عنوان مقاله [English]
Introduction: The foreign and domestic markets are demanding for high quality citrus varieties. The physical and chemical properties of the newly released cultivars are also important for fresh market or processing. The fruit quality is a complex combination of size, firmness, taste, texture, pleasant aromas caused by a chemical compounds (soluble solid content, sugars, organic acids, aromas) and bioactive properties. Therefore, it is important to consider these indices for the introduction of a new cultivar. In this regard, the Citrus and Subtropical fruits Research Center has focused on improving its appearance, internal and organoleptic quality in releasing the new Jahangir cultivar compared to the Clementine as control.
Materials and Methods: In this study, Jahangir fruits a hybrid between Clementine mandarin (female parent) and Salustiana orange (male parent) (Citrus clementina Hort. Ex Tanaka × C. sinensis (L.) Osbeck cv. Salustiana) was used for comparison with Clementine (Citrus clementina Hort. Ex) Tanaka) as control during the last two years lead to the cultivar introduction. Fruits were randomly selected from different locatiosn on the tree (15 fruits from three trees) and evaluated at harvesting time (zero storage point). Then 30 fruits per box selected and placed in cold storage (5 °C, 85% RH). Different physico-biochemical and sensory characteristics of fruits were evaluated at 0, 20 and 40 days intervals during storage. Characteristics evaluation were including fruit lenght, width, thickness, arithmetic, geometric, equivalent and harmonic means, fruit aspect ratio, sphericity, surface area, true volume, apparent volume, volume error, density, peel and pulp firmness, peel thickness, weight, juice percentage, seed number, peel color indices (L*, a*, b*, hue angle, chroma and CCI), total soluble solid (TSS), titratable acidity (TA), technological index (TI), pH, electrical conductivity (EC), total phenol, ascorbic acid and antioxidant capacity during experiment.
Results and Discussion: Results showed that fruit size (length and two diameters), weight, means of arithmetic, geometric, equivalent and harmonic diameters, surface area and true volume of Jahangir mandarin were significantly higher than Clementine. The different mean diameters of each cultivar was the same as that equivalent diameter that is the most real mean fruit diameter. The higher spherical coefficient (>1) also indicated that Jahangir fruit was longer than the control. Additionally, aspect ratio of Jahangir was also higher than Clementine, which means that Jahangir fruit was a few flat than control. Jahangir had higher levels of L*, b*, C and hue than the control of clementine. In contrast, Jahangir's a* and CCI indices were lower than those of clementine. Therefore, except for L* which is slightly lower than citrus standard (65-70), other indices in both cultivars were conformity within the citrus standard range. Seeds of Jahangir were more than control but both were in the mid seed group (9-15 seeds) of citrus. Jahangir peel was also less easily peeled than control. The weight loss of Jahangir fruit was significantly (almost half) lower than that of clementine at each sampling but increased during storage. It seems Jahangir has a peel with higher density and adhesion than to clementine, which partly prevents the fruit from dehydration. The amount of TSS of fruit juice was higher than that of clementine at harvest and storage but increased in both cultivars during storage. In addition, TA (0.34%) was lower in Jahangir fruit than Clementine (0.45%). Therefore, the ratio of TSS to TA was much higher in Jahangir mandarin (44.25) than clementine (26.16). Juice percentage of Jahangir fruit (44.87%) was significantly higher than Clementine (40.12%). The high percentage of Jahangir fruit juice is a positive trait for this cultivar. Technology index changed depending on cultivar and also during storage. This index was higher in Jahangir fruit than in Clementine with 6.45 and 4.67, respectively. The antioxidant capacity only affected significantly by storage time which showed a decreasing trend during storage. Ascorbic acid content was only affected by cultivar and was higher in control than Jahangir. Lower levels of ascorbic acid in the Jahangir may be due to increased respiration that results in the elimination of ascorbic acid. The phenolic content of Jahangir fruit was higher (0.43 mg/g) than clementine (0.4 mg/g). PCA analysis showed that most of the Jahangir samples placed in the left part of the PCA graph which were dominated by the traits such as taste, sweetness, good peel and pulp appearance and overall acceptance and were more accepted by the sensory evaluators.
Conclusion: In this study, different qualitative characteristics of Jahangir fruit compared to Clementine which are important for the producers. Accordingly, the Jahangir fruit was larger in size but slightly flatter than the Clementine fruit. Jahangir fruit peel color indices were within the standard range of citrus fruits. Jahangir fruit is favored among commercial available mandarins due to ease of peeling, high juice percentage, technology index, vitamin C, phenol and antioxidant capacity. It also had better storability than Clementine because of less water loss and decline of organoleptic properties.