Articles
Real-time aroma measurements of Conference pears to monitor storage quality using a broadband mid-infrared trace gas sensor
Article number
1386_48
Pages
357 – 364
Language
English
Abstract
For pome fruit, it is beneficial to be stored under controlled atmospheric conditions to prevent fast senescence and quality loss.
Since the fruit metabolism can change during the season, storage under dynamic controlled atmosphere (DCA) is preferable.
In DCA storage the oxygen level set point is dynamically adapted in relation to a biological response of the stored fruit.
In this research, Conference pears were stored in two different treatments: CA (3 kPa O2, 0.7 kPa CO2) and RQ-DCA (0.7 kPa CO2). Different emitted volatile species of the stored pears were monitored using a newly-developed broadband mid-infrared trace gas sensor.
The sensor measured different marker compounds for ripening (ethylene), fermentation (ethanol, acetaldehyde and ethyl acetate) and rotting (methanol and acetone) in the storage headspace.
To validate the mid-infrared trace gas sensor, the same gasses in the headspace were sampled and measured with TDU GC-MS. Quality attributes (i.e., colour, soluble solid content, firmness, acidity and internal defects) were measured at harvest, and after 5 and 9 months of storage.
Results show that fruit with more internal defects (cavities and browning) can be related to an increased production of marker volatiles linked to fermentation (i.e., ethanol, acetaldehyde and ethyl acetate). The combination of measurements of quality attributes related to the outer appearance (e.g., better colour and firmness retention) and aroma measurements to describe the internal state of the fruit in a non-destructive manner will help in the optimization of storage procedures.
The validation of the sensor with TDU GC-MS showed great potential but further calibration is needed.
Since the fruit metabolism can change during the season, storage under dynamic controlled atmosphere (DCA) is preferable.
In DCA storage the oxygen level set point is dynamically adapted in relation to a biological response of the stored fruit.
In this research, Conference pears were stored in two different treatments: CA (3 kPa O2, 0.7 kPa CO2) and RQ-DCA (0.7 kPa CO2). Different emitted volatile species of the stored pears were monitored using a newly-developed broadband mid-infrared trace gas sensor.
The sensor measured different marker compounds for ripening (ethylene), fermentation (ethanol, acetaldehyde and ethyl acetate) and rotting (methanol and acetone) in the storage headspace.
To validate the mid-infrared trace gas sensor, the same gasses in the headspace were sampled and measured with TDU GC-MS. Quality attributes (i.e., colour, soluble solid content, firmness, acidity and internal defects) were measured at harvest, and after 5 and 9 months of storage.
Results show that fruit with more internal defects (cavities and browning) can be related to an increased production of marker volatiles linked to fermentation (i.e., ethanol, acetaldehyde and ethyl acetate). The combination of measurements of quality attributes related to the outer appearance (e.g., better colour and firmness retention) and aroma measurements to describe the internal state of the fruit in a non-destructive manner will help in the optimization of storage procedures.
The validation of the sensor with TDU GC-MS showed great potential but further calibration is needed.
Authors
M. Janssens, B.E. Verlinden, K. Eslami Jahromi, Q. Pan, F.J.M. Harren, B.M. Nicolaï
Keywords
CA, DCA, volatiles, fermentation, long-term storage, TDU GC-MS, super continuum light source
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