Effects of vitamin D2-fortified shiitake mushroom on bioavailability and bone structure.

Bioavailability and bone loss inhibitory effects of vitamin D2 derived from UV-irradiated shiitake mushroom were determined in vivo. The effect of the absence of ovaries on the bioavailability of vitamin D2 and bone structure was also investigated. Sham operated (sham) and ovariectomized (OVX) rats were divided in 3 groups according to their diets, i.e. control: only vitamin D-deficient diets; UV(X): vitamin D-deficient diets with non-irradiated mushroom powder; UV(O): vitamin D-deficient diets with irradiated mushroom powder. The obtained results showed that vitamin D2 from shiitake mushroom was able to increase bone mineral density and trabecular bone structure of femur bone as well as its bioavailability. The absence of estrogen induced adverse effects not only on bioavailability of vitamin D2 but also on trabecular bone. In conclusion, vitamin D2-fortified shiitake mushroom might help postmenopausal women increase vitamin D2 bioavailability and retard trabecular bone loss. Abbreviations: OVX: ovariectomized; 25(OH)D: 25-hydroxyvitamin D; 1,25(OH)2D: 1,25-dihydroxyvitamin D; BMD: bone mineral density; micro-CT: micro computed tomography; RSM: response surface methodology; RP-HPLC: Reverse phase-high performance liquid chromatography; MS/MS: tandem mass spectrometry; E2: estradiol; NTx: N-terminal telopeptide of type I collagen; BV/TV: bone volume/total volume; BS/BV: bone surface/bone volume; Tb.Th: trabecular thickness; Tb.Sp: trabecular separation.

Optimization of UV irradiation conditions for the vitamin D2-fortified shiitake mushroom (Lentinula edodes) using response surface methodology.

The aim of this study was to investigate the optimal conditions to process vitamin D2-fortified shiitake mushrooms through UV irradiation for industrial processing. Response surface methodology was used to identify the optimum conditions of the following highly influential factors on vitamin D2 synthesis: temperature, UV dosage, and moisture content. The optimal conditions of those variables were 40.56 °C, 36.27 kJ/m2, and 80.46%, respectively, and UV dosage was the most effective variable. The amount of vitamin D2 obtained under the optimal conditions was 29.87 ± 1.38 µg/g (dry mass: DM) which was well matched with the predicted value of 32.33 µg/g DM. The effects on the texture and color of shiitake mushrooms were also evaluated after the fortification process under the optimal conditions, and no adverse effects were observed compared to those of fresh shiitake mushrooms.