Longitudinal analyses of lignin deposition in green asparagus by microscopy during high oxygen modified atmosphere packaging

Lignification is the most important factor that negatively affects quality of fresh green asparagus and limits its marketability after harvest. The study was to investigate the effect of high oxygen modified atmosphere packaging (high-O2 MAP) on lignification of green asparagus. The texture and lignin content of green asparagus were determined. Lignin deposition in cell wall was observed by fluorescence microscopy, light microscopy and transmission electronic microscopy (TEM). Lower shearing force and lignin content were found in 60 % and 80 % high-O2 MAP during 30 days storage time. 100 % high-O2 MAP slowed the rate of increase in shearing force and lignin levels after 18 days storage time. Microscopic observation results showed that less lignin deposition and cell wall thickening were observed in high-O2 MAP, especially 60 % and 80 % high-O2 MAP. The work justified that high-O2 MAP, especially 60 % and 80 % high-O2 MAP, could effectively keep the tender texture of green asparagus, retard the lignin deposition and slow down the lignification progress. Comprehensive microscopic observation was feasible to illustrate the lignification of during high-O2 MAP.