Aquaphotomics Monitoring of Lettuce Freshness during Cold Storage

Area of Science:

• Agricultural Science
• Food Science
• Spectroscopy

Background:

• Fresh-cut leafy vegetables are highly perishable, necessitating rapid, non-destructive quality control methods.
• Estimating the freshness of produce like lettuce during cold storage is challenging due to its short shelf life.

Purpose of the Study:

• To develop a rapid, non-destructive near-infrared spectroscopy (NIRS)-based method for evaluating changes in lettuce during cold storage.
• To utilize an aquaphotomics approach to monitor alterations in the water molecular structure within lettuce leaves.

Main Methods:

• Applied near-infrared spectroscopy (NIRS) and aquaphotomics to analyze lettuce leaves during cold storage.
• Utilized difference spectra, principal component analysis (PCA), and linear discriminant analysis (LDA) to analyze spectral data.
• Employed partial least squares regression (PLSR) to predict storage time based on spectral changes.

Main Results:

• NIRS successfully predicted storage time for inner and outer lettuce leaves with high accuracy (R² = 0.80-0.86).
• Aquaphotomics revealed changes in water molecular structure, indicating moisture loss, cell wall damage, and altered water binding states.
• Water spectral patterns (WASPs) effectively described lettuce quality changes, including loss of juiciness and firmness.

Conclusions:

• The aquaphotomics approach using NIRS provides a reliable, non-destructive method for monitoring lettuce quality during cold storage.
• Water molecular structure changes, as analyzed by WASPs, serve as a multidimensional biomarker for assessing lettuce freshness and predicting shelf life.
• This method can aid in rigorous quality control for fresh-cut leafy vegetables.