Intensified ultrafiltration process for fouling mitigation during concentration of bioactive compounds from hibiscus (Hibiscus sabdariffa L.) extract: Innovation by using ultrasound and 3D turbulence promoters

Abstract

Here we evaluated the application of different techniques (turbulence promoter and ultrasound) to mitigate fouling occurrences during ultrafiltration of hibiscus extract. The turbulence promoter was designed as cylindrical pins which were assembled on the membrane surface. The integrated process with the turbulence promoter and ultrasound increased the steady-state flux of hibiscus extract through the 5 kDa membrane from 97.55 ± 0.05 to 367.61 ± 0.74 kg h−1m−2. In addition to the considerable flux increase, the membrane fouling was mitigated due to the application of ultrasound and turbulence promoters. The 5 kDa membrane was able to retain more than 60 % of total phenolic compounds, total anthocyanins, cyanidin-3-glucoside, delphinidin, quercetin, myricetin, and rutin in the hibiscus extract. Thus, the application of turbulence promoter and ultrasound in the ultrafiltration process showed great potential to significantly mitigate the membrane fouling and to improve the permeate flux, without compromising the quality of the permeate extract.