Optimization and characterization of pigment production from Boletus edulis Bull.: Fr. by ultrasonic‐assisted extraction

Abstract

In this study, ultrasonic-assisted extraction method was applied to extract Boletus edulis pigment, and its stability and antioxidant activity were also investigated. The optimal extraction process condition was liquid-solid ratio of 38 ml/g, ethanol concentration of 55%, ultrasound time of 42 min, and ultrasound power of 450 w, resulting in the highest yield of 84.77%. The crude B. edulis pigment was found to have high stability at low temperatures away from light and pH values at a range of 3–5. Glucose, citric acid, Ca2+, Na+, and K+ increased the stability of B. edulis pigment, while Cu2+, Fe2+, and Al3+ had a negative effect on the pigment stability. Finally, research on antioxidant activity showed that B. edulis pigment had strong scavenging activities on DPPH·, ABTS·+, and OH, and the IC50 values of them were 0.352, 0.13, and 0.41 mg/ml, respectively. Overall, this study indicated that B. edulis pigment presented certain stability and antioxidant, and could be used as food antioxidant and coloring in food industry. Practical applications Nowadays, microorganisms pigments, especially fungal pigments, have been shown to be an excellent alternative source of natural pigments. Research on fungal pigments should focus on obtaining a wider variety of hues, using pigments with health benefits, increasing shelf life and reducing production costs. This study will contribute a novel method to develop natural pigments with an extended shelf life. In addition, the immense advantages of B. edulis pigments over other natural or synthetic pigments have opened new avenues in the market for a wide range of applications in food industry.