Ultraviolet Irradiation Increased The Content Of Vitamin D₂in Aga-ricus Bisporus

Vitamin D has biological functions of regulating calcium, phosphorus metabol-ism and bone homeostasis. Lacking of vitamin D can lead to bone diseases such as rickets in children, osteoporosis and osteomalacia in adult. Agaricus bisporus (Agari-cus bisporus Imbach) containing high ergosterol which can be converted into vitamin D2, is considered as an important material for researching of high vitamin D function-al food. In this study, seven Agaricus bisporus strains treated with ultraviolet irradia-tion were used to observing the change of the vitamin D2content in Agaricus bisporus. By comparing the vitamin D2content in Agaricus bisporus strains among different treatments, the best ultraviolet irradiation combination, and the best strain were se-lected. The results were as follows:1. The results showed that the sporocarp of ’Ag10’、’Ag11-1’、’Ag’、’Ag11-2’ and ’Zhenong NO.1’appeared white belonging to white mushroom, while the sporo-carp of ’Beijing brown’ and ’Brown Ag10’were brown belonging to brown mu-shroom; There was no significant difference in the pileus diameter, stem length and stem diameter, whereas there were significant differences in the thickness of sporo-carp in the seven strains; The yield of the seven strains were quite different. The yields of the five white mushroom strains were significantly higher than those of the two strains of brown mushrooms.2. Before irradiation, we found that ’Brown Ag10’was the highest, and’Ag10’ was the lowest. The content of ergosterol in the seven strains sporocarp were all re-duced after ultraviolet irradiation. After ultraviolet irradiation, the erosterol content of ’Zhenong NO.1’sporocarp was the highest,’Ag10’was the lowest;It was found that ultraviolet irradiation time and distance had significant effect on the content of ergos-terol which were lower and lower with increasing of irradiation time and decreasing of irradiation distance.3.The vitamin D2content of sporocarp after ultraviolet irradiation was increased dramatically, for the increasing rate of ’Zhenong NO.1’was maximum,’Brown Ag10’ was minimum. Results showed that irradiation distance and irradiation time had sig-nificant effect on the content of vitamin D2in sporocarp, and the effect of irradiation time on the vitamin D2content was stronger than that of the irradiation distance. And the vitamin D2content increased with extending irradiation time, with shortenning irradiation distance. Comparing of the9irradiation treatment combinations,20min/30cm was the best treatment combination; For the seven strains, the vitamin D2content of ’Beijing brown’ was the highest; Comparing of the two exposure periods under the9irradiation treatment combinations, there was no significant differences between the two exposure periods under6irradiation treatment combinations in’Bei-jing brown’. So,’Beijing brown’ can be selected in production in the future.4. Comparing the effect on the content of vitamin D2of ultraviolet treatment be-fore and after harvesting, the results showed that the effect of before harvest irradia-tion was similar to after harvest, the content of vitamin D2increased significantly, and the stains, irradiation distance and irradiation time all had extremely significant effect on the content of vitamin D2in sporocarp. The vitamin D2content of ’Beijing brown’ was the highest, and that of ’Ag10’was the lowest; The vitamin D2content under irra-diated after harvesting was higher than that of before in the five strains of ’Ag10’,’Ag11-2’,’Zhenong NO.1’,’Beijing brown’ and ’Brown Ag10’, but ’Ag11-1’and ’Ag’ were the opposite. Comparison of the two exposure periods under the9irradiation treatment combinations, results showed that there was no significant difference be-tween the two exposure periods under the treatment combination of15min/30cm in the four strains (’Ag10’,’Ag1-1’,’Beijing brown’,’Brown Ag10’).5. The results showed that the vitamin C content of Agaricus bisporus strains treated by ultraviolet irradiation were reduced slightly, and the vitamin E content had no significant difference compared with the control. In the seven strains, the content of vitamin C of’Ag11-1’was the highest, and that of ’Beijing brown’ was the lowest. For the three irradiation distance, the order of vitamin C content from high to low was50cm,30cm and40cm; For the four irradiation time, the order of vitamin C content from high to low was0min,20min,15min and10min.6. The final result showed that20min/30cm was the best treatment combination; and ’Beijing brown’ was the best strain.