1. Use of 1-methylcyclopropene (1-MCP) as a strategy to improve
postharvest life of Abate Fetel pears
Bruno G. Defilippi, Paula Robledo and Daniel Manríquez
Institute of Agricultural Research (INIA-La Platina), P.O. Box 439-3, Santiago, Chile
Abstract
Material and methods
Ethylene plays an important role in coordinating the ripening process on climacteric fruit, including pears. About Abate Fetel, despite having a good storage potential, little information is available about the effect of ethylene inhibition (pre- and postharvest) in the development of quality attributes. Therefore, the main objective of this study was to evaluate the effect of two formulations of 1-methylcyclopropene (1-MCP), one applied in preharvest (HarvistaTM Technology) and the second one after harvest (SmartFreshSM). In order to develop a commercial strategy, including doses of both formulations, timing of application and storage potential, the trials were performed during three seasons in the same orchard: 2006/07, 2007/08 and 2008/09. Evaluations included both quality and physiological parameters, such as total soluble solids, titratable acidity, flesh firmness, color development, ethylene production and respiration rates, among others. In general, the fruit applied with both formulations of 1-MCP kept a higher firmness than the non-applied fruit during cold storage, especially with SmartFreshSM. Similarly, during shelf-life the fruit applied with 1-MCP took longer in reaching the ready to eat stage, both in terms of firmness and color development. As shown for other species, there was an important effect of the maturity stage at harvest and storage time on the effectiveness of both formulations.
Season 2006/07
Harvista: 150 mg a.i. L-1
3 application times
HARVEST
(H)
H-21d.
H-14 d.
H-7 d.
H+7 d.
H+14 d.
Season 2007/08
SmartFresh: 300 and 600 nL L-1
24 h. at 0°C
Storage time: 60, 90 and 120 days
Season 2008/09
T0: Control (no treatments)
T1: Harvista, 150 mg a.i. L-1
T2: SmartFresh, 300 nL L-1 (SF)
Results
From season 2006/07: Harvista applications were performed from early stages of fruit ripening, being the last one (H–7) done close to the rise in respiration rate and ethylene production (Figure 1). After cold storage and shelf-life, the application performed closest to harvest (H–7) had firmer fruit than the applied earlier. This effect was concomitant with a lower production of ethylene (Figure 2).
(SF)
(SF)
(SF)
(SF)
HARVEST
(H)
H-7 d.
H+7 d.
H+14 d.
H+21 d.
Fig. 1. Flesh firmness, respiration rate and ethylene production on Abate Fetel pears without Harvista applications. Harvest (H) is the commercial harvest.
From season 2008/09: As observed in earlier experiments, we did not see an effect of Harvista applications on maturity attributes until harvest, i,.e. color development, pulp firmness and soluble solids content. During postharvest, SmartFresh and Harvista applications kept higher values of firmness compared to non-treated fruit (Figure 4). Besides, pears applied with SmartFresh took longer in reaching the ready to eat stage than the other treatments (Table 1). However, the effect of both formulations on firmness was influenced by harvest time and length of storage.
Control
Harvista
SmartFresh
Control
Harvista
SmartFresh
Fig. 2. Flesh firmness and ethylene production after 60 days of storage at 0°C. Three application times of Harvista were evaluated.
After cold storage
7 20C
Trials have been performed at Agricola La Torre S.A., Rengo, Chile. We thanks Mauricio Suarez and Carlos Figueroa for helping us in the study.
Figure 4. Flesh firmness after storage in Abate Fetel pears applied with SmartFresh and Harvista
Table 1. Days to reach the ready to eat stage in pears applied with SmartFresh and Harvista
Control
SmartFresh
Harvista
45 d. at 0°C 6 10 9
60 d. at 0°C 12 7 5 4 3
Days at 20°C to reach a ready to eat stage H
H + 7
H + 14
H + 21
From season 2007/08: Fruit applied with both concentrations of SmartFresh kept higher values of firmness during storage than non-applied fruit, both after storage and shelf-life. No major differences were observed between 300 and 600 nL L-1 (ppb).
Final remarks
Trials performed last season (2009/10) confirmed the results obtained previously in terms of maintenance of fruit firmness with 1-MCP applications with both formulations, and a delay in reaching the ready to eat stage. No benefits have been observed by using both formulations together.
Fig. 3. Flesh firmness and ethylene production after storage at 0°C in pears applied with SmartFresh.