Safe coating formulated from biopolymer can be an alternative for better packaging for fruits. Among biopolymers used for safe coating, polysaccharides attracted more attention due to its biocompatibility and edibility. However, polysaccharide-based materials have weaknesses such as low water barrier and mechanical properties which result in lower capability on preserving the coated fruits. Hence, the incorporation of nanoparticles (NPs) such as zinc oxide (ZnO) is expected to increase the ability of polysaccharide-based coating for the enhancement of fruit shelf life. In this review paper, the basic information and the latest updates on the incorporation of ZnO NPs into the polysaccharide-based safe coating for fruit are presented. Various research has investigated polysaccharide-ZnO nanocomposite safe coating to prolong the shelf life of fruits. The polysaccharides used include chitosan, alginate, carrageenan, cellulose, and pectin. Overall, polysaccharide-ZnO nanocomposites can improve the shelf life of fruits by reducing weight loss, maintaining firmness, reducing the ripening process, reducing respiration, reducing the oxidation process, and inhibiting microbial growth. Finally, the challenges and potential of ZnO NPs as an active agent in the safe coating application are also discussed.

Clays are low-price and very useful material for water treatment purpose. In this work, we reported the application of activated natural kaolinite material which obtained from Wediombo beach, Yogyakarta for methylene blue adsorption. The natural kaolinite material was activated under an acidic condition to obtain the activated kaolinite material. The activated kaolinite material was characterized using Fourier transform infrared, X-ray diffraction, scanning electron microscope, and surface analysis. From the adsorption experiment, the activated kaolinite material gave moderate adsorption percentages for methylene blue. The adsorption kinetics followed the Ho and McKay kinetic model while the adsorption isotherm followed Langmuir model. The qmax value for methylene blue adsorption using activated natural kaolinite material was at a moderate level (3.40 mg g-1). The plausible adsorption mechanism of methylene blue on the surface of activated kaolinite material happened through hydrogen bondings and/or electrostatic interactions. These findings are important for a wastewater treatment using a low-cost adsorbent material.

Systematic structural modulation with electron-withdrawing substituents was carried out to enhance the photovoltaic performances of quinoxaline-based polymers.

Natural dyes have gained much attentions as the cheap photosensitizer for dye-sensitized solar cells because of their abundant availability in nature. One of potential natural dyes is betalain dye. Betalain dye mostly can be found in family plant of Caryophyllales. This dye has carboxyl groups and can absorb light until wavelength of 600 nm since betalain dye can be in red-purple color. However, betalain dye is still reported to give a lower efficiency in dye-sensitized solar cells device because of its nature properties as compared to the synthetic dyes. This encourages many researchers to investigate the method for developing betalain ability in purpose to enhance the cell device efficiency. To date, there are two methods having been reported for their positive results in increasing the efficiency of cell device based on betalain dye, i.e., combining the betalain dye with other natural dyes, and selecting the suitable solvent and pH in betalain dye extraction. Therefore, in this review, the summary about potential of betalain dye as photosensitizer and what properties of this dye have as the photosensitizer would be described. The summary of methods for optimizing betalain dye in improving the conversion efficiency of dye-sensitized solar cell also will be presented for better understanding the potential of this dye.