Changes of Steroidal Composition in the Process of American Ginseng Bioconversion Using Ganoderma lucidum Mycelium
| Autor: | Huei-Ling Dai, 戴慧玲 |
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| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 American ginseng (Panax quinquefolius L.) is a popular ingredient of products of functional food and Traditional Chinesse Medicine. Considerable amount of water-extracted residue was generated as the increase of consumption on ginseng-related health food products. The ginseng residue still contains a great amount of bioactive substances, such as phytosterols. In this study, Lingzhi (Ganoderma lucidum) mycelia were applied to degrade cellulose and lignin in cell walls of the ginseng residue and to release and to bioconverse phytosterols. The growth of Lingzhi mycelium brings the mushroom bioactive ergosterol into the fermentation product. The ginseng residue used as fermentation medium contained 72.32 mg/ 100 g (on dry basis) of phytosterols that was 30% higher than original ginseng raw material. The major phytosterols were β-sitosterol, stigmasterol and campesterol in the order of their contents. The ratios of free, ester and glycoside forms of the phytosterols were 36%, 24% and 39%. To observe the changes of steroidal composition during the growth of Lingzhi mycelium, 1% and 10% mycelia were inoculated on ginseng residue for 4, 8, 14 and 30 days. Our results indicated that, the content of ergosterol increased as the mycelium grew, the content reached 36.52- 77.31 mg/ 100 g at 30th day. Total content of phytosterols only slightly changed by the mycelia but the forms of phytosterols significantly altered. The contents of glycosides sigmificantly decreased from 38% to 5- 23% and the content of free form increased from 36% to 46- 81%; the content of esters mild changed in the range 13- 33%. The changes could be observed at first and second sampling points, 4th and 8th day, and the timing was in accordance with the changes of β-glucosidase activity. The groups of those mycelia being adapted to ginseng before inoculation showed higher conversion ratio than those un-adapted groups. The conversion ratios of those groups of 1% mycelium inoculation was similar with 10% groups, although the growth of mycelium was slower. Our results indicated that the fermentation composite of American ginseng-Ganoderma mycelium contained higher free form of phytosterols than original ginseng with additional ergosterol, a vitamin D precursor. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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