Aerogel doped by sulfur-functionalized graphene oxide with convenient separability for efficient patulin removal from apple juice

Patulin (PAT) contaminant causes severe food safety issue throughout apple industry. Although adsorption is the feasible approach to remove PAT, the limited adsorption capacity and separation difficulty of most adsorbent is the major drawback that remains to be overcome. Here GO-SH doped aerogel was prepared and used for removal PAT from apple juice. The intrinsic porous of the aerogel and abundant active sites including -COOH, -NH₂ and -SH offered the PAT adsorption capacity of 24.75 μg/mg that superior to most reported adsorbents. Furthermore, it could reduce 89 ± 1.23% PAT in real apple juice without juice quality deterioration and cytotoxicity. Importantly, the aerogel with good mechanical strength and structure stability could endure the complex juice solution so that there was no any residue after convenient separation of the aerogel, which proved that the proposed aerogel was a promising adsorbent to be applied to apple juice industry for PAT removal.

Highly efficient and cost-effective removal of patulin from apple juice by surface engineering of diatomite with sulfur-functionalized graphene oxide

Patulin (PAT) contamination of apple juice leads to a serious food safety issue. Developing an excellent adsorbent to efficiently remove PAT is more desirable. Herein, a cost-effective and efficient adsorbent (GO-SH/diatomite) with abundant active sites was successfully fabricated via surface engineering of diatomite with sulfur-functionalized graphene oxide (GO-SH) nanosheets, which exhibited excellent selective adsorption capacity toward PAT. The adsorption behavior, adsorption mechanism, stability and cytotoxicity were investigated by systematic studies. The adsorption results showed that its maximum adsorption capacity was 10.68 μg/mg. Moreover, attributed to the specific interaction between PAT and thiol group, more than 90% of PAT was removed from apple juice without any juice quality deterioration. Importantly, the risk of food safety issue of apple juice caused by residual GO-SH/diatomite was negligible due to the properties of easy removal and excellent biocompatibility, which guaranteed its potential application in apple juice industry for PAT removal.

Patulin removal from apple juice using a novel cysteine-functionalized metal-organic framework adsorbent

Patulin (PAT) is one of the most common toxic contaminants of apple juice, which causes severe food safety issues throughout the apple industry. In order to remove PAT efficiently, a metal-organic framework-based adsorbent (UiO-66(NH₂)@Au-Cys) was successfully synthesized and used for PAT removal from juice-pH simulation solution and real apple juice. Batch adsorption experiments were systematically performed to study the adsorption behavior for PAT. The results showed that adsorption process could be well described by the Pseudo-second order model and Freundlich isotherm model. The maximum adsorption capacity (4.38 µg/mg) was 10 times higher than the microbe-based biosorbents. Thermodynamic investigation demonstrated that adsorption process was spontaneous and endothermic. Furthermore, no marked cytotoxicity on NIH 3T3 cell lines was observed when the concentration of the adsorbent was lower than 10 μg/mL. Therefore, UiO-66(NH₂)@Au-Cys is a potential adsorbent for PAT removal from apple juice with little quality changes.

The validated and sensitive HPLC-DAD method for determination of patulin in strawberries

This work outlines HPLC coupled with DAD detection for accurate quantification of patulin (mycotoxin) in strawberries. The optimized extraction of fruit samples through the modified QuEChERS technique in acetonitrile acidified with acetic acid (1%, v/v) and citrate-buffered salts followed by dispersive solid phase extraction using a primary secondary amine and graphitized carbon is described. The method presents LOD and LOQ of 1.5 and 5µg/kg, respectively and has been validated in strawberry matrix at three concentration levels (5, 10 and 50µg/kg), according to SANTE/11945/2015 and the 2002/657/EC Decision requirements. All validated patulin levels show high percentage of patulin recovery. The validation procedure also includes the intermediate precision performed within three successive days in samples spiked with patulin. The developed method was applied for analysis of fresh and frozen strawberries purchased at local markets. Patulin level in analyzed samples was below the level of detection.