Effects of membrane pore size and transmembrane pressure on ultrafiltration of red‐fleshed dragon fruit (Hylocereus polyrhizus) juice

Abstract

BACKGROUND Red‐fleshed dragon fruit contains high amounts of heat‐sensitive betacyanin pigments that require non‐thermal technologies in their processing. Ultrafiltration (UF) can be a promising alternative technique for fruit juice clarification and cold sterilization. RESULTS This study reported clarification of red‐fleshed dragon fruit juice by UF employing polyethersulfone UF membranes with pore sizes of 5, 10, and 20 kDa operated at three different transmembrane pressures of 1, 2 and 3 bar. Findings indicated that dragon fruit juice was best ultrafiltrated with the 10 kDa UF membrane at 3 bar, which resulted in the highest permeate flux (around 7.9 kg m−2 h−1), lowest retention of betacyanins (30.6%) and phenolic compounds (11.3%), as well as having the closest 2,2‐diphenyl‐2‐picrylhydrazyl hydrate scavenging ability as compared to that of the control. Resistance analyses presented that cake resistance (69–94%) played the major role in decreasing flux and was the dominant fouling cause in the UF process, while reversible (5–25%) and irreversible resistances (1–16%) had lesser impacts. Membrane characterizations using scanning electron microscopy and Fourier‐transform infrared spectroscopy suggested that the chemical structure and surface morphology of the UF membrane were hardly altered after being used and washed with detergents. Liquid chromatographic–mass spectroscopic analyses demonstrated that UF was successfully employed for juice clarification without affecting heat‐sensitive compounds of fruit juices such as betacyanins. CONCLUSION Simultaneous selection of suitable membrane pore size and operation pressure is crucial for UF of fruit juice. UF is a promising technique in processing bioactive compound‐containing liquid foods. © 2021 Society of Chemical Industry

Clean Label “Rocha” Pear (Pyrus communis L.) Snack Containing Juice By-Products and Euglena gracilis Microalgae

“…As main conclusions of this section, it can be said that: (i) there is some freedom in choosing the most convenient parameters—a lower temperature to preserve bioactive compounds and sensory attributes ( 27 ), or a higher temperature to have a better flow and a better clarified juice yield (due to lower viscosity); (ii) even if turbid juices' turbidities are significantly ( p < 0.05) different, the process produces consistent results—clarified juice is always similar in terms of turbidity—accommodating some raw material variations (essential for industrial processes); (iii) given the high level of differences between the two turbid juices used for M100 tests, it cannot clearly be pointed the best membrane. However, small pore sizes can induce high retention of phenolics and antioxidants ( 73 ); (iv) temperature-membrane combinations need to be set considering the juice characteristics and objectives, having an impact on both resulting juices' quality and process parameters.…”

ZIF-Derived Co/Zn Bimetallic Catalytic Membrane with Abundant CNTs for Highly Efficient Reduction of p-Nitrophenol

“…The membrane flux is critical for the CoZn@CM catalytic membrane. The flux will influence the pressure drop in the catalytic membrane reactor, and low flux can result in high pressure drop, thereby making the run of the catalytic membrane reactor unstable. Moreover, the flux affects the mass transfer and the residence time of the reactants. , Hence, in this study, the flux of the CoZn@CM catalytic membranes was investigated.…”

Impact of different treatments on chemical composition, physical, anti-nutritional, antioxidant characteristics and in vitro starch digestibility of green-kernel black bean flours

“…Anthocyanin content was determined by the pHdifferential spectrometric method (Giusti & Wrolstad, 2001), while total phenolic content (TPC) was measured using the Folin -Ciocalteu method (Jagtap & Bapat, 2015). The antioxidant capacities were evaluated through 2,2-diphenyl-2picrylhydrazyl hydrate (DPPH) free radical scavenging ability (Le et al, 2021) and ferric reducing antioxidant power (FRAP) (Guo et al, 2003). The mineral contents were analyzed by performed by inductively coupled plasma mass spectrometry (Feitosa et al, 2018).…”