Effectiveness of citrus fruit peel as a biosorbent for the mitigation of aflatoxins in vitro

Abstract

We assessed the effectiveness of novel and cost-effective citrus fruit peel (oranges, agro-waste material) for the removal of four aflatoxins B₁, B₂, G₁, and G₂ in vitro. The biosorbent was described using SEM, XRF, XRD, FITR spectroscopy, and point of zero charge. The adsorption performance was optimised in a batch experiment by altering the various parameters, such as biosorbent dose (1–15 mg/mL), the preliminary concentration of AFs (20–200 ng/mL), pH (1–9), the incubation period (10–60 min), and temperature (10–45 °C). Maximum removal (90%) was achieved when using biosorbent at 10 mg, each AF concentration 100 ng/mL, pH 3, and incubation time 45 min at 37 °C. The experimental data were well-described by the Langmuir isotherm model and the monolayer coverage (Qe) was calculated to be 78.5, 77.8, 79.2, and 75.6 ng/mg for aflatoxin B₁, B₂, G₁, and G₂, respectively. The thermodynamic and kinetic studies suggested that the adsorption performance was endothermic and obeyed the pseudo-second-order rate model. Studies at different pH also proved that the adsorption of toxins would be strong and sufficient under pH variation, as found in the gastrointestinal tract. Thus the biosorption of AFs by orange peel powder might be an efficient low price detoxification method in humans and animals.

Keywords:

• Citrus peel
• aflatoxins
• biosorbent
• isotherm
• kinetic
• thermodynamic

Acknowledgments

The authors appreciatively thank the Feed and Feed Safety Laboratory, FMRRC, PCSIR Laboratories Complex, Karachi, Pakistan for the assistance with the presented work.

Disclosure statement

No potential conflict of interest was reported by the author(s).