Evaluation of how sulfur-fumigation reduces the edible quality and flavor of Gastrodia elata Blume Rhizoma

Gastrodiae Rhizoma (GR) is the dried tuber of Gastrodia elata Blume, which belongs to Orchidaceae family. GR is a food of medicine-food homology. Sulfur fumigation (Sf) of GR is a routine procedure performed during GR production to preserve and improve its appearance and color. However, all related studies have focused on the effect of Sf on GR medicinal constituents but have neglected its effect on the edible quality of GR. We analyzed the effects of Sf on the masticatory texture, nutritional content, and flavor compounds of GR. Compared with the hot air drying-treated GR alone, further Sf (1/20) treatment decreased the pH value by 0.94 units, increased whiteness by 1.13 times, reduced cooking loss by 22.91%, decreased polysaccharide content by 44.49%, and decreased medicinal ingredient content by 11.77%. Furthermore, flavor analysis revealed that Sf decreased the sour, sweet, umami, and salty tastes of GR, whereas increased its bitterness. Sf-treated GR exhibited an off odor due to an increase in aldehydes (furfural, benzaldehyde, hexanal, phenylacetaldehyde), leading to a poorer aroma. Conclusively, Sf reduces the edible quality and flavor of GR.