Abstract:

This study aimed to examined the effects of hot-air constant temperature drying, hot-air variable temperature
drying and microwave vacuum drying on formaldehyde content and quality of dried Lentinula edodes. L. edodes was treated
with different drying methods, and formaldehyde content, soluble sugar, soluble protein, shrink rate, and rehydration rate
of the dried products were measured. Results showed that formaldehyde content of L. edodes treated with hot-air constant
temperature drying was higher than that of L. edodes treated with hot-air variable temperature drying. Formaldehyde content
of L.edodes subjected to pretreatment followed by hot-air drying was reduced significantly compared to direct hot-air drying,
but the former exhibited poor sensory quality, higher shrink rate, lower rehydration rate, and loss of soluble sugar and
soluble protein. Formaldehyde content of L. edodes treated with microwave vacuum drying was low, and close to that of
L. edodes subjected to pretreatment followed by hot-air drying. L. edodes treated with microwave vacuum drying exhibited
moderate rehydration rate and loose texture. L. edodes subjected to pretreatment followed by microwave vacuum drying
exhibited reduction of formaldehyde content, loss of soluble sugar and soluble protein, no significant difference with respect
to shrink rate and rehydration rate compared to direct microwave vacuum drying. This study can provide certain references
to control quality and formaldehyde content of L. edodes in drying process.

Key words: drying, Lentinula edodes, formaldehyde, quality