Green nanosensor for precise detection of formaldehyde in fruits and vegetables extract.

Present study reports fabrication of a low cost and eco-friendly formaldehyde nanosensor based on green magnetite nanoparticles synthesized using Mango (Mangifera indica L.) tree leaves extract. The formaldehyde is found in air, water and food. When inhaled or consumed formaldehyde has carcinogenic effects on human health. In this study the cyclic voltammetry technique was used to characterize the performance of the nanosensor. The green nanosensor fabricated in this study, to detect formaldehyde, demonstrated good sensitivity (193.4 µA mg-1 Lcm-2) in linearity range 0.03-0.5 mg/L with low threshold detection limit (0.05 mg/L). The green nanosensor also showed shelf life of four weeks without considerable change in the initial peak oxidation current. The real sample analysis was performed in various fruits and vegetables (Litchi chinensis, Syzygium cumini, Solanum lycopersicum and Cucumis sativus). The recovery rates were more than 93 % in sample extracts for formaldehyde detection. The comparison of the nanosensor for detection of formaldehyde with the colorimetric sensor revealed that the green nanosensor reproducibility (RSD = 1.8 %) is better than colorimetric sensor (RSD = 3.23 %). The results from the comparative studies of green nanosensor with colorimetric sensor established the potential of the green nanosensor as a forefront technology for futuristic smart detection of formaldehyde.

Guar gum and chitosan-based composite edible coating extends the shelf life and preserves the bioactive compounds in stored Kinnow fruits.

The present investigation aimed to elucidate the effects of chitosan (CH) and guar gum (GG) based composite edible coating on physicochemical quality and storability of Kinnow fruit under ambient conditions. Composite coating materials were prepared by using tamarind (TAM) seed starch and jackfruit (JACK) seed starch with CH and GG separately. The results indicated that GG + TAM coated fruits maintained significantly (P ≤ 0.01) lower physiological losses in weight (PLW) (3.12 %), decay incidence (0.83 %), and respiration rate (13.57 ml CO2 kg-1 h-1) compared to control. The reduced activity of pectin methylesterase (PME) (0.97 µmol min-1 g-1 FW) and lipoxygenase (LOX) (1.97 µmol min-1 g-1 FW) were noted in GG + TAM coated fruits. Also, the GG + TAM coated fruits retained higher fruit firmness (6.77 N), titratable acidity (TA) (0.94 %), ascorbic acid (AA) (27.83 mg 100 g-1), total phenols (213.05 mg GAE 100 g-1 FW), antioxidants activity (23.57 µmol TE g-1) along with higher sensory score over the control. Based on findings, it can be concluded that GG + TAM coating could be gainfully utilized for prolonging the shelf life of Kinnow fruits up to 25 days without losing desirable quality traits at ambient storage.

Synergistic effects of silver nanoparticles augmented Calothrix elenkinii for enhanced biocontrol efficacy against Alternaria blight challenged tomato plants.

The biocontrol efficacy of a cyanobacterium Calothrix elenkinii (Ce), silver nanoparticles (AgNPs) and their augmented complex (AgNPs-Ce) was evaluated. Foliar application of AgNPs-Ce reduced the disease severity by 47-58%, along with significant increases of 44-45%, 40-46% and 23-33% in leaf chlorophyll, carotenoid content, and polyphenol oxidase activity in the A. alternata infected tomato plants. A significant reduction in the pathogen load was recorded, both by plate counts and microscopic observations in the AgNPs, Ce and AgNPs-Ce treatments, while AgNPs-Ce also effectively reduced ergosterol content by 63-79%. Amplification using PCR-ITS primers revealed very faint bands or none in the AgNPs-Ce treated leaves, illustrating the inhibition of fungal growth. Significantly higher yield was recorded in the pathogen challenged plants receiving AgNPs-Ce, AgNPs, and Ce treatments. Higher expression of elicited antioxidant enzymes, along with enhanced plant growth attributes and lowered fungal load highlight the biocontrol potential of AgNPs-Ce treatment in A. alternata infected plants. This synergistic association can be explored as a promising biocontrol option against A. alternata challenged tomato plants under various agroclimatic conditions.