Shiitake mushrooms compounds

S-compounds reported in this study are new to the volatiles of Shiitake mushroom (compounds with a in Table II). 

Trithiolanes have received increasing attention since the identification of diastereomeric 3,5-dimethyl-l,2,4-trithiolane in the volatiles of boiled beef (13). The parent 1,2,4-trithiolane is a component of Shiitake mushrooms (14) and red algae (15). In addition to 3,5-dimethyl-l,2,4-trithiolane, Kubota et al. (16) identified 3-methyl-5-ethyl-l,2,4-trithiolane and 3,5-diethyl-l,2,4-tri-thiolane in both syn and anti forms in boiled Antarctic Gulls. Both compounds were described as garlicky. Flament and co-workers (17) reported the identification of 3-methyl-5-ethyl-l,2,4-trithiolane and 3-methyl-5-isopropyl-l,2,4-trithiolane in a commercial beef extract. ... 

Chen, C. C., Ho, C. T. (1986). Identification of sulfiirous compounds of Shiitake Mushroom (Lentinus edodes, Lange Sing). J. Agric. Food Chem., 34, 830-833. 

The edible Shiitake mushrooms (Lentinus edodes) are another rich source of sulfur compounds, cyclic and noncyclic. Blending of the fresh mushrooms with water at pH = 7 followed by pentane extraction and GC/MS analysis of the extract showed Me2 S3 as one of the major constituents (besides various disulfanes). When the blending was carried out at pH = 9.0, at which enzymes have their maximum activity, additional S compounds like Mc2S4 and cyclic species (see below) were extracted and detected by GC/MS. This result clearly shows that the work-up procedure does influence the kind of products to be detected. 

The major advantage of the seunpling technique developed, was that some trace chemicals could be trapped tind described for the first time as Black Truffle aroma constituents. In particular, some compounds, important flavor contributors, generally appearing in small concentrations, such as benzaldehyde, propanal, ethyl acetate, anisole or dimethyl disulfide - previously identified in Shiitake mushrooms (9) - could be characterized. This was also the case for three aromatic compounds, toluene, xylene and ethyl benzene, well known as raw vegetable constituents (1 ). In addition, two aliphatic esters, isopropyl and sec-butyl formates, and one cyclic sulfur compound (2-formyl thiophene) previously reported respectively in plums and apples (W) and in coffee and bread products (n) were identified. 

Enzymic Formation of Volatile Compounds in Shiitake Mushroom (Lentinus edodes Sing.)... 

Volatile compounds of Shiitake mushroom (Lentinus edodes Sing.) are composed of eight-carbon containing alcohols and sulfur compounds. l-Octen-3-ol and 2-octen-l-ol are the major C8-compounds comprising the "mushroom" character of Shiitake mushroom. The characteristic "sulfurous" note of Shiitake mushroom is composed of cyclic S-compounds, such as lenthionine (C2 H4 S5, 1,2,3,5,6-pentathiepane),... 

Fresh Shiitake mushrooms exhibit only a slight odor, but upon drying and/or crushing, a characteristic sulfurous aroma gradually develops. Lenthionine (1,2,3,5,6-pentathiepane, C2H4S5), a cyclic S-compound known to possess the characteristic aroma of Shiitake... 

It has been established that in many edible mushrooms such as Agaricus campestris and Agaricus bisporus, the C8-compounds are formed enzymically during the oxidation of linoleic acid (16-20). In the present study, the identification of l-octen-3-ol and 2-octen-l-ol as major C8-compounds in macerated fresh Shiitake mushrooms suggested a similar biosynthetic origin. The amount of C8-compounds (primarily l-octen-3-ol and 2-octen-l-ol) in the blanched (97°C, 8 min) or the hot-air dried (commercial process)... 

Shiitake mushrooms was only 1 - 4 % of that of macerated fresh Shiitake mushrooms, confirming again the enzymic origin of these compounds. 

Figure 1. Proposed pathway of formation of S-compounds in Shiitake mushroom. (1) lentinic acid (2) des-glutamyl lentinic acid (3) a thiosulfinate, SE-3 (4) methylene disulfide (5) lenthionine (7) 1,2,3,4,5,6-hexathiepane.

Tressl et al. (16, 17) had shown that linolenic acid (C 18 3) could also be enzymically converted to volatile C8-compounds. However, 1,5-octadien-3-ol and 2,5-octadien-l-ol would be two major C8-compounds formed. No significant amount of 1,5-octadien-3-ol and 2,5-octadien-l-ol could be detected in the volatile components of Shiitake mushrooms blended with sunflower oil hydrolysate (Table I). Instead, significant amount of 1,5-octadien-3-ol or 2,5-octa-dien-l-ol was observed in the sample to which soybean oil hydrolysate was added (20). This is in good agreement with the linolenic acid content in sunflower oil (trace) and soybean oil (ca. 7%). ... 

The enzymic activities involved in forming S-compounds can be clearly shown by comparing the S-compounds formed at pH 9.0 (fresh mushrooms blended in pH 9.0 buffered solution) and in the control (fresh mushrooms blended in chloroform), as shown in Table II. Since the enzymes were totally inactivated by chloroform, only trace amounts of S-compounds were detected in the control sample. Analyses of S-compounds in commercial dry Shiitake mushrooms proved similar results (6j. On the other hand, enzymic activities in forming S-compounds were affected by the pH during blending (6). The maximal pH during enzymic formation of S-compounds is around 9.0. The methods used in this study will be published in detail (Chen and Ho, 1986). 

There are 19 S-compounds which have been identified in Shiitake mushrooms (Table II), and Figure 2 shows the structures of these compounds. These S-compounds can be classified into 4 major groups, containing 1, 2, 3 and 6 carbons. Fourteen out of the 19... 

It is worth noting that all the S-compounds identified in the enzymic reaction mixture could also be detected in the products of synthetic reaction of lenthionine or 1,2,4-trithiolane. Therefore, it is reasonable to assume that chemical reactions may be the dominant forces in the final stages of S-compounds formation. The report of Ito et al. (24) supports the above assumption. They found that the formation of lenthionine in dry Shiitake mushrooms was affected by pH and temperature during rehydration. Since dry mushrooms should be void of enzymic activities, the findings of Ito et al. (24) might actually result from non-enzymic reaction of an intermediate (such as methylene disulfide). 

Table II. Volatile sulfurous compounds identified in Shiitake mushroom...

Figure 2. Structures of S-compounds identified in the enzymic reaction mixture of Shiitake mushrooms. Numbers refer to those listed in Table II.

Identification of Volatile Compounds in Shiitake Mushrooms Using Modern Extraction Techniques... 

As previously mentioned three hundred smd ninety-one components were found to be present in the three combined analyses. This is also a significant increase compared to the eighty-one reported in the flavor database issued by TNG (TNG, 2000) (/7). The analysis included nitrogen and sulfur containing compounds, which to the authors best knowledge, were reported in Shiitake mushrooms for the first time. 

Eri, S. Da Costa, N.C., Identification of volatile compounds in shiitake mushrooms using modem analytical techniques including GC-olfactometry, 7th Symposium of Flavor Chemistry and Biology, Wartburg, Germany, 2004. 

Lenthionine (1,2,3,5,6-pentathiepane) was the first cyclic polysulfane isolated from an organism, however, in the very first report it was stated that this compound is not present in Shiitake mushrooms, but is formed from an unknown precursor by the action of an enzyme when the mushroom was immersed in water overnight. 

Trithiane itself has been found among the volatile sulfurous compounds of Shiitake mushrooms extracted from the homogenate of fresh mushrooms <1986JFA830> and 2,4,6-triethyl-l,3,5-trithiane was identified among the flavor compounds in the steam distillate of onions <1992MI459> analyzed by GC and characterized by GC-MS. Other than that, 1,3,5-trioxane derivatives are not found that often in natural products as their sulfur analogs. Only... 

The pentathiocane (278) has been isolated and identified by mass spectrometry as a volatile component of Shiitake mushrooms (Lentinus edodes Sing.) <86Mi 926-01 >. The compound s genesis is believed to be via methylene disulfide <86MI 926-02). 

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