Monitoring texture and other quality parameters in spinach plants using NIR spectroscopy

Abstract

Green colour, texture and dry matter are important attributes to appreciate freshness and quality in spinach. However, there is currently no fast, economical and non-destructive method which allows producers to measure these parameters simultaneously in the plant, in a matter of seconds. However, Near-infrared (NIR) spectroscopy might bridge this gap. NIR spectra of intact spinach leaves and modified partial least square regression models were developed for colour (a* and b*), texture (maximum fracture force, toughness, stiffness and displacement) and dry matter. A calibration equation with a high prediction performance was devised for dry matter content (r2cv = 0.74), while calibration models for all the textural parameters analysed were considered suitable for screening purposes (r2cv > 0.6). For colour-related parameters, the models allowed test samples to be rough screened. We, therefore, suggest that the analysis of green colour, texture and dry matter of spinach leaves in situ, on the plant, using NIRS technology could prove to be a valuable tool for optimizing cultural practices such as fertilization and irrigation and to assess the quality of the spinach leaves when harvested.