Terms Of Total Phenolic Content Research Articles

Application of pressurized liquid extraction (PLE) to obtain bioactive fatty acids and phenols from Laminaria ochroleuca collected in Galicia (NW Spain)

The increase of pathologies like cardiovascular diseases, obesity or diabetes due to the nature of diet is a matter of concern in our society. Because of this, there is a high interest in healthy natural products that could prevent the appearance of such diseases. This paper aims to study the content of fatty acids (FAs) and phenolic compounds of brown alga Laminaria ochroleuca (L. ochroleuca) and to determine the nutritional quality of the lipids extracted using pressurized liquids extraction (PLE) technique. PLE was applied to the algae using four solvents of different polarity (hexane, ethyl acetate, ethanol and ethanol:water 1:1). Results showed that the higher yield (52%), is obtained with ethanol: water solvent, however, both ethyl acetate and ethanol enrich unsaturated fatty acid (USFA) (palmitoleic, linolenic, linoleic, oleic, araquidonic and eicosapenataenoic) in the lipid fraction of L. ochroleuca, providing extracts up to 55% of their total fatty acid content compared to other solvents. The nutritional quality of the lipids in all PLE extracts was assessed by considering the ω-6/ ω-3 fatty acid ratio and two dietary indexes involved in the risks of coronary heart disease, atherogenic (AI) and thrombogenic (TI). The lower (best) index values are for ethanol extract, 4.4 (ω-6/ ω-3), 0.74 (AI) and 1.05 (TI), followed of ethyl acetate, 4.4 (ω-6/ ω-3), 0.87 (AI) and 1.24 (TI). Finally, the antioxidant capacity of PLE alga extracts in terms of total phenol content (TPC) was analyzed by the Folin-Ciocalteu method. The ethanol: water extracts showed the highest TPC with a concentration up to 173.65 mg eq. gallic acid / g PLE extract.

Total Phenolic Content, Total Flavonoid Content and Radical Scavenging Activity from Zingiber zerumbet Rhizome using Subcritical Water Extraction

Subcritical water extraction (SWE) is an alternative technique that implement water as a solvent. The objective of this work was to compare the efficiency of SWE in temperature range from 100oC to 180oC at extraction times ranging from 5 to 25 minutes with an ethanolic soxhlet extraction in terms of total phenolic content (TPC), total flavonoid content (TFC) and radical scavenging activity (RSA) from Zingiber zerumbet. Results showed the highest TPC were obtained at 180oC and 25 min (19.88 mg GAE/g dry sample). The TFC is observed to be slightly fluctuated with time at the respective temperature. The RSA reached the maximum of 83.9 % inhibition at 180oC and 10 minutes of SWE. A direct linear correlation shows the strong correlation were observed between TPC and RSA(R2=0.910) compared to moderate correlation (R2=0.785) perceived in TFC. It shows that using SWE, phenolic content in Zingiber zerumbet more contributed to its radical scavenging activity compared to its flavonoid content. In comparison to soxhlet extraction, SWE process for Zingiber zerumbet extract is favorable for TPC and antioxidant properties. However the values for TFC in general is lower compared to soxhlet extraction. SWE is a potential alternative extraction process that should be further explored.

Antioxidant of green tea and pickle tea product, miang, from northern Thailand

Consumption of tea offers health benefits attributed to phenolic compounds. In Thailand, tea mostly belongs to Camellia sinensis var. assamica which is grown in the northern region. Although, Assam tea cultivation is for tea manufacture, it is also originally grown as part of the forest and is being recognized as agroforestry system. Local northern Thais commonly use mature tea leaves to make a pickle tea product called 'miang' to chew on during working hours (similar to chewing tobacco) and as a common household guest reception snack. While this product still has low economic value, it is gradually gaining more attention from Thai researchers due to its health benefit potential. This study aims to investigate phenolic content in miang in comparison to the benchmark green tea product. A sample of freshly picked tea shoots (the first top 3 leaves) and mature tea leaves (leaves 4-6 from top) and the processed products from tea shoots and mature tea leaves (green tea and miang, respectively) from the same crop were compared in terms of total phenolic content and antioxidant activity measured by FRAP and ORAC assay. The results indicated lower content of phenolic compounds and antioxidant activity measured by both assays in mature tea leaves compared to tea shoots. However, when green tea and miang were extracted under conditions that mimic normal consumption manner, i.e., brewing for green tea and grinding for miang, the results showed that miang had a comparable amount of total phenolic content and antioxidant activity. The results from the same extraction conditions between green tea and miang is also provided in this paper.

A Comparative Study on the in vitro Antioxidant and Antimicrobial Potentials of Three Endemic Ononis L. Species from Turkey.

In this study, the antioxidant capacity, antimicrobial activity and phenolic contents of aerial parts and roots extracts of three endemic Ononis L. (Leguminosae) species (O. sessilifolia Bornm., O. basiadnata Hub. & Mor., O. macrosperma Hub. & Mor.) were investigated for the first time. The phenolic contents of the extracts [water and ethanol (EtOH)] and fractions [dichloromethane, EtOAc and n-butanol] were determined using Folin-Ciocalteu's phenol reagent. Also, their antioxidant capacities were studied using qualitative DPPH˙ (1,1-diphenyl-2-picrylhdrazyl radical) and TBA assays. The antimicrobial activity of these extracts and fractions compared with standard antibiotics were studied using disc diffusion assays against various Gram-positive and Gram-negative bacteria and fungi. The total phenolic contents of the water extracts were found to range between 14.78-80.33 mg/g, and the EtOH extracts ranged from 67.19-145.33 mg/g. EtOAc fractions of the three species were rich in terms of total phenolic contents when compared with other extracts (242.56-620.89 mg/g). The most significant results in the TBA assays were obtained in EtOH extracts of O. macrosperma (IC50=0.13±0.17 µg/mL), O. sessilifolia (IC50=1.41±0.58 µg/mL) and root (IC50=1.96±0.39 µg/mL). EtOAc fractions rich in phenolic content were also found to be the most effective in antioxidant activity assays. Although all water extracts had no antimicrobial activity, EtOH extracts and n-butanol fractions showed generally moderate activity against bacteria. Some EtOAc fractions except for O. sessilifolia showed less activity against Escherichia coli, Staphylococcus aureus, MRSA and Candida albicans.

Effect of Supplementation with Green and Black Tea on Microbiological Characteristics, Antimicrobial and Antioxidant Activities of Drinking Yoghurt

The influence of supplementation with green and black tea on microbiological properties, antimicrobial and antioxidant activities of drinking yoghurt were investigated during 21 days of storage. The samples supplemented with 2% either green or black tea had higher viable counts of both yoghurt starter bacteria than those of infused by the ratio of 4%. Both green and black tea extracts showed antimicrobial activity on E. coli, B. cereus, S. aureus and C. albicans however this effect was detected higher in samples containing green tea. The samples added green tea extract had the highest DPPH scavenging activity when compared to those supplemented with black tea extract throughout the storage. Green tea had a superior effect than black tea in terms of total phenolic content of drinking yoghurt samples.

Extraction of polyphenolic antioxidants from orange peel waste using deep eutectic solvents

Abstract Extraction of polyphenolic compounds from orange peel (OP) via solid-liquid extraction (SLE) using deep eutectic solvents (DES) was investigated in this work as a means to develop sustainable separation processes to recover natural antioxidants from food waste biomass. In particular, choline chloride-based DES paired with glycerol and ethylene glycol were explored as potential extractants to evaluate the effect of the solvent structure (i.e. number of hydroxyl groups and hydrogen bond acceptor/donor ratio) on the polyphenol extraction efficiency. Afterwards, the effect of different operating parameters (i.e. solvent concentration, temperature, time and solid/liquid ratio) were further evaluated to determine the optimal extraction conditions for polyphenols recovery in terms of total phenolic content (TPC) and antioxidant activity based on DPPH radical scavenging method. Under optimum conditions (DES 10 wt.% water, temperature of 333.15 K, 1:10 solid/liquid ratio and extraction time of 100 min), choline chloride-based DES outperformed the benchmark solvent (aqueous (aq.) ethanol 30 wt.% water) for the extraction of polyphenolic compounds from OP, with [Ch]Cl:EG 1:4 providing the highest TPC (3.61 mg gallic acid equivalent per gram of orange peel (GAE/g OP) and antioxidant potential (30.6 µg/ml). Although ethylene glycol (EG) has provided the highest TPC (5.84 mg GAE/g OP), DES have proved more selective towards target polyphenolic compounds. Additionally, Scanning Electron Microscopy (SEM) was performed to illustrate the structural modifications occurred on the biomass before and after the extraction process, supporting DES as efficient solvents for cell wall dissolution. Lastly, characterization and quantification of individual polyphenolic profiles in the extracts were completed via high performance liquid chromatography (HPLC), displaying ferulic acid as the most abundant compound followed by ρ-coumaric acid and gallic acid.

Dietary oregano (Origanum vulgare L.) aqueous extract improves oxidative stability and consumer acceptance of meat enriched with CLA and n-3 PUFA in broilers.

The effect of a dietary oregano aqueous extract on meat fatty acid profile, quality, and consumer acceptance in chickens fed a diet rich in polyunsaturated fatty acids (PUFA) was evaluated in 3 consecutive trials.For each trial, 171 day-old Ross 308 chicks were randomly divided in replicates of 19 birds each and assigned to one of 3 experimental diets: 1) basal control diet, 2) basal diet supplemented with 0.2 g/kg of oregano aqueous extract, and 3) basal diet supplemented with 150 ppm of vitamin E (as positive control). To better analyze the antioxidant activity of both oregano and vitamin E, all the experimental diets were enriched with a fatty acid supplement consisting in a mixture of PUFA at the same dose (1.16 %) in both starter and finisher feeds. Oregano supplementation positively influenced (P < 0.05) broiler live performance. No differences were observed in physicochemical or proximal composition or in total fatty acid composition of breast meat. Dietary oregano influenced meat composition in terms of total phenolic content, antioxidant capacity, and thiobarbituric acid-reactive substances, improving meat resistance to oxidation, compared to both other groups. During consumer tests, meat from the 3 dietary groups obtained the same liking score in a blind session. Under informed condition, consumer perception was positively influenced by labeling for all the considered attributes. Furthermore, consumers showed a higher expectation for meat derived from chickens fed the oregano extract when compared to that deriving from the other 2 groups.Results obtained in the present study allow stating that using oregano aqueous extract in diets enriched with PUFA can represent a valid solution to increase live weight of chickens, improve resistance to oxidation of meat, and positively influence consumer perception of poultry meat.

Evaluation of phenolic composition, antioxidant, anti-inflammatory and anticancer activities of Polygonatum verticillatum (L.)

ObjectivePolygonatum verticillatum (L.) All. (Ruscaceae), one of the Ashtawarga plants, is widely used for treatment of various ailments. The present study was undertaken to determine the phenolic composition, antioxidant, anti-inflammatory and anticancer activities of several extracts (petroleum ether, dichloromethane, chloroform, ethanol, and aqueous) from the rhizomes of the plant. MethodsCoarsely powdered dry rhizome was successively extracted with different solvents of increasing polarity (petroleum ether, dichloromethane, chloroform, ethanol and water). The phenolic compositions, in terms of total phenolic content (TPC), total flavonoid content (TFC) and total condensed tannin content (TTC), were evaluated with the Folin–Ciocalteu assay, aluminum chloride colorimetric assay and vanillin spectrophotometric assay, respectively. Total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays were used to assess the antioxidant potential of each extract. A protein denaturation model and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay were used to evaluate in vitro anti-inflammatory and anticancer activities, respectively. Gas chromatography–mass spectrometry (GC/MS) analysis was carried out to demonstrate various phytoconstituents in each extract. Correlation studies were also performed between phenolic composition (TPC, TFC and TTC) and different biological activities. ResultsEthanol extract showed maximum TPC (0.126 mg/g, gallic acid equivalent in dry sample), TFC (0.094 mg/g, rutin equivalent in dry sample) and TTC (29.32 mg/g, catechin equivalent in dry sample), as well as antioxidant and anti-inflammatory properties. Chloroform extract exhibited the strongest cytotoxicity against the human breast cancer cell line, MCF-7. GC/MS analysis revealed the presence of 90 different phytoconstituents among the extracts. Antioxidant and anti-inflammatory activities had a positive correlation with TPC, TFC and TTC. However, the anticancer activity showed a negative correlation with TPC, TFC and TTC. ConclusionFrom the present study, it can be concluded that P. verticillatum possessed remarkable antioxidant, anti-inflammatory, and anticancer activities, which could be due to different secondary metabolites of the plant. Phenolic compounds are likely responsible for antioxidant and anti-inflammatory activities. However, flavonoids and other compounds might contribute to the anticancer potential of the plant.

Pengaruh Dua Metode Pengeringan Pada Aktivitas Antibakteri Ashitaba (Angelica keiskei ) Terhadap Streptococcus mutans

The aim of this study was to determine a change that occurs in total phenolic content (TPC) and antibacterial activity of ashitaba (Angelica keiskei) after dried using two different methods : sun and oven drying. The effectiveness of the drying methods was evaluated in term of total phenolic content (TPC) by using spectrophotometric assay with Folin-Ciocalteu reagent and antibacterial activity againts Streptococcus mutans by in vitro macrodilution assay. Oven drying at 60oC possessed high TPC (2,98 ± 0,0935 g EAG/100g) compared to sun drying method (1,72 ± 0,0142 g EAG/100g). Simillar pattern was also observed in antibacterial activity. Oven drying have higher antibacterial activity with the MBC (minimal bactericidal concentration) value of 0,5 mg/mL againts Streptococcus mutans. Therefore, sun drying is not suggested for drying method of ashitaba in terms of total phenolic content and antibacterial activity compared with oven drying methods.

Development and stability evaluation of water-in-edible oils emulsions formulated with the incorporation of hydrophilic Hibiscus sabdariffa extract

New functional oils (extra virgin olive oil, EVOO and sunflower oil, SO) containing antioxidants from Hibiscus sabdariffa extract were developed by W/O emulsion. Their physical and chemical stability was measured over time. The lowest coalescence rate was obtained with 8 and 12 wt% surfactant amount for EVOO and SO emulsions, respectively. Before the evaluation of the oxidative stability, an optimization of phenolic compounds extraction from emulsions by multi-response surface methodology was performed. EVOO emulsions were chemically more stable over time than SO emulsions in terms of total phenolic content (TPC), antioxidant activity and chemical composition measured by HPLC-ESI.TOF-MS. TPC significantly increased (from 2.02 ± 0.07 to 2.71 ± 0.06 mg Eq GAE/g extract) and the antioxidant activity measured by TEAC remained constant for 1 month of storage. Thus, W/O emulsion technology has proven to be a potential method to vehiculize and stabilize bioactive compounds from H. sabdariffa into edible oils.

Evaluation of antioxidant properties of extractable and nonextractable polyphenols in peel and flesh tissue of different peach varieties

Our work was performed to determine the total phenolic content (TPC) and antioxidant properties from peel and flesh fruit tissues of four peach varieties, measured separately in extractable polyphenols (EPPs) and nonextractable polyphenols (NEPPs) for the first time. TPC in peach peels was approximately two or three times higher than that in the flesh tissues of all the tested peach varieties. Likewise, a similar pattern was presented for the antioxidant activities. As well as EPPs, NEPPs were also contributors to total antioxidant activity (TAA) of peach peels and fleshes, even though they accounted for less percentage of TAA compared with EPPs. Correlation analysis showed that TPC of peach extracts had a high relationship (p < .05) with their corresponding TAA. In addition, in terms of TPC and TAA, a strong correlation between EPPs and NEPPs, peels and fleshes was also detected. Practical applications Our research specifically demonstrated that NEPPs in peach tissues (peel vs. flesh), usually ignored in previous studies, are also important dietary antioxidants, which may exert vital biological properties and could be usefully applied to the food, pharmaceutical, or cosmetic industries for development of diverse nutraceuticals or value-added products.

Recovery of anthocyanins and other phenolic compounds from purple eggplant peels and pulps using ultrasonic-assisted extraction

In order to enhance the extraction efficiency of anthocyanins and other phenolic compounds from fresh purple eggplant parts (peels and pulps), conventional extraction, grinding process and assisted ultrasonic probe were used. The effects of both ultrasonic time and maceration conditions including pH medium, ethanol/water mixture, temperature and nature of particles (square and ground) were evaluated. Among the examined parts, the peels were found to be rich in anthocyanins. The obtained results showed that the most efficient factors for the extraction of polyphenols are pH medium, nature of particles and temperature. It was found that a temperature of 75°C and pH 2.0 were the best values to achieve high yield of polyphenols from the ground peels treated for 60min. Under these optimal conditions, the total yield of phenolic compounds was 23.101mg GAE/g DM. However, an ultrasonic time of 30min produced 29.011mg GAE/g DM in square peel extracts using acidified water as solvent. Further, in terms of total phenolic content, both colorimetric and HPLC analyses confirmed the beneficial effects of the increase of ultrasonic time on the yield of anthocyanins from square peels. In addition, five anthocyanins extracted from eggplant peels were identified as delphinidin-3-rutinoside, delphinidin-3-rutinoside-5-glucoside, petunidin-3-rutinoside, where malvidin-3-rutinoside-5-glucoside and cyanidin-3-rutinoside were detected for the first time in eggplant peel extracts. Microscopic evaluation proved that ultrasonic processing and its contact time have significant effects on the structure changes, which caused damage in cells for pretreated samples in comparison with untreated ones. These results indicated that suitable ultrasonic pretreatment, can reduce the extraction time with high yield of phenolic compounds.

Optimizing a sustainable ultrasound-assisted extraction method for the recovery of polyphenols from lemon by-products: comparison with hot water and organic solvent extractions

Response surface methodology (RSM) based on a three-factor and three-level Box–Behnken design was employed for optimizing the aqueous ultrasound-assisted extraction (AUAE) conditions, including extraction time (35–45 min), extraction temperature (45–55 °C) and ultrasonic power (150–250 W), for the recovery of total phenolic content (TPC) and rutin from lemon by-products. The independent variables and their values were selected on the basis of preliminary experiments, where the effects of five extraction parameters (particle size, extraction time and temperature, ultrasonic power and sample-to-solvent ratio) on TPC and rutin extraction yields were investigated. The yields of TPC and rutin were studied using a second-order polynomial equation. The optimum AUAE conditions for TPC were extraction time of 45 min, extraction temperature of 50 °C and ultrasonic power of 250 W with a predicted value of 18.10 ± 0.24 mg GAE/g dw, while the optimum AUAE conditions for rutin were extraction time of 35 min, extraction temperature of 48 °C and ultrasonic power of 150W with a predicted value of 3.20 ± 0.12 mg/g dw. The extracts obtained at the optimum AUAE conditions were compared with those obtained by a hot water and an organic solvent conventional extraction in terms of TPC, total flavonoid content (TF) and antioxidant capacity. The extracts obtained by AUAE had the same TPC, TF and ferric reducing antioxidant power as those achieved by organic solvent conventional extraction. However, hot water extraction led to extracts with the highest flavonoid content and antioxidant capacity. Scanning electron microscopy analysis showed that all the extraction methods led to cell damage to varying extents.

Antioxidant Properties of Fractions for Unripe Fruits of Capsicum annuum L. var. Conoides.

Capsicum plant, especially for C. annuum, is an abundant resource for bioactive antioxidants, but few studies have examined the unripe fruit part of the Capsicum plant. MeOH extract of unripe fruits of C. annuum L. var. conoides (UFCA) was chromatographed over a silica gel column using a gradient of CH2Cl2/MeOH as eluent to produce 9 fractions. Antioxidant activities are evaluated along with cell viabilities of 9 fractions of UFCA. The antioxidant properties were analyzed in terms of total phenol content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2-azinobis (3-ethyl-benzothiazoline-6- sulfonic acid) (ABTS) radical scavenging, ferric reducing, and ferrous ion-chelating ability. The cell viability of human oral cancer cells (Ca9-22) was measured by 3-(4,5-dimethylthiazol-2-yl)-(3-carboxymethoxyphenyl)-2- (4-sulphophenyl)-2H-tetrazolium (MTS) assay. Except for TFC, fractions (Frs.) 1 and 2 showed the lowest level of these antioxidant properties. Frs. 3 to 9 showed dose-responsive induction for antioxidant effects. Fr. 8 and Fr. 5 respectively showed the highest levels of TPC and TFC for 1162 ± 11 gallic acid equivalents (GAE) (mg)/UFCA (g) and 1295 ± 32 quercetin equivalents (QCE) (mg)/UFCA (g). The cell viability of Fr. 3 was moderately decreased (78.2%) while those of Frs. 4, 5, and 9 were dramatically decreased (55.6, 57.8, and 46.8%, respectively) in oral cancer Ca9-22 cells. UFCA-derived 14 compounds/mixtures derived from Frs. 1, 2, 3, 4, and 8 displayed differential antioxidant performance for these analyses. Taken together, fractions of UFCA displayed diverse antioxidant and anticancer effects for oral cancer cells. Some fractions of UFCA may be potent natural antioxidant supplements for antioral cancer cell treatment.

&lt;em&gt;In vitro&lt;/em&gt; antioxidant and &lt;em&gt;in vivo&lt;/em&gt; anti-inflammatory activity of &lt;em&gt;Curcuma albiflora&lt;/em&gt; Thw.

Curcuma albiflora Thw. is a poorly explored plant which is termed as Harankaha locally. Among other Harankaha plants, C. albiflora is threaten and restricted to Sabaragamuwa province only. Therefore, current study was conducted to quantify phytochemicals in terms of total phenolic content (TPC), total flavonoid content (TFC) and prove or disprove its antioxidant and anti-inflammatory activity using ferric reducing antioxidant power (FRAP), DPPH, ABTS+, and oxygen radical absorbance capacity (ORAC) assays, and carrageenan-induced paw oedema, formaldehyde-induced paw oedema, and cotton pellet induced granuloma tests in Wistar rats respectively. Whole plant extract from composite samples was prepared using 50% ethanol (in water) and 50% dichloromethane (in methanol) as solvents mixture by continuous extraction (6 h). Antioxidant values of TPC, TFC, and FRAP were 31.25 ± 1.48, 11.22 ± 0.13, and 17.90 ± 0.38 mg/g respectively. IC50 values (ppm) of DPPH and ABTS+ were 827.78 ± 6.06, and 188.84 ± 2.99 respectively. ORAC value was 128.10 ± 3.29 mg/g. The correlation of TFC was shown that it may link to flavonoid content. Since, C. albiflora inhibited (61% at 1h) 1st phase in the acute model, and at the late phase on sub-chronic model considering insignificant on cotton pellet granuloma test was shown that its anti-inflammatory activity (as 19.5% on 400 mg/kg) may not relate on prostaglandin. Further experiments are warrant to identify a mechanism of anti-inflammatory activity of C. albiflora.

One-step sample preparation for convenient examination of volatile monoterpenes and phenolic compounds in peppermint leaves using deep eutectic solvents

Deep eutectic solvents (DESs) were investigated as an extraction medium for one-step sample preparation for chemical characterization of peppermint (Mentha piperita L.). Rather than applying discontinuous, time-consuming extraction methods to prepare two types of extracts, peppermint leaves were extracted efficiently into a DES, which was composed of choline chloride and d-(+)-glucose at a 5:2 molar ratio. The produced peppermint extracts contained volatile monoterpenes and phenolics at levels sufficient for direct chemical examination of peppermint leaves. The extracted monoterpenes in DES could be quantified via a newly developed method based on headspace solid-phase microextraction coupled to gas chromatography. The same extracts were also directly used to assess phenolics in terms of total phenolic content, total flavonoid content, and antioxidant activity. The proposed method allowed one-step sample preparation for extraction of volatile monoterpenes and phenolics of peppermint leaves and could be applied to various peppermint samples obtained from different origins.

Analysis of 17 polyphenolic compounds in organic and conventional legumes by high-performance liquid chromatography-diode array detection (HPLC-DAD) and evaluation of their antioxidant activity

Consumption of legumes has become popular among health-conscious consumers due to the high levels of nutrients such as proteins, dietary fibres, minerals, vitamins and micronutrients like polyphenols. Ten legumes cultivars organically and conventionally grown were compared regarding their chemical profiles in terms of total phenolic content (TPC), total anthocyanin content (TAC), total flavonoid content (TFC) and their antioxidant capacity. The chemical profiles (i.e. free phenolics and anthocyanins) were determined with aid of new high-performance liquid chromatography-diode array detection (HPLC-DAD) method able to identify two individual anthocyanins and 15 polyphenols. Results showed that phenolic acids, namely gallic acid, caffeic acid, syringic acid and ferulic acid, are mainly significantly higher in the organic samples with respect to the conventional ones. All organic legumes showed a higher antioxidant capacity with respect to conventional samples with the exception of red and yellow dehulled lentils.

Effect of Sun, Oven and Freeze-Drying on Anthocyanins, Phenolic Compounds and Antioxidant Activity of Black Grape (Ekşikara) (Vitis vinifera L.)

The aim of this study was to determine whether a change occurs in the phenolic compounds and antioxidant activity of grapes after drying. Grapes pre-treated with potassium hydroxide solution were dried using three different drying methods, namely freeze drying, oven drying and sun drying. The effectiveness of the drying methods was evaluated in terms of total phenolic content, antioxidant activity (ABTS, FRAP and DPPH), individual phenolics and anthocyanins. Losses in total phenolic content of the grapes were found to be 1.89, 20.26 and 46.79% for freeze-, oven- and sun-dried grapes respectively. The DPPH and ABTS antioxidant activities of the grapes decreased after drying by all three methods, while an increase was observed in the FRAP value of freeze-dried grapes compared to the fresh sample. No significant effect of drying methods was observed on the gallic acid, 2,5-dihydroxybenzoic acid and (-)-epigallocatechin gallate contents of the grapes. The highest levels of procyanidin B1, (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, chlorogenic acid, trans-resveratrol and rutin were determined in freeze-dried grapes. Sun and oven drying caused drastic decreases in all anthocyanins, while no loss of anthocyanin was observed in freeze-dried grapes. Sun drying was found as the most detrimental drying method for grapes in terms of phenolic compounds and antioxidant activity when compared to the other drying methods.

Process optimization of polyphenol extraction from carob (Ceratonia siliqua) kibbles using microwave‐assisted technique

Microwave-assisted extraction (MAE) method was investigated to recover phenolic compounds from carob kibbles and validated using response surface methodology. The study parameters were microwave power (170–900 W), ethanol concentration (30–90%), and solvent-to-sample ratio (10–30 mL/g) in terms of total phenolic content (TPC) and condensed tannins. Among optimized parameters (340 W, 45%, 30 mL/g), microwave power and ethanol concentration were found more influential parameters to get higher yields of TPC and condensed tannins. Moreover, the results of TPC (70.11 mg GAE g−1 DM), condensed tannins (4.11 mg CE g−1 DM), free radical scavenging activity (94.42%), ferric ion reducing potential (22.67 mg Fe+3 100 g−1 DM), and gallic acid (1.576 mg/g DM) obtained from optimal MAE conditions were found comparable to ultrasound-assisted extraction method. The newly developed MAE method illustrates its potential to recover phenolic compounds from plant sources in a short duration. Practical applications Based on the results presented in this work, it is proposed that carob kibble could be considered as interesting raw material to get extracts rich in antioxidant properties. This extract could be used as an alternative to synthetic antioxidants in bio-food products as natural preservative. Therefore, carob kibbles could be recommended for production of extracts rich in antioxidants, instead of being discarded from gum factory as by-product. In addition, microwave-assisted extraction method could be employed to increase time efficiency of the process.

The effect of harvest time on the bioactive properties and volatile components of lavender (Lavandula officinalis)

This study was designed to determine the effect of harvest time on the bioactive properties and volatile components of flowers, leaves and stems of Lavandula officinalis. The bioactive properties were examined in terms of total phenolic content, antiradical activity and antioxidant capacity by the Folin-Ciocalteu, 1.1-diphenyl-2-picrylhydrazyl scavenging and phosphomolybdenum methods, respectively. Volatile components were detected with gas chromatography-mass spectrometry. Water and methanol were used for extraction solvent and three different parts of the day (morning, midday and evening) were selected for harvest time. Water extracts had higher total phenolic contents (337.2-771.5 mg gallic acid equivalents (GAE)/g dry extract) than methanolic extracts (170.3-320.8 mg GAE/g dry extract), and in general, midday values were less than morning and evening rates and had a significant difference depending on harvest time. A similar feature was observed in respect to antioxidant properties. The inhibition rat...