Antifungal Activity of Gelatin-Tapioca Starch Film and Coating Containing Copper Nanoparticles against Colletotrichum gloeosporioides Causing Anthracnose

Abstract

This study aimed to fabricate a nontoxic coating containing copper nanoparticles (CuNPs) to protect fruits from pathogenic Colletotrichum gloeosporioides causing anthracnose on several tropical fruits. We used a green approach, in which CuNPs were synthesized by reducing CuSO4 with ascorbic acid in the presence of gelatin and glycerol as the capping agents. The formation of CuNPs was confirmed by UV-vis absorption spectra of the reaction mixture, which showed a surface plasmon resonance peak at 578–594 nm. The x-ray diffraction spectrum of the CuNPs indicated the presence of mostly metallic copper with some minor impurities of Cu2O, CuO, and Cu(OH)2. Transmission electron microscopy (TEM) images and dynamic light scattering studies showed that the sizes of 90% of CuNPs were in 100–300 nm range. A 30–50 nm capping layer of gelatin surrounding CuNPs can be observed in the TEM images. Comparing FTIR spectra of the used reagents and CuNPs confirmed the depletion of ascorbic acid, as well as the gelatin layer protecting CuNPs. The synthesized CuNPs showed dose-dependent antifungal activity against C. gloeosporioides with 100% growth inhibition at 200 ppm copper. Gelatinized tapioca starch was then added to the CuNPs solution to obtain a film-forming mixture to produce stand-alone composite films on Petri dishes and coatings on mangoes. C. gloeosporioides could not grow on the surface of nutrient agar in contact with the films containing 245 ppm CuNPs, while they grew normally on control films without CuNPs. For the in vivo antifungal tests on mangoes, both the control and the CuNPs-containing coatings equally inhibit fungal growth, possibly due to the low oxygen permeability of the protein and starch components in the films. This study thus demonstrated the potential applications of composite coatings using biodegradable polymers that contain CuNPs in postharvest protecting fruits from phytopathogenic fungi.

Temperature adaptations of the thermophilic snail Echinolittorina malaccana: insights from metabolomic analysis

“…The enhancement of glycerophospholipid metabolism under extreme heat stress in E. malaccana could be important in stabilizing cellular membranes. Glycerophospholipids (mainly phosphatidylethanolamine and phosphatidylcholine) are important components of cell membranes (Nguyen et al, 2020;Overgaard et al, 2008), and have close relations with the permeability of the cell membrane and the activity of ATPases (Nemova et al, 2017). The regulation of glycerophospholipid content under thermal stress may be an adaptive response to warmer temperature (Bolstridge et al, 2010;Hunsberger et al, 2014).…”

Green Management of Postharvest Anthracnose Caused by Colletotrichum gloeosporioides

“…The antimicrobial activity of proteins can also be enhanced by using nanoparticles (NPs), which are promising solutions. Nguyen et al [ 97 ] tested gelatin coatings with silver NPs for the control of C. gloeosporioides in vitro and in situ on mangoes. They observed a complete inhibition of fungal growth on Petri dishes but did not find significant inhibition on mangoes compared to the control.…”

Antifungal potential of silver and copper nanoparticles against Lasiodiplodia theobromae causing stem-end rot of mango

“…Nano Cu ở nồng độ 4000 ppm không ức chế hoàn toàn sự phát triển của nấm L. theobromae XB1, tuy nhiên kết quả tương tự với nghiên cứu của Johari và đồng tác giả (2014). Ở các nồng độ thấp hơn, sợi nấm mọc thưa, mảnh và phát triển yếu hơn là do hoạt động kháng nấm của nano Cu đến màu sắc, hình thái, cấu trúc và mật độ của sợi nấm (Nguyen et al, 2020). Các đặc tính kháng khuẩn và kháng nấm của một số hạt nano như Ag, TiO2 và ZnO cũng đã được thừa nhận.…”