In this study, optimization of production parameters influencing melanin production in an economical fruit waste extract was attempted using a garden soil isolate (Bacillus safensis). Taguchi approach was adopted for screening of critical parameters and further optimization was done using a central composite design of response surface methodology (RSM). At optimum conditions (pH 6.84 and Temp 30.7 °C), a significant yield of ∼6.96 mg/mL was observed. Statistical analysis revealed that the experimental results fitted well to the statistical model with model R2 value 0.982. The optimization of process parameters using RSM reported a 15% increase in the pigment yield than average yield obtained from the studied model. The melanin produced was confirmed by UV–visible spectroscopy, FTIR and XRD analysis. Moreover melanin obtained has significant photoprotective, radical scavenging and metal chelating activity. Thus, B. safensis has the potential to be a new source for the production of melanin, which is of industrial interest.

This paper studied the effects of sericin-based edible coating material on the quality and shelf-life of tomatoes over 40 days of storage at 25°C and relative humidity of 70%. The key constituents of the coating material are sericin (1.5%), chitosan (1.0%), Aloe vera (1.0%), and glycerol (1.5%) in an aqueous solution and applied onto tomatoes in a simple dip-coating technique. Weight loss, firmness titratable acidity (TA), total soluble solids (TSS), pH, and lycopene content were investigated and scanning electron microscopy was used to observe the semipermeable nature and the thickness of the coating layer. The results stated that the developed coating material reduced weight and firmness losses in tomatoes. With increased storage time, fruit TA content was increased and the values of pH, TSS, lycopene content, total phenolic content, and total antioxidant concentration stood low in comparison with uncoated tomatoes. With no evidence of wrinkles (up to 21 days), visible cracks, or deterioration on coated fruits during the study period, the application of sericin-based coating might be useful commercially for maintaining the postharvest quality control of tomatoes and even other fruits as well.

We have fabricated ZnO nanoflake structures using degummed silk fibers as templates, via soaking and calcining the silk fibers bearing ZnO nanoparticles at 150 °C for 6 h. The obtained ZnO nanostructures were characterized using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and UV-vis and fluorescence spectroscopic analysis. The size (~500–700 nm) in length and thicknesses (~60 nm) of ZnO nanoflakes were produced. The catalysis performances of ZnO nanoflakes on silk fibers (ZnSk) via photo-degradation of naphthalene (93% in 256 min), as well as Rose Bengal dye removal (~1.7 mM g−1) through adsorption from aqueous solution, were practically observed. Further, ZnSk displayed superb antibacterial activity against the tested model gram-negative Escherichia coli bacterium. The produced ZnSk has huge scope to be used for real-world water contaminants remediation applications.

In the recent years, functionalised Au nanoparticles using eco-friendly chemical routes are under the focus for developing several technological applications. However, a simple, reproducible, and controlled synthesis of high-quality nanoparticles is challenging in these approaches. In this work, readily available green chemicals were utilised and the usefulness of and Taguchi approach for optimisation of synthesis procedure was designed for the synthesis of possible lower size Au nanoparticles of size 93 ± 7 nm. L16 orthogonal array, by which the influence of four factors in four levels may well be tested, was chosen. Analysis of variance was done on the attained results and optimum condition suggested by statistical estimations was tested through a verification test. The identified key parameters for synthesising lower size Au nanoparticles are reducing agent (curcumin + cinnamic acid + citric acid), additive (zero), sonication time (30 min), and temperature (50°C) after performing the optimisation technique. Furthermore, this study also provides a selective approach to obtain different shape/shape Au nano to colloidal structures through different trail selection within the Taguchi experimental array.

Natural polymers like silk can be augmented in vivo with metallic elements to improve their intrinsic properties and stability. This study demonstrates the uptake of Ag and/or TiO 2 nanoparticles as diet supplements by silkworms. Nanoparticles dose on morphological changes in silk fibroin fibres and a change in overall silk yield was investigated. Though significant fibre reinforcement with Ag and/or TiO 2 was not noticed; an increase of 6% in the silk production was observed when silkworms fed with a particular composition of Ag + TiO 2 nanoparticles (0.37 mM each) in their diet. Here, an average diameter of the degummed silk fibre was ∼10.91µM with a roughness parameter value R q being 134. This value is comparable to silk fibres obtained from silkworms fed with Ag + TiO 2 (0.22 + 0.53 mM) nanoparticles and this R q value was also low when compared to the other tested compositions with nanoparticles. Silks from the control samples (devoid of nanoparticles in their feed) had high diameter fibres and are with low R q values and silk yield. However, nanoparticle supplementation to the silkworm's diet resulted in low diameter silk fibres with varying roughnessess and with improved silk yield for the tested doses.