Effect of active modified atmosphere packaging with different initial gas compositions on nutritional compounds of shiitake mushrooms (Lentinus edodes)

• Polysaccharide contents of shiitake mushrooms decreased in all the MAPs.
• All the active MAPs increased total phenolic content and free amino acid levels.
• Low oxygen packaging induced an anaerobic atmosphere and damage to tissue membranes.
• High oxygen and medium oxygen packaging better maintained nutritional compound levels.

The effect of active modified atmosphere packaging with different initial gas compositions on fresh shiitake mushrooms was investigated. Shiitake mushrooms were packaged under each of the following conditions: (1) high oxygen packaging (HOP), 100% oxygen initially; (2) medium oxygen packaging (MOP), 50% O2 and balanced with N2 initially; (3) low oxygen packaging (LOP), 3% O2/5% CO2, balanced with N2 initially. Passive modified atmosphere packaging with air inside initially (AIR) was used as the control treatment. All the packaged samples were stored at 10 °C with 90% RH for 7 days. During storage, gas compositions, electrolyte leakage, crude water-soluble polysaccharides, total phenolic content and free amino acid content were determined. The results showed that ethanol release was high in LOP and AIR but retarded in MOP and HOP. No packaging could prevent the decrease in polysaccharide content decreasing. Both the active and passive modified atmosphere packaging maintained the color and integrity of the mushrooms. The active modified atmosphere packaging had a significant effect on the increase of total phenolic content and total amount of free amino acids. LOP had a harmful impact on mushrooms with high levels of electrolyte leakage. In conclusion, HOP and MOP had a better effect on maintaining the nutritional compounds of shiitake mushrooms.