Deviation from the biological age model as an early indication of chilling injury on kiwifruit
Firmness at harvest is considered an indication of biological age for the prediction of softening during storage for kiwifruit (Actinidia spp.). Firmer fruit should remain firmer after storage if fruit softening is solely dependent on aging. However, batches of fruit harvested early at high firmness may become softer after long-term cold storage. Such a deviation of the biological age model may be the consequence of chilling injury or differences in storage conditions such as temperature and ethylene gradients within and among storages and packages. This study investigated if deviation from the biological age model across individual fruit within fruit batches can be used as an early indicator of chilling injury risk before the occurrence of visible chilling injury symptoms. Actinidia chinensis var. chinensis 'Zesy002' kiwifruit were harvested from eight vines of a commercial orchard in Te Puke, New Zealand, on four occasions from early April to late May, 2017, to obtain fruit with different susceptibilities to chilling injury. Acoustic firmness (AF) of the same 80 fruit (10 fruit per vine) from each harvest was measured non-destructively at 2-week intervals during the first 6 weeks of storage using an Aweta Acoustic Firmness Sensor. Flesh firmness and visible chilling injury were measured after 3 or 6 months of cold storage. The results indicated that correlation the relation between AF measured at harvest and that measured after 6 weeks of storage may have the potential to be used as an early indication of chilling injury risk. This would allow high-risk fruit batches to be marketed earlier to avoid fruit loss.
Feng, J., Wohlers, M., Nangul, A., Martin, P. and Brummell, D. (2021). Deviation from the biological age model as an early indication of chilling injury on kiwifruit. Acta Hortic. 1311, 31-38
acoustic firmness, harvest maturity, prediction, storage disorders