Oguzhan Caliskan

Determining total phenolic content and total antioxidant capacity of loquat cultivars grown in Hatay

Several fruit characteristics of five loquat (Eriobotrya japonica (Thunb.) Lindl.) cultivars/selections grown in Dörtyol, Hatay, Turkey were investigated in 2008. The cultivars/selections included ‘Baduna 5’, Güzelyurt 1, ‘Hafif Çukurgöbek’, ‘Ottaviani,’ and Type 1. The characteristics evaluated included fruit weight, width, length, seed number and weight, flesh/seed ratio, total soluble solids (TSS), pH, acidity, total phenolic (TP) content, and total antioxidant capacity (TAC), determined by the ferric reducing antioxidant power (FRAP) assay. The analyses were conducted by three replicates, with 30 fruits in each replicate. The results indicated that there were significant differences among the cultivars, for all the traits tested. For example, ‘Hafif Çukurgöbek’ and ‘Ottaviani’ had smaller fruits than others, although ‘Hafif Çukurgöbek’ had heavier seeds. The flesh/seed ratio was the highest in Type 1, while ‘Hafif Çukurgöbek’ had the highest pH and high soluble solids. ‘Baduna 5’ and ‘Hafif Çukurgöbek’ had the highest acidity. The TP ranged from 129 (‘Baduna 5’) to 578 (‘Hafif Çukurgöbek’) mg gallic acid equivalent (GAE)/kg fresh fruit (fw). ‘Hafif Çukurgöbek’ also had the highest FRAP mean (12.1 mmol Trolox Equivalent (TE)/kg fw). The results suggest that loquat cultivars have a variable range of TP content and a relatively high total antioxidant capacity, which is crucial for human health.

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.

Relationships among Crataegus accessions sampled from Hatay, Turkey, as assessed by fruit characteristics and RAPD

The genus Crataegus known as hawthorns, is the largest genus among the Maloideae, which comprises 265 species. Turkey is one of the genetic centers of Crataegus and there are more than 20 species found in Turkey. The fruits of Crataegus are used as food and have high flavonoid, vitamin C, glycoside, anthocyanidin, saponin, tannin, and antioxidant levels. In this study, we attempted to characterize 15 Crataegus accessions sampled from Hatay, located in Eastern Mediterranean region of Turkey. The accessions belonged to several species; C. aronia (L.) DC. var. aronia, C. aronia var. dentata Browicz, C. aronia var. minuta Browicz, C. monogyna Jacq. subsp. azarella (Griseb.) Franco, and C. orientalis Pall. ex M. Bieb. var. orientalis. Fruit characteristics of the accessions exhibited considerable variation. The multivariate, principle component and cluster analyses indicated that the accessions belonged to three groups: (1) C. aronia var. arona accessions; (2) C. aronia var. dentata accessions; and, (3) C. monogyna subsp. azarella and C. orientalis var. orientalis accessions. The principle component analysis results also revealed that the first three components explained 46, 21, and 14% of the variation, comprising a total of 81%. The fruit length and width, leaf area, and soluble solids contents were highly correlated characteristics for the first three components. The 19 RAPD primers generated a total of 107 bands, where 76 of these were polymorphic. The molecular data analyses by principle coordinate and clustering showed similar results to those of pomological characteristics. There were three groups, (1) C. aronia var. arona accessions; (2) C. aronia var. dentata accession; and, (3) C. monogyna subsp. azarella. C. orientalis var. orientalis accession grouped with C. aronia var. arona accessions. Therefore, it can be concluded that, overall, the diversity patterns of pomological and molecular data, generated by RAPD, for Crataegus are in good agreement and the accessions of C. aronia var. aronia, C. aronia var. minuta, C. monogyna subsp. azarella and C. orientalis var. orientalis accessions.

Correlations among Important Fruit Quality and Plant Characteristics of Some Fig Genotypes

Experiments were carried to determine correlations of important fruit and plant characteristics using 30 fig genotypes. The correlation coefficients between these traits were calculated using SAS program. Fruit weight, fruit diameter, fruit length, neck length, ostiolium width, abscission of the stalk from the twig, ease of peeling, fruit skin cracks, thickness of the fruit skin, texture of skin, fruit ribs, fruit internal cavity, TSS (total soluble solids), pH, acidity, TSS/acidity, trunk diameter, shoot length, yield per tree were traits examined in the study. According to five-year data, fruit weight was found to have positive correlation by fruit diameter (r = 0.92; P < 0.01), fruit length (r = 0.81; P < 0.01), neck length (r = 0.35; P < 0.01), ostiolium width (r = 0.23; P < 0.01), trunk diameter (r = 0.26; P < 0.01), fruit skin cracks (r = 0.26; P < 0.01) and negative correlation by TSS (r = -0.26; P < 0.01) and fruit ribs (r = -0.21; P < 0.01). Relations between some traits such as ostiolium width, abscission of the stalk from the twig, ease of peeling, fruit skin cracks, texture of skin and fruit ribs are deviated based on the years. Some relationships between fig fruit characteristics exist, which may help researchers to solve some problems such as ostiolium width and fruit skin cracking. These studies may contribute to producing fruit with a good quality and help to evaluate new cultivars.

Yield and Fruit Characteristics of Various Apricot Cultivars under Subtropical Climate Conditions of the Mediterranean Region in Turkey

Seven apricot cultivars (“Beliana,” “Canino,” “Precoce de Colomer,” “Feriana,” “Rouge de Sernhac,” “Tokaloglu,” and “Macar”) were evaluated at the experimental orchard of the Department of Horticulture, Faculty of Agriculture, Mustafa Kemal University, Hatay, Turkey. Phenological and pomological characteristics such as flowering period, average fruit weight, yield, fruit dimensions, flesh/seed ratio, acidity, and total soluble solids (TSSs) were examined. In addition, yield parameters of the cultivars were evaluated. Over four years, the highest average fruit weight was obtained from “Rouge de Sernhac” (37.9 g), while “Feriana” had the lowest (30.9 g). The flesh/seed ratio was the highest in the “Canino” (16.8). “Canino” had the highest TSS content with 14.5%, whereas “Beliana” had the lowest TSS value with 10.6%. “Beliana” and “Feriana” ripened the earliest (May 20) while “Precoce de Colomer” ripened latest (June 7). The average yield was highest on “Rouge de Sernhac” (41.2 kg/tree). “Beliana” and “Feriana” cultivars are recommended for precocity, and “Rouge de Sernhac” and “Tokaloglu” for middle season in Dortyol, Turkey.