Effects of high-pressure freezing and deep-frozen storage on cell structure and quality of cordyceps sinensis.

Cordyceps sinensis (CS) is a kind of fungus with many biologically active components and it is better to preserve its freshness after harvesting. Therefore, the effect of high-pressure freezing and deep-frozen storage at −80 °C on the cell integrity and viability, quality-related attributes and microstructure of CS samples were investigated and compared with that of liquid nitrogen freezing (LNF), immersion freezing (IF) and normal frozen storage at −20 °C during 8 weeks of storage. LNF combined with deep-frozen storage exhibited the smallest damage to the cell integrity and viability, the most intact tissue and cellular structure, thereby minimizing quality loss. But the change rates showed high-pressure shift freezing (HPSF) combined with deep-frozen storage caused the slowest deterioration of the cell integrity, viability and quality-related attributes during the storage. Therefore, LNF combined with deep-frozen storage was the best way to freeze the CS samples, but HPSF combined with deep-frozen storage might be the better way for the long-term preservation of highly perishable fresh products with a cellular structure. • Quality and structural changes of CSs caused by HPF, LNF and IF were compared. • LNF combined with deep-frozen storage showed minimum quality and structural loss. • The deterioration rates of CSs caused by HPSF and stored at −80 °C were slowest. • Quality deterioration of CS was linked to cell integrity and viability damages. [ABSTRACT FROM AUTHOR]