Effects of UV-C treatment and ultrafine-grinding on the biotransformation of ergosterol to vitamin D2, physiochemical properties, and antioxidant properties of shiitake and Jew's ear.

In the present study, the impact of ultraviolet (UV)-C treatment and ultrafine grinding on the conversion of ergosterol to vitamin D2, physiochemical properties, and antioxidant properties of shiitake and Jew's ear was assessed. After exposure to UV-C, vitamin D2 contents of both the mushroom samples has increased significantly (p < 0.05). Whereas, ultrafine grinding along with UV-C treatment has a synergistic effect on bioconversion of ergosterol to vitamin D2 and this effect is more prominent in low dose UV-C irradiation groups (2 kJ/m2). Ultrafine grinding significantly (p < 0.05) improved the water holding capacity (WHC), water solubility index (WSI) and polysaccharide dissolution rate (PDR). However, UV-C treatment led to insignificant changes in the physiochemical properties of mushroom samples. A significant improvement was also observed in the antioxidant profiles especially tannin contents of mushrooms followed by the ultrafine grinding and UV-C treatment.

Vitamin D2 Stability During the Refrigerated Storage of Ultraviolet B-Treated Cultivated Culinary-Medicinal Mushrooms.

The effects of ultraviolet B (UVB) irradiation on the synthesis of vitamin D2 and its stability during refrigerated storage was determined in fresh cultivated culinary-medicinal mushrooms (Agaricus bisporus, Pleurotus ostreatus, and Lentinus edodes) after harvest. The irradiated mushrooms were stored at 4°C for up to 10 days. The concentrations of vitamin D2 and ergosterol were determined using ultrahigh-performance liquid chromatography/tandem mass spectrometry. The cultivated mushrooms not treated with UVB were devoid of vitamin D2. After UVB irradiation, we obtained mushrooms with a large amount of ergocalciferol. A. bisporus showed the lowest vitamin D2 content (3.55 ± 0.11 µg D2/g dry weight); P. ostreatus contained 58.96 ± 1.15 µg D2/g dry weight, and L. edodes contained 29.46 ± 2.21 µg/g dry weight. During storage at 4°C, the amount of vitamin D2 was gradually decreased in P. ostreatus and L. edodes, whereas in A. bisporus vitamin D2 gradually increased until the sixth day, then decreased. Mushrooms exposed to UVB radiation contain a significant amount of vitamin D2 and are therefore an excellent food source of vitamin D.

Improved Extraction and Quality Characterization of Water-Soluble Polysaccharide from Gamma-Irradiated Lentinus edodes.

Gamma irradiation was applied to the improved extraction of water-soluble polysaccharides (WSPs) from dried Lentinus edodes. Irradiation provided a dose-dependent increase in extraction yield (0 kGy, 2.01%; 7.5 kGy, 4.03%; 15 kGy, 7.17%) and purity (0 kGy, 78.8%; 7.5 kGy, 83.1%; 15 kGy, 85.6%) of the WSPs from hot-water extraction. The effect of irradiation was evident in the degraded microstructures and reduced molecular weights of the WSPs. However, nuclear magnetic resonance, Fourier-transform infrared, and X-ray diffraction spectroscopic analyses provided comparable structures of WSPs from nonirradiated and irradiated samples. UV-visible spectra showed a dose-dependent decline in intensity, but an improvement in thermal properties of the WSPs from the irradiated mushroom samples was observed.

Vitamin D and Vitamin D from Ultraviolet-Irradiated Mushrooms (Review).

Vitamin D may have an important role in many aspects of human health, from bone fractures to prostate cancer, cardiovascular disease, neuromuscular problems, and diabetes. Vitamin D is produced in the human body by the skin after sunlight absorption, but as human lifestyles change, so does the time of exposure to sunlight, necessitating dietary supplementation of vitamin D. Mushrooms have the advantages that they are the only source of vitamin D in the produce aisle and they are one of the few nonfortified food sources. Here, we review the current literature on enhancement of the vitamin D content in mushrooms and literature evidence on the bioavailability of vitamin D in humans and animals after ingesting ultraviolet (UV)-irradiated mushrooms. We also present available literature on health safety after UV irradiation of mushrooms, and we discuss issues arising in the attempt to incorporate UV irradiation into the mushroom production line.

Extracts from Lentinula edodes (Shiitake) Edible Mushrooms Enriched with Vitamin D Exert an Anti-Inflammatory Hepatoprotective Effect.

Vitamin D has been known for its anti-inflammatory properties. Extracts derived from Lentinula edodes (Shiitake) edible mushroom exert an anti-inflammatory effect. These extracts contain high levels of ergosterol, which converts into ergocalciferol (vitamin D2) following exposure to ultraviolet light, followed by absorption and hydroxylation into the active form 25-hydroxyvitamin D [25(OH)D]. To determine the anti-inflammatory effect of overexpression of vitamin D in edible mushrooms, L. edodes mushrooms were exposed to ultraviolet-B light, freeze-dried, followed by measurement of vitamin D2 contents, in their dry weight. C57B1/6 mice were orally treated with vitamin D2-enriched or nonenriched mushroom extract prior and during concanavalin A-immune-mediated liver injury. Exposure to ultraviolet light increased vitamin D2 content in Shiitake edible mushrooms. Following feeding of vitamin D-enriched mushroom extracts to mice with immune-mediated hepatitis, a significant decrease in liver damage was noted. This was shown by a decrease in alanine aminotransferase and aspartate aminotransferase serum levels, a decrease in proportion of mice with severe liver injury, and by improvement in liver histology. These effects were associated with a decrease in serum interferon gamma levels. A synergistic effect was noted between the anti-inflammatory effect of the mushroom extracts and that of vitamin D. Oral administration of vitamin D-enriched L. edodes edible mushroom exerts a synergistic anti-inflammatory effect in the immune-mediated hepatitis. The data support its potential use as safe immunomodulatory adjuvant for the treatment of HCV and nonalcoholic steatohepatitis.

Absorbed-dose estimation and quality attributes of gamma-irradiated fresh shiitake mushrooms.

BACKGROUND: The general use of food irradiation requires reliable identification methods as well as extensive quality characterization. Shiitake (Lentinus edodes) mushrooms, packed in polystyrene trays and covered with polyvinylchloride film, were investigated for dose-dependent identification and quality characterization upon gamma irradiation (0, 1, 2, and 3 kGy). RESULTS: Thermoluminescence (TL) analysis of separated minerals provided excellent results to characterize the irradiated mushrooms. Low-dose re-irradiation (200-600 Gy), medium-dose re-irradiation (1-3 kGy) and high-dose re-irradiation (2-6 kGy) were performed and compared using an additive dose method. An electronic-nose analysis showed a difference in the volatile profiles of mushrooms following irradiation. One-kGy-irradiated mushrooms showed similar or better quality attributes to those of the control samples. Scanning electron microscopy revealed the dose-dependent degradation in microstructure of mushrooms upon irradiation. CONCLUSION: An absorbed dosed estimation was possible using TL analysis in which 1-3 kGy re-irradiation technique gave most promising results. An E-nose analysis effectively distinguished the samples based on irradiation history. The best quality attributes were observed at 1 kGy irradiation. However, the drastic effects of irradiation were prominent in 2 and 3 kGy-irradiated mushrooms.

Dietary calcium and vitamin D2 supplementation with enhanced Lentinula edodes improves osteoporosis-like symptoms and induces duodenal and renal active calcium transport gene expression in mice.

The two main sources of vitamin D3 are de novo synthesis induced by exposure to ultraviolet (UV) light from the sun, and diet. Vitamin D3 deficiency causes rickets or osteoporosis. Oak mushrooms (Lentinula edodes) that are exposed to UV radiation contain enhanced vitamin D2 and have much higher calcium content than unmodified (non-irradiated) mushrooms. Such modified edible mushrooms have been proposed as a natural alternative source of dietary vitamin D. In the current study, we have examined whether modified oak mushrooms could improve or prevent osteoporosis-like symptoms in mice fed with low calcium and vitamin D3-deficient diet. Four-week-old male mice were fed low calcium, vitamin D3-deficient diets supplemented with 5, 10, or 20% unmodified, calcium-enhanced, or calcium plus vitamin D2-enhanced oak mushrooms for 4 weeks. To assess the effects of the supplemented diets, we evaluated femur density and length, bone histology, the expression of active calcium transport genes, and serum calcium levels. Mice fed with low calcium and vitamin D3-deficient diet developed osteoporosis-like symptoms within 4 weeks. Femur density and tibia thickness were significantly higher in mice fed calcium plus vitamin D2-enhanced mushrooms, and the expression of duodenal and renal calcium transport genes was significantly induced. These results indicate that in mice, vitamin D2 and/or calcium derived from irradiated oak mushrooms may improve bone mineralization through a direct effect on the bone, and by inducing the expression of calcium-absorbing genes in the duodenum and kidney.