Impact on Vitamin D2, Vitamin D4 and Agaritine in Agaricus bisporus Mushrooms after Artificial and Natural Solar UV Light Exposure

Abstract

Commercial mushroom production can expose mushrooms post-harvest to UV light for purposes of vitamin D2 enrichment by converting the naturally occurring provitamin D2 (ergosterol). The objectives of the present study were to artificially simulate solar UV-B doses occurring naturally in Central Europe and to investigate vitamin D2 and vitamin D4 production in sliced Agaricus bisporus (button mushrooms) and to analyse and compare the agaritine content of naturally and artificially UV-irradiated mushrooms. Agaritine was measured for safety aspects even though there is no rationale for a link between UV light exposure and agaritine content. The artificial UV-B dose of 0.53 J/cm(2) raised the vitamin D2 content to significantly (P < 0.001) higher levels of 67.1 ± 9.9 μg/g dry weight (DW) than sun exposure (3.9 ± 0.8 μg/g dry DW). We observed a positive correlation between vitamin D4 and vitamin D2 production (r(2) = 0.96, P < 0.001) after artificial UV irradiation, with vitamin D4 levels ranging from 0 to 20.9 μg/g DW. The agaritine content varied widely but remained within normal ranges in all samples. Irrespective of the irradiation source, agaritine dropped dramatically in conjunction with all UV-B doses both artificial and natural solar, probably due to its known instability. The biological action of vitamin D from UV-exposed mushrooms reflects the activity of these two major vitamin D analogues (D2, D4). Vitamin D4 should be analysed and agaritine disregarded in future studies of UV-exposed mushrooms.

A Review of Mushrooms as a Potential Source of Dietary Vitamin D

“…However, the amount of vitamin D 2 generated depends on the time of day, season, latitude, weather conditions, and exposure time. Since these mushrooms have a higher surface area to volume (hence, more ergosterol is exposed), sun-exposed sliced mushrooms produce more vitamin D 2 than whole mushrooms from the same amount of UV radiation exposure [ 11 , 39 , 40 ]. At midday in mid-summer in Germany, the vitamin D 2 content of sliced mushrooms was as high as 17.5 μg/100 g FW after 15 min of sun exposure and reached 32.5 μg/100 g FW after 60 min of sun exposure [ 40 ].…”

“…Mushrooms will generate vitamin D 2 in response to exposure to UV radiation both during growing phase and post-harvest; however, commercial growers use UV lamps post-harvest for practical reasons. Fresh mushrooms, when deliberately exposed to a UV radiation source post-harvest, will generate significant amounts of vitamin D 2 often reaching 40 μg/g dried mass (DM) ( ca 320 μg/100 g FW) [ 11 , 15 , 17 , 36 , 40 , 41 , 42 , 43 , 44 , 45 ]. The most effective wavelength to stimulate the production of vitamin D 2 in mushrooms is UV-B radiation (280–315 nm) [ 43 ].…”

“…The two main dietary forms of vitamin D are D 2 , found in fungi and yeast, and D 3 , found in animals; lesser amounts of vitamin D 3 and D 4 are also found in fungi [ 9 , 10 , 11 , 12 ] ( Figure 1 ). Few foods in the Western diet are a good source of vitamin D, with the best naturally occurring dietary source being oily fish.…”

Lactic Acid Fermentation of Edible Mushrooms: Tradition, Technology, Current State of Research: A Review

“…Drying mushrooms with this method usually proceeds at a temperature of 25 to 30°C and lasts approximately 7 days (Muyanja et al, 2014). Additionally, during the sunlight exposure, the content of vitamin D 2 in mushrooms increases under the influence of UV-B radiation and photoconversion of ergosterol (Ko, Lee, Lee, & Park, 2008;Urbain, & Jakobsen, 2015;Urbain, Valverde, & Jakobsen, 2016).…”

Vitamin D Content of Australian Native Food Plants and Australian-Grown Edible Seaweed

“…Although the major source of vitamin D for humans is cutaneous synthesis from sun exposure [3], when sun exposure is inadequate to maintain vitamin D status, dietary sources make a small but useful contribution [4]. In the Australian food supply, fish, meat, eggs, dairy and fortified margarine are known sources of vitamin D3, while mushrooms are a source of vitamin D2 and small amounts of vitamin D3 and D4 [5,6]. Many animal products also contain the hydroxylated metabolite of vitamin D3, 25-hydroxyvitamin D3 (25(OH)D3), which likely has a greater biological activity than vitamin D3 itself [7,8].…”