In-field measurement of fruit respiration for determining climacteric activity and harvest maturity of mango

Publication Type

Contribution to conference

Authors

Nagle M; Spreer W; Mahayothee B; Janjai S; Sardsud V; Müller J

Year of publication

2010

Published in

Proceedings of the XVIIth World Congress of the International Commission of Agricultural Engineering (CIGR)

Band/Volume

1-9/

Conference name

XVIIth World Congress of the International Commission of Agricultural Engineering (CIGR) - Section VI: Postharvest Technology and Process Engineering

Conference location

Quebec City (Canada)

Conference date

13-17 June 2010

Mango is a widely cultivated crop and is a climacteric fruit characterized by changes in respiration during development. Mangos are commercially harvested directly after the pre-climacteric minimum at a mature yet unripe state after which optimal post-harvest ripening occurs. Since methods for evaluating harvest maturity are typically subjective, destructive or expensive methods, much potential exists for rapid, accurate and economical technology. A sound approach for determining maturity stage of mango is the measurement of CO2 production, as it is directly related to climacteric activity. Non-dispersive infrared (NDIR) is a simple spectroscopic technology used in gas detection, which is economical and highly accurate. NDIR sensors provide the possibility for developing tools for mango producers to measure fruit respiration, gauge mango development and optimally schedule harvest activities. The objective of this study was to investigate commercially available NDIR sensors for monitoring fruit respiration in mango orchards. An in-field system incorporating NDIR sensors for measurement of fruit respiration was developed. Experiments were carried out in Chiang Mai, Thailand and included two local varieties. A group of fruits was monitored on-tree during development and another was periodically sampled for analysis. Standard fruit respiration experiments were performed using a gas chromatograph for comparative studies with field measurements. Climacteric curves of fruits were successfully detected in the field. Measurements were found to stabilize quickly and could easily be made in a few minutes. Moderate rise of temperature and change of atmospheric composition in the measurement system was not found to impact respiration. Fruit size was found to affect absolute respiration rates. The pre-climacteric minimum occurred consistently below 13 ml CO2 kg-1 hr-1. Respiration values from the field were found to correspond with laboratory measurements (R2 = 0.96). In conclusion, tests with non-destructive CO2 sensors showed excellent potential, but practical modification of the system must be considered for use by farmers.