Modelling peach and nectarine ripening during storage using the IAD maturity index
Consumer dissatisfaction due to poor and variable eating quality of peaches and nectarines can severely limit sales growth in domestic and export markets. The effect of fruit maturity at harvest on subsequent ripening behaviour and eating quality during storage is extremely important, but not fully understood. A recent technology, the index of absorbance difference (IAD), provides a non-destructive index of fruit physiological maturity and enables accurate monitoring of fruit ripening behaviour before and after harvest. Prunus persica L. 'Summer Flare 34' and 'Summer Bright' nectarine and 'September Sun' peach were segregated at harvest into classes based on ethylene production rate and then monitored during storage. 'Summer Bright' and 'September Sun' were monitored with a DA-meter and the IAD was measured twice weekly for up to 42 days during storage at both 0 and 7°C, whilst the effect of ambient temperature on ripening was determined by monitoring 'Summer Flare 34' at 3-day intervals for up to 10 days at 18°C. Changes in the IAD ripening index were best described by a logistic sigmoidal curve. Storage temperature, cultivar and maturity class at harvest affected the magnitude of single curve parameters but not the type of relationship between ripening and storage time. A series of sigmoidal curves were identified and differences in the y-intercept (i.e., IAD value at harvest) were mainly explained by cultivar and maturity stage at harvest, while differences in the slope and inflection point were mostly due to storage temperature. Adjusted correlation coefficients were cultivar dependent and decreased with storage temperature, with weaker correlations found for fruit at 0°C, due to a lower rate of ripening during storage. In this study, a common postharvest ripening trend was identified among the peach and nectarine cultivars studied with a logistic sigmoidal curve best describing the change in IAD during storage.
Stefanelli, D., Lopresti, J., Hale, G., Jaeger, J., Frisina, C., Jones, R. and Tomkins, B. (2017). Modelling peach and nectarine ripening during storage using the IAD maturity index. Acta Hortic. 1154, 17-24
fruit quality, fruit maturity, non-destructive monitoring, index of absorbance difference, storage period