Chemically characterized nanoencapsulated Homalomena aromatica Schott. essential oil as green preservative against fungal and aflatoxin B1 contamination of stored spices based on in vitro and in situ efficacy and favorable safety profile on mice.

ABSTRACT

Present study deals with the efficacy of nanoencapsulated Homalomena aromatica essential oil (HAEO) as a potent green preservative against toxigenic Aspergillus flavus strain (AF-LHP-NS 7), storage fungi, AFB1, and free radical-mediated deterioration of stored spices. GC-MS analysis revealed linalool (68.51%) as the major component of HAEO. HAEO was encapsulated into chitosan nanomatrix (CS-HAEO-Ne) and characterized through SEM, FTIR, and XRD. CS-HAEO-Ne completely inhibited A. flavus growth and AFB1 biosynthesis at 1.25 µL/mL and 1.0 µL/mL, respectively in comparison to unencapsulated HAEO (1.75 µL/mL and 1.25 µL/mL, respectively). CS-HAEO-Ne caused significant reduction in ergosterol content in treated A. flavus and provoked leakage of cellular ions (Ca+2, Mg+2, and K+) as well as 260 nm and 280 nm absorbing materials. Depletion of methylglyoxal level in treated A. flavus cells illustrated the novel antiaflatoxigenic efficacy of CS-HAEO-Ne. CS-HAEO-Ne exhibited superior antioxidant efficacy (IC50 (DPPH) = 4.5 µL/mL) over unencapsulated HAEO (IC50 (DPPH) = 15.9 µL/mL) and phenolic content. CS-HAEO-Ne depicted excellent in situ efficacy by inhibiting fungal infestation, AFB1 contamination, lipid peroxidation, and mineral loss with acceptable sensorial profile. Moreover, broad safety paradigm (LD50 value = 7150.11 mg/kg) of CS-HAEO-Ne also suggests its application as novel green preservative to enhance shelf life of stored spices.