Effect of modified atmosphere packaging on storage quality and lignification process of postharvest asparagus (Asparagus officinalis L.)

Abstract

Asparagus (Asparagus officinalis L.) often deteriorates due to intense metabolism that leads to excessive lignification and spoilage. Modified atmosphere packaging (MAP) is beneficial for the preservation of asparagus. In the study, postharvest asparagus was divided into four groups: perforated plastic bags (CK), air MAP (A-MAP), high-oxygen MAP (H-MAP) and low-oxygen MAP (L-MAP). Changes in physicochemical quality, lignification and antioxidant capacity were assessed to determine the optimal treatment group. All MAP groups reduced weight loss and microbial proliferation in asparagus, with H-MAP group best preserving sensory quality. H-MAP decreased lignin accumulation by 20.52 %, which was also reflected in the alleviation of asparagus hardening. Thinner sclerenchyma and fewer vascular bundles were also observed through fluorescence microscopy in H-MAP group. That was attributed to suppressed phenylalamine ammonia-lyase (PAL) and peroxidase (POD) activities that regulated phenylpropanoid metabolism and lignin polymerization. Moreover, CK and A-MAP groups experienced peroxidation, leading to quality deterioration. H-MAP and L-MAP provided early stress protection and later enhanced reactive oxygen species (ROS) clearance, and H-MAP showed the most significant effect. At the end of the storage period, the malonaldehyde (MDA) content of H-MAP group was 2.23 μmol/g (69.04 % of CK group). Therefore, H-MAP offered benefits in preserving the quality of postharvest asparagus by inhibiting lignification and enhancing antioxidant capacity. Future research will focus on further optimization within the H-MAP to determine the optimal ratio of O₂ and CO₂, and employ omics approaches to elucidate the underlying mechanisms, thereby making it a promising commercial storage solution.