ABTS Values Research Articles

Antioxidant and Antidiabetic Activities of Mempening (Lithocarpus bancanus) Leaves

Background: Lithocarpus bancanus or commonly called as mempening in Talang Mamak Tribe, Indonesia is a plant that is used as a traditional medicine. Objective: This study aim to evaluated antioxidant and antidiabetic activities of L. bancanus leaves extract. Material and Methods: The methanol extract was obtained by maceration of the leaves. The n-hexane, dichloromethane and ethyl acetate fractions were prepared by successive partition process of the methanol extract. Antioxidant activities were evaluated by various antioxidant assays, including DPPH (1,1-diphenyl-2-picrylhydrazyl), FRAP (ferric reducing antioxidant power), CUPRAC (cupric reducing antioxidant capacity), and ABTS (2,2’-azonobis 3-ethylbenzothiazoline-6-sulfonic acid) method. Total phenolics were estimated based on the Folin–Ciocalteu method, while, aluminum chloride methods were employed to estimate total flavonoids. Antidiabetic activies was determined by inhibiting the activity of α-glucosidase method. Results: antioxidant activity assay against DPPH radical as well as the total phenolic and flavonoid content of L. bancanus leaves showed that the methanol extract possessed IC50 value of 39.469 ± 0.273 μg/mL with total phenol and flavonoid were 11.426 ± 0.432 mg GAE/g dry weight sample and 15.423 ± 0.213 mg QE/g respectively. The FRAP, CUPRAC and ABTS values of methanol extract were 3494.302 ±0.456, 26665.501 ± 5.940 and 2857.977 ± 0.715 μM TE/g dry weight sample respectively. Antidiabetic activity of methanol extract with IC50 value of 30.565 ± 0.331 μg/mL. Conclusion: It could be concluded that leaves of L. bancanus have antioxidant and antidiabetic properties.

Encapsulation of Amazonian Blueberry juices: Evaluation of bioactive compounds and stability

Bioactive compounds of Clidemia japurensis and Clidemia hirta juices were encapsulated in maltodextrin (MD) of different dextrose equivalents (DE – MD10, MD20 AND MD30). Microparticles containing the encapsulated juices were obtained by freeze-drying process. The stability of the encapsulated bioactive compounds was evaluated under different relative humidity (22 and 77%) at 25 °C by DPPH and ABTS methods. Twelve bioactive compounds were identified by UFLC-Q-TOF-MS/MS and classified as organic acids, flavonoids and anthocyanins. The juices presented good antioxidant properties [DPPH value of 943 ± 15 (C. japurensis) and 994 ± 14 μM TE (C. hirta); ABTS value of 1119 ± 24 (C. japurensis) and 1273 ± 18 μM TE (C. hirta)]. Encapsulation Efficiency (EE) ranged from 97.0 to 99.8% (DPPH) and from 87.8 to 99.1% (ABTS). The encapsulated juices did not present activity water (AW) values that could favor microbial growth. The powdered juices prepared using lower DE carrier resulted in better retention and stability of the bioactive compounds due to the low water adsorption According to the ABTS results, the bioactive compounds of C. hirta and C. japurensis encapsulated in MD10 carrier and stored at RH = 22% presented half-life time around 45 and 37 days, respectively. These results represent an interesting possibility of application in food industry.

Polish honey as a source of antioxidants – a comparison with Manuka honey

The aim of this study was to determine the physicochemical and antioxidant properties of four Polish kinds of honey compared to Manuka honey. Moisture content, water activity as well as color features of honey samples were examined. Phenolic content, ferric reducing/antioxidant power assay (FRAP), and ABTS assay were also quantified. Manuka honey had the highest content of polyphenols and the best antioxidant capacity (based on Tukey’s test), whereas multiflower honey had the lowest biological potential. The results indicated that buckwheat Polish honey is a good source of antioxidants compared to Manuka honey and should be more widely consumed. The total polyphenolic content was found to be highly correlated with the FRAP and ABTS values. The results of correlation analysis between dielectric honey parameters and phenolic content as well as antioxidant capacity suggest the possibility of using dielectric loss coefficient and relative permittivity as indicators of honey biological potential.

Potential of a new beetroot cultivar ‘Śnieżna kula’ (<i>Beta vulgaris</i> L. ssp.)

Beetroot is a vegetable known since antiquity, valued due to its high pro-health potential resulting from the high content of betalaine pigments, mainly betanin. Due to the allergenic nature of this compound, there may be some of the restrictions concerning red beetroots consumption. This study analysed the physicochemical characteristics of a new white beetroot cultivar ‘Śniezna Kula’ (‘Snowball’), which can become an alternative to red beetroot. The effects of the size and particular parts of the roots were assessed on betalain pigment, reducing sugar, total sugar, phenolic compounds, nitrate (III) and nitrate (V) contents, and on the antioxidant capacity (expressed as a FRAP and ABTS value). The mass of the beetroots of the ‘Śniezna Kula’ cultivar varied and ranged from 279 to 1118 g. The analysed beetroot is devoid of red betalain pigments. The total sugar content was the highest for group B (401–600 g) with an average of 33.5 mg kg−1 FW. The roots with a less weight, i.e. those of groups A contained their greater amount phenolic compounds and chlorogenic acid (415 mg kg−1 FW i 279 mg kg−1 FW, respectively). A the same time, less roots contained more nitrates (V), ranging from 3 301 to 3 534 mg kg−1 FW. The inner parts of the root contained more nitrates (III) and (V), while the outer parts of the roots were richer in polyphenols and chlorogenic acid. The antioxidant capacity was correlated with polyphenol and chlorogenic acid contents. The roots for group A (<400 g) the bottom under leaf part and the bottom under leaf part proven antioxidant capacity respectively 17.5; 16.3 mmol Fe2+ kg−1 FW (FRAP) and 8.50; 8.40 mmol Trolox kg−1 (ABTS).

Oxidative balance in follicular fluid of ART patients of advanced maternal age and blastocyst formation.

Objective:To evaluate the follicular fluid oxidative balance of infertile patients of advanced-maternal-age and the correlation between oxidative imbalance in the follicular fluid and the embryological outcomes.Methods:Follicular fluid (FF) from infertile patients of advanced-maternal-age undergoing ART treatments were collected and frozen in cryovials at -86°C until further use, and analyzed at the Biochemistry and Nutrition Institute of San Marcos University. As controls, we used FF from oocyte donors. The FF was then assayed for oxidative balance by ABTS, FRAP and TBARS assays. In order to establish the correlation between oxidative balance and embryo quality, we correlated the number of usable blastocysts (freshly transferred or frozen blastocysts) with the results from ABTS, FRAP and TBARS.Results:Follicular fluid from patients of Advanced-maternal-age (AMA group) significantly differed from the values found in the control group; the ABTS value was higher and the FRAP value was lower, in comparison to the FF from oocyte donors (control group). The lipid peroxidation was not different between those two groups. Furthermore, there was no significant correlation among the results of the assays, or when correlated with the proportion of usable blastocysts.Conclusion:Ovarian oxidative balance seems to be critical for oocyte quality in advanced-maternal-age patients; however, we still need more studies on oxidative stress indicators, on a larger set of patients.

MICROBIOLOGICAL, CHEMICAL COMPOSITIONS AND ANTIOXIDANT CAPACITY OF TARHANA CHIPS FERMENTED WITH KEFIR

In this study, the tarhana samples which fermented with kefir showed higher antioxidant activity than tarhana samples which fermented with yogurt (without kefir grains). The control tarhana chips (fermented with yogurt) samples (0.47±0.51 µmol/g TE) had significantly (P&amp;lt;0.05) lower antioxidant capacity (DPPH radical scavenging activity) than the fermented with kefir (0.67±0.02 µmol/g TE) samples. The ABTS values (0.83±0.28 µmol/ TE gr and 0.71±0.32 µmol/ TE gr) of extracts were significantly different in YT sample and KT samples fermented with kefir. The difference in antioxidant activities of traditional tarhana chips and tarhana with kefir grains was statistically significant (P&amp;lt;0.05). The analysis of total coliform group bacteria, total aerobic mesophilic bacteria, total Lactobacillus spp., and yeast-mould counts were conducted in samples. None of the samples contained coliform group bacteria. At the end of fermentation, count of Lactobacillus spp. and total aerobic mesophilic bacteria for traditional tarhana chips and fermented chips with kefir determined 8.47-8.94 log cfu/g and 7.43-7.95 log cfu/g, respectively. Yeast counts in the samples of chips fermented with kefir was found 6.89 log cfu/g. As a result, the use of kefir instead of yogurt in tarhana chips production is highly recommended as a tarhana type which has the potential to be a highly functional product with a high nutritional value due to its significant increase in antioxidant properties and its contribution to protein content.

&lt;em&gt;Moringa oleifera&lt;/em&gt; leaf extract as a biostimulant on growth and other physio-chemical attributes of rubber (&lt;em&gt;Hevea brasiliesnsis&lt;/em&gt;) under drought and heat stress conditions

Drought and high temperature are the major impediments limiting growth of Hevea. We studied the efficacy of foliar applied Moringa (Moringa oleifera) leaf extract (MLE) as a biostimulant on the response of Hevea to sub-optimal climatic conditions. Rubber plants of clone RRISL 203 cultivated in the Intermediate Zone (IZ) and Dry Zone (DZ) were spray treated with water (mock treatment), MLE at 5, 10 and 15% concentrations for IZ and 3 and 5% for DZ. Physiological parameters viz. net photosynthesis (Pr), chlorophyll content (Cc), stomatal conductance (gs) and leaf water potential (Ψ) were recorded after three months from the commencement of treatments whilst girth measurements were recorded at three and twelve months after treatments in the IZ. Total phenolic content (TPC) and antioxidant activities, employing FRAP (ferric reducing assay power) and ABTS (2,2’-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) techniques, were estimated after three months from first spraying in the DZ. Significantly higher Pr, Cc and gs values were recorded from plants treated with MLE at all three concentrations as compared to control. Significantly higher TPC values (17.17 and 15.90 mg of gallic acid equivalent/ g of leaf sample), and FRAP values (14.79 and 14.70 mg of trolox equivalent/g of leaf sample) and ABTS values (70.26 and 59.43 mg of TE/g of leaf sample) were recorded in plants treated with MLE at both concentrations (3 and 5%) as compared to control (12.50 mg of GAE/g of leaf sample, 10.68 mg of TE/g of leaf sample and 49.96 mg of TE/g of leaf sample), respectively. A significantly higher girth (11.5 cm) was recorded in plants treated with MLE at 5% as compared to control (9.66 cm) after 12 months of treatments. Improved growth and physio-chemical attributes of rubber plants could be attributed to the beneficial effect of MLE as a biostimulant and therefore, exogenous application of MLE could effectively be utilized as an environmental friendly and inexpensive strategy for growth improvement in Hevea under sub-optimal climatic conditions.

Chemical compositions and antioxidant activity of adlay seed (Coixlachryma-jobi L.) oil extracted from four main producing areas in China.

Adlay oil (AO) is an important component of adlay seeds that has many beneficial functions to human health. In this study, the variations in the chemical composition and antioxidant activity of AOs extracted from adlay samples obtained from four main producing areas of China were first investigated. Results revealed that the AO of the adlay samples varied from 7.398 ± 0.486% to 8.464 ± 0.725%. The highest contents of total fatty acid, triolein, total phenolic, and total flavonoid were observed in Xingren AO, whereas coixol content was found to be highest in Pucheng AO. The AO samples were grouped successfully in accordance with the origins by partial least squares-discriminant analysis and hierarchical cluster analysis based on the contents of the chemical components. Furthermore, AOs exhibited considerable levels of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity (IC50 , 0.924 ± 0.113 to 1.116 ± 0.109 mg/mL) radical scavenging activity, ferric-reducing antioxidant power (FRAP) activity (EC50 , 0.019 ± 0.002 to 0.028 ± 0.002 mg/mL) activity, and β-carotene-linoleic acid bleaching activity (IC50, 0.233 ± 0.008 to 0.414 ± 0.012 mg/mL) activity. Total phenolic and total flavonoid both demonstrated highest correlation with ABTS values (r = -0.952 and r = -0.960, respectively). The results derived from above studies suggest that geographic origin has a certain influence on the phytochemical profiles and antioxidant activity of the AOs. PRACTICAL APPLICATION: The chemical composition and antioxidant activity of adlay oils extracted from the adlay samples obtained from four main producing areas of China were evaluated, including total fatty acid, triolein, total phenolic, and total flavonoid, and ABTS radical scavenging activity, FRAP activity, and β-carotene-linoleic acid bleaching activity.

Phenolic profiling and in vitro bioactivity of Moringa oleifera leaves as affected by different extraction solvents.

In this work the (poly)-phenolic profile of Moringa oleifera leaves was comprehensively investigated through untargeted metabolomics, following a homogenizer-assisted extraction (HAE) using three solvent systems, i.e. methanol (HAE-1), methanol-water 50:50 v/v (HAE-2) and ethyl acetate (HAE-3). This approach allowed to putatively annotate 291 compounds, recording mainly flavonoids and phenolic acids. Thereafter, antioxidant capacity, antimicrobial activity and enzyme inhibition were assayed in the different extracts. HAE-1 extract showed the highest total phenolic content (31.84 mg/g), followed by HAE-2 (26.95 mg/g) and HAE-3 (14.71 mg/g). In addition, HAE-1 and HAE-2 extracts exhibited an expressive activity against Bacillus cereus and Listeria innocua. The HAE-2 leaf extract was characterized by the highest DPPH and ABTS values (being 49.55 and 45.26 mgTE/g), while ferric reducing antioxidant power was found to be higher in HAE-1 (58.26 mgTE/g). Finally, the enzyme inhibitory effects of M. oleifera leaf extracts were investigated against five enzymes, namely acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, α-amylase and α-glucosidase. All of the tested extracts exhibited inhibitory effects on AChE and BChE with a higher activity for HAE-3 and HAE-1, whilst HAE-1 showed the higher impact on tyrosinase, glucosidase and amylase activities. Taken together, these findings suggest that M. oleifera leaf extracts are a good source of bioactive polyphenols with a potential use in food and pharma industries.

Amino Acid Profile, Functional Properties and In-vitro Antioxidant Capacity of Cucurbita maxima and Cucurbita mixta Fruit Pulps and Seeds

The study aimed at evaluating the amino acid profile, fatty acid profile, anti-nutritional factors, functional properties and in-vitro antioxidant activities of Cucurbita maxima and Cucurbita mixta fruit pulps and seeds. Freshly harvested Cucurbita mixta and Cucurbita maxima fruit were processed into flour as; Pa: Cucurbita maxima pulp flour, Pi: Cucurbita mixta pulp flour, Sa: Cucurbita maxima seed flour and Si: Cucurbita mixta seed flour and were evaluated for amino acid profile, fatty acid profile, anti-nutritional factors, functional properties and in-vitro antioxidant activities. Triplicate data were analysed and means were separated using New Duncan Multiple Range Test (NDMRT) at p&lt;0.05. The protein content of the fruit pulps and seeds flour samples were 12.77 g/100 g (Pi), 13.22 g/100 g (Pa), 15.37 g/100 g (Sa) and 16.86 g/100 g (Si). Total essential amino acid was 5.33 mg/100 g of protein (Pa) 6.62 mg/100 g of protein (Pi), 9.85 mg/100 g of protein (Sa) and 14.61 mg/100 g of protein (Si). Total essential amino acid of Pi and Si are significantly higher (p&gt;0.05) than Pa and Sa. Statistically, saturated fatty acid and polyunsaturated fatty acid of the Pi and Si were significantly lower (p&lt;0.05) than Pa and Sa respectively. Antioxidant activities against ABTS* (Pi) is significantly higher (p&gt;0.05) than Pa and with no significant differences (p&lt;0.05) between ABTS values of Si and Sa. While there is a significant difference (p&lt;0.05) between Si and Sa as well as Pi and Pa antioxidant activities against DPPH* respectively. In conclusion, Cucurbita seeds and pulps flour contains high protein content, appreciable amount of essential minerals, lower Na/K molar ratio of less than one and they also exhibit a good free radical scavenging abilities against DPPH*, ABTS* and ability to reduce Fe3+ to Fe2+ with high content of total phenol and flavonoid.

Antioxidant properties and selected phenolic acids of five different tray-dried and freeze-dried mushrooms using methanol and hot water extraction

Mushrooms are health foods due to their nutritional values and antioxidant properties. This study investigated chemical properties, total phenolic content (TPC), antioxidant activities (2, 2-diphenyl-1-picrylhydrazyl; DPPH and 2, 2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid); ABTS) and selected phenolic acids from five different tray-dried and freeze-dried mushrooms (Pleurotus ostreatus, Pleurotus pulmonarius, Schizophyllum commune, Volvariella volvacea and Lentinus edodes). The extracts were prepared using methanol and hot water extractions. The results revealed that V. volvacea had the highest protein (28.70%) and ash (9.48%) contents. There were significant differences among some tray dried and freeze dried mushrooms regarding TPC, DPPH and ABTS. However, tray drying tended to improve TPC, DPPH and ABTS in P. ostreatus, P. pulmonarius and L. edodes. Among five mushroom species, both methanol and hot water extractions of V. volvacea had the highest TPC, DPPH and ABTS values but there were no significant differences between mushrooms prepared using tray drying and freeze drying. Moreover, the yield and contents of gallic acid and p-hydroxybenzoic acid from the hot water extracts were higher than from the methanol extracts. Therefore, tray-dried V. volvacea had the most potential as a natural antioxidant and could be used as a functional ingredient in healthy food products.

Production of White, Red and Black Quinoa (Chenopodium quinoa Willd Var. Real) Protein Isolates and Its Hydrolysates in Germinated and Non-Germinated Quinoa Samples and Antioxidant Activity Evaluation.

Red, black and white seeds quinoa were germinated at 28 °C during 24 (G1), 48 and 72 h (G3). Red quinoa presented a higher percentage of germination with a value of 46% of germination at 72 h. Quinoa protein isolate (QPI) was obtained by alkaline extraction (pH 8.0) followed by an isoelectric precipitation (pH 4.5) from white, red and black quinoa seeds, germinated QPI-G1 or QPI-G3 and non-germinated QPI-NG, Chenopodium quinoa Willd var. Real. QPI-G1, QPI-G3 and QPI-NG were subject to a simulated gastric digestion (DG) and in vitro duodenal digestion (DD). The antioxidant activity was evaluated using the 1, 1-diphenyl-2-picryl hydrazyl (DPPH), azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and oxygen radical absorbance capacity (ORAC) methods. Gastric and duodenal digest of QPI-NG and QPI-G1 and QPI-G3 from white, red and black quinoa presented antioxidant activity. QPI-G1-DD of white quinoa presented the highest antioxidant activity with a DPPH value of 167.98 µmoL TE/g of digest, QPI-G1-DD of red quinoa with an ABTS value of 204.86 µmoL TE/g of digest and QPI-G1-DD of black quinoa with an ORAC value of 401.42 µmoL TE/g of digest. QPI-G3-DD of white quinoa presented higher antioxidant activity with a DPPH value of 186.28 µmoL TE/g of sample, QPI-G3-DD of red quinoa with an ABTS value of 144.06 µmoL TE/g of digest and QPI-G3-DD of black quinoa with an ORAC value of 395.14 µmoL TE/g of digest. The inhibition of reactive oxygen species (ROS) production in the zebrafish embryo model (Danio rerio) was evaluated. Protein profiles of QPI from white, red and black from germinated quinoa and non-germinated quinoa were similar with proteins between 10 kDa to 100 kDa with the presence of globulins 11S and 7S and 2S albumins.

The Influence of Light Wavelength on Growth and Antioxidant Capacity in Pachyrhizus erosus (L.) Urban

Pachyrhizus erosus is a plant that is traditionally used in Asia as a food and herbal medicine. This study examined the impact of light-emitting diodes (LEDs), light-emitting plasma (LEP), and fluorescent lamps (FLs) on the growth, antioxidant properties, and phenolic metabolites of P. erosus. Phenolic compound concentration and composition were determined by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) system. Radical scavenging activity was measured using stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. P. erosus antioxidant activity and phenolic compound composition were improved by the application of LEDs and LEP. Blue LED light also produced significantly higher DPPH radical scavenging activity and ABTS values than the other LED and fluorescent light treatments. In P. erosus seedlings, dry weight, fresh weight, plant height, leaf area, and chlorophyll content were greater under blue LED than under FL light. Furthermore, growth under the blue LED enhanced the epidermal cell length, epidermal cell width, and number of stomata. Antioxidant activity and total phenolic and total flavonoid contents positively correlated in the P. erosus grown under blue LED light condition. Among LED treatments, blue LED produced higher total phenolic compounds, dominated by malonyl daidzin and l-phenylalanine. DPPH assay was highly and significantly correlated with vitexin, salicylic acid, p-coumaric acid, p-hydroxybenzoic acid, l-phenylalanine, daidzein, and daidzin. The present study demonstrated that changes in the growth pattern, antioxidant activity, composition, and metabolite concentration occurred in response to light of different wavelengths in P. erosus seedlings. Thus, LED exposure has the potential to enhance the growth characteristics, metabolite accumulation, and antioxidant properties of P. erosus.

Effects of UV-B radiation on phenolic accumulation, antioxidant activity and physiological changes in wheat (Triticum aestivum L.) seedlings

The production of secondary metabolites and the antioxidant defense systems could be activated in response to ultraviolet-B (UV-B). The effects of UV-B radiation on the phenolic content, antioxidant activity, and physiological changes in wheat seedlings were investigated. Results showed that the free, bound and total phenolic contents and antioxidant activities significantly increased in wheat seedlings after UV-B exposure from the third and fourth day. UV-B radiation of 20 μW/cm2 led to the highest accumulation of phenolics. Total phenolics, DPPH and ABTS values significantly increased by 26.3, 25.1 and 12.0%, respectively, on day 4 as compared to unirradiated wheat seedlings. The highest respiratory rate and phenylalanine ammonia-lyase activity were also observed with the radiation. The increased UV-B radiation intensified the lipid peroxidation in wheat seedlings and changed the activities of antioxidant enzymes involved in the scavenging of reactive oxygen species. The activities of superoxide dismutase, peroxidase and catalase decreased, while the ascorbate peroxidase activity increased with the enhanced UV-B radiation intensity. This study showed that wheat seedlings could be developed as a functional food ingredient after moderate UV-B radiation.

Mixed fermentation of jujube juice (Ziziphus jujuba Mill.) with L. rhamnosus GG and L. plantarum‐1: effects on the quality and stability

SummaryThis study was conducted aiming at improving the quality of jujube juice by mixed fermentation of lactobacilli. Selection of favourable lactobacilli and addition of nitrogen sources were explored as an efficient method to improve the viability of probiotic in jujube juice. After fermentation, the viability increased to 9.15 ± 0.10 Log CFU mL−1, while the content of lactic acid increased to 5.61 ± 0.03 mg mL−1. The total phenolic and total flavonoid content were 2663.03 ± 11.95 μg mL−1 and 163.95 ± 0.47 μg mL−1 respectively. Moreover, the stability of fermented jujube juice during refrigeration was investigated, which showed that the viability dropped to 8.84 ± 0.6 Log CFU mL−1 and the concentration of lactic acid slowly increased to 6.51 ± 0.04 mg mL−1; the ABTS value showed a 4.26% reduction and FRAP value did not significantly (P &lt; 0.05) change during refrigerated storage. In addition to the existing knowledge, our data aid to the future applications of the jujube as a potential ingredient in novel probiotic foods formulation.

Effect of different extraction solvents on phenolic compounds and antioxidant capacity of hop flowers (Humulus lupulus L.)

We investigated the potential of wild hop and determined the effects of different solvent extractions on quality and quantity of hop extracts. Three different solvents - aqueous-ethanol (75%), methanol and acetone - were applied to elicit the secondary metabolites of Humulus lupulus L. cones by automatic Soxhlet system, and extraction yield, total phenolic content, total flavonoid content and antioxidant capacity were compared. The antioxidant activity tests, DPPH, ABTS and FRAP, were used to analyze the antioxidant capacity of extracts. The crude extract obtained by aqueous-ethanol, methanol and acetone extraction were 98.65±5.2, 61.39±3.25, 69.28±4.1 mg g‑1 dry matter, respectively. The total phenolic content (TPC) as well as the total flavonoid content (TFC) of aqueous extracts exhibited the highest values. Also the antioxidant activity of extracts was different: the acetone extract had the highest value of IC(50) in the DPPH test, while the methanol extract has the highest antioxidant activity (1.79±0.25 mM Fe2+ g(‑1)) in the FRAP test, and the best result of percent inhibitors of ABTS (58.12±0.48) was observed for the aqueous-ethanol extract. In addition, ABTS value in aqueous-ethanol extract was 6.45±0.33 mmol Trolox equivalent g‑1 sample, significantly higher than others. No significant correlation was found among antioxidant measurement methods. Overall, 75% ethanol is suggested for the extraction of phenolic compounds from hop flowers due to its polarization diversity. Finally, the wild hop flowers have high antioxidant activity and a remarkable amount of phenolic compounds. They could be applied in food industries as a rich source of antioxidant activity. Characterization of the genetic diversity of wild hops is underway.

Purification and studying some characters of laccase enzyme from irradiated Pleurotus ostreatus ATCC 56270

Purification of laccase enzyme by anion exchange chromatography using DEAE sepharose and sephacryl HR are successful in purifying laccase. The molecular weight of laccase was 75 KDa determined by SDS- PAGE. The optimum pH for activity was 5 and for stability was (6.5-7.5), the optimum temperature for activity was 35oC and stability of the enzyme was stable up to 55oC, the enzyme retained 100% of its activity after 20 minutes incubation, 85% of its activity after 1h incubation at the same temperature. The energy of activation (Eact) of the purified laccase between 20oC and 45oC at its optimum pH was 16.3 k Jmol-1. The apparent Km value of the enzyme for ABTS was estimated to be 1.4 mM under standard assay conditions, kcat value of ABTS was calculated to be 3450 min-1, Vmax is the maximum initial rate in the Michaelis- Menten equation (1.2 µmol L-1 min -1).Microencapsulation of laccase was exhibited that free laccase (35U/ml) has higher activity than encapsulated laccase (24.3 U/ml).

Behavior of bioactive compounds and antioxidant activity of mango (Azucar cultivar) juice during storage at 4 ºC

Mango (Mangifera indica L.) is one the fruits that have shown antioxidant activity and high nutritional value. It was evaluated the effect of storage time and temperature on polyphenol content, ascorbic acid and antioxidant activity of mango (cv. Azucar) juice stored up to 64 days at 4 °C. Total polyphenol content was measured by Folin-Ciocalteu method, mangiferin and ascorbic acid were measured by HPLC (High-Performance Liquid Chromatography) and antioxidant activity was measured by ORAC (Oxygen Radical Absorbance Capacity), and ABTS•+ (2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) method. Total phenolic content decreased after 16 days of juice storage. Ascorbic acid values did not show significant differences until 48 days of storage, and mangiferin content was very similar throughout storage time. The antioxidant activity measured by ORAC method was similar until the end of the storage; however, ABTS value decreased after 32 days of juice storage. In conclusion, storage up to 32 days of mango juice at 4 °C did not alter its antioxidant activity and ascorbic acid content.

In-vitro Assessment of Antimicrobial, Antibiofilm and Antioxidant Potential of Essential Oil from Rosemary (Rosmarinus officinalis L.)

The present study was conducted to investigate in-vitro antimicrobial, antibiofilm and antioxidant efficacy of Rosemary essential oil (REO) for its potential application in meat products. The oil was tested against four Gram positive (Bacilluscereus, Listeria monocytogenes, Staphylococcus aureus and Enterococcus faecalis) and six Gram negative (Salmonella entericaserovar Typhi, Escherichia coli, Shigella flexneri, Pseudomonas aeruginosa, Proteus mirabilis and Klebsiella pneumoniae) organisms using zone of inhibition and Minimum Inhibitory Concentration (MIC) estimation. Widest inhibition zone was exhibited by Staphylococcus aureus whereas, Enterococcus faecalis and Salmonella enterica showed the largest MIC values. Antibiofilm activity (%) was determined by using pure culture of L. monocytogenes and S. aureus as positive control, whereas 1, 1 diphenyl-2picrylhydrazyl (DPPH) and 2-2-azinobis-3ethylbenthiazoline-6-sulphonic acid (ABTS) radical scavenging activity was taken as parameter for antioxidant activity. The results showed that with application of REO, biofilm formation of both L.monocytogenes and S. aureus was inhibited by 73.0 and 77.65%, respectively in comparison to their respective controls. Six different concentrations of oil was used for determination of ABTS and DPPH radical scavenging activity and it was ranging from 8.16–51.80% for DPPH whereas ABTS values ranged from 6.81–44.16% for rosemary oil under investigation. It can be concluded that rosemary essential oil possesses potent antimicrobial, antibiofilm and antioxidant activity, and may be used as a natural preservative to extend the storage stability of meat products.

Differences in antioxidant activity, total phenolic and flavonoid contents of commercial and homemade tomato pastes

Abstract Tomato paste is an important industrial product of food industry, which has been also produced in the homes of tomato producing countries. Although literature on the physical and chemical composition of commercial and homemade types of tomato pastes is available, studies on their antioxidant activity (ABTS), total phenolic content (TPC) and total flavonoid content (TFC) are inexistent. The aim of this study is to compare the TPC, TFC and ABTS values of homemade and commercial types of tomato pastes, as well as their pH, brix and color values. Commercial (n = 9) and homemade (n = 6) tomato pastes were obtained from either national markets or homes that produce tomato pastes in various cities of Turkey. The TPC and TFC values of commercial tomato pastes were 209.62 ± 17.02 mg gallic acid equivalent (GAE) and 42.52 ± 4.85 mg catechin equivalent (CE), respectively, and they were significantly higher (p