Setting-up of a simplified handheld optical device for decay detection in fresh-cut Valerianella locusta L.

• The evolution of spectra of fresh-cut Valerianella during shelf-life was studied.
• PLS-RCA technique was applied to spectra for the selection of the relevant variables.
• Four effective wavelengths were selected: 520 nm, 680 nm, 710 nm and 720 nm.
• MLR was applied in order to verify the effectiveness of the selected wavelengths.
• A simple, handheld optical device implementing the four wavelengths is depicted.

The aim of this work was to study the feasibility of a simplified handheld and low-cost optical device. This study was focused on identifying the most significant vis/NIR wavelengths able to discriminate freshness levels during shelf-life of fresh-cut Valerianella locusta L.The shelf-life of Valerianella leaves was monitored using a portable commercial vis/NIR spectrophotometer and by traditional analyses (pH, moisture and total phenols content). The Valerianella samples were stored at three temperature: 4 °C, 10 °C, and 20 °C. Through PLS-RCA technique, standardized regression coefficients of PLS models were used to select the relevant variables, representing the most useful information of full spectral region. The four selected wavelengths were 520 nm, 680 nm, 710 nm and 720 nm. Multiple linear regression was applied in order to verify the effectiveness of selected wavelengths. Results demonstrate the feasibility of a simplified device for quickly monitoring the shelf-life of fresh-cut Valerianella leaves.