عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The effect of Ca, Zn and B foliar application (five g l-1) and their mixed applications as well as two harvest dates (1st and 15st of August) on PPO activity of two commercial Asian pears (‘KS’9 and ‘KS’13) fruits at the time of harvest and during storage were investigated. Results showed that the PPO activity increased from harvest time to three months after storage and then decreased. During storage, PPO showed lower activity in the fruits harvested from foliar sprayed trees compared with nonsprayed trees for both harvest dates and in both cultivars. In the first harvest date (1st of August), PPO activity of foliar sprayed treatments were 256 (control), 212 (Ca), 163 (Zn), 171 (B) and 112 (Ca + Zn + B) for ‘KS’9 and 286 (control), 240 (Ca), 184 (Zn), 193 (B) and 136 unit activity min-1 per 100g-1 FW (Ca + Zn + B) for ‘KS’13. In the early harvested fruits (1st of August), the amount of PPO showed lower activity than the late harvested fruit during five months storage in two studied cultivars. Hence, it is concluded that Ca, Zn and B applications and earlier fruit harvest could affected to decrease in the enzymatic browning disorder and increase the storage longivity of fruits.
1. Arzani K, Khoshghalb H, Malakouti MJ and Barzegar M (2008) Postharvest physicochemical changes and properties of Asian (Pyrus serotina Rehd.) and European (Pyrus communis L.) pear cultivars. Hort. Environ. Biotechnol. 49(4): 244-252.
2. Arzani K (2005)Progress in national Asian pear project: Study on the adaptation of some Asian pear (Pyrus serotina Rehd.) cultivars under Iran environmental conditions. Acta Hortic. 671: 209-212.
3. Carbonar M and Mattera M (2001) Polyphenoloxidase activity and polyphenol levels in organically and conventionally grown peach (Prunus persica L., cv. Regina bianca) and pear (Pyrus communis L., cv. Williams). Food Chem. 72: 419- 424.
4. Crisosto CH, Gamer D and Crisosto GM (1994) Late harvest and delayed cooling induce internal browning of ‘Ya Li’ and ‘Seuri’ Chinese pears. HortScience. 29: 667-670.
5. Ding C, Chachin K, Ueda Y and Wang CY (2002) Inhibition of loquat enzymatic browning by sulfhydryl compounds. Food Chem. 76: 213-218.
6. Guan J and Li G (2001) The influence of calcium on memberane permeability and lipid peroxidation Yali pear. In: The Proceedings of the International Symposium on Asian Pear. 25-29 August, Kuaryoshi, Tottori, Japan p. 63 (Abst.).
7. Khoshghalb H, Arzani K, Malakouti, MJ and Barzegar M(2007) The relationship between antioxidant level and internal browning disorder in some Asian pear (Pyrus serotina Rehd.) fruit genotypes. 10th International symposium on pear, 22-26 May Portugal. Pp. 90 (Abst.).
8. Lee M, Kim Y, Kim N, Kim G, Kim S, Bang K and Park I (2002) Prevention of browning in potato with a heat-treated onion extract. Biosci. Biotech. Bioch. 66(4): 856-858.
9. Martinez MV and Whitaker JR (1995) The biochemistry and control of enzymatic browning. Trends Food Sci. Tech. 6: 195-200.
10. Malakouti MJ (2007) Zinc is a neglected element in the life cycle of plants. Middle Eastern and Russian J. Plant Sci. Biotech. 1(1): 1-12.
11. Negishi O, Negishi Y and Ozawa T (2002) Effects of food materials on removal of Allium-specific volatile sulfur compounds. J. Agr. Food Chem. 50: 3856-3861.
12. Sapers GM (1993) Browning of foods: Control by sulfites, antioxidants and other means. Food Technol. 47(10): 75-84.
13. Veltman R, Kho RM, van Schaik AC and Sanders MG (2000) Ascorbic acid and tissue browning in pears (Pyrus communis L. cvs. Rocha and Conference) under controlled atmosphere conditions. Postharvest Biol. Tec. 19: 129-137.
14. Veltman R, Lentheric L, Van der Plas H and Peppelenbos W (2003) Internal browning in pear fruit (Pyrus communis L. cv Conference) may be a result of a limited availability of energy and antioxidants. Postharvest Biol. Tec. 28: 295-302.
15. Zauberman G, Ronen R, Akerman M, Weksler A, Rot I and Fuchs Y (1991) Post-harvest retention of the red colour litchi fruit pericarp. Sci. Hortic. 47: 89-97.