| Summary: | 碩士 === 國立中興大學 === 食品科學系 === 92 === Abstract
Agaricus blazei Murill, Agrocybe cylindracea, Boletus edulis and Coprinus comatus are edible and medicinal mushrooms. Because of their richness in carbohydrate, dietary fiber, protein, vitamins and minerals, they usually act as healthy materials. The study aims to analysis the proximate composition, taste quality from fruit bodies, then to obtain extracts with different solvents, and to examine their antioxidant properties.
According to the analyzed of the proximate compositions in these four fruit bodies, the moisture contents of them ranged from 8.75 to 10.86%. Based on dry weight, some differences were found among them. All fruit bodies were high in carbohydrate content. The highest values of the components in these four mushrooms are crude protein（26.74 %）in A. blazei, crude fat（5.76 %）in B. edulis, crude fiber（19.54%）in A. cylindracea and carbohydrate （58.37%）in C. comatus .
The non-volatile taste components in these mushrooms include soluble sugars, free amino acid and flavor 5''-nucleotides. These four mushrooms contained arabitol, mannitol, glucose and trehalose. But A. cylindracea had higher amount of sugar in total. On the other hand, the result of total free amino acid and flavor 5''-nucleotides assay showed that these four mushrooms contained umami taste and abundant essential amino acid. Among them, glutamic acid, aspartic acid, lysine and tyrosine were found to be four major free amino acids. Contents of MSG-like and bitter components were significantly high in A. blazei（4.40 and 4.73 mg/g）. Contents of total 5''-nucleotides were in the descending order of C. comatus（15.08 mg/g） > A. cylindracea （8.56 mg/g） ~ A. blazei （8.00 mg/g） > B. edulis （2.76 mg/g）.
In the antioxidant activity by the conjugated diene method of ethanolic extracts from A. blazei, A. cylindracea, B. edulis and C. comatus, the EC50 values of C. comatus（0.58 mg/ml）was the lowest, The reducing powers of ethanolic extracts from A. blazei（0.69 mg/ml）were better than others at 10.0 mg/ml. The ethanolic extracts from A. blazei, A. cylindracea, B. edulis and C. comatus fruit bodies scavenged 1,1-diphenyl-2-picrylhydrazyl radicals by 94.87, 89.16, 88.76 and 84.52% at 5 mg/ml, respectively. At 10 mg/ml, chelating abilities were in the order of B. edulis（50.98%）~ A. blazei（48.55%）> C. comatus（40.71%）~ A. cylindracea（39.92%） Over all, these antioxidant properties increased with increasing concentration.
The hot-water extracts from A. blazei, A. cylindracea, B. edulis and C. comatus, the EC50 values of A. cylindracea（0.91 mg/ml）was the lowest, The reducing powers of hot-water extracts from B. edulis（1.18 mg/ml）were better than others at 10.0 mg/ml. Excellent scavenging ability on 1, 1-diphenyl-2- picrylhydrazyl radicals （50.6%） was observed with hot extract from C. comatus at 10.0 mg/ml. The chelating abilities were in the order of A. cylindracea（90.40%） ~ C. comatus （89.47%）> A. blazei（82.60%） > B. edulis（67.91%）, at 10 mg/ml.
Total phenols were the major naturally occurring antioxidant components found in all samples. Among them, the ethanolic extracts from A. blazei（5.80 mg/g） and the hot-water extracts from B. edulis （5.81 mg/g） were the highest.
In conclusion, these four mushrooms contained abundant high protein, high fiber, high carbohydrate, low fat, umami taste and abundant essential amino acid. Mushrooms not only become nutrients of high protein, low fat and free cholesterol, but also provide an alternative for food flavor. Therefore, mushrooms have great potential as healthy food or flavoring agent.
Keyword: Agaricus blazei, Agrocybe cylindracea, Boletus edulis, Coprinus comatus, taste quality, antioxidant properties
|
|---|
