不同木屑基质配比对香菇子实体品质与风味物质形成的影响及其生理机制

Abstract

To alleviate the contradiction between mushroom production and forest conservation， sawdust of apple pruning branches was used to replace oak sawdust at ratios of 0， 25%， 50%， 75% and 100% to formulate five cultivation substrates， and the effects of substrate ratios on mycelial growth， extracellular enzyme activities， yield， and fruiting-body quality and flavor of Lentinula edodes strain “808” were investigated. With increasing apple-branch sawdust， the C/N ratio and lignin content of the substrates decreased， whereas hemicellulose increased. The treatment with 50% replacement (T3) maintained the highest activities of CMCase， xylanase， amylase and acid protease during the browning and primordium-formation stages， and gave the highest yield (1 185 g per bag) and biological efficiency (89.5%)， 9.2% and 7.4% higher than the pure-oak control. Fruiting bodies of T3 contained significantly more crude protein， total amino acids， 5′-nucleotides and equivalent umami concentration (EUC)， and showed the highest relative contents of characteristic volatiles such as 1-octen-3-ol and sulfur-containing compounds. Correlation analysis indicated that cellulase and xylanase activities were significantly and positively correlated with yield and quality indices. These results suggest that replacing 50% of oak sawdust with apple-branch sawdust can maintain yield and improve quality and flavor of L. edodes， and the underlying mechanism is closely related to substrate-induced enhancement of extracellular enzyme secretion and improved carbon-nitrogen nutrition.