Classification of Browning on Intact Table Grape Bunches Using Near-Infrared Spectroscopy Coupled With Partial Least...

Area of Science:

• Horticulture and Postharvest Technology
• Spectroscopy and Chemometrics
• Plant Physiology

Background:

• Table grape browning is a significant postharvest physiological disorder affecting cold-stored grapes.
• Current management strategies are limited, impacting the sustainable growth of the table grape industry.
• Non-destructive techniques are needed for early detection and classification of browning phenotypes.

Purpose of the Study:

• To investigate the efficacy of near-infrared (NIR) spectroscopy combined with chemometric methods for non-destructively classifying table grape browning.
• To differentiate between chocolate browning and friction browning in 'Regal Seedless' table grapes during cold storage.
• To develop quality control methods for packed table grapes before export.

Main Methods:

• Utilized near-infrared (NIR) spectroscopy on intact 'Regal Seedless' table grape bunches subjected to varying cold storage durations.
• Employed partial least squares discriminant analysis (PLS-DA) and artificial neural networks (ANN) for spectral data analysis and classification.
• Evaluated model performance using classification error rate (CER), specificity, sensitivity, and kappa scores.

Main Results:

• NIR spectroscopy coupled with PLS-DA showed better classification error rates for chocolate browning (25%) compared to friction browning (46%) in weeks 3-4.
• ANN models demonstrated strong agreement in classifying chocolate browning (weeks 3-6) and moderate agreement for friction browning (weeks 3-4).
• Specificity and sensitivity for chocolate browning classification were superior to those for friction browning.

Conclusions:

• NIR spectroscopy offers a promising non-destructive approach for classifying distinct table grape browning types.
• The developed models can aid in pre-export quality assessment, reducing postharvest losses.
• This technology has significant implications for enhancing quality control and marketability in the global table grape industry.