Comparison between an acoustic firmness sensor and a near-infrared spectrometer in segregation of kiwifruit for storage potential

Commercially harvested kiwifruit (Actinidia deliciosa and A. chinensis) are inevitably variable in storage potential as a consequence of non-selective single harvests of orchards. A small proportion of kiwifruit with short storage life could cause significant financial loss through rejection of whole consignments and/or the cost of repacking, particularly late in the marketing season. Segregation of the harvested crop on an individual fruit basis using non-destructive measurements could allow fruit with poor storage potential to be sold earlier and those with good storage potential to be sold later, reducing costs associated with repacking and fruit losses. This study compared two non-destructive measurement technologies, near-infrared spectroscopy (NIR) and Aweta acoustic firmness sensor (AFS) for segregation of kiwifruit at harvest by the likelihood of fruit failing during cool storage and simulated shelf life. The results indicated that NIR is better than Aweta AFS in segregating both A. deliciosa 'Hayward' and A. chinensis 'Zesy002' (marketed as Zespri^® SunGold Kiwifruit, commonly known as Gold3) kiwifruit. The discriminant models based on fruit attributes estimated from NIR at harvest segregated out 75% of the poor-storing fruit at false positive rates of 30 and 40% for 'Hayward' and 'Gold3', respectively. The benefit of fruit segregation increased with extended storage time.