| Summary: | 碩士 === 國立中興大學 === 食品暨應用生物科技學系所 === 98 === Ergothioneine (EGT) is a kind of precious amino acid, it can prevent the oxidative damage and anti-inflammation in organism. EGT exist in plants and animal tissues, it cannot be biosynthesized in human, only can be absorbed from the diet. In recent the research discovered the rich content of EGT in the mushroom, especially the Pleurotus mushroom content higher EGT. Content of EGT in Pleurotus eryngii (1521.6 mg/kg dw) is the highest from the 28 kinds of common mushrooms. Therefore, this research used the submerged fermentation to cultivate the P. eryngii to produce the high EGT content P. eryngii mycelia. In addition, the research also analyzed the proximate components, nutritional components, taste and physiologically active components, antioxidant properties and evaluation of anti-inflammation effect on the fruiting bodies (FB), base of fruiting bodies (BFB) and high EGT content mycelia (HEM) of P. eryngii.
Cultivated mushroom mycelium with the liquid culture has lots of benefits content simple, fast alternative, stabled quality and easy to scale up. The research reported to study the optimal conditions for submerged culture of P. eryngii, to increase the EGT content in the P. eryngii mycelia. The result showed that optimal conditions for high content of EGT were inoculated with 10 % (v/v), 2 % glucose as the carbon source, 0.5 % yeast extract as nitrogen source and the cultivated at 25℃ on a shaking incubator at 125 rpm, then added 4 mM Histidine after cultivated 7 days, after cultivated 18 days the EGT content were 48.09 mg/L. Used the same optimal culture to cultivated the P. eryngii mycelia at 10 L fermenter with the following conditions: temperature, 25℃; aeration rate, 1 vvm; agitation speed, 150 rpm, after cultivated 18 days the EGT content of mycelia was 62.20 mg/L.
With regard to proximate composition carbohydrate (57.42 %, 59.88 % and 27.81 %) were the major components found in FB, BFB and HEM. With regard of physiologically active components, FB content highest ergosterol, 6.17 mg/g, otherwise the contents of polysaccharide and ergothioneine of HEM were 155.13 mg/g and 3.93 mg/g, higher than FB and BFB. With regard to taste characteristics, the contents of 5’-nucleotide and free amino acid of HEM (20.33 mg/g and 10.56 mg/g) were higher than FB and BFB, however, the content of soluble sugar and the taste characteristics of FB were better than BFB and HEM.
On the antioxidant activity, Trolox equivalent antioxidant capacity (TEAC) of HEM (20.59 μmole Trolox/g) was significant higher than FB (13.42 μmole Trolox/g ) and BFB (0.11 μmole Trolox/g). The ethanolic extract from HEM at the concentration of 20 mg/mL, the antioxidant activity (78.79 %), the reducing power (1.92) and the scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals (95.02 %) were higher than BFB, furthermore, the total phenol and flavonoid were also rich in HEM than in BFB and FB.
In the anti-inflammation effect test, we investigated the effect of hot water and ethanolic extract from FB, BFB and HEM of P. eryngii on LPS-induced NO and TNF-α production in RAW 264.7 cell. The results showed that the ability of inhibition NO and TNF-α production in LPS-induced RAW 264.7 cell the ethanolic extracts were effective than the hot water extracts. The NO content of FB, BFB and HEM were 10.80 μM, 10.99 μM and 10.90 μM, all of that were significant lower than control (15 μM), when the ethanolic extracts concentration was 1000 μg/mL, and when the concentration were 500 μg/mL, the TNF-α content of FB, BFB and HEM were 3.05 ng/mL, 3.59 ng/mL and 2.78 ng/mL, that were also significant lower than control. The results suggest the ethanolic extracts from FB, BFB adn HEM from P. eryngii have an anti-inflammatory activity.
Overall, added amino acid (histidine, cysteine and methionine) could increase the EGT content of P. eryngii mycelia, and the HEM was rich in nutritional component, essential amino acids, umami components, physiologically active components, antioxidant activity and anti-inflammation activity.
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