عنوان مقاله [English]
Introduction: Plums (Prunus spp.) as one of the most popular stone fruits, have low calories and high nutritional value. Over the past decades global production of European and Japanese plums reached from 6,110,870 tons in 1990 to 11,528,337 tons in 2013. In the same period plum production in Iran reached from 118,936 tons to 305,262 tons. Great variety of plum fruits caused differences in chemical composition as well. Plum fruits are rich in bioactive compounds or biochemicals such as vitamins (A, C and E), anthocyanins and other phenolic compounds which have high antioxidant activity.
Materials and Methods: This research was done in a randomized complete block design with three replications in Horticultural Research Station at College of Agriculture and Natural Resources of Tehran University in 2013-2015. Fruit quality characteristics such as vitamin C content, color traits of the fruit skin and flesh, the content of carotenoids, anthocyanins, total phenolics and antioxidant capacity of 16 plum and prune cultivars and genotypes were evaluated.
Results and Discussion: Analysis of variance showed significant differences in terms of all measured factors. The highest L* index (brightness) of fruit skin was observed in 'Tanasgol" and "Compooti" and then in "Golden Drop" and "Shams" cultivars and the lowest level of that was measured in "Sugar" and "Gogeh Sabz" cultivars. "Black Star" and "Gogeh Germez" Showed the highest brightness of fruit flesh among examined cultivars and the lowest brightness of fruit flesh was investigated in "Sugar". A* color index of skin and flesh of fruit also showed significant differences among investigated cultivars and the highest level of that in "Ozarak" cultivar was observed. "Gogeh Sabz" and "Golden Drop" also had the lowest level of this index. "Gogeh Germez" had the highest of a*color index of fruit flesh and "Japanese" cultivar was in second place. The lowest level of this index was measured in "Ozarak" and "Shams" cultivars. "Tanasgol" and "Compooti" had the highest fruit skin b*color index among cultivars and "Santarsa", "Sugar," "Stanley" and "Bukhara" showed the lowest of that. "Black Star" and after that "Tanasgol" and "Dargazi" had the highest b*color index of fruit flesh. "Japanese" had also the lowest b* color index of fruit flesh. The intensity or color purity varied among cultivars and the highest of that was observed in "Tanasgol" and "Compooti" and then in "Ozarak". "Black Star" had the highest chroma of fruit skin and the highest fruit flesh color intensity. The lowest of this index in the fruit flesh was observed in "Santarosa", "Sugar" and "Japanese" cultivars. Vitamin C (ascorbic acid) content varied in investigate cultivars. "Gogeh Germez" and "Japanese" had the highest vitamin C content and "Stanley" was showed the lowest amount of vitamin C. "Golden Drop ","Santarosa" and "Compooti" showed the highest total carotenoid among examined cultivars and "Gogeh Germez" had the lowest total carotenoid. "Gogeh Germez" and "Compooti" had the highest and lowest amount of anthocyanin index respectively. The highest total phenol and antioxidant activity was measured in "Ozarak". The lowest total antioxidant capacity was in"Gogeh Sabz". The results showed that There was high correlation (r= 0.93) between antioxidant capacity and a* fruit skin color index. High correlation (r= 0.83) between phenol content and antioxidant capacity of fruits was also observed. Between a* color index of fruit skin and phenolic content was observed high correlation (r= 0.89). As well as between anthocyanin and phenolic content and between anthocyanin and a* fruit skin color index, respectively (r= 0.86) and (r= 0.59) high correlation was detected.
Conclusions: "Ozarak" in terms of antioxidant activity and total phenol component was superior. The highest amount of anthocyanin related to the "Gogeh Germez". "Golden Drop"," Santarosa" and "Compooti " had the highest total carotenoid and "Gogeh Germez" and "Japanese" had the highest vitamin C content among investigated cultivars. By identification of superior cultivars In terms of phytochemical compounds, these cultivars can be used in breeding programs to improve these nutritional quality of fruits. The results showed that the major phenolic compounds were gathered on the skin of plum fruits. Hence the "Ozarak" cultivar having the highest a*color index of fruit skin had the highest total phenol and antioxidant capacity among the investigated cultivars but "Gogeh Germez" by having the highest a*color index of fruit flesh and anthocyanins content higher than "Ozarak" cultivar, had low phenolic content and antioxidant capacity compared to the "Ozarak".