Ecofriendly Fruit Switches: Graphene Oxide-Based Wrapper for Programmed Fruit Preservative Delivery To Extend Shelf Life

Abstract

According to Food and Agriculture Organization 2015 report, post-harvest agricultural loss accounts for 20-50% annually; on the other hand, reports about preservatives toxicity are also increasing. Hence, preservative release with response to fruit requirement is desired. In this study, acid synthesized in the overripe fruits was envisaged to cleave acid labile hydrazone to release preservative salicylaldehyde from graphene oxide (GO). To maximize loading and to overcome the challenge of GO reduction by hydrazine, two-step activation with ethylenediamine and 4-nitrophenyl chloroformate respectively, are followed. The final composite shows efficient preservative release with the stimuli of the overripe fruit juice and improves the fruit shelf life. The composite shows less toxicity as compared to the free preservative along with the additional scope to reuse. The composite was vacuum-filtered through a 0.4 μm filter paper, to prepare a robust wrapper for the fruit storage.

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“…GO was modied with amine groups through the attack of nucleophilic EDA on the electrophilic epoxide ring in GO as previously reported. 30 Aer synthesis, GO and AGO were characterized through various techniques, including XRD, TEM, UV-vis, Raman and EDX.…”

“…2A; red curve). 30 Aer AmB loading, GO-AmB and AGO-AmB showed the co-appearance of 1630 and 1590 cm À1 peaks corresponding to GO and AGO, respectively, with additional peaks at 1070 (C-O stretch) and 870 cm À1 (C-H stretch) corresponding to AmB ( Fig. 2A; blue and pink curve), conrms successful loading of AmB.…”

“…1C; red curve). 30,34 Raman analysis showed the characteristics GO peaks at 1604 cm À1 , corresponding to the G band, which arose due to the E 2g phonon of sp 2 carbon atoms, while the peak at 1352 cm À1 corresponded to D bands, assigned to the zone boundary phonons with an A 1g symmetry ( Fig. 1D; black curve).…”

“…In the case of AGO, due to amine conjugation the negative charge of GO was shied to +9 mV. 30 Aer the loading of AmB in GO and AGO, the average value of charge was shied to the negative side with À35 mV in GO-AmB and À7 mV in AGO-AmB. This may be due to the carboxyl groups in the AmB drug molecules.…”

“…The GO obtained in the previous step was amine functionalized as previously reported by us and others. 29,30 Briey, 50 mg of GO was dispersed in 50 mL of 95% ethanol by probe sonication and 325 mL of EDA was added. Then, the reaction mixture was allowed to react with EDA for 24 h at R.T under continuous stirring.…”