| Summary: | 博士 === 國立中興大學 === 食品暨應用生物科技學系所 === 106 === Mineral is a naturally occurring compound, usually present in crystalline form. Mineral is one of a necessary nutrient for human body and be related with body growth, tissue structure, metabolism regulation and help keeping healthy. The human body can not synthesize minerals on its own and it can only be obtained from external food sources or through additional nutritional supplements. Mushrooms contain many nutrition substances and components, minerals are also one of them. People now pay more attention on personal health. From the researches and reports, it indicated the annual values and the market values that related to fungal health food products have become importance year by year. This finding pointed out the potential development abilities in the future by consuming these type of products to improve human body health.
In this study, two different pre-treatment methods, dry ash and microwave digestion was deployed respectively into twenty-five kinds of selected different ediable and medicinal mushroom samples, including its mycelia, fruiting bodies and wild sclerotium (Lignosus rhinocerus only) parts. The atomic absorption spectroscopy (AAS) was used to analyze the contents and differences of seven minerals, including potassium, sodium, calcium, magnesium, copper, iron and zinc in each sample and to discuss the possible influences on these two pre-treatment methods. Expect the Duncan''s multiple range test, a statistical analysis tool, the principal component analysis (PCA) was also deployed to calculate the data collected and to find latent variables through decreasing the complexity of high-dimensional data and finding the pattern of correlation between datasets.
Agaricus mushrooms were available as white button, crimini, and portabella. Soluble metabolites were identified and quantified using proton nuclear magnetic resonance (1H NMR) spectroscopy technology. In addition, five different ediable and medicinal mushrooms, included Agaricus brasiliensis, Lentinula edodes, Taiwanofungus camphoratus and Ganoderma lucidum (China and Taiwan, respectively) were selected and use the same technology (1H NMR) to identified and quantified their soluble metabolites.
Lignosus rhinocerus, which is classified as a precious medicinal mushroom was selected to do the further examination, including the strain identification and the analysis in general composition, flavor characteristics, physiologically active substances and the antioxidant compounds.
The results of seven minerals content in selected mushroom samples shows that Inonotus obliquus contained highest potassium (47.25 mg/g), the wild sclerotium part of L. rhinocerus has rich content in calcium (543.94 μg/g) ; high content of magnesium identified in Lentinula edodes, which was 1.74 mg/g. Volvariella volvacea identified the better content of copper and iron (64.31 and 136.63 μg/g, respectively). Taiwanofungus camphoratus and Armillaria mellea have rich content in potassium and sodium (9 - 14 mg/g) of mycelia part whereas Cordyceps sinensis has relative better content in zinc and copper (162 and 11.38 μg/g, respectively). These finding provide clues that with the known medical values of medicinal mushrooms, the minerals content could also be develop as a source of nutritional supplements. Meanwhile, the results of principal component analysis showed that A. mellea has a high correlation with the present of sodium and potassium; similar tendencies of correlation also exhibited in the following samples, Auricularia auricula-judae (calcium), Trametes versicolor (copper and magnesium), Volvariella volvacea (copper) and Agrocybe cylindracea, Auricularia fuscosuccinea, Pleurotus ostreatus (Japan) were linked to the present of zinc. Overall, except focus on the proportion sources of carbon and nitrogen, the appropriate minerals supplied could link on the growth of mushrooms.
In the results of the Agaricus mushrooms. Totally, 32 compounds were measured and quantified. Mannitol was the most significant compound (6.54-17.51 g/kg). White button had the highest amounts of soluble metabolites (20.21 g/kg) whereas portabella had the lowest (8.17 g/kg). The results indicated with maturity increased, the descending tendency on soluble metabolites have observed. Overall, 1H NMR technique could quantify soluble metabolites in mushrooms and provide an explanation between the maturity of Agaricus mushrooms and the profile of its soluble metabolites.
In the results of five kinds of ediable and medicinal mushrooms, A. brasiliensis contained 35 compounds and G. lucidum (China) had 16 compounds. A. brasiliensis contained high amounts of 4-aminobutyric acid, proline, alanine and pyroglutamate (3.78 - 10.05 g/kg) whereas T. camphoratus contained the highest amount of betaine (1.69 g/kg). Ganoderma lucidum (Taiwan), G. lucidum (China) exhibited different profiles of metabolites. The results not only showed the profile of soluble metabolites but also indicated the different environments influence the nutrients content in mushrooms.
In the results of strain identification of L. rhinocerus, the ITS-1 sequence of sclerotium is 652bp; in mycelium is 650bp. Based on the results and morphology, we could confirm the correction of the strain used in the study. The general composition indicated the difference in wild sclerotium and in culitived mycelium. Mycelium of L. rhinocerus shows more compound contents in γ-aminobutyric acid (GABA), ergothioneine and ergosterol than wild sclerotium. Lovastatin did not idenified in sclerotium. In the flavor characteristics, mycelium contain more soluble sugars (85.77 mg/g) while only trehalose identified in sclerotium. The nucleoside and nucleotide content was 98.31 and 333.39 μg/g in sclerotium and mycelium, respectively. Inosine monophosphate (5''-IMP) was the major source of the flavor exist in mycelium. Moreover, multiple antioxidant compounds were identified in the 70% ethanolic extracts of L. rhinocerus. Results from the examination indicated the potential develop abilities of L. rhinocerus in future.
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