Improved postharvest quality and respiratory activity of straw mushroom (Volvariella volvacea) with ultrasound treatment and controlled relative humidity

- A specialized ultrasound equipment was utilized to treat straw mushroom.
- 10-min ultrasound at 95% RH prolonged straw mushroom postharvest quality to 72 h.
- Ultrasound treated straw mushroom retained appearance, odor, and nutrient contents.
- Ultrasound at 95% RH lowered enzymes activities involved in respiratory pathways.

The present study proposed a synergistic method to extend the postharvest quality of straw mushroom (Volvariella volvacea) by controlling the conditions of ultrasound treatment and relative humidity (RH). Results showed that 10-min ultrasound treatment combined with storage at 95% RH prolonged the postharvest quality of straw mushroom from 24 h or 48 h to 72 h. The appearance of straw mushroom was maximally kept with original odor, minimum weight loss of 28.83%, malonaldehyde (MDA) content of 5.06 nmol g−1, and higher total soluble sugar (TSS) of 28.32 g kg−1 and total soluble protein (TSP) of 30.27 g kg−1. The ultrasound treatment also inhibited the browning and respiratory rates via inactivating the browning-related PPO activity to 236.52 U g−1, and PGI to 0.038 U g−1, SDH to 3.62 U mg−1 Pro, CCO to 9.29 U mg−1 Pro and G-6-PDH/6-PGDH to 69.87 μmol NADP g−1 min−1 activities of involved in respiratory pathways after 72 h of storage. Our results suggest that ultrasonic treatment with the control of relative humidity could potentially reduce the quality deterioration of straw mushroom.