Antifungal effects of chitosan films incorporated with essential oils and control of fungal contamination in peanut kernels

Abstract

The study investigated the effects of chitosan (CS) combined with essential oils (EOs) in controlling the fungal contamination in peanut kernels. The antifungal activities of CS and EOs were evaluated against Aspergillus flavus and Penicillium citrinum. CS (2%, w/v in 1% v/v acetic acid) packaging films were formulated by incorporating different EOs (4%) separately, that is, thyme (TEOs), cinnamon (CEOs), and lemongrass (LEOs), respectively. CEOs showed lowest minimum inhibitory concentration (MIC) of 40 μl/ml against A. flavus and P. citrinum. CS films incorporated with CEOs showed high tensile strength and smooth morphology with less fissures in comparison to films incorporated with TEOs and LEOs. CEO‐based CS films showed complete inhibition of fungal growth at 28°C and 5°C for 24 days. The combination of CS and CEOs coating restricted the A. flavus and P. citrinum contamination to 9.8% and 13.4%, respectively, in artificially inoculated peanut kernels at 28°C for 14 days of storage. CS can be used in combination with EOs to control postharvest fungal contamination in peanuts. Practical applications CS are well known for the formulation of food packaging films; however, antifungal activity of CS is limited. This study explains the antifungal effects of CS and EOs. The combination of CS and EO can be used to reduce the concentration of EOs as antifungal agents which otherwise might affect the organoleptic attributes of food. The CS films incorporated with EOs are possible to use for shelf life extension and prevention of postharvest fungal contamination of agriculture commodities.

Essential Oils and Their Application in Food Safety

“…BoŽik et al (2017) showed complete inhibition of A. flavus, A. parasiticus, and A. clavatus in oats by lemongrass, oregano, and thyme EOs. Chein et al (2019) investigated the efficacy of thyme, cinnamon, and lemongrass EOs to control the contamination of A. flavus and Penicillium citrinum at the lowest minimum inhibitory concentration of 40 µl/ml in peanuts kernels. Omidbeygi et al (2007) investigated the antifungal property of thyme and summer savory EOs against A. flavus in tomato paste at effective concentrations of 0.35 and 0.5 µg/ml, respectively.…”

Incorporating ε-Polylysine Hydrochloride, Tea Polyphenols, Nisin, and Ascorbic Acid into Edible Coating Solutions: Effect on Quality and Shelf Life of Marinated Eggs

“…Chitosan (CS), a linear cationic polysaccharide resulting from chitin deacetylation, is considered a suitable coating material due to its antimicrobial capacity and uniform lm-forming ability (Lai et al 2022). Chitosan exhibits antioxidant activity and broad-spectrum antibacterial activity against Salmonella, Lactobacillus, Listeria monocytogenes, and yeast (Chein et al 2019;Lin et al 2020; Molamohammadi et al 2019). In addition, several studies have reported that the combination of chitosan with other substances may show enhanced antibacterial and antioxidant effects compared to either single agent alone.…”

Prevalence of fungi in fresh tomatoes and their control by chitosan and sweet orange (Citrus sinensis) peel essential oil coating

“…The effects of EO, CS, and their combined mixture (EO + CS) on fungal hyphae were determined by following the method described by Chein et al 24 Potato dextrose broth (PDB, Himedia, India), 20 mL containing Tween 80 (2%, v/v) was inoculated with fungal spores (10 4 spores/ml) and placed in a shaking incubator (Wisecube, Seoul South Korea) at 30 °C and 180 rpm. After 48 h, hyphae were harvested by centrifugation (DLAB D3024R, China) at 4,500× g for 5 min, and were then washed (twice) with phosphate buffer saline (PBS, pH 7.4).…”

“…The reported variations in MIC values of EO might be due to the variations in composition of EO due to different extractions methods, cultivation season, different test strains of fungi. 24,34 FTIR analysis Functional groups of EOs from fresh and dried peels of sweet orange were identified by FTIR (Fig. 2 and supplementary material, Table S1).…”

“…Due to their edible nature, CS and EO based coatings can be used as an alternative to synthetic preservatives to extend the shelf life of fresh tomatoes and other agriculture commodities. Chein et al 24 reported that the combined mixture of CS and cinnamon EO inhibited the growth of A. flavus and P. citrinum in peanut kernels and the inhibition was significantly higher than the treatments of peanut kernels with EO and CS separately. According to another study, the combined mixture of CS and oregano EO showed high antifungal activity and affected the morphology of spores and mycelia of R. stolonifer and A. niger.…”