Preparation of Cellulose Fiber Loaded with CuO Nanoparticles for Enhanced Shelf Life and Quality of Tomato Fruit.

The present study reports on the preparation of a cellulose fiber (CF) composite from D. lutescens, combined with copper oxide nanoparticles (DL@CF/CuO), to prolong the shelf life of tomatoes after harvest. The isolated cellulose fiber material was comprehensively characterized using XRD, FTIR, and FE-SEM analyses. The DLCF and DL@CF/CuO nanoparticles exhibited crystalline cellulose, as indicated by the XRD investigation. Both DLCF and DL@CF/CuO showed O-H and C-H FTIR spectra with identifiable vibrational peaks. The FE-SEM images depicted the dispersion of DL@CF/CuO-based fibers in a cellulose fiber matrix containing CuO nanoparticles. A 0.3% (wt/wt), a solution of DL@CF/CuO was coated onto the surface of early ripening tomato fruits. After a 25-day storage period at 25-29 °C and 85% RH, the results showed a significant extension in the shelf life of the tomato fruits, in line with changes in physiological properties and fruit quality. The extension of shelf life in tomato fruit epidermis treated with DL@CF/CuO was confirmed through FE-SEM analysis. L929 fibroblast cells were treated with the developed DL@CF/CuO nanocomposite, and no signs of toxicity were detected up to 75 µg/mL. Additionally, the DL@CF/CuO nanocomposite exhibited significant antifungal activity against Aspergillus flavus. In conclusion, this study provides novel insights for sustainable food security and waste control in the agricultural and food industries.

Correction: Marslin, G., et al. Secondary Metabolites in the Green Synthesis of Metallic Nanoparticles. Materials 2018, 11, 940.

The authors have overlooked a few mistakes when rearranging the Table 1 and Table 2 and references at the final stages, which were carried-over to the published version of the review [...].

Secondary Metabolites in the Green Synthesis of Metallic Nanoparticles.

The ability of organisms and organic compounds to reduce metal ions and stabilize them into nanoparticles (NPs) forms the basis of green synthesis. To date, synthesis of NPs from various metal ions using a diverse array of plant extracts has been reported. However, a clear understanding of the mechanism of green synthesis of NPs is lacking. Although most studies have neglected to analyze the green-synthesized NPs (GNPs) for the presence of compounds derived from the extract, several studies have demonstrated the conjugation of sugars, secondary metabolites, and proteins in these biogenic NPs. Despite several reports on the bioactivities (antimicrobial, antioxidant, cytotoxic, catalytic, etc.) of GNPs, only a handful of studies have compared these activities with their chemically synthesized counterparts. These comparisons have demonstrated that GNPs possess better bioactivities than NPs synthesized by other methods, which might be attributed to the presence of plant-derived compounds in these NPs. The ability of NPs to bind with organic compounds to form a stable complex has huge potential in the harvesting of precious molecules and for drug discovery, if harnessed meticulously. A thorough understanding of the mechanisms of green synthesis and high-throughput screening of stabilizing/capping agents on the physico-chemical properties of GNPs is warranted to realize the full potential of green nanotechnology.