| Abstract: | Edible and medicinal mushrooms are relatively low in calories and fat but rich in proteins, chitin, vitamins, and minerals; they are also health foods. After the mushrooms are harvested, it continue to breath and metabolism. Therefore, many physiologically active contents will change during harvest time. Preservation of raw mushrooms commonly used frozen, refrigerated, cans and radiation ( UV light, γ- rays and pulsed light), etc. Lovastatin is not only a secondary metabolites from Monascus species but a kind of statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) medicines, which inhibit the rate-limiting enzyme in the production of cholesterol, lowering total and LDL cholesterol levels. Recently, some research have found that fruiting bodies of Pleurotus ostreatus (Japan) and Agaricus bisporus contain vast amount of lovastatin, whereas mycelia of Cordyceps sinensis, Antrodia salmonea and Antrodia camphorata are also rich in lovastatin.
In this study, lovastatin is analysed in fruiting bodies and mycelia of mushrooms. Among fruiting bodies, A. bisporus and P. ostreatus (Japan) are refrigerated at 4℃ for 3, 6 and 9 days, irradiated with UV light (for 30, 60 and 120 minutes) ,γ-ray (at doses of 0.5, 2 and 5 kGy) ,and pulsed light (at doses of 10, 30 and 50). Among mycelia, the change of lovastatin contents during the growth of P. ostreatus (Japan), A. salmonea and A. camphorata in submerged and solid state fermentation. Then we further discuss the appropriate medium to enhance the lovastatin contents.
Fruiting bodies of the results show that the contents of lovastatin in A. bisporus and P. ostreatus (Japan) are increased during storage at 4℃; A. bisporus is 22.9-51.1 µg/g, and P. ostreatus (Japan) is up to 200.9 µg/g at 3 day. After UV irradiation, the lovastatin contents are 25.4-30.8 and 65.3-66.7 µg/g, respectively (not significant). γ-ray irradiation treatment on A. bisporus and P. ostreatus (Japan), the decrease of lovastatin content are 22.2-18.6 and 59.3-21.4 μg/g, respectively. The lovastatin contents in A. bisporus and P. ostreatus (Japan) has a tendency to decrease after pulsed light (21.7 - 10.4 and 58.2 - 30.0 µg/g, respectively). Overall, lovastatin contents in P. ostreatus (Japan) are higher than A. bisporus.
On mycelia aspects, the lovastatin content increases as the growing days increases; high lovastatin production of 64.5 µg/g at 12th day in submerged fermentation under the appropriate medium by P. ostreatus (Japan), and the maximum value of the lovastatin yield is soybean (21.2 μg/g) > brown rice (13.3 μg/g) > buckwheat (6.6 μg/g) in solid state fermentation. By A. salmonea, high lovastatin production of 3419.0 µg/g at 24th day in submerged fermentation, and the maximum value of the lovastatin yield is brown rice (10.9 μg/g) > soybean (9.1 μg/g) > buckwheat (8.5 μg/g) in solid state fermentation. In addition, high lovastatin production of 3562.8 µg/g at 16th day in submerged fermentation by A. camphorata, and the maximum value of the lovastatin yield is brown rice (34.2 μg/g) > buckwheat (4.7 μg/g) > soybean (1.8 μg/g) in solid state fermentation. Generally, lovastatin contents in A. salmonea and A. camphorata are more than P. ostreatus (Japan).
The outcome of co-culture of Monascus purpureus and P. ostreatus (Japan) revealed that the biomass contents is co-culture (0.90 g/100ml)> P. ostreatus (Japan) (0.83 g/100ml)> M. purpureus (0.50 g/100ml), lovastatin contents is co-culture (2040.1 µg/g)> M. purpureus (1343.9 µg/g)>P. ostreatus (Japan) (70.6 µg/g), polysaccharide contents is P. ostreatus (Japan) (75.8 mg/g)>co-culture (28.1 mg/g) >M. purpureus (25.4 mg/g), and antioxidative capacity of co-culture is between M. purpureus and P. ostreatus (Japan). Briefly, the lovastatin production and function are much stepped up through co-culture.
In the area of physiological analysis, the ergosterol (biomass) content increases as the growing days increases, high ergosterol production from salmonea fungus brown rice (280.1 mg/g) and camphorata fungus brown rice (215.5 mg/g). However, the maximum level of polysaccharide contents are camphorata fungus brown rice (10.58 mg/g) > brown rice (4.53 mg/g). On anti-oxidative components, the flavones and total phenol content of camphorata fungus brown rice are high than brown rice, 1.33 and 0.05 mg/g, respectively. As for ethanolic extracts from brown rice and camphorata fungus brown rice which antioxidant activity (EC50 value), the reducing power is brown rice (3.71 mg/mL) > camphorata fungus brown rice (4.22 mg/mL), scavenging ability on DPPH is camphorata fungus brown rice (4.54 mg/mL) > brown rice (6.93 mg/mL), and chelating ability on ferrous ions is camphorata fungus brown rice (5.38 mg/mL) > brown rice (9.78 mg/mL). In sum, A. camphorata can promote the function of brown rice. |
