Concentration of vitamin D2 in white button mushrooms (Agaricus bisporus) exposed to pulsed UV light

Enrichment of vitamin D-2 in Agaricus bisporus white button mushroom (WBM) using continuous UV light needs a longer exposure time, which can lead to discoloration. Using a Xenon pulsed UV light source, the yield of vitamin D-2 was evaluated in freshly harvested button mushrooms and mushroom slices after exposure to 2.5, 3, 6 and 9 pulses of UV light at an average dose of 1.150 J/cm(2) energy per pulse. Increase in vitamin D-2 content was proportionate to the number of pulses of UV light. There was no difference in the vitamin D-2 content of mushrooms between 200 g and 500 g punnets for the corresponding number of pulses (737 +/- 81, 847 +/- 38, 1148 +/- 182, 1611 +/- 444% versus 747 +/- 48, 911 +/- 35, 1307 +/- 109, 2028 +/- 181% Daily Value/serving, respectively; P > 0.05). Mushrooms in the top layer showed significantly higher amounts of vitamin 02 content than those in the bottom layer of a 500 g punnet (657 +/- 22, 796 +/- 76, 1433 +/- 138. 1878 +/- 178% versus 129 +/- 60, 237 +/- 117, 403 +/- 35, 830 +/- 257% DV/serving, respectively; P < 0.01). A single layer of sliced mushrooms (similar to 5 mm thick) showed higher amounts of vitamin D-2 content than sliced mushrooms packaged together after pulsed UV light exposure (7882 +/- 1074, 6867 +/- 944, 10,826 +/- 472, 13,001 +/- 1635% versus 1221 +/- 281, 1293 +/- 210. 1598 +/- 207, 2018 +/- 459% DV/serving, respectively; P < 0.001). Discoloration of whole or sliced mushrooms was not observed. Thus, pulsed UV light provides a highly effective method for increasing vitamin D-2 levels in A. bisporus white button mushroom. Crown Copyright (C) 2011 Published by Elsevier Inc. All rights reserved.