Effect of pre-packaging on asparagus quality after simulated transportation and marketing

Abstract The effects of different polymeric films used as punnet overwraps on the quality of fresh green asparagus ( Asparagus officinalis L.) were evaluated under conditions similar to those experienced during export by air to Japan, followed by 6 days of simulated marketing. Two perforated and two non-perforated films were used. After simulated marketing, unwrapped spears and spears wrapped with 4.1% perforated polypropylene (PY-30) film were unuseable while the market quality of spears packaged with 0.3% perforated polypropylene (PY-1), plasticised polyvinylchoride (PVC) and heat-shrink polyolefin (XDR) films was fair to good. Non-perforated films produced a modified atmosphere inside the package. During simulated transit, the composition of the atmosphere in the PVC packages was 5–6% CO 2 and 15–16% O 2 . In the course of simulated marketing, the composition equilibrated at 2–3% CO 2 and 18–19% O 2 . Atmosphere modification was greater in the XDR film packages, being 14–15% CO 2 and 4–5% O 2 during simulated transport and 6–7% CO 2 and 14–15% O 2 after marketing. The major effect of pre-packaging in slowing deterioration was to reduce moisture loss. Further improvement in the quality of spears from non-perforated packages was attributed to modified atmosphere effects. Higher than normal levels of CO 2 in the in-package atmosphere retarded pathogen growth, tip opening and, for XDR packaged spears, fibre development. PVC and PY-1 were the best films for pre-packaging fresh asparagus under the conditions described here. XDR is not recommended, as spears from some packages were injured by excessive CO 2 accumulation or O 2 depletion. PY-30 did not keep moisture loss to an acceptable level.