The evaluation of harvest date and post harvest treatment on Iranian raisin quality
Mahmoud Koushesh Saba, Kazem Arzani and Abdolhamid Sherafaty
Abstracts Book, 6th International Postharvest symposium, 8-12 April 2009, Antalya, Turkey. 256 pages.
2009
บทคัดย่อ
Drying is probably the oldest method for preserving fruits and initially was used as a way of storing foods for the low supply season. Dried grapes, commonly known as raisins, have a great economic importance for many countries. The yield and quality features of raisin was affected by pre-harvest such as irrigation, nutrition, pruning, crop per vine, bunch growth condition, pest and disease control methods and the proper harvest time and post-harvest factors such as proper handling of bunches, applying a suitable method for raisin production, environmental conditions and the duration of drying time. Combinations of different harvest date (four harvest dates) with post harvest alkaline emulsion (three alkaline solutions) were tested in 'Paycamy' grape green raisin production. Some raisin quantitative and qualitative characteristics such as: yield, drying ratio (fresh: raisin yield), raisin wastes, sugar content, price, color, homogeneity of color, raisin size, alkaline solution residues and surface texture of raisin (shrinkage) were measured. Results showed that harvest date and post harvest treatment affected yield, drying ratio (fresh: raisin yield), raisin wastes, sugar content, price, color, homogeneity of color, raisin size, alkaline solution residues and surface texture of raisin. Harvest date results showed that grape °Brix and raisin sugar content increased from 15.5 to 21 and 53% to 62% respectively. In addition, fourth harvest yield increased raisin yield up to 30% compared to the first harvest.