XÂY DỰNG PHƯƠNG PHÁP XÁC ĐỊNH HOẠT LỰC ENZYM NATTOKINASE TRONG THỰC PHẨM BẢO VỆ SỨC KHOẺ BẰNG QUANG PHỐ HẤP THỤ PHÂN TỬ

Abstract

Aims: Development of method for determination of nattokinase activity in dietary supplements by ultraviolet spectrophotometry. 

Methods: Nattokinase activity determination indirectly through the estimation of its hydrolysate.  After the fibrinolytic reaction, the soluble hydrolysate products of Nattokinase are measured at 275 nm. 

Results: The optimal conditions of the extraction process were investigated, the reaction was carried out at pH 8.5, the reaction temperature was 37 °C and the reaction time was 60 minutes. The limit of detection (LOD) and limit of quantification (LOQ) of the method were 4.4 (FU/g) and 14.8 (FU/g), respectively. The repeatability (RSDr) and internal reproducibility (RSD_R) of the method ranged from 1.9 to 5.4 %. The method was applied to determine the activity of Nattokinase enzyme in 10 dietary supplement samples collected in Hanoi. The analysis results showed that the activity of Nattokinase enzyme in 10 samples ranged from 77.0 to 96.2 % compared to the value declared on the product label. 

Conclusion: The validated parameters have met the requirement of Association of Official Analytical Collaboration (AOAC). The method uses simple equipment, the validation results are highly reliable, so it can be used to research the production of dietary supplement containing Nattokinase enzyme as well as control the quality of dietary supplement on the market.