Study On The Regularity Of Vitamin D₂ Content In Edible Mushroom Increased By UV-C And UV-B

Ergosterol in edible mushroom is converted into vitamin D2 after ultraviolet irradiation,which can be used to alleviate vitamin D deficiency and has great significance to human health.This paper established a method for the determination and extraction of vitamin D2 from edible mushroom,and explored the effects of different ultraviolet rays and different parts on the content of vitamin D2 and ergosterol in edible mushroom.The changes of vitamin D2 and ergosterol in white button mushrooms during the storage period were studied by means of air conditioning and cold storage.Ultra performance liquid chromatography-mass spectrometry(UPLC-MS/MS)was used to determine vitamin D2 content in edible mushrooms.The optimized instrument conditions are as follows:the optimal fragmentor voltage was 120 eV,and the collision energy of quantitative and qualitative ions were 22 eV and 12 eV,respectively.For the liquid chromatography,ZORBAX Eclipse plus C18(2.1×150 mm,3.5 ?m)was used as the analytical column,and the mobile phase was methanol-water with a volumetric ratio of 95:5.There was a good linear relationship between the peak area and the vitamin D2 concentration in the range of 1~40 g/mL.The correlation coefficient of the resultant standard curve was over 0.999.The detection limit was 20.0 ?g/kg and the limit of quantity was 60.0 ?g/kg.The recovery ratio was 77.0%~92.5%,and the RSD value was 2.4%~4.9%.The method was accurate and reliable.White button mushrooms after UV-C irradiation were used as experimental material.Volume ratio of alcohol and alkali was determined by single factor experiment.Taking liquid to solid ratio,saponification temperature and saponification time as independent variables,the extraction of vitamin D2 is the response value,the effect of various factors on the extraction of vitamin D2 and the optimum process parameters were determined by the response surface methodology.The results show that the best saponification process of vitamin D2 in white button mushrooms is that the volume ratio of alcohol and alkali is 2:1(mL/mL),the liquid-solid ratio is 12:1(mL/g),the saponification temperature is 75?,and the saponification time is 63 min.Under this condition,the extraction of vitamin D2 is 8.13 ?g/g,which is similar to the theoretical value.It is practical and feasible.The ultraviolet wavelength has an important effect on the production of vitamin D2 in edible mushroom.The contents of vitamin D2 and ergosterol in different parts of edible mushroom were different.UV-B and UV-C irradiation on edible mushroom alone or in combination can significantly increase the content of vitamin D2 in the edible mushroom.Under the same irradiation method,pleurotus edodes increased the most,reaching 86.25 mg/g,followed by lentinus edodes and white button mushrooms.More vitamin D2 was produced by UV-B irradiation than by UV-C and combined irradiation.After ultraviolet irradiation,the content of vitamin D2 in the mushroom stalk was little difference that in the cap,and only a little vitamin D2(0.57 mg/g)was found in the pleura.The content of vitamin D2 in different parts of white button mushrooms after irradiation was higher than that after whole irradiation.The ergosterol content in gill is the highest,followed by cap and stalk.The freeze-dried powder of white button mushrooms produced more vitamin D2 than freeze-dried tablets,and all of them were higher than the whole fresh white button mushrooms.Storage time and preservation measures affect the changes of vitamin D2 and ergosterol contents in white button mushrooms.Combined with air conditioned storage,under 0? and 4?,the study compared the vitamin D2,ergosterol contends and colour of white button mushrooms treated by UV-B and UV-C in 1st,7th,14 th days.The content of vitamin D2 decreased with the prolongation of storage time.0 ? combined with air conditioned storage is helpful to maintain stable vitamin D in the white button mushrooms.Ergosterol content first increased and then decreased during storage.After UV-C irradiation,4? of air conditioned storage conditions more conducive to the formation of ergosterol,followed by 0? storage,4? air conditioned storage air,0? air conditioned storage.With the extension of storage time,the surface of white button mushrooms increase in browning,L * value decreased.At earlier storage,the L * value of white button mushrooms after UV irradiation was lower than control group,extend the storage time,the control of L * value decline than UV treated white button mushrooms,UV-C treatment can effectively inhibit the white button mushrooms browning in the late storage.