Innovative Approach for Controlling Black Rot of Persimmon Fruits by Means of Nanobiotechnology from Nanochitosan and Rosmarinic Acid-Mediated Selenium Nanoparticles

Abstract

The protection of persimmon fruits (Diospyros kaki L.) from postharvest fungal infestation with Alternaria alternata (A. alternate; black rot) is a major agricultural and economic demand worldwide. Edible coatings (ECs) based on biopolymers and phytocompounds were proposed to maintain fruit quality, especially with nanomaterials' applications. Chitosan nanoparticles (NCt), rosmarinic acid bio-mediated selenium nanoparticles (RA/SeNPs) and their composites were produced, characterized and evaluated as ECs for managing persimmon black rot. The constructed NCt, RA/SeNPs and NCt/RA/SeNPs composite had diminished particles' size diameters. The ECs solution of 1% NCt and NCt/RA/SeNPs composite led to a significant reduction of A. alternata radial growth in vitro, with 77.4 and 97.2%, respectively. The most powerful ECs formula contained 10 mg/mL from NCt/RA/SeNPs composite, which significantly reduced fungal growth than imazalil fungicide. The coating of persimmon with nanoparticles-based ECs resulted in a significant reduction of black rot disease severity and incidence in artificially infected fruits; the treatment with 1% of NCt/RA/SeNPs could completely (100%) hinder disease incidence and severity in coated fruits, whereas imazalil reduced them by 88.6 and 73.4%, respectively. The firmness of fruits is greatly augmented after ECs treatments, particularly with formulated coatings with 1% NCt/RA/SeNPs composite, which maintain fruits firmness by 85.7%. The produced ECs in the current study, based on NCt/RA/SeNPs composite, are greatly recommended as innovatively constructed human-friendly matrix to suppress the postharvest destructive fungi (A. alternata) and maintain the shelf-life and quality of persimmon fruits.

Keywords: Alternaria black rot; Diospyros kaki; antifungal; edible coatings; firmness; nanomaterials; nanopolymers; postharvest.

Figure 1

FTIR spectra of screened molecules including chitosan nanoparticles (NCt), rosmarinic acid (RA) and their composites with SeNPs*; The vertical red lines indicate the derived peaks from NCt and the blue lines indicate the derived peaks from RA.

Figure 2

Scanning features of synthesized nanoparticles, including plain synthesized selenium nanoparticles (Se) and encapsulated rosmarinic acid/SeNPs into chitosan nanoparticles (CG).

Figure 3

Examples of infected persimmon fruits after coating. (A): uncoated; (B): water-dipped; (C): water-dipped after 7 days; (D): coated with 1.0% nanochitosan; (E): coated with 0.5% nanochitosan/rosmarinic acid/Se nanocomposite; (F): coated with 1.0% nanochitosan/rosmarinic acid/Se nanocomposite, after 14 days of storage for treatments (A,B,D–F).