Objective Fresh bamboo shoots are bamboo shoot products that have not been blanched or pickled, with a crispy taste and refreshing flavor. However, fresh bamboo shoots breathe vigorously, which are prone to dehydration and wilting, making them difficult to keep fresh, thus affecting their sales. Spontaneous modified atmosphere packaging reduces the respiratory intensity of packaged fruits and vegetables by regulating the gas composition of the internal environment. Studying the effects of different modified atmosphere packaging treatments on the postharvest storage quality and lignification of fresh bamboo shoots could provide references for the selection of fresh-keeping packaging for fresh bamboo shoots.

Method The peeled fresh bamboo shoots were packed in the spontaneous modified atmosphere preservation bag (thickness 20μm, O₂transmission rate 11 643 cm³/m²·d·atm, water vapor transmission rate 62.586 g/m²·d), and the vacuum bag made of nylon was used as control. The packaged fresh bamboo shoots were stored in the cold storage to study the quality change and the difference of lignification degree during storage.

Result Compared with traditional vacuum preservation techniques, spontaneous modified atmosphere packaging could significantly reduce the respiratory intensity of fresh bamboo shoots during storage by creating a low oxygen and low carbon dioxide(O₂ < 5%, CO₂ < 5%) environment inside the bag through the respiration of the bamboo shoots themselves and the gas permeability of the membrane material. The peak intensity was only 46.93% of that of vacuum treatment. After 21 days of storage, modified atmosphere packaging significantly inhibited the browning and membrane lipid peroxidation of bamboo shoots. The brightness of the core of packaged bamboo shoots decreased by only 6.17% compared with that upon harvest, while that of vacuum packaging decreased by 17.74%. The content of malondialdehyde in vacuum packaged bamboo shoots was 2.93 times that in modified atmosphere packaging. In terms of lignification, the lignification rates of bamboo shoots in two types of packaging began to increase after 14 days of storage. The activities of key enzymes for lignification of bamboo shoots (phenylalanine ammonia lyase, peroxidase, cinnamon dehydrogenase) peaked in vacuum packaging, and lignification intensified; however, there was no peak in the related enzyme activity of bamboo shoots in the modified atmosphere packaging, and the enzyme activity increased slowly, delaying the lignification of bamboo shoot and maintaining the crisp taste of the bamboo shoots. After 21 days of storage, the lignin content of packaged bamboo shoots decreased by 15.01% compared to vacuum packaged bamboo shoots, effectively extending the freshness period of fresh bamboo shoots.

Conclusion The low oxygen and low carbon dioxide gas environment in the spontaneous modified atmosphere packaging bag is conducive to the storage of fresh bamboo shoots, and the quality and nutrient content are significantly better than those of vacuum packaging treatment. It has a good market prospect for fresh bamboo shoots.