Functionalized nanoencapsulated Curcuma longa essential oil in chitosan nanopolymer and their application for antioxidant and antimicrobial efficacy.

The present study reports on the encapsulation of Curcuma longa (L.) essential oil (CLEO) in chitosan nanopolymer as a novel nanotechnology preservative for enhancing its antibacterial, antifungal, and mycotoxin inhibitory efficacy. GC-MS analysis of CLEO showed the presence of α-turmerone (42.6 %) and ß- turmerone (14.0 %) as the major components. CLEO-CSNPs were prepared through the ionic-gelation technique and confirmed by TEM micrograph, DLS, XRD, and FTIR. In vitro, bactericidal activity of CLEO-CSNPs at a concentration of 100 µg/mL showed significant antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, which mostly rely on ROS production and depend on its penetration and interaction with bacterial cells. Furthermore, the CLEO-CSNPs during in vitro investigation against F. graminearum completely inhibited the growth and zearalenone and deoxynivalenol production at 0.75 µL/mL, respectively. Further, CLEO-CSNPs enhanced antioxidant activity against DPPH• and ABTS•+ with IC50 values 0.95 and 0.66 µL/mL, respectively, and without any negative impacts on germinating seeds were observed during the phytotoxicity investigation. Overall, experiments concluded that encapsulated CLEO enhances antimicrobial inhibitory efficiency against stored foodborne pathogens.

Nanoencapsulation of garlic essential oil using chitosan nanopolymer and its antifungal and anti-aflatoxin B1 efficacy in vitro and in situ.

The present study investigated the comparative efficacy of garlic essential oil (GEO) and its nanoencapsulated within chitosan nanomatrix (GEO-CSNPs) as a novel preservative for the protection of stored food commodities from fungal infestations, aflatoxin B1 (AFB1) contamination and lipid peroxidation against a toxigenic strain of Aspergillus flavus. GC-MS examination of GEO showed the presence of allyl methyl tri-sulfide (23.10 %) and diallyl sulfide (19.47 %) as the major components. GEO-CSNPs were characterized through TEM micrograph, DLS, XRD, and FTIR instrumentation. During the in-vitro investigation, GEO-CSNPs at 1.0 µL/mL dose completely inhibited the growth of A. flavus while preventing the synthesis of AFB1 at 0.75 µL/mL compared to the pure GEO. The biochemical analysis reveals that A. flavus exposed to GEO-CSNPs significantly changed its ergosterol level, ions leakage, mitochondrial membrane potential (MMP), and antioxidant system. Additionally, GEO-CSNPs exhibited enhanced antioxidant activity against DPPH compared with GEO. Likewise, during in-situ experiments on A. hypogea GEO-CSNPs MIC and 2 MIC concentration prohibited fungal development, AFB1 synthesis, and lipid peroxidation or inflicting any negative impacts on germinating seeds. Overall, investigations concluded that GEO-CSNPs could be used as a novel preservative agent to improve the shelf life of stored food commodities.