Clarification of guava juice by an ultrafiltration process: analysis on the operating pressure, membrane fouling and juice qualities

Abstract

Fresh guava juice was clarified using ultrafiltration (UF) process on a laboratory scale in this study. The observation was undertaken to determine the effect of the operating pressure (OP) on the permeate flux (J) behaviour, the fouling mechanisms as well as the quality attributes of the guava juice i.e. pH, turbidity, colour, total soluble solids (TSS), total phenolic content (TPC) and ascorbic acid content (AAC). The clarification of guava juice was performed in a batch mode using a 100 kDa polymeric membrane in a dead-end module at an operating pressure OP of 1.0, 1.5, 2.0 and 2.5 bar. The results showed that a high OP resulted in high flux during the UF process. The flux-pressure curves exhibited no increase for an OP higher than 2.0 bar (Plim), with a limiting flux (Jlim) identified at 17.22 kg/m2 /hr. Intermediate and total pore-blocking has been identified as the major fouling mechanisms in the process. The resulting juice after filtration showed a reduction of more than 97% turbidity with a lower TSS by 7 to 17%, compared to the fresh juice. The UF process permitted a good level of clarification with improvement in colour properties with a stable pH at 3.8. However, a 19 to 27% and 18 to 22% reduction of TPC and AAC, respectively were found in the filtered juice with respect to the fresh juice. For appropriate flux behaviour and juice quality attributes, the process UF should be conducted at 2.0 bar.

Bioactive compounds from Cucumis melo L. fruits as potential nutraceutical food ingredients and juice processing using membrane technology

“…Indeed, the flux trajectory comprises two distinct zones. These observations corroborate the results for the clarification of prickly pear juice (Ennouri et al, 2006), pomegranate juice (Cassano et al, 2011), lemon juice (Maktouf et al, 2014), and guava juice (Omar et al, 2019). The initial permeate flux of the M14 membrane (around 44 L/h/m 2 ) decreased and tended to stabilize, until it reached a steady state of about 20 L/h/ m 2 .…”

White-flesh guava juice clarification by a fixed-angle conical rotor centrifuge laboratory and characterization of continuous disk stack centrifuges

“…(2022) described an increase in TSS after cryocentrifugation of prickly pear juice. When clarifying guava juice with ultrafiltration using 100 kDa polyethersulfon membrane, Omar et al. (2020) observed a 7–17% decrease in TSS value compared to that of fresh juice.…”

Effect of Processing on Biofunctionality of Selected Tropical Fruit Juices

“…However, due to the high content of colloidal particles that cause turbidity and, depending on the desired final product, one or more clarification steps that may include enzymatic treatment, the use of fining agents and/or filtration might be included to improve consumer acceptance. , Nevertheless, clarification may also have an impact on the nutritional and functional properties when compared to the cloudy juice. The few publications on this respect have focused on the retention of ascorbic acid and show that enzymatic maceration with the right combination of pectinase concentration, incubation temperature, and time seems to improve the retention of this vitamin during processing parallel to increasing fruit juice yield. − More recently, Omar et al evaluated the use of ultrafiltration to clarify guava juice and, despite the good results obtained concerning turbidity and total soluble solids reduction, a considerable loss of ascorbic acid was measured as well.…”

“…The few publications on this respect have focused on the retention of ascorbic acid and show that enzymatic maceration with the right combination of pectinase concentration, incubation temperature, and time seems to improve the retention of this vitamin during processing parallel to increasing fruit juice yield. 170−172 More recently, Omar et al 173 evaluated the use of ultrafiltration to clarify guava juice and, despite the good results obtained concerning turbidity and total soluble solids reduction, a considerable loss of ascorbic acid was measured as well.…”