Effect of modified atmosphere packaging in minimally fresh industrially processed Batavia lettuce

A comparative study on the influence of passive and active modified atmosphere packaging on the quality decay of fresh industrially processed Batavia lettuce is presented. The lettuce was processed under usual and controlled conditions in a semi-industrial plant, using a clean room and the following procedure: reception, shredding, washing, draining, rinsing, centrifugation and packaging. Following industrial practices, the processed lettuce was packaged in sealed polypropylene bags using passive and active modified atmospheres. During a storage period of 10 days at 4°C, the quality attributes (texture, colour, browning), head space gas composition, functional content (antioxidant activity, chlorophylls) and microbial counts were monitored. All measured parameters showed negative effects, except the microbial counts, when a high concentration of CO₂ wass used, possibly due to the fermentative processes. A chlorine concentration of 100 mg L^-1 and 10.0 g L^-1 ascorbic acid as antioxidant was suggested. A passive modified atmosphere could be used in the packaging of fresh-cut Batavia lettuce during shelf life of 7 days, maintaining all physical, chemical and microbiological qualities.