Purpose of review: This review focuses on spectral indices for assessing fruit maturity as well as non-destructive mechanical techniques for the estimation of fruit firmness, a key factor in fruit management. Findings: Increasing consumer demand for better quality and safer fruits has driven research towards the non-destructive assessment of fruit ripening. Spectral indices may consist of a single wavelength, differences or ratios between wavelengths, allowing for the detection of pigment changes specifically related to fruit ripening. Spectral indices have been studied in the last ten years by several authors who found good correlations with pigment content of different fruit species and, thus, with their degree of maturity, while correlation with flesh firmness was not as good. Most of the authors employed spectral indices to grade fruits at harvest into different maturity classes showing different postharvest behaviour and organoleptic characteristics at consumption. In this way spectral indices could be used to reduce sample variability at harvest and to assign batches of fruit with similar degrees of maturity to different destinations (storage, shelf life, direct market, transport). Mechanical non-destructive techniques for firmness estimation have been developed in order to find an alternative to the destructive Magness-Taylor test. These techniques include the measurement of variables extracted from a quasi-static force-deformation curve, the analysis of impact forces, and the measurement of acoustic responses to vibrations and impacts. The instruments are simple and cheap, and acceptable results were obtained, but non-destructive techniques did not necessarily measure the same quality attribute as their destructive counterparts. The authors often observed poor relationships between acoustic firmness and the Magness-Taylor test, and non-destructive impact measurements were found to be highly sensitive to change in turgidity but less able to follow changes in ripening. Directions for future research: Further studies should focus on the simultaneous use of different non-destructive techniques. In such a way the resulting information is more complete and accurate than that obtained when an individual technique was used.
|Autori:||Vanoli, M.;Buccheri M.|
|Data di pubblicazione:||2012|
|Titolo:||Overview of the methods for assessing harvest maturity|
|Rivista:||STEWART POSTHARVEST REVIEW|
|Appare nelle tipologie:||1.1 Articolo in rivista|