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    Changes in chemical composition, antioxidant activities and total phenolic content of Arbutus Andrachne fruit at different maturation stages
    (Codon Publications, 2009) Özgen, M.; Torun, A.A.; Ercisli, S.; Serce, S.
    Several characteristics of Arbutus andrachne L. fruit harvested at four maturation stages (green, green-orange, orange-red and red) have been examined. Soluble solids, pH, acidity, organic acids, specific sugars, and several nutrient element concentrations (N, P, K, Ca, Mg, Fe, Zn, Mn, Cu) have been determined. The total phenolic content along with antioxidant activity, determined by FRAP and TEAC methods, were also measured. There were significant differences among most of the traits tested. The average soluble solids increased from 16.0 to 20.6% going from the green to the red stages, while the acidity decreased from 0.54 to 0.45%. All of the element concentrations were statistically different among the various stages, with N and Ca being the most variable. The total acidity was found to be the highest in the orange-red and red stages (0.52 and 0.50 g/100 g, respectively). The main organic acid was malic acid (0.32 g/ 100 g) followed by ascorbic and citric acids (0.09 and 0.03 g/ 100 g) respectively. The red (17.84 g/ 100 g) and orange-red (16.25 g/100 g) stages had the highest total sugar values. Fructose was the main sugar in the fruit with an overall average of 8.91 g/ 100g. The total phenolic content was highest at the red stage (3,904 mg gallic acid (GA) /kg fresh weight (fw)), followed by the green stage (3,589 mg GA/kg fw). The antioxidant activities were highest at the red stage as determined by both the TEAC and FRAP methods (26.5 and 21.8 LImol TE/g fw).
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    Öğe
    Determining total phenolics and antioxidant activity of selected Fragaria genotypes
    (Chemical Publishing Co., 2007) Özgen, M.; Serçe, S.; Gündüz, K.; Yen, F.; Kafkas, E.; Paydas, S.
    Strawberries are known to have high antioxidant properties. In present study, we determined total phenolics and antioxidant activity of a group of Fragaria genotypes representing the Turkish diploid strawberry genotypes, dominating cultivars and some selections and hybrids. The average total phenolic compounds and antioxidant capacities were highest in wild material 7914 ?g GAE/gfw and 70.2 ?mol TE/gfw, respectively. The average of total phenolic compounds for hybrids was the highest (2467 ?g GAE/gfw) and followed by selections (2395 ?g GAE/gfw) and varieties (2318 pg GAE/gfw). The values increased during the season progress. A similar trend was observed on antioxidant activity of selected strawberries. The antioxidant capacity in the wild material was detected more than 3 fold higher than the F. xananassa groups (70.2 vs. 19.9, 21.4, 21.1 ?mol TE/gfw). The present results showed that there is a great variability among the strawberry genotypes tested for total phenolic compounds and antioxidant capacities. Therefore, in addition to taste and aroma characteristics high antioxidant properties should be important for cultivar selection by consumers and breeders for healthy diet.