|Authors: ||R. Spielmanns, J. Spielmanns, L. Damerow, M.M. Blanke|
|Keywords: ||pomegranate (Punica granatum L.), non-destructive determination, fruit quality, micro-morphology, sensor technology, shelf life, sustainability|
Non-destructive methods for determining the quality of fresh horticultural produce are needed to help meet market demands and enhance overall sustainability of production.
Two innovative methods were tested for this purpose: a new luster sensor technology (type CH-72) and three-dimensional microscopy (type VHX 5000), as well as the combination of both innovative techniques.
Yellow organically-grown 'Golden Globe' and red conventionally-grown 'Wonderful' pomegranate fruit were stored for over three weeks either at room temperature at 20°C (VPD 11.7 mbar) or in the refrigerator at 6°C (VPD 4.7 mbar), both at 50% RH. Changes in micromorphology, i.e., degree of fruit shriveling, and the roughness according to the depth of shrivel or undulations were examined.
The luster levels decreased during the time of the experiment.
The luster level of red pomegranate fruit dropped from 194-340 (average: 250) relative units to 195-270 (average: 220) relative units after three weeks of storage at 20°C. The luster levels of yellow fruit dropped more dramatically from 200-410 (average: 310) relative units to 175-210 (average: 190) relative units after storage at room temperature.
These changes in luster level were associated with a 2.5- to 3-fold increase in undulation; the average depth of fruit surface undulation increased from 0.45 mm with fresh fruit to 1.4 mm in fruit stored at room temperature.
Luster levels and 3D images of pomegranate fruit were recorded for the first time.
The results may indicate that the luster sensor may be used to detect changes in surface appearance like glossiness and degree of shriveling in yellow but, to a lesser extent, in red pomegranate fruit.
Further research is required before a commercial application can be considered.
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