A study was conducted to optimize the solid-state fermentation process of tartary buckwheat using Monascus purpureus.This process converted insoluble flavonoids into soluble flavonoids and produced monacolin K, which had lipid-lowering effects.The aim was to improve the biological activity of the fermentation product and its development prospects.High-yielding strains of M. purpureus were screened for the production of Monacolin K.The solid-state fermentation process was optimized to enhance the yield of Monacolin K and soluble flavonoids.The yield of Monacolin K was the primary indicator, while soluble flavonoids, color value, and antioxidant activity served as reference indicators.Optimization was achieved through single-factor experiments and response surface experiments using the strain HQ-1.The optimal fermentation conditions were determined as follows:25 grams of tartary buckwheat mixed with 21 milliliters of nutrient solution containing 2.77 g/L NH4NO3, 1.82 g/L ZnSO4, 1 g/L MgSO4·7H2O, 1 g/L KH2PO4, with a pH adjustment to 2.58 and 11 days fermentation duration. Under these conditions, the yield of Monacolin K reached 162.26 mg/100 g.Furthermore, the extraction amounts of specific flavonoids, including rutin, quercetin, kaempferol, chlorogenic acid, and ferulic acid, increased by 63%, 110%, 593%, 192%, and 57%, respectively.Additionally, the DPPH and ABTS antioxidant activities increased by 232% and 44%, respectively.These findings provide valuable insights into the key factors affecting the fermentation process and offer a practical basis for the development of tartary buckwheat tea technology.
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