Fabrication, characterization, and bioactivity assessment of chitosan nanoemulsion containing allspice essential oil to mitigate Aspergillus flavus contamination and aflatoxin B1 production in maize.

The direct incorporation of essential oils (EOs) into real food system faces numerous challenges due to high volatility, intense aroma, and instability. This research aimed to enhance the stability and bio-efficacy of Pimenta dioica essential oil (PDEO) through encapsulation in chitosan (CN) nanoemulsion. The nanoemulsion (CN-PDEO) was fabricated through ionic-gelation technique. CN-PDEO exhibited high nanoencapsulation efficiency (85.84%) and loading capacity (8.26%) with the particle size ranging between 18.53 and 70.56 nm. Bio-efficacy assessment results showed that CN-PDEO presented more effective antifungal and antiaflatoxigenic activity against Aspergillus flavus (AF-LHP-VS8) at lower doses (1.6 and 1.0 µL/mL) than the pure PDEO (2.5 and 1.5 µL/mL, respectively, p < 0.05). Additionally, CN-PDEO preserved model food (maize) from aflatoxin B1and lipid peroxidation without altering their sensory properties during storage with high safety profile (p < 0.05). Overall results concluded that CN-PDEO can be recommended for shelf-life extension of stored maize and other food commodities.

Nanostructured Pimpinella anisum essential oil as novel green food preservative against fungal infestation, aflatoxin B1 contamination and deterioration of nutritional qualities.

Application of synthetic preservatives to control the contamination of stored food commodities with aflatoxin B1 causing considerable loss in nutritional value is a major challenge. However, employment of essential oils for protecting food commodities is much limited due to high volatility, and increased susceptibility to oxidation. Therefore, objective of the present investigation was encapsulation of Pimpinella anisum essential oil in chitosan nanobiopolymer (CS-PAEO-Nm) to improve its bioefficacy, and sensorial suitability for application in food system. The synthesized CS-PAEO-Nm was characterized through SEM, FTIR, and XRD and evaluated for improved biological activity. The CS-PAEO-Nm exhibited improved antifungal (minimum inhibitory concentration = 0.08 µL/mL) and antiaflatoxigenic (minimum aflatoxin inhibitory concentration = 0.07 µL/mL) activities. CS-PAEO-Nm treatment significantly inhibited ergosterol, enhanced leakage of ions and induced impairment in defense enzymes (p < 0.05). In situ minerals and macronutrient preservation, and acceptable sensorial characteristics suggested possible recommendation of nanoencapsulated PAEO as potential safe green food preservative.

Assessment of chemically characterized Salvia sclarea L. essential oil and its combination with linalyl acetate as novel plant based antifungal, antiaflatoxigenic and antioxidant agent against herbal drugs contamination and probable mode of action.

The present investigation reports antifungal and antiaflatoxigenic efficacy of Salvia sclarea essential oil (SSEO) and its combination with Linalyl acetate (LA) (1:1) against herbal drug deteriorating molds and aflatoxin B1 contamination. GC-MS analysis of SSEO showed Linalyl Acetate (LA) (61.33%) and Linalool (LL) (17.59%) as major components. The SSEO and LA combination displayed better antifungal and antiaflatoxigenic activity as compared to SSEO and LA used individually. SSEO and LA combination was effective in reduction of ergosterol and enhanced leakage of vital ions and UV-absorbing materials in a dose dependent manner. The combination caused significant reduction in cellular methylglyoxal content, an aflatoxin inducer suggesting its future application for development of aflatoxin resistant herbal drug varieties through green transgenics. The combination also showed pronounced antioxidant activity as compared to SSEO and LA used separately. Interestingly, the combination showed significant in situ protection of Picrorhiza kurroa rhizomes against mould infestation.

Assessment of chemically characterised Myristica fragrans essential oil against fungi contaminating stored scented rice and its mode of action as novel aflatoxin inhibitor.

The study reports chemically characterised Myristica fragrans essential oil (MFEO) as plant based food preservative against fungal and aflatoxin B1 (AFB1) contamination of scented rice varieties. The chemical profile of MFEO revealed elemicin (27.08%), myristicine (21.29%) and thujanol (18.55%) as major components. The minimum inhibitory and minimum aflatoxin inhibitory concentrations of MFEO were 2.75 and 1.5 mg/ml, respectively. The MFEO was efficacious against a broad spectrum of food deteriorating fungi. MFEO caused decrease in ergosterol content of fungal plasma membrane and enhanced leakage of cellular ions, depicting plasma membrane as the site of action. The MFEO caused reduction in cellular methylglyoxal content, the aflatoxin inducer. This is the first report on MFEO as aflatoxin suppressor. The essential oil may be recommended as plant based food preservative after large scale trials and reduction in methylglyoxal suggests its application for development of aflatoxin resistant varieties through green transgenics.

Assessment of chitosan biopolymer encapsulated α-Terpineol against fungal, aflatoxin B1 (AFB1) and free radicals mediated deterioration of stored maize and possible mode of action.

This study reports enhanced efficacy of encapsulated α-Terpineol to control fungal, aflatoxin B1 (AFB1) and free radicals mediated deterioration of stored maize samples. The α-Terpineol loaded chitosan nanoemulsion (α-TCsNe) was characterized through SEM, FTIR and XRD techniques. The α-TCsNe exhibited enhanced antifungal activity against aflatoxin secreting strain of Aspergillus flavus (AF-LHP-S1) and 12 other food borne moulds as well as AFB1 production at 0.4 and 0.3 µL/mL, respectively. Further, α-TCsNe inhibited ergosterol synthesis, methylglyoxal (the aflatoxin enhancer) content and enhanced cellular contents release. α-TCsNe showed enhanced radical scavenging activity with IC50 value equivalent to 39.57 and 6.23 µL/mL for DPPH and ABTS, respectively. In addition, α-TCsNe completely inhibited AFB1 production in stored maize samples during in situ investigation. Overall, α-TCsNe holds a promising potential and can be recommended as a novel antifungal preservative to improve the shelf-life of stored maize samples against fungal and aflatoxin contamination.