Response of kiwifruit (Actinidia deliciosa cv. Allison) to post-harvest treatment with 1-methylcyclopropene.

摘要

Effects of different concn. of 1-methylcyclopropene (1-MCP) on the post-harvest shelf life and quality of cv. Allison kiwifruits were determined. Fruits were treated with 1-MCP at 0.5 mul--1, 1.0 mul--1 or 2.0 mul--1, un-treated fruits served as controls. Each 1-MCP treatment was applied for 24 h at 20 degrees C. After treatment, fruits were transferred to ambient temp. storage (22 degrees +or- 4 degrees C; 65-70% RH) for 18 days, during which time observations on various physical, physiological and biochemical parameters were recorded at 3-day intervals. Results indicated that 2.0 mul--1 1-MCP was the most effective treatment to delay softening and ripening in kiwifruits, as these fruits had the lowest mean wt. loss (9.8 +or- 0.2%), highest mean fruit firmness (32.7 +or- 0.2 N), and began to ripen only after 12 days in storage, whereas untreated fruits started ripening on day 6 of storage. Activities of fruit softening enzymes such as polygalacturonase (PG; 58.5 +or- 0.3 mug galacturonic acid g--1 FW h--1) and lipoxygenase (LOX; 3.96 +or- 1.3 mumoles linoleic acid oxidized min--1 g--1 FW h--1) were lower, and total phenols (TP) contents (24.3 +or- 0.3 mg 100 g--1) and antioxidant (AOX) activities (12.5 +or- 0.03 mumol Trolox g--1 FW h--1) were higher in 1-MCP-treated fruits than in untreated fruits (PG, 98.3 +or- 0.5 mug galacturonic acid g--1 FW h--1; LOX, 4.39 +or- 1.0 mumoles min--1 g--1 FW h--1; TP, 5.3 +or- 0.6 mg 100 g--1; AOX, 4.7 +or- 0.02 mumol Trolox g--1 FW h--1, respectively). In addition, 1-MCP-treated fruits exhibited lower rates of respiration (48.3 +or- 0.4 ml CO₂ kg--1 h--1) and ethylene production (30.2 +or- 0.02 mul kg--1 FW h--1) than untreated fruits (58.9 +or- 0.6 ml CO₂ kg--1 h--1; 38.7 +or- 0.04 mul kg--1 FW h--1, respectively). Similarly, 1-MCP-treated fruits had higher titratable acidity (TA; 1.33 +or- 0.3%) and ascorbic acid (AA) contents (115.9 +or- 2.6 mg 100 g--1 pulp) and lower soluble solids contents (SSC; 8.33 degrees +or- 0.2 degrees Brix) than untreated kiwifruits (TA, 1.0 +or- 0.2 %;AA, 105.3 +or- 2.2 mg 100 g--1 pulp; SSC, 13.7 degrees +or- 0.3 degrees Brix, respectively). 2.0 mul--1 1-MCP can be used for the postharvest treatment of cv. Allison kiwifruits to enhance shelf life and marketability by approx. 6 days.