title: Vitamin D2 formation and bioavailability from Agaricus bisporus button mushrooms treated with ultraviolet irradiation.
abstract: Agaricus bisporus mushrooms contain an abundance of ergosterol, which on exposure to UV irradiation is converted to vitamin D2. The present study evaluated the effects UV-C irradiation on vitamin D2 formation and its bioavailability in rats. Fresh button mushrooms were exposed to UV-C irradiation at mean intensities of 0.403, 0.316, and 0.256 mW/cm(2) from respective distances of 30, 40, and 50 cm for periods ranging from 2.5 to 60 min. Vitamin D2 and ergosterol were measured by HPLC-MS/MS. The stability and retention of vitamin D2 were assessed including the extent of discoloration during storage at 4 degrees C or at room temperature. Exposure to UV-C irradiation at 0.403 mW/cm(2) intensity from 30 cm distance resulted in a time-dependent increase in vitamin D2 concentrations that was significantly higher than those produced at intensities of 0.316 and 0.256 mW/cm(2) from distances of 40 and 50 cm, respectively. Furthermore, the concentrations of vitamin D2 produced after exposure to UV-C irradiation doses of 0.125 and 0.25 J/cm(2) for, 2.5, 5, and 10 min were 6.6, 15.6, and 23.1 microg/g solids, equivalent to 40.6, 95.4, and 141 microg/serving, respectively. The data showed a high rate of conversion from ergosterol to vitamin D2 at short treatment time, which is required by the mushroom industry. The stability of vitamin D2 remained unchanged during storage at 4 degrees C and at room temperature over 8 days (P = 0.36), indicating no degradation of vitamin D2. By visual assessment or using a chromometer, no significant discoloration of irradiated mushrooms, as measured by the degree of "whiteness", was observed when stored at 4 degrees C compared to that observed with mushrooms stored at room temperature over an 8 day period (P < 0.007). Vitamin D2 was well absorbed and metabolized as evidenced by the serum response of 25-hydroxyvitamin D in rats fed the irradiated mushrooms. Taken together, the data suggest that commercial production of button mushrooms enriched with vitamin D2 for improving consumer health may be practical.
authors.affiliation: Centre for Plant and Food Science, College of Health and Science, University of Western Sydney, Penrith South DC, NSW 1797, Australia.
authors.forename: Sundar Rao
authors.initials: SR
authors.lastname: Koyyalamudi
authors.forename: Sang-Chul
authors.initials: SC
authors.lastname: Jeong
authors.forename: Chi-Hyun
authors.initials: CH
authors.lastname: Song
authors.forename: Kai Yip
authors.initials: KY
authors.lastname: Cho
authors.forename: Gerald
authors.initials: G
authors.lastname: Pang
mesh_terms: D000364:Agaricus / Q000737:chemistry* / Q000528:radiation effects; D000818:Animals; D001682:Biological Availability; D004355:Drug Stability; D004872:Ergocalciferols / Q000032:analysis / Q000378:metabolism* / Q000493:pharmacokinetics*; D004875:Ergosterol / Q000032:analysis / Q000378:metabolism; D005519:Food Preservation; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D004872:Ergocalciferols; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D004875:Ergosterol