No abstract

Processing pineapple industry produces huge amounts of waste thus contributing to worsen the global environmental problem. Valorising pineapple waste through further processing until it is transformed into valuable products using environmentally friendly techniques is both, a challenge, and an opportunity. The aim of this review is to characterize and highlight the phytochemical constituents of pineapple peel, their biological activity, and to evaluate the current state-of-art for the utilization of pineapple waste from the processing industry for obtaining pharmaceuticals, food, and beverages, biocombustibles, biodegradable fibers, and other different usage. Pineapple residues are rich in many bioactive compounds such as ferulic acid, vitamin A and C as antioxidant, and containing alkaloids, flavonoids, saponins, tannins, cardiac glycoside, steroids, triterpenoids and phytosterols may provide a good source of several beneficial properties, as well as bromelain that showed significant anticancer activity. Also, pineapple processing residues contain important volatile compounds used as aroma enhancing products and have high potential to produce value-added natural essences.

In recent years, scientists’ interest in agricultural waste has increased, and the waste has become attractive to explore and benefit from, rather than being neglected waste. Banana peels have attracted the attention of researchers due to their bioactive chemical components, so we focused on this review article on the antioxidant and antimicrobial activities of banana peels that can be used as good sources of natural antioxidants and for pharmaceutical purposes in treating various diseases. Banana is an edible fruit belonging to the genus Musa (Musaceae), cultivated in tropical and subtropical regions. Banana peels are used as supplementary feed for livestock in their cultivation areas. Its massive by-products are an excellent source of high-value raw materials for other industries by recycling agricultural waste. Hence, the goal is to use banana by-products in various food and nonfood applications and sources of natural bioactive compounds. It can be concluded that banana peel can be successfully used in food, pharmaceutical, and other industries. Therefore, banana residues may provide new avenues and research areas for the future.

Excessive use of pesticides and fertilizers in agriculture in order to increase yields has proved unnecessary because a large part of them remain unused and have negative effects on the environment and human health. Therefore, it is a great challenge for farmers to replace the application of pesticides and fertilizers with nanopesticides and nanofertilizers, with the aim of reducing the use of mineral fertilizers and increasing yields, as well as supporting agricultural development. This review provides a detailed overview of the classification of pesticides, commonly used nanoparticles in agriculture and their function, as well as impact of nanopesticides and nanofertilizers on the environment. The application of nanopesticides and nanofertilizers and new delivery mechanisms to improve crop productivity are reviewed and described. Particularly, the advantage of the nanoencapsulation process is emphasized for both pesticides and fertilizers. For hydrophobic pesticides, it may be a tool to provide greater stability, dispersion in aqueous media, and allowing a controlled release of the active compound, which increases its effectiveness. In nanofertilizers, micro-or macronutrients can be encapsulated by nanomaterials which allow to release of nutrients into the soil gradually and in a controlled way maintaining soil fertility, thus preventing eutrophication and pollution of water resources. Risks assessment of application of nanopesticides and nanofertilizers in agriculture are required for their correct and safe application.

The essential oil of Syzygium (S.) aromaticum (CEO) is known for its good biological activity. The aim of the research was to evaluate in vitro and in situ antimicrobial and antibiofilm activity of the essential oil produced in Slovakia. The main components of CEO were eugenol 82.4% and (E)-caryophyllene 14.0%. The antimicrobial activity was either weak or very strong with inhibition zones ranging from 4.67 to 15.78 mm in gram-positive and gram-negative bacteria and from 8.22 to 18.56 mm in yeasts and fungi. Among the tested bacteria and fungi, the lowest values of MIC were determined for Staphylococcus (S.) aureus and Penicillium (P.) expansum, respectively. The vapor phase of CEO inhibited the growth of the microscopic filamentous fungi of the genus Penicillium when tested in situ on bread. The strongest effect of mycelia inhibition in a bread model was observed against P. expansum at concentrations of 250 and 500 μL/mL. The best antimicrobial activity of CEO in the carrot model was found against P. chrysosenum. Differences between the mass spectra of Bacillus (B.) subtilis biofilms on the tested surfaces (wood, glass) and the control sample were noted from the seventh day of culture. There were some changes in mass spectra of Stenotrophomonas (S.) maltophilia, which were observed in both experimental groups from the fifth day of culture. These findings confirmed the impact of CEO on the protein structure of older biofilms. The findings indicate that, besides being safe and sensorially attractive, S. aromaticum has antimicrobial activity, which makes it a potential substitute for chemical food preservatives.