Thermosensitive Hydrogel for Encapsulation and Controlled Release of Biocontrol Agents to Prevent Peanut Aflatoxin Contamination.

Jiachang Feng,Jiachang Feng,Dongxue Yin,Dongxue Yin,Wenfu Wu,Jianpeng Dou,Jianpeng Dou,Wenfu Wu,Youzhen Zhang,Zidan Wu,Youzhen Zhang

doi:10.3390/polym12030547

Jiachang Feng, Jiachang Feng + Show 9 more

Open Access

https://doi.org/10.3390/polym12030547

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Journal: Polymers	Publication Date: Mar 3, 2020
Citations: 20	License type: CC BY 4.0

Affiliation: Jilin Agricultural University, Jilin University

Abstract

Starch, alginate, and poly(N-isopropylacrylamide) (PNIPAAm) were combined to prepare a semi-interpenetrating network (IPN) hydrogel with temperature sensitivity. Calcium chloride was used as cross-linking agent, the non-toxigenic Aspergillus flavus spores were successfully encapsulated as biocontrol agents by the method of ionic gelation. Characterization of the hydrogel was performed by Fourier-transform infrared spectroscopy (FTIR), scanning electron micrograph (SEM), and thermogravimetry analysis (TGA). Formulation characteristics, such as entrapment efficiency, beads size, swelling behavior, and rheological properties were evaluated. The optical and rheological measurements indicated that the lower critical solution temperature (LCST) of the samples was about 29–30 °C. TGA results demonstrated that the addition of kaolin could improve the thermal stability of the semi-IPN hydrogel. Morphological analysis showed a porous honeycomb structure on the surface of the beads. According to the release properties of the beads, the semi-IPN hydrogel beads containing kaolin not only have the effect of slow release before peanut flowering, but they also can rapidly release biocontrol agents after flowering begins. The early flowering stage of the peanut is the critical moment to apply biocontrol agents. Temperature-sensitive hydrogel beads containing kaolin could be considered as carriers of biocontrol agents for the control of aflatoxin in peanuts.

Highlights

Aflatoxin contamination of peanuts, caused by the invasion of toxigenic strains of Aspergillus flavus and Aspergillus parasiticus, has attracted extensive attention
MostPNIPAAm of the sample beads were in shape, The characterization theTable synthesized was obtained from spherical the gel permeation chromatograph (GPC) test, and the and data their showed thatfrom the average molecular andinPDI
Thermosensitive hydrogel beads were successfully prepared by combining PNIPAAm with starch–alginate hydrogel

Summary

Introduction

Aflatoxin contamination of peanuts, caused by the invasion of toxigenic strains of Aspergillus flavus and Aspergillus parasiticus, has attracted extensive attention. The pods are in direct contact with soil fungi, and soil is the main source of mold that infects peanuts [1]. Previous studies have shown that sterilized grains such as rice and barley can be used as biocontrol carriers [3,4]. These starch-rich carriers provide favorable conditions for the growth and sporulation of fungi after absorbing water. A bioplastic mainly composed of modified starch has been studied to verify the possibility of replacing grains [6]. The bioplastic granules act as carriers of biocontrol fungus, in which starch can provide the carbon source. A sprayable bioplastic formulation prepared from inoculated recycled bioplastic has been verified to be effective at delivering biocontrol fungus to corn [7]

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