Antifungal Features and Properties of Chitosan/Sandalwood Oil Pickering Emulsion Coating Stabilized by Appropriate Cellulose Nanofiber Dosage for Fresh Fruit Application

Abstract

A novel composite edible coating film was developed from 0.8% chitosan (CS) and 0.5% n sandalwood oil (SEO). Cellulose nanofibers (CNFs) were used as a stabilizer agent of oil-in-water Pickering emulsion. We found four typical groups of CNF level-dependent emulsion stabilization, including (1) unstable emulsion in the absence of CNFs; (2) unstable emulsion (0.006–0.21% CNFs); (3) stable emulsion (0.24–0.31% CNFs); and (4) regular emulsion with the addition of surfactant. Confocal laser scanning microscopy was performed to reveal the characteristics of droplet diameter and morphology. Antifungal tests against Botrytis cinerea and Penicillium digitatum, between emulsion coating stabilized with CNFs (CS-SEOpick) and CS or CS-SEO was tested. The effective concentration of CNFs (0.24%) may improve the performance of CS coating and maintain CS-SEO antifungal activity synergistically confirmed with a series of assays (in vitro, in vivo, and membrane integrity changes). The incorporation of CNFs contributed to improve the functional properties of CS and SEO-loaded CS including light transmission at UV and visible light wavelengths and tensile strength. Atomic force microscopy and scanning electron microscopy were employed to characterize the biocompatibility of each coating film formulation. Emulsion-CNF stabilized coating may have potential applications for active coating for fresh fruit commodities.

Antifungal features and properties of Pickering emulsion coating from alginate/lemongrass oil/cellulose nanofibers

“…Previous reports explained that lower transparency of samples through the existence of oil droplets in the matrix scattering the transmitted light (Yao et al ., 2017). Furthermore, the use of stabiliser, CNF, was believed to affect the internal and surface structure and to block the light spectrum efficiently (Wardana et al ., 2021). These results indicated that the incorporation of LGO Pickering emulsion may improve the light‐barrier features of the Alg‐based coating film.…”

“…CNF‐stabilised Pickering emulsion stock was prepared by homogenising CNF 0.24% and 0%, 0.25%, 0.5% and 0.75% LGO in distilled water using a high‐speed homogeniser (T 25 digital ULTRA‐TURRAX® ‐ IKA, Germany) at 15 000 rpm for 2 min, in accordance with the previous study by Wardana et al . (2021). At the same time, Alg solution was prepared by gelatinising Alg powder 1% in distilled water.…”

“…However, pure coatings made exclusively with one type of biopolymer have poor performance, particularly regarding antimicrobial properties. Incorporation of essential oil into the main biomatrix is considered by some researchers to overcome this concern (Horison et al ., 2019; Kawhena et al ., 2021; Wardana et al ., 2021).…”

Cellulose nanofiber‐based emulsion coatings with enhanced hydrophobicity and surface adhesion for preserving anthocyanins within thermally processed blueberries packed in aqueous media

“…CNF can also act as a stabilizer when incorporating into an emulsified coating. Second, polysaccharides, such as CS, XG, carboxymethyl cellulose (CMC), and their derivatives, were utilized as emulsifier, stabilizer and thicker to enhance the stability of emulsion‐based coating (Haghighi et al, 2019; Jung et al, 2015; Wardana et al, 2021). CS is widely used in food coatings because it is nontoxic and has excellent emulsion stability and antibacterial property (Sun et al, 2021).…”

Functional enhancement of hydroxypropyl cellulose‐based bionanocomposite films incorporating chitosan nanoparticles

“…Earlier investigations found the improvement of functional properties using nanofiller incorporation into the main matrices including zinc oxide nanoparticles into cassava starch and Chi (Wardana et al, 2018(Wardana et al, , 2022, nanoclay into Salvia macrosiphon seed mucilage (Davachi & Shekarabi, 2018), magnetic iron oxide-NP (nanoparticle) into gelatin (Mehmood et al, 2020), and sulphurcoated iron oxide-NP into carrageenan (Saedi et al, 2021). On the other hand, recent investigations have been giving much attention to polysaccharide nanofillers owing to the safety aspect and compatibility of edible films and/or food packing production (Azeredo et al, 2009;George & Siddaramaiah, 2012;Kalateh-Seifari et al, 2021;Saedi et al, 2021;Wardana et al, 2021a). ChiNP is a polysaccharidebased compound that offers excellent physicochemical properties, nontoxic, edible, and bioactive (Yang et al, 2010).…”