| Owing to the intrinsic factors and some extrinsic environmental conditions(such as temperature,humidity,oxygen),many Chinese medicinal materials(CMMs),if not handled properly in the processes of growth,harvesting,processing and storage,can be easily contaminated by Aspergillus flavus,Penicillium viridicatum and Aspergillus carbonarius to produce mycotoxins of serious toxicity.Commonly-used methods for mould-proof including far infrared array,microwaves,SO2-steaming and non toxigenic strains combating methods exhibit some shortcomings and defects,such as sterilization,chemical residues,destruction,et al.The natural plant mould-proof tablet prepared of plant essential oils would have wide prospects for exploitation as green,efficient,non-toxic and non-polluting antifungal agents,besides they have a good scent and facilitate application.So,in this study,the antifungal activities of 11 plant essential oils(Cinnamon essential oil,Litsea cubeba essential oil,et al.)were firstly evaluated regarding their activities against Aspergillus flavus,Penicillium viridicatum and Aspergillus carbonarius.Then,the prescription composition was investigated and the green,efficient,non residual,non-polluting natural plant mould-proof tablets were prepared for quality evaluation and application for scientific preservation of notoginseng and ginger.The main contents are described as follows:1 Preparation of natural plant mould-proof tabletFirstly,the antifungal activity of 11 plant essential oils against Aspergillus flavus,Penicillium viridicatum and Aspergillus carbonarius on culture dish were evaluated,which was determined based on the smallest fungal circle zone.Results showed that Cinnamon essential oil,Litsea cubeba essential oil,Palmarosa oil and Thyme essential oil on the above fungi exhibited significantly stronger antifungal effects than the others.The values of minimal inhibitory concentrations(MICs)further confirmed the strongest inhibitory effect of Cinnamon essential oil against Aspergillus flavus and Aspergillus carbonarius,as well as the strongest inhibitory effect of Litsea cubeba essential oil for Penicillium viridicatum.The two were selected for combined use at the ratio of 1:3 for the preparation of natural plant mould-proof tablets.Then,the type and usage of auxiliary adsorbent were determined through single factor method with adsorption,appearance and formability as the investigation indexes.In addition,pelleting process conditions were optimized with appearance,hardness and formability of the tablets as the evaluation indicators.Finally,the prescription of natural plant mould-proof tablet was described as:1%SiO2 as the adsorbent and glidant,40%?-Lactose monohydrate as the diluent,60%?-Cellulose as the binder,1%magnesium stearate as the lubricant,with the addition of 30 ?L of mixed essential oil of Cinnamon and Litsea cubeba.2 Quality and stability of the natural plant mould-proof tabletResults showed that of the natural plant mould-proof tablets with satisfactory hardness>7 kgf,and good friability met the requirements of the Chinese Pharmacopoeia(2015 version)and can be of mass production.The influence of air flow rate,temperature,humidity and the content of essential oil on releasing speed of the natural plant mould-proof tablets were evaluated by using the weight loss method.Results indicated that the mould-proof tablets should be kept sealed in a dry and low temperature environmental condition.While the influence of humidity and the amount of essential oil on releasing speed of the tablets that was not obvious.In addition,the studies on appearance stability of the tablets showed that they were stable within 30 days at high air flow velocity,and would be stable for 90 days at 4?,25? and 40? and low air flow velocity.Results of GC-MS analysis expressed that no changes were observed regarding the main component of the tablets to show good stability.Increased loss was determined with the increase of temperature.The lowest loss was got when the tablets were stored at 4?.Therefore,the natural plant mould-proof tablet should be preserved at low temperature3 Application of the natural plant mould-proof tablet for preservation of gingerFirstly,an UFLC-MS/MS method was established for the simultaneous determination of five mycotoxins(AFBi,AFB2,AFG1,AFG2 and OTA).Then,the mildew and influence of natural plant mould-proof tablet on the mildew of ginger were investigated through the appearance observation and determination of the five mycotoxins in this CMM after 20-day inoculation with the toxigenic fungi at 28? and 90%RH,as well as that under the action of the natural plant mould-proof tablet.Results of appearance observation showed that the ginger powder after 2-day inoculation became moldy with the observed mycelium,which was confirmed through scanning electron microscopy(SEM)determination.AFB1 and OTA were found at high contents in all the infected samples;while,the infected ginger powder samples under the action of the natural plant mould-proof tablet went to be moldy after 16-day inoculation without AFs or OTA,and a little AFB1 and OTA were detected after 20-day inoculation.The findings indicated that the prepared natural plant mould-proof tablet can inhibit the mildew and production of the five mycotoxisn in ginger.Then,an UPLC-PDA method was established for simultaneous determination of four bioactive components(6-gingerol,8-gingerol,10-gingerol and 6-shogaol)in ginger after 20-day inoculation with the toxigenic fungi at 28 ? and 90%RH,as well as that under the action of the natural plant mould-proof tablet to investigate the influence of the natural plant mould-proof tablet on the toxigenic fungi and the internal quality of ginger.Results showed that the four bioactive components of ginger after infection of the three kinds of fungi decreased with increasing the inoculation time.While,the content of 6-shogaol increased in the first 6 days,and then decreased quickly;the contents of 6-gingerol,8-gingerol and 10-gingerol in ginger under the action of the natural plant mould-proof tablet had no obvious changes.Therefore,the natural plant mould-proof tablet can significantly inhibit the mildew and production of mycotoxins in ginger,and ensure the active ingredients and the internal quality of ginger,as well as improve efficacy,and reduce the toxicity.4 Application of the natural plant mould-proof tablets for preservation of Radix notoginsengFirstly,an UFLC-MS/MS method was established for the simultaneous determination of five mycotoxins(AFB1,AFB2,AFG1,AFG2 and OTA).Then,the mildew and influence of natural plant mould-proof tablets on the mildew of Radix notoginseng were investigated through the appearance observation and determination of the five mycotoxins in this CMM after 20-day inoculation with the toxigenic fungi at 28? and 90%RH,as well as that under the action of the natural plant mould-proof tablets.Results of appearance observation showed that the Radix notoginseng after 2-day inoculation became moldy with the observed mycelium.AFB1 and OTA were found at high contents in all the infected samples.AFs and OTA were not detected in Radix notoginseng under the action of the natural plant mould-proof tablet after 20-day inoculation.The prepared tablets can inhibit the mildew and production of the five mycotoxisn in Radix notoginseng.Then,an UPLC-PDA method was established for simultaneous determination of three bioactive components(R1,Rb1 and Rg1)in Radix notoginseng after 20-day inoculation with the toxigenic fungi at 28? and 90%RH,as well as that under the action of the natural plant mould-proof tablet to investigate the influence of the natural plant mould-proof tablet on the toxigenic fungi and the internal quality of Radix notoginseng.Results showed that the content of Rgi in Radix notoginseng after infection of the three kinds of fungi decreased significantly with increasing the inoculation time.While,the content of Ri and Rb1 basically remained unchanged;the contents of R1,Rg1 and Rb1 in Radix notoginseng under the action of the prepared plant mould-proof tablets had no obvious changes.Therefore,the natural plant mould-proof tablet can significantly inhibit the mildew and production of mycotoxins in Radix notoginseng,to ensure the active ingredients and the internal quality of ginger,as well as improve efficacy,and reduce the toxicity. |
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