Assessment of portable firmness gun for stonefruit

Evaluation a portable Bluetooth impact probe prototype for rapid flesh firmness assessments in peaches and nectarines.

Background and aim of the study:

• Portable non-destructive devices for rapid maturity assessment are sought after by the horticultural industries for in situ and post-harvest use
• New handheld instruments provide the opportunity to collect large volumes of data via smartphones and wireless communication (Bluetooth/WiFi)
• Flesh firmness is a measure of fruit maturity and quality in stone fruit

What the research found:

• The portable probe was user-friendly, reduced data collection time and avoided fruit sample destruction
• Predictions for peach and nectarine’s fruit firmeness were not affected by skin characteristics
• The prediction of fruit firmeness was best in softer fruit, suggesting suitability in the post-harvest chain
• Future studies could focus on the application to softer fruit crops, such as berries

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Methods

• Experiment conducted in 2019/20 on 200 fruit per cultivar
• Peach cultivars: 'August Flame', ‘O’Henry', ‘Redhaven’ and 'September Sun’
• Nectarine cultivars: ‘August Bright’, 'Autumn Bright' and 'September Bright’

Portable impact probe

• Exerts a known force through a non-penetrating tip.
• Bluetooth wireless data communication.
• Device outputs: Peak acceleration (PA); Full width at half maximum (FWHM)

Reference determination of Flesh Firmness

A penetrometer (FT327, FACCHINI srl, Alfonsine, Italy) equipped with an 8-mm tip.

Science paper

Evaluation of a portable impact probe for rapid assessments of flesh firmness in peaches and nectarines

A. Scalisi^1,a, M.G. O’Connell^1,2, A. McGlone³ and S. Langdon-Arms³

¹Tatura SmartFarm, Agriculture Victoria, Tatura, Victoria, Australia; ²Centre for Agricultural Innovation, The University of Melbourne, Australia; ³The New Zealand Institute for Plant and Food Research Limited, Hamilton, New Zealand.

Abstract

Flesh firmness (FF) is traditionally measured with penetrometers, although these instruments are time-consuming; their error rate increases in soft fruit; measurements cannot be rapidly and non-destructively collected in situ before harvest; and data collection and management often require scribing in a notebook or specific computer software. We assessed the accuracy and user-friendliness of a portable impact probe to non-destructively detect FF in peach and nectarine cultivars close to harvest time. The study was carried out at the Tatura SmartFarm (Victoria, Australia) during summer 2019/20 on fruit of three nectarine and four peach cultivars (n=200 per cultivar). FF was measured with a hand-held penetrometer and with a non-invasive device based on an impact probe interfaced with a smartphone via Bluetooth. The device measured the impact probe’s acceleration profile when hitting the fruit surface and generated two measures of the bounce profile – the peak acceleration (PA) and the full width at half maximum (FWHM). The relationships of PA and FWHM with FF of peach and nectarine fruit were characterized by power functions. The Akaike Information Criterion was used to select the best models and the relative standard errors of the models were used as comparable measures of error. Both PA and FWHM showed similar robustness in their relationship with FF, although the latter demonstrated higher measurement variability in soft fruit and slightly reduced prediction ability in mature fruit than the former. Our results suggested that the impact probe was a good indicator of FF when fruit were softer and more mature, but lost accuracy with hard and unripe fruit. Hence, the impact probe used in this study is less suitable for early, pre-harvest, in situ FF determination but more appropriate for FF estimation of softer fruit in the post-harvest chain.

Scalisi, A., O’Connell, M.G., McGlone, A. and Langdon-Arms, S. (2022). Evaluation of a portable impact probe for rapid assessments of flesh firmness in peaches and nectarines. Acta Hortic. 1346, 837-844
DOI: 10.17660/ActaHortic.2022.1346.107
https://doi.org/10.17660/ActaHortic.2022.1346.107

Acknowledgements

A. Scalisi^1,a, M.G. O’Connell^1,2, A. McGlone³, S. Langdon-Arms³

¹Agriculture Victoria, Tatura, Victoria, Australia; ²Centre for Agricultural Innovation, The University of Melbourne, Australia; ³The New Zealand Institute for Plant and Food Research Limited, Hamilton, New Zealand.

The experiment was supported by the Tatura SmartFarm stone fruit experimental orchard project (SF17006 Summerfruit Orchard – Phase II) funded by Hort Innovation using Summerfruit levy and funds from the Australian Government with co-investment from Agriculture Victoria. We gratefully acknowledge the technical support and assistance of Cameron O’Connell and Laura Phillips.