Modelling visual quality losses of fresh-cut romaine lettuce
Models for the prediction of quality loss of fresh-cut lettuce can have different uses. For example, they can be used by the industry to take product management and logistic decisions, and they can also be useful for Quantitative Microbiological Risk Assessment studies (QMRA). Such models should include the effect of modified atmosphere packaging. Changes in the visual quality of fresh-cut lettuce as affected by temperature and gas composition were assessed using controlled atmosphere experiments. Four temperatures (2, 4, 7 and 12°C) and five oxygen concentrations (0.1, 0.5, 1, 3, and 5%) were combined to a total of 20 different storage conditions. Carbon dioxide level was 10% in all cases. Visual quality was analysed throughout the storage period. A visual quality model applicable to a range of storage conditions relevant for the preservation of fresh-cut lettuce quality (i.e., 2-12°C, 0.1-5% O2) was developed. Based on the goodness-of-fit statistic (R2) and model complexity, a linear model as the most suitable primary model was selected. Moreover, secondary models were used to model the quality loss rate as a function of temperature or temperature plus O2 concentration. Primary and secondary modelling was performed in one step on the global data set. Parameters were estimated by nonlinear regression analysis, and a model with a coefficient of determination (R2) of 0.78 and a mean squared error (MSE) of 0.81 was selected. The visual quality model was further combined with respiration models of fresh-cut lettuce and packaging film permeability models, selected from the scientific literature. The output of the integrated model was the prediction of visual quality level as a function of storage temperature and packaging design.
López-Gálvez, F., Vermeulen, A., Devlieghere, F., Tudela, J.A., Jacxsens, L. and Gil, M.I. (2021). Modelling visual quality losses of fresh-cut romaine lettuce. Acta Hortic. 1311, 23-30
leafy greens, temperature, modified atmosphere, browning, shelf life