenolic acids in extracts of four plant organs: tuber, leaf, flower, and stem. Employing three heating conditions (20 °C, 60 °C, and microwaving), corrected total phenolic content (TPC) was highest in the leaves (4.5–5.7 mg gallic acid equivalents g−1 dry substance), followed by flower (2.1–2.9), tuber (0.9–1.4), and lowest in stem extracts (0.1–0.2). A previously overlooked interference of the Folin–Ciocalteu assay, namely a signal contribution from ascorbic acid, caused overestimation of TPC in various organs ranging from 65% to 94%. Radical scavenging activity of extracts correlated significantly with TPC, both on corrected (R2 = 0.841) and uncorrected (R2 = 0.884) values. Out of the identified phenolic acids determined by quantitative HPLC-UV analysis, chlorogenic and dicaffeoylquinic acids accounted for 72–82% of corrected TPC in leaf and tuber extracts. Optimization of leaf extraction was tested in a 23-factorial Central Composite Face (CCF) design. Temperature was the most important model term, and a solvent strength of less than 50% ethanol promoted the highest TPC yields. Further developments in extraction processing of crop residues may open avenues for improving the utilization of Jerusalem artichoke in valuable products.

Kinetic Improvement of Bioactive Compounds Extraction from Red Grape (Vitis vinifera Moldova) Pomace by Ultrasonic Treatment.

Grape pomace from a red grape variety (Vitis vinifera Moldova) cultivated in the northeastern region of Romania has been studied as a source for the extraction of total monomeric anthocyanin (TMA) and total phenolic content (TPC) using ultrasonic treatment. The method of extraction described here uses two different solvents, namely 2-propanol and methanol. For each of the extraction solvents, we evaluated the singular influence and the impact of interactions between process parameters (solvent concentration, ultrasonic frequency, temperature, and extraction time) on the extraction yields of anthocyanins and phenolic compounds. Response surface methodology was implemented via a Box–Behnken design to optimize the extraction of TMA and TPC from grape pomace. According to the optimization, in order to achieve the highest yield of TPC (62.487 mg gallic acid equivalent (GAE)/g (d = 1.0)), the following conditions are necessary: solvent—2 propanol, solvent concentration 50%, temperature −50 °C and extraction time 29.6 min.