MA-PACKAGED FRUIT AND VEGETABLES - DISCREPANCY BETWEEN VISUAL AND OVERALL FRESHNESS OF GREEN PRODUCE AND RELATIONS TO PRODUCT QUALITY

Freshness of MA-packaged fresh fruit and vegetables is the most important quality attribute for purchase and consumption. If green produce are packaged in films with too low an O₂ transmission rate (OTR) or distributed at higher temperatures or at a slower rates than expected, quality deteriorations occur that could influence product freshness and consumer trust. Discrepancy between visual and overall freshness occurs when packaged fresh produce looks fresh but are perceived spoiled upon opening of the package. To study discrepancy of packaged fresh produce and the underlying quality attributes, wild rocket was packaged in L-OTR (0.65 pmols^-1 m^-2 kPa^-1) and H-OTR film (17.4 pmols^-1 m^-2 kPa^-1) and stored for 6 days at different combinations of time and temperatures which influenced the inside O₂ and CO₂ concentrations. The H-OTR combinations were: 1) 6 days at 2°C; 2) 2 days at 2°C and 4 days at 10°C; and 3) 3 days at 2°C and 3 days at 20°C. The L-OTR combinations were: 4) 2 days at 2°C and 4 days at 10°C; and 5) 4 days at 2°C and 2 days at 20°C. Visual freshness scores ranged from 2.7 to 11.8 and overall freshness scores from 1.3 to 12.2 on a scale from low (0) to high (15) intensity. Visual and overall freshness scores were of similar magnitude when compared for wild rocket packaged in H-OTR film but differed for wild rocket packaged in L-OTR film. The inside O₂ gas concentrations of the H-OTR packages ranged from 13.4 to 19.9 kPa while it went down to around 0.5 kPa in the L-OTR packages. Inhomogeneous color and texture, loss of green color, yellowing and browning of the cut leaf surface influenced visual freshness of leaves from the H-OTR packages. No discrepancy was observed between H-OTR packages because overall freshness was highly correlated to visual freshness (r=0.98). In contrast, discrepancy was observed in the L-OTR packages. In these packages overall freshness was related to off-odor formation and changes in color. Multispectral analysis could detect color and texture differences between wild rocket samples but not differences that were related to off-odor formation.