An Ecological Approach to Control Pathogens of Lycopersicon esculentum L. by Slow Release of Mancozeb from Biopolymeric Conjugated Nanoparticles

To control insects, weeds, and infections in crops, old-fashioned pesticide formulations (with massive quantities of heavy metals and a variety of chemicals) are used. By biological amplification via the food chain, many of these established pesticide formulations have accumulated in living systems and caused environmental pollution. To form a nanoparticulate matrix with a diameter ranging from 322.2 ± 0.9 to 403.7 ± 0.7 nm, mancozeb was embedded in chitosan-gum acacia (CSGA) biopolymers and loadings were confirmed via TEM and FTIR. Differential scanning calorimetry analyses were carried out as part of the investigation. Inhibition of Alternaria alternata by nanoparticles (NPs) with 1.0 mg/mL mancozeb (CSGA-1.0) was 85.2 ± 0.7 % at 0.5 ppm, whereas for Stemphylium lycopersici it was 62.1 ± 0.7% in the mycelium inhibition method. NPs demonstrated antimicrobial action in pot house environments. After ten hours, the mancozeb was liberated from the nanoformulations due to polymer matrix diffusion and relaxation, compared to 2 h for commercial mancozeb. Even while drug-loaded conjugated nanoparticles have equivalent antifungal activities, they have a lower release rate and, hence, reduced toxicology compared to commercial mancozeb. Therefore, this method can be employed to implement sustainable farming techniques in the future.

Synthesis, characterization, and utilization of potato starch nanoparticles as a filler in nanocomposite films

The nanoparticles for the preparation of nanocomposite starch films were synthesized from potato starch using the acid hydrolysis method. The films were prepared by incorporating starch nanoparticles into the film formulation at 0.5, 1, 2, 5, and 10% level of total starch. The control starch film was prepared without the incorporation of starch nanoparticles (SNPs) in film formulation. The starch and SNPs were analyzed for physicochemical and morphological properties. The absorption capacity of SNPs for water and oil was significantly (p < 0.05) lower as compared to native starch. Whereas, the swelling power and solubility of SNPs were significantly (p < 0.05) higher than the swelling power and solubility of starch, respectively. The starch granules were oval and spherical with regular surfaces whereas the SNPs had irregular cracked exteriors spaces. The water vapor transmission rate (WVTR) from nanocomposite starch films was significantly (p < 0.05) lower than the control starch film. The burst strength of films was increased significantly (p < 0.05) with an increased level of SNPs incorporation in film formulation. The incorporation of SNPs increased film thickness and biodegradability. Thus, the present study revealed that the incorporation of SNPs in film formulation resulted in improved film properties.

Impact on various properties of native starch after synthesis of starch nanoparticles: A review

In recent years, interdisciplinary research is more focused on particle size, which helps in exploring the relation between micro and macroscopic properties of various materials. Starch nanoparticles are generally synthesized by using acid/enzymatic hydrolysis, gamma irradiation, simple nanoprecipitation, ultra-sonication, and homogenization treatments. The properties like amylose content, pasting, rheological, morphological, size distribution, etc. are affected after the formation of nanoparticles from starch. This study emphasizes how various properties are changed in starch nanoparticles. Starch nanoparticles are mainly used in the formulation of nano-emulsion, nano starch-based composite film, and drug delivery. The impact on various native starch properties after the preparation of starch nanoparticles are less reported. So, all the aspects related to various starch properties and their nanoparticles are extensively reviewed in this study so that the listed findings can be utilized in future processes to increase the various foods and non-food utilization of starch nanoparticles.

Synthesis and characterization of nano starch-based composite films from kidney bean (Phaseolus vulgaris)

This study was aimed to synthesize and evaluate the nano starch-based composite films by the addition of nano starch in film formulation at 0.5, 1, 2, 5 and 10% level of total starch. The acid hydrolysis technique was used to reduce the size of starch granules of kidney bean starch. The physicochemical properties of both native and nano starch were determined. Nano starch showed a higher value for swelling power, solubility, water and oil absorption capacity when compared with native starch. The particle size of kidney bean nano starch was 257.7 nm at 100% intensity. The size of starch granule affects various properties of films. The thickness, solubility and burst strength of the composite films were increased significantly (p ≤ 0.05) with an increase in the concentration of nano starch in film formulation. While the moisture content and water vapour transmission rate (WVTR) were decreased significantly (p ≤ 0.05) with an increase in the concentration of nano starch in film formulation. The results suggested that kidney bean starch could be used for the development of packaging films. The utilization of nano starch in film formulations had an additional advantage in improving the film properties.

Development of starch nanoparticles based composite films from non-conventional source - Water chestnut (Trapa bispinosa)

In the present study, starch was isolated from a non-conventional source (water chestnut) and various physicochemical properties were investigated. Nano starch was prepared by adopting the acid hydrolysis method having a yield of 27.5%. Particle size distribution of native and nano starch was 5559 nm and 396 nm. The unique feature of water chestnut starch was the shape of starch granule that looked oval, ellipsoidal, mixed with spherical granules without cracks and smooth surface. While the water chestnut nano starch appeared as an agglomerated form with irregular and rough surface. Water chestnut starch nanocomposites films with varying concentrations of starch nanoparticles (SNPs) were synthesized by a solution casting method. The thickness, moisture content, water vapour transmission rate, water solubility, burst strength of native starch and nano starch composite films were evaluated. The results showed that native starch film had thickness (0.041 ± 0.07 mm) moisture content (4.17 ± 0.32%), water vapour transmission rate (4.678 × 10-3 ± 0.42 g-2 s-1), water solubility (35.71 ± 0.17%) and burst strength (976.4 ± 12.47 g), respectively. The incorporation of SNPs results in an increase in thickness and burst strength while moisture content, water vapour transmission rate and solubility of films were decreased with the increase in the concentration of SNPs which is essential features of a good package.

Synergistic activity between Bacillus thuringiensis Cry1Ab and Cry1Ac toxins against maize stem borer (Chilo partellus Swinhoe)

AIM

To select a toxin combination for the management of maize stem borer (Chilo partellus) and to understand possible mechanism of synergism among Bacillus thuringiensis Cry1A toxins tested.

METHODS AND RESULTS

Three Cry1A toxins were over expressed in Escherichia coli strain JM105 and used for diet overlay insect bioassay against C. partellus neonate larvae, both alone and in combinations. Probit analysis revealed that the three Cry1A toxins tested have synergistic effect against C. partellus larvae. In vitro binding analysis of fluorescein isothiocyanate (FITC)-labelled Cry1A toxins to midgut brush border membrane vesicle (BBMV) shows that increase in toxicity is directly correlated to an increase in binding of toxin mix.

CONCLUSIONS

A high Cry1Ac to Cry1Ab ratio leads to an increase in efficacy of these toxins towards C. partellus larvae and this increase in toxicity comes from an increase in toxin binding.

SIGNIFICANCE AND IMPACT OF THE STUDY

Use of Cry1Ab and Cry1Ac combination could be an effective approach to control C. partellus. Furthermore, we show it first time that possible reason behind increase in toxicity of synergistic Cry1A proteins is an increase in toxin binding.