Cu-chitosan nano-net improves keeping quality of tomato by modulating physio-biochemical responses

Abstract

Minimizing the post-harvest losses in fruits and vegetables is one of the challenging tasks in agriculture. To address this issue, we report nano-net of Cu-chitosan nanoparticles (Cu-chitosan NPs) which has the ability to extend the shelf-life of stored tomato. The application of Cu-chitosan NPs (0.01–0.04%) significantly curtailed microbial decay (< 5 versus > 50% in control), physiological loss in weight (14.36 versus 28.13% in control), respiration rate (0.01173 versus 0.01879 g CO2 kg−1 h−1) and maintained fruit firmness (34.0 versus 17.33 N in control) during storage. Further, these NPs significantly retarded loss of titratable acidity, retained total soluble solids, total and reducing sugars, lycopene, ascorbic acid and inhibited polyphenol oxidase. Likewise, NPs effectively preserved L* (lightness), a* (red/green) and b* (blue/yellow) values and maintained organoleptic score. Scanning electron microscopy study confirmed that Cu-chitosan NPs orchestrate into an invisible-intangible nano-net over tomato surface which may plausibly act as a potential barrier at all possible openings (stem scar, cuticle wax, lenticels, and aquaporins) to control microbial infection, moisture loss, gas exchanges and respiration rate. Overall, nano-net extended keeping quality of tomatoes up to 21 days at room temperature (27 ± 2 °C, 55 ± 2% relative humidity).

Chitosan-Phenylalanine Nanoparticles (Cs-Phe Nps) Extend the Postharvest Life of Persimmon (Diospyros kaki) Fruits under Chilling Stress

“…Some recent studies reported that fruit coated with Cs were prevented from reducing in weight, water vapor transmission rate and O 2 /CO 2 by increasing surface and interface roughness and due to a smaller pore size, thus preventing the percentage of weight loss [41]. Menna et al [25] reported Cu-chitosan nano significantly prevented weight loss in tomato during 21 days storage, which is in accordance with our study. Furthermore, chitosan/nano-TiO 2 composite treatment could prevent weight loss in mango fruits [27].…”

“…Application of nano-SiO 2 /chitosan caused an increase of TSS in tomato fruit compared with control [41]. Meena et al [25] reported that Cu-chitosan nano-net treatment significantly prevented the increase of TSS by decreasing respiration and metabolic activities, as a result decreasing sugars in tomato. However, in another study chitosan-silica nanocomposites had no effect on TSS content [48].…”

“…Cs-Phe NPs treatment formed a thin layer on the surface of the fruit and modified the exchange of gas O 2 and CO 2 in the fruit, directly affecting the fruit respiration rate and further delaying the decrease in firmness [41]. Meena et al [25] reported that fruit coated with Cs prevented the reducing of firmness; for example, cu-chitosan nano-net maintained firmness in tomato fruit for 15 days with the entire surface of the fruit covered and controlled moisture loss and gas exchanges and decreased respiration rate. Cs-Phe NPs treatment in this study significantly prevented decrease in the firmness of persimmon fruits, which is consistent with the results reported by Meena et al [25].…”

“…Meena et al [25] reported that fruit coated with Cs prevented the reducing of firmness; for example, cu-chitosan nano-net maintained firmness in tomato fruit for 15 days with the entire surface of the fruit covered and controlled moisture loss and gas exchanges and decreased respiration rate. Cs-Phe NPs treatment in this study significantly prevented decrease in the firmness of persimmon fruits, which is consistent with the results reported by Meena et al [25]. The keeping of stiffness of the coated fruits Coatings 2021, 11, 819 9 of 18 with chitosan/titanium dioxide nanocomposite due to increased antioxidant enzymes has been reported during storage in mango fruit [27].…”

“…In another study chitosan combined with cellulose nanoparticles had positive effects on strawberry fruit by decreasing weight loss and enhancing antioxidant compounds in comparison with chitosan treatment during 21 days of cold storage [24]. Meena et al [25] reported that Cu-chitosan nanoparticle treatment successfully maintained qualitative and quantitative characteristics such as maintaining firmness, preventing decrease of titrable acidity, ascorbic acid, lycopene, and phenolic compound, and preventing increased decay in tomato fruit by inducing increase antioxidant system activity and many desirable physico-chemical characteristics of nanoparticles during 21 days of storage.…”