Study on the formaldehyde content of Lentinula edodes
Date Issued
2014
Date
2014
Author(s)
Wu, Wan-Chen
Abstract
Lentinula edodes, a common nutrient-rich edible mushroom in Asia, has special flavor after dehydration. Lenthionine is a cyclic organosulfur compound produced from lentinic acid through an enzymatic biosynthesis in L. edodes. Formaldehyde is a by-product produced from this pathway. Previous studies from the other authors have showed that the formaldehyde content in L. edodes could be as high as 600 mg/kg. This study investigated the activity of γ-glutamyl transferase (GGT) which is the important enzyme of the flavor synthesis pathway and the formaldehyde content of L. edodes after postharvest precooling. The formaldehyde contents in L. edodes at different storage and drying temperature were also examined. First, L. edodes was stored at 5˚C and 25˚C separately for 7 days. The formaldehyde contents of L. edodes stored at 5˚C did not have significant differences within 7 days. However, the formaldehyde content of the sample stored at 25˚C decreased rapidly at day 5. This was probably due to the decay of the L. edodes sample. In the second part, the residual formaldehyde content of L. edodes was found to be the highest after drying at 40˚C. This could be attributed to an incomplete dehydration and enzyme activity after drying at 40˚C procedure. In the third part, the formaldehyde content and GGT enzyme activity in L. edodes were investigated at different precooling temperatures. Our results showed that the formaldehyde content was the highest and the GGT activity was the lowest after precooling at 5˚C. This could be due to the lesser water loss and better quality conserve of L. edodes precooled at low temperature. In conclusion, storing under low temperature within 7 days would not affect the formaldehyde content of L. edodes. The highest formaldehyde content of L. edodes was found after dried at 40 ˚C. After precooling at low temperature, the formaldehyde content was not directly proportional to the GGT activity.
Subjects
香菇
預冷
乾燥
甲醛
γ-麩胺基轉移酶
Type
thesis
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