Effect of Microbial Fermentation and Heat on Phenolic Compounds in Buckwheat Straw and Alkaloids in Poppy Capsules

The aim of this study was to verify the effect of fermentation by Neurospora intermedia or Aspergillus niger on the content of flavonoids in buckwheat straw and alkaloids in poppy capsules in comparison with heat treatment and autoclaving. Stems of buckwheat (Fagopyrum esculentum) and capsules of poppy (Papaver somniferum) were heated at 200 °C for 20 min, autoclaved at 121 °C for 20 min, or fermented with A. niger or N. intermedia for 3, 6, and 9 days. The alkaloids in poppy (morphine, narcotoline, noscapine, codeine, thebaine, narceine, and papaverine) and flavonoids in buckwheat (rutin, isoquercitrin, quercetin rhamnosyl galactoside, and hyperoside) were identified and quantified by HPLC and LC–MS. Autoclaving poppy capsules significantly increased the content of morphine, thebaine, and codeine. Fermentation of capsules with the fungus N. intermedia significantly increased the content of narceine. Nine-day cultivation of buckwheat straw with A. niger completely reduced the content of all studied flavonoids.