| dc.description.abstract | The search for new routes of synthesis of silver nanoparticles has intensified in recent years. Thus, research on the biological method of green synthesis of nanoparticles using vegetable extracts, as a reducing agent, has been gaining more and more attention because it is a simple, fast, efficient and economically viable procedure. The objective of this work was to synthesize silver nanoparticles (AgNPs) from aqueous extract of grape residue cv BRS Violet, to characterize and evaluate its use as a protective coating of cv Gala apples. The residue of grapes cv BRS Violet was submitted to different drying processes (48 ° C and freeze-drying) and the different samples obtained were defined as in-house residue (RIN), dried in a greenhouse (RIS), dried greenhouse (RMS) and lyophilized ground whole residue (RIML). All the residues were evaluated by physical-chemical parameters (SST, pH, Aw, moisture, titratable total acidity in NaOH, ash content, protein content, energy content and vitamin C content), antioxidant activity (DPPH and ABTS) and instrumental analysis (physical colorimetry,UV-VIS, MEV-EDS, FTIR, XRD, TGA and DSC). The data obtained were treated by the Shapiro-Wilk Normality Test and showed a tendency for non-normal distribution (p ≤ 0.05). Thus, they were evaluated by the Spearman Correlation Matrix and Principal Component Analysis (PCA). The interactions between all the analytical parameters suggested higher values of antioxidant activity for RIML, which expressed important antitumor activity against HL-60 cells (acute myeloid leukemia) and Jurkat (T-lymphocyte leukemia) cells. Therefore, the aqueous extract of RIML (E1) was selected for the production of AgNPs. The concentration of AgNO3 solution (1.4 mmol L-1 and 2.6 mmol L-1), concentration of extract (1: 160 and 10:40), and time of synthesis (90 and 120 minutes) ) and the best AgNP synthesis condition (48 ° C; E1 extract: 2.6 mmol L-1 AgNO3 and 90 minutes time) was defined. AgNPs formed from E1 were monitored spectrophotometrically (200-600 nm) and colorimetrically every 15 minutes and for up to 10 days. An absorption band between 400 and 500 nm characterized the synthesized nanoparticle and negative Zeta Potential (-26.55 ± 0.9 mV) indicated the stability of this solution, which showed antimicrobial activity against all the microorganisms tested by the analysis of (Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis and Proteus Mirabilis) and Gram-negative bacteria (Escherichia coli, Salmonella Typhimurium and Salmonella Gallinari). The AgNPs obtained from E1 were incorporated into the formulated food coating (starch and sorbitol) and then characterized by MEV-EDS, FTIR and XRD This nanomaterial was used to protect the surface of Gala apples and evaluated during a storage period at room temperature (25ºC) The microbicidal effect of silver nanoparticles (AgNPs) on the NaOH ratio, and the overall appearance fungi that potentially affect the apple culture was tested and the properties of the synthesized nanomaterial incorporated in starch films were applied to apples cv Gala and demonstrated a strong protective action prolonging the useful life of the fruits for up to 16 days, an increase of 12 days in relation uncoated control. | |
