ISHS Acta Horticulturae 1256: VI International Conference Postharvest Unlimited
The use of DA meter to assess apple and pear maturity in Chile |
| Authors: | C.A. Torres, A. Valdivia, G. Jorquera, O. Hernandez |
| Keywords: | fruit ripening, IAD, instrument, UV-Vis, spectroscopy |
| DOI: | 10.17660/ActaHortic.2019.1256.10 |
| Abstract:
The DA meter is a non-destructive portable instrument that by means of measuring the chlorophyll content indirectly by absorbancy on the fruit surface, predicts its ripeness through the index of absorbance difference (IAD). In order to assess its potential use for the Chilean pome industry, the DA index was compared to other maturity indices for apples (‘Brookfield®Gala’, ‘Granny Smith’, ‘Scarlett’, ‘Cripps Pink’) and pears (‘Forelle’, ‘Packham’s Triumph’, ‘Abate Fetel’). Maturity was assessed periodically preharvest from 30 days prior commercial harvest, and during cold storage (180 days; 1°C, 95-98% RH). On apples, the IAD correlated well with days after full bloom (DAFB) in all cultivars tested, the highest being ‘Cripps Pink’ (-0.876) and the lowest ‘Granny Smith’ (-0.571). Pearson’s coefficients for IAD vs. individual maturity indices such as, flesh firmness, soluble solids (ss), starch index (SI), background colour, among others, were lower and varied among cultivars. ‘Brookfield®Gala’ showed the highest Pearson coefficient for flesh firmness (0.703), ss (-0.850), SI (-0.933), and background colour (-0.822). Correlations of IAD and time in storage decreased considerably compared to those obtained preharvest, with the highest being for ‘Scarlett’ (-0.572) and the lowest for ‘Cripps Pink’ (-0.373). On pears, all cultivars tested showed relatively high correlations between the IAD and DAFB: ‘Abate Fetel’ (-0.783), ‘Packham’s Triumph’ (-0.761), and ‘Forelle’ (0.741). However, the highest correlations did not exceed r=0.68, which was for IAD vs. flesh firmness. Only ‘Forelle’ showed an acceptable correlation between IAD and time in storage (-0.726). The DA meter appears to be a promising new device to assess fruit maturity for some apple and pear cultivars in Chile. Nevertheless, additional testing needs to be done for each particular microclimate and different growing seasons. | |
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