บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Influence of 1-methylcyclopropene (1-MCP) on ripening and cell-wall matrix polysaccharides of avocado (Persea americana) fruit.

Jeong, J., Huber, D. J. and Sargent, S. A.

Postharvest Biology and Technology. Volume 25, Number 3, 2002. Pages 241-256.

2002

บทคัดย่อ

Influence of 1-methylcyclopropene (1-MCP) on ripening and cell-wall matrix polysaccharides of avocado (Persea americana) fruit.

West Indian-type avocado (P. americana cv. Simmonds) fruits were treated with two different concentrations (0.09 and 0.45 micro litre litre-1) of 1-methylcyclopropene (1-MCP) for three exposure times (6, 12, and 24 h) at 20 deg C. Fruits were then stored at 20 deg C in ethylene-free air for ripening assessment. Firmness, weight loss, respiration and C2H4 production, peel colour, cell-wall enzymes (polygalacturonase (PG), pectinmethylesterase [pectinesterase], alpha -, beta -galactosidase, and Cx-cellulase) and cell-wall matrix polysaccharides (polyuronides and hemicellulose) were monitored during storage. 1-MCP treatment at 0.45 micro litre litre-1 for 24 h at 20 deg C delayed the ripening of avocado fruit by 4 days at 20 deg C. This delay was characterized by a significant reduction in the rate of fruit softening and in the timing and intensity of the ethylene and respiratory climacterics. Avocado treated with 1-MCP (0.45 micro litre litre-1) for 24 h at 20 deg C also showed significantly less weight loss and retained more green colour than control fruit at the full-ripe stage (10-20 N). The delay in avocado ripening was influenced by 1-MCP concentration, exposure duration, and exposure temperature. 1-MCP treatment affected the activity trends of all cell-wall enzymes measured and completely suppressed increases in PG activity for up to 12 days. Consistent with the activity trends of PG, polyuronides from 1-MCP treated fruits when fully ripe exhibited less extensive molecular mass downshifts compared with the control fruits. The data indicate that the primary phase of avocado fruit softening occurs in the absence of appreciable PG activity. 1-MCP treatment also delayed and slightly reduced the depolymerization of 4 M alkali-soluble hemicelluloses, including xyloglucan.