Technical assessment of reverse osmosis for concentration of fresh tea leaf extract

Abstract

This paper focused on the concentration of waste fresh tea leaf extract, byproduct of tea processing, by application of reverse osmosis. The concentration was carried out by plate and frame crossflow system equipped HR98PP membrane, operating as concentration mode with full recirculation of retentate. Results show that permeate flux increased with increase in operating pressure. Modeling of permeate flux based on osmotic pressure model at 30 and 40 bar of operating pressure was proposed. Hermia's model was applied for analyzed the membrane fouling in operation process. Good agreement between complete pore blocking model and experimental data was found. The recovery yields and contents of total solid (TS), total polyphenols (PPs) and antioxidant capacity (AC), consequently effectiveness, at 40 bar of operating pressure were higher than those at 30 bar. At 40 bar of operating pressure and 7.57 of concentration factor, the recovery yields of TS, PPs, and AC were 83.7, 85.1, and 79.6%, respectively. Contents of TS, PPs, and AC in retentate and permeate were 64.62 and 1.91 g/L; 25.82 and 0.61 g GAE/L; 97.87 and 3.35 mM TEAC, respectively. Maximum theoretical content of TS at 40 bar was estimated as 341 g/L. Results imply that it is potential to apply reverse osmosis for concentration of waste fresh tea leaf extract to produce instant powder with high content of polyphenols. Practical applications The concentration of waste fresh tea leaf extract by reverse osmosis membrane Modeling of permeate flux in reverse osmosis Fouling mechanism was analyzed by Hermia's model. Recovery yields and contents of total solid, total polyphenols and antioxidant capacity in concentrate against concentration factor were estimated.

Flux decline and fouling analysis in reverse osmosis of watermelon juice

“…This suggested that the increased pressure was responsible for the increase in turbulent flow, thereby reducing fouling phenomena. The complete blocking mechanism has also observed in many concentration processes by RO, such as waste fresh tea leaf extract (Lai et al, 2021) and skim milk (Arend, Castoldi, Rezzadori, Soares, & Brião, 2019).…”

“…The set of Equations (7 and 8) were solve by the fourth order Runge–Kutta method in Matlab software (version R2018a). This mathematical model has been successfully applied in modeling in concentration waste fresh tea leaf extract by RO (Lai et al, 2021), as well as purification and concentration rice protein by ultrafiltration (Doan & Lai, 2021).…”