## 1 Introduction  
One of the major problems in food production is the overuse of toxic agrochemicals during the production of plants which has a serious negative impact on the environment, food safety, and consequently, on human health. Researchers are increasingly turning to natural ways of treating plants to abandon or at least limit the use of agrochemicals [1]. One of the ways to reduce their overuse is through controlled and targeted delivery of biological (i.e., microorganisms) and chemical agents. Conveniently, controlled, and targeted delivery can be achieved via the encapsulation method, and this has proven to be a suitable way of delivering nutrients for organic and sustainable crop production. Encapsulation into microparticles is an advanced, promising, and fast-developing technology that has significant advantages over other agroformulations in terms of protecting the living organisms from external conditions and the possibility of a higher survival rate. The main benefits of biological and chemical agents' encapsulation include sustained and controlled release, greater efficiency, and relatively beneficial impact on the environment [2]. As a result of consumer needs and wishes, the production of high-quality, safe, and functional food is becoming increasingly popular. The concept of functional foods refers to foods with a relatively higher content of biologically active compounds, which are thought to have a beneficial effect on human health, reduce the risk of some diseases, and they can even stimulate faster healing of tissues. Although functional foods are not fully defined, the scientific literature considers that these products provide additional benefits beyond the general benefits of nutritional intake and the pure need to satisfy hunger [3,4]. Plant secondary metabolites (PSM) are biologically active compounds often used in healthy nutrition, traditional medicine, and in a wide array of industrial applications [5,6]. Plant secondary metabolites, such as polyphenols, are composed of several groups of structurally distinct natural compounds biogenetically obtained by shikimate-phenylpropanol-flavonoid biochemical pathways. Plants require these metabolites for pigmentation, growth, reproduction, resistance to pathogens, and many other biochemical processes and functions, while these metabolites represent adaptive characteristics that underwent natural selection during evolution. The effective defense mechanism of plants can be attributed to the wide range of PSM they synthesize [7]. With a wide range of different PSMs, plants can respond to different stressors. Given that the production of specific plant protection features can be extremely costly, new ways of enhancing defense need to be investigated and exploited. Methods involving increased expression of endogenous compounds (i.e., PSM) can significantly affect plant characteristics for resistance to invaders [7]. A high proportion of PSM can also have an important impact on human nutrition and health, by increasing the intake of antioxidants and nutrients [8]. Therefore, not only would the increase of biologically active compounds during plant cultivation have benefits for human consumption, but their primary role would be to increase the plant's defense mechanisms against pests and pathogens. Furthermore, with significant interest in the increased production of PSM, obtaining high yields can be ideal for commercial exploitation (e.g., functional ingredients). Various strategies, such as screening and selecting high-performance cell lines, cell cultures from different parts of plants, metabolic engineering, media optimization, plant growth regulators, and others, have been used so far to increase PSM production in plant cells [9], but most of these strategies are very expensive and inefficient.