Amodio M.L., Derossi A., Mastrandrea L., Dechiara M.L.V., Colelli G. (Department of Science of Agricultural, Food and Environment, University of Foggia, Italy)
The aim of this work was to find a relation between degradation patterns of internal and external attributes of fresh-cut fruits and vegetables to be used as a fast method to estimate the rate of degradation of internal quality based on easy quality indicators. Model crops included melon and pineapples as fruits, and rocket leaves, iceberg and lamb lettuce as vegetables. All samples were stored in passive modified atmosphere at 0, 5 and 15 degrees C for a maximum of 11 days. External and sensorial attributes such as visual appearance, off-odor, aroma, and color were monitored, whereas as internal quality attributes ascorbic acid, phenolic content and antioxidant activity were assessed. Both first-order kinetic and Weibullian model were compared for the ability to fit the kinetic of quality degradation over time. Weibullian model gave more accurate results than conventional kinetics, accounting for 85 to 99% of the variance of experimental data. After the individuation of internal and external quality markers for each product, and considering that the time was the common variable among the mathematical models, a new mathematical equation was obtained. In all case a good correlation between internal and external quality attributes was found. Generally, a reduction of 20% of ascorbic acid was observed for all studied products at 5 degrees C when they reached the limit of marketability (score of 3). Also, the same reduction of ascorbic acid was shown to be related with 40% of reduction of O2 concentration. Useful correlation were also found between off-odor and ascorbic acid for lamb lettuce (r2 = 0.90) and for firmness and appearance score for iceberg lettuce (r2 = 0.90).