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Novel approach for measuring sugar and acidity non-destructively in whole table grape bunches
- Daniels, A. J., Opara, U. L., Poblete-Echeverria, C., Nieuwoudt, H. H.
- Acta horticulturae 2018 no.1201 pp. 317-324
- acidity, fruit quality, image analysis, infrared spectroscopy, monitoring, non-climacteric fruits, pH, prediction, quality control, robots, shelf life, sugars, table grapes, vineyards
- Table grapes are non-climacteric fruit and the quality will not improve after harvest. The quality, therefore, should be maintained from harvest, through post-harvest and finally the retail shelf. However, due to the multi-faceted nature of table grape quality, it is very difficult to put a monitoring tool in place, which can measure both the chemical (TSS, TA, and pH) as well as the physical (appearance) accurately and timeously. Huge losses are, therefore, still suffered due to both inaccurate pre-harvest determination and postharvest quality prediction of table grapes. Only preventative measures are put into place to try to maintain grape quality at harvest throughout the production chain. The necessity for new approaches and the application of cutting-edge technologies that can accurately assess the external and internal quality of fruit is, therefore, essential. Infrared spectroscopy has been successful, both in scanning, imaging and robotic applications that are customised to meet the needs for quality control in the vineyards, at the pack house before, during and after storage, including an assessment of the shelf life of packed grapes. Whereas the old approach involved the prediction of single parameters, TSS, TA and pH, with IR spectroscopy they can be done simultaneously and on whole bunches.