Memnune Sengul

Antioxidant properties and total phenolic content of eight Salvia species from Turkey.

Methanolic extracts of eight Salvia species, namely S. aethiopis, S. candidissima, S. limbata, S. microstegia, S. nemorosa, S. pachystachys, S. verticillata, and S. virgata, sampled from Eastern Anatolia in Turkey, were screened for their possible antioxidant activities by two complementary test systems, namely DPPH free radical scavenging and beta-carotene/linoleic acid. Total phenolic content of the extracts of Salvia species were performed Folin-Ciocalteu reagent and gallic acid used as standard. A wide variation has been observed among species in terms of antioxidant activity and total phenolic content. In both DPPH and beta-carotene system, the most active plant was Salvia verticillata with a value of IC50=18.3 microg/ml and 75.8%, respectively. This species also has the highest total phenolic content (167.1 mgGAE/g DW). The total amount of phenolics was between 50.3 to 167.1 mgGAE/g DW among species. A positive linear correlation was observed between total phenolic content and antioxidant activity of the extracts. The results suggest that the extract of Salvia species, notably Salvia verticillata with the highest antioxidant activity, can be used as natural antioxidants in the food industry.

Antioxidant Activity, Total Phenolic Content and Selected Physicochemical Properties of White Mulberry (Morus Alba L.) Fruits

In this study, total phenolic content, antioxidant activity, mineral content and selected physicochemical properties of three white mulberry phenotypes (Morus alba L.) grown in Turkey were measured. Moisture, total soluble solids, total sugar, sucrose, reducing sugar, protein, ash, pH, titratable acidity, color (L, a, b), vitamin C, total phenolic, antioxidant activity of fruits were determined between 72.85–79.75 g/100 g fresh fruit, 21.25–28.50 g/100 g fresh fruit, 12.18–17.02 g/100 g fresh fruit, 1.57–4.36 g/100 g fresh fruit, 9.42–15.46 g/100 g fresh fruit, 0.82–0.89 g/100 g fresh fruit, 2.20–2.65 g/100 g fresh fruit, 5.70–5.86, 0.25–0.28 g/100 g fresh fruit, 31.24–68.69, −2.46 to 15.68, 4.58–21.74, 10.15–21.50 mg/100 g fresh fruit, 18.16–19.24 μg gallic acid equivalent/mg of sample, and 33.96–38.96%, of sample respectively. Fruits were generally found high in P and low in Ca.

Characterization of Red Raspberry (Rubus idaeus L.) Genotypes for Their Physicochemical Properties

The worldwide tendency for growing more small fruits, including raspberries, shows permanent increase because this group of fruits has a relatively higher content of bioactive nutrients. To study the health benefits of red raspberry fruits, 11 preselected wild-grown and 1 well-known cultivar, Heritage, were evaluated for some of their physicochemical properties such as fruit weight, total antioxidant capacity (measured by beta-carotene bleaching and FRAP assays), total phenolics, ascorbic acid, soluble solid content (SSC), and acidity. Fruit weight, SSC, and ascorbic acid contents were between 1.47 and 2.32 g, 10.87% and 13.60%, and 21 and 36 mg/100 g, respectively. Antioxidant activity and total phenolic content varied among genotypes and the ERZ5 genotype had the highest antioxidant capacity as ascertained by both methods. This genotype also had the highest total phenolic (2031 microg GAE/g FW) content. There are linear relationships between antioxidant capacities and total phenols. The present study demonstrates the potential of certain wild genotypes, notably ERZ5, for improving the nutritional value through germplasm enhancement programs.

Antioxidant activities and fatty acid composition of wild grown myrtle (Myrtus communis L.) fruits.

The fruits of eight myrtles, Myrtus communis L. accessions from the Mediterranean region of Turkey were evaluated for their antioxidant activities and fatty acid contents. The antioxidant activities of the fruit extracts were determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. The fatty acid contents of fruits were determined by using gas chromatography. The methanol extracts of fruits exhibited a high level of free radical scavenging activity. There was a wide range (74.51-91.65%) of antioxidant activity among the accessions in the β-carotene-linoleic acid assay. The amount of total phenolics (TP) was determined to be between 44.41-74.44 μg Gallic acid equivalent (GAE)/mg, on a dry weight basis. Oleic acid was the dominant fatty acid (67.07%), followed by palmitic (10.24%), and stearic acid (8.19%), respectively. These results suggest the future utilization of myrtle fruit extracts as food additives or in chemoprevention studies.

Phenolic and antioxidant diversity among persimmon (Diospyrus kaki L.) genotypes in Turkey.

The amount of research on the healthy benefits of fruits has increased in recent years. The objective of the present study is to determine the antioxidant activity and total phenolic content of 18 selected persimmon genotypes. The genotypes were established in a collection parcel at the Black Sea Agricultural Research Institute, Samsun, Turkey. The β-carotene bleaching method was used to determine antioxidant activity and the Folin–Ciocalteau colorimetric method to determine total phenolics in persimmon fruits. The total phenolic content in fruits, estimated as gallic acid equivalents, ranged from 15.7 mg/g dry weight for 08 TH 12 to 42.3 mg/g gallic acid equivalent for the 08 TH 10 genotype. The highest antioxidant activity was observed in 08 TH 10 as 91.6%, while the lowest was in 14 TH 01 (51.7%), respectively. The antioxidant activities of butylated hydroxyanisole and butylated hydroxytoluene were 93.4% and 91.8%, respectively. A low correlation (R=0.711) was obtained between total phenolic content and antioxidant activity among genotypes. The results indicate that antioxidant activity in persimmon fruits is strongly affected by genotype.

Seasonal Variation of Total Phenolic, Antioxidant Activity, Plant Nutritional Elements, and Fatty Acids in Tea Leaves (Camellia sinensis var. sinensis clone Derepazari 7) Grown in Turkey

Seasonal variations of total phenolic, antioxidant activity, PNE (Plant Nutrient Elements), and fatty acids in fresh tea leaves grown in Turkey were studied. Fresh tea leaves sampled from Derepazari 7 clone [Camellia sinensis L. var. sinensis (Theaceae)] were analyzed and compared during the three commercial harvest seasons (May 15, July 15, and September 15) in both 2005 and 2006. The levels of total phenolics and antioxidant activity was higher at 2nd harvest time (62.88 μ g/mg and 89.27%). The seasonal variations of the individual fatty acids were significant (P < 0.05) between the three harvest seasons. The amount of N and P in tea leaves was the highest at 1st harvest; however K, Ca, Mg, S, and Mn were highest at 2nd harvest time. This study revealed that total phenolics could be used as quality descriptors for monitoring the seasonal variations in Turkey-grown tea leaves.

Rheological Characteristics of Carob Pekmez

This study investigated the physicochemical properties and rheological behavior of carob pekmez. Rheological measurements were undertaken at 30, 40, 50, 60, and 70°C using a rotational viscometer at the shear rate of 5, 10, 20, 50, and 100 1/s. The flow characteristics of carob pekmez were described by the power law and Herschel-Bulkley models. The Herschel-Bulkley model was found to be the best to describe the rheological property with the coefficient of determination higher than 0.998. Carob pekmez exhibited a time-independent shear thickening behavior. An Arrhenius equation was used to describe the effect of temperature on viscosity and Ea value of the carob pekmez was calculated as 103.86 kJ mol−1.

Phytochemical characterization of several hawthorn (Crataegus spp.) species sampled from the Eastern Mediterranean region of Turkey.

Background: We evaluated the total phenolic content, antioxidant capacity as well as antioxidant activity of five Crataegus species (A1, A2, Y1, Y2, Y4 accessions of Crataegus aronia var. aronia; B2, B3, B5, B6, B7, B9, Y5 accessions of C. aronia var. dentata; B10 accession of C. aronia var. minuta; Y3 accession of Crataegus orientalis var. orientalis and A3 accession of Crataegus monogyna subsp. azarella). Materials and Methods: Antioxidant activity and total phenolic content of fruits were determined by β-carotene bleaching and Folin–Ciocalteu assays. Antioxidant capacity was determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Results: C. monogyna subsp. azarella had the highest total phenol, antioxidant activity and antioxidant capacity of 55.2 mg gallic acid equivalents (GAE)/g dry weight (DW), 81.9% and 31.2%, respectively. C. aronia var. aronia was found to have the lowest total phenolic content (35.7 mg GAE/g DW). The antioxidant activities of fruit extracts increased in the order of C. orientalis var. orientalis < C. aronia var. minuta < C. aronia var. dentata < C. aronia var. aronia < C. monogyna subsp. azarella according to β-carotene/linoleic acid assay. In recent years, C. aronia var. dentata has gained importance as a commercial species in this region. B3 and B7 accessions had fruit weight more than 14 g, and considerable total phenol content, antioxidant activity and antioxidant capacity. Conclusion: This investigation shows the potential value of hawthorn fruit species as a good source of natural antioxidants and that consumption of hawthorn fruit or its products may contribute substantial amounts of antioxidants to the diet.

Total Phenolic Content, Antioxidant, and Antibacterial Activity of Rumex crispus Grown Wild in Turkey

Abstract In the current study, we evaluated total phenolic content, antioxidant activity (by using β -carotene bleaching assay), and antibacterial activity of aqueous and methanol extracts of the aerial part of the Rumex crispus L. (Polygonaceae) naturally grown in the Eastern Anatolia region of Turkey. The aerial part of the plant had high total phenolic content (56.31 μ g/mg DW). The antioxidant activity of aqueous and methanol extracts of the aerial part of R. crispus L., BHA, and BHT were found to be 92.35%, 95.49%, 98.16%, and 96.66%, respectively. Although the antioxidant activity of the aqueous and methanol extracts of R. crispus was lower than that of the BHA and BHT, the difference between these was not statistically significant, p < 0.05. The methanol extract possessed strong antibacterial activity against Agrobacterium tumefaciens, Bacillus cereus, Bacillus subtilis, Pseudomonas corrugate, Pseudomonas syringae pv. tomato, Salmonella typhimurium, Serratia liquefaciens, Vibrio cholerae, Yersinia frederiksenii, and Yersinia pseudotuberculosis. Therefore, the aerial part of R. crispus can be used as an effective and safe source of antioxidants and antibacterial agent.

Yield and quality responses of drip-irrigated spinach to different irrigation quantities in a semi-arid region with a high altitude

The effect of different irrigation quantities on the growth, marketable yield, crop quality (antioxidant activity, mineral and total phenolic content) and irrigation water use efficiency (IWUE) of spinach grown in a semi-arid region of high altitude (1795 m a.s.l.) was determined. Plants were irrigated with three different irrigation quantities which determined considering 100 (I1), 85 (I2) and 70% (I3) of the evaporation obtained from a Class A pan. Irrigation quantities in the I1, I2 and I3 treatments as two years average were 290, 264.3 and 238.6 mm, respectively. The I1 treatment provided the highest growth, marketable yield (28.06 t*ha-1) and IWUE (9.7 kg*m-3). However, mineral and total phenolic content and antioxidant activity in the leaves of spinach were significantly higher under lower water application conditions. The I2 treatment resulted with the highest antioxidant activity and content of N, K, Mg, Na, Fe, Cu and total phenolics. As a result of the study, I1 treatment in spinach production could be suitable for water sufficient regions due to higher yield and IWUE. However, I2 treatment may be more appropriate for water scarce semi-arid regions of high altitude for obtaining higher minerals and antioxidant activity.