Optimization of ultraviolet irradiate conditions for vitamin D2 synthesis in shitake mushrooms (Lentinula edodes) by using response surface methodology

Abstract

The determination of the optimum conditions for the conversion of ergosterol to vitamin D2 in shitake mushrooms (Lentinula edodes) was studied using response surface methodology (RSM). The effects of the three main variables ambient temperature (20–40°C), exposure time (60-180 min), and irradiation intensity (0.6–1.8 W/m2) were investigated. According to the RSM ridge analysis, the optimum conditions were as follows: ambient temperature of 34.2°C, exposure time of 175.6 min, and irradiation intensity of 1.41 W/m2. Under these optimum conditions, the maximum vitamin D2 content of 117.93 µg/g in shitake mushrooms was obtained, which agreed fairly well with the predicted value of 122.60 µg/g.