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  • br Conflict of interest br

    2024-04-15


    Conflict of interest
    Acknowledgement We wish to thank the Program of National Key R&D Program of China (2017YFD0200500) and the Fundamental Research Funds for the Central Universities (KYTZ201604) for partially funding this work.
    Introduction Chitosan ((1→4)-2-amino-2-deoxy-β-d-glucose) is one of the most abundant marine-based biopolymers. Chitosan has found application in various fields like agricultural, textile, medicinal and environmental due to its unique properties such as biodegradability, non-toxicity, and ubiquity [1]. Chitosan has a wide range of biological applications, including, plant growth stimulator, drug carrier, antimicrobial agent, etc. In addition, chitosan is effective in eliciting plant innate immunity against diseases in many plants like tobacco, rapeseed, rice, grapevine, paddy etc. [2]. The solubility of chitosan is a limiting factor for its applications. It is soluble only under acidic conditions. The limited solubility of chitosan in water can be overcome by its nanomaterial form. Thus chitosan nanoparticles (ChNP) are generally preferred to improve the PFI 3 processability and also to modify some of its properties like solubility, antimicrobial activity and the interactive ability [3]. Typically the small size of ChNP provides a larger surface area for the contact of nanoparticles with the substrate thus improving the activity [4]. Availability of bioactive compounds compatible with the environment is one of the main challenges of modern agriculture. ChNP is a promising alternative in this aspect, due to its biological activity and easy-to-obtain methods. The addition of ChNP to soil increases the microbial population and improves nutrients availability. ChNP has been accepted as growth promoters accelerating seeds germination, plant growth as well as the agricultural yield [5]. ChNP is an effective antimicrobial agent with activity against a wide range of bacteria, fungi, and virus. It, therefore, is a promising alternative to many chemical fungicides and bactericides in controlling various plant pathogens. There has been many reports on the antifungal activity of ChNP against R. solani [6], F. oxysporum [7], Colletotrichum gloeosporioides [8], Penicillium digitatum [9], Fusarium eumartii [10], Xanthomonas [11], Agrobacterium tumefaciens [12] and viriods [13]. Chitosan is reported to have scavenging activity against free radicals, chelate metal ions thus preventing the donation of hydrogen resulting in the antioxidant activity of chitosan. In addition, the small size and low molecular weight of nanoparticle appear to contribute to the antioxidant capacity of ChNP [14]. The non-toxicity and biodegradability of ChNP make it an excellent coating material of fruits and vegetables. ChNP coating has the potential to prolong storage life and to control decay of many fruits such as strawberries, papaya cucumber, carrot, apple, citrus, kiwifruit, peach, pear, strawberry, and sweet cherry [15]. Another aspect of ChNP coating is that functional ingredients, such as antimicrobial agents and nutraceuticals could be incorporated [16].
    Materials and methods
    Results and discussions Chitosan nanoparticles were formed by the interaction between negatively charged polyanion, and positively charged amino group (−NH3) of chitosan [26]. The nanoparticles formed were spherical shaped due to the agglomeration of chitosan and tripolyphosphate [17]. The ChNP obtained were freeze-dried and stored for further use.
    Conclusion
    Conflict of interests
    Acknowledgements
    Introduction For a long period, the security of foods, agricultural commodities and Chinese herbal medicines (CHMs) due to fungal contamination especially toxigenic fungi such as Aspergillus flavus, Penicillium viridicatum and Aspergillus carbonarius et al. (Asghar et al., 2017; Baquião et al., 2016; Geremew et al., 2016; Rundberget et al., 2004; Zhang et al., 2017) has attracted more and more consideration. One of the most important reasons is that these toxigenic fungi can naturally produce secondary metabolites-mycotoxins, which exhibit serious toxicities and considerable risks to the consumers (Edite Bezerra da Rocha et al., 2014). Among these mycotoxins, aflatoxins (AFs) mainly produced by Aspergillus flavus are toxic and carcinogenic metabolites, which have been classified as the Group IA carcinogen by the International Agency for Research on Cancer (IARC) (Al-Zoreky and Saleh, 2017; Iqbal et al., 2017; Yang et al., 2017). OTA mainly produced by Aspergillus carbonarius (Kanapitsas et al., 2016) and Penicillium viridicatum (Bragulat et al., 2008) is reported to be a nephrotoxin, an immune suppressant, as well as a carcinogen, and is reported to be related with Balkan Endemic Nephropathy (BEN) of human (Grollman and Jelakovic, 2007; Vecchio et al., 2012; Vrabcheva et al., 2004). Therefore, over the last few decades, exploring for effective, safe, and economic candidates for controlling or prohibiting fungal contamination and mycotoxins residue in the above-mentioned matrices has got increasing focus and interests of researchers.