Concentration of betanin from model beetroot extracts by using nanofiltration: parameter estimation and sensitivity analysis

BACKGROUND

Nowadays, research focusing on natural compounds is getting more importance across the globe. Recently, natural bioactive compounds have gained the attention of researchers as a consequence of their exemplary physicochemical properties and exceptional utility in the food and pharma industries. However, separating and concentrating these bioactive compounds from their origin sources still poses a considerable challenge to their profitable commercial usage. The current study focuses on the application of a facile nanofiltration method for recovering betanin from model beetroot extract solutions using a polyamide nanofiltration membrane. Furthermore, the three-parameter Spiegler–Kedem model was used to determine the transport parameters of the membrane and theoretically predict the performance of the membrane. Additionally, variance-based sensitivity analysis methods were deployed to study the sensitivity of different operating and membrane transport parameters.

RESULT

The results indicate that the membrane exhibited the highest rejection of 99% and permeate flux of 3.14 ⨯ 10⁻⁵ m³ m⁻² s⁻¹ at 0.6 MPa pressure and 600 mL min⁻¹ flow rate. The data obtained through the Spiegler–Kedem model were coherent with the experimental observations. Simulations on sensitivity analysis revealed that specific hydraulic permeability and cross-membrane pressure majorly influence permeate flux and rejection.

CONCLUSION

This study showed that nanofiltration with 150 Da cut-off membranes effectively concentrated betanin with 99% rejection. Higher cross-membrane pressure and higher feed flow rates were preferable operating conditions for higher rejections. Variance-based sensitivity analysis showed that cross-membrane pressure and hydraulic permeability are the most influential parameters affecting permeate flux and rejection. © 2024 Society of Chemical Industry (SCI).