Effects of Vacuum Pre-Cooling on Quality of Mushroom after Cooling and Storage
Experiments were conducted to determine if vacuum cooling has an effect on the physical and chemical quality characteristics of mushroom after cooling and storage. Pressure, temperature and mass variations of mushroom were obtained during vacuum cooling. The pressure was decreased from 10000 Pa to 600 Pa within 4 min and then maintained it until the end of vacuum cooling process. Accordingly the temperature of mushroom dropped from initial 25.1 °C to 2.4 °C within 25 min, and the mass loss was 5.3%. Subsequently, vacuum cooled mushroom were stored at 1±0.5°C. and 85-95% of relative humidity for 2 weeks. The effects of vacuum cooling on the color, firmness, polyphenol oxidase and membrane permeability of mushroom after cooling and storage were determined. The results showed that vacuum cooling significantly reduced the polyphenol oxidase and membrane permeability.