Essential oils, particularly lemon essential oil (LEO), have attracted increasing interest as natural antimicrobial and antioxidant agents for food preservation. However, their direct incorporation into food systems is limited by high volatility, poor water solubility, oxidative instability, and potential sensory impacts. Encapsulation has emerged as an effective technological strategy to overcome these constraints by improving the stability and controlled release of LEO, especially in lipid-based food matrices such as margarine. This review critically summarizes recent advances (2020–2024) in the extraction, physicochemical characterization, and encapsulation of LEO, with particular emphasis on food-grade delivery systems, including biopolymers and inorganic carriers such as silica. Encapsulation efficiency, protection mechanisms, and release behavior are discussed in relation to oxidative stability and functional performance in real food applications. Special attention is devoted to light margarine as a model lipid system, highlighting the advantages and limitations of different encapsulation strategies in delaying lipid oxidation while preserving sensory quality. Finally, emerging challenges related to scalability, regulatory acceptance, and safety, together with future perspectives on smart food packaging and sustainable encapsulation technologies, are outlined to support the effective translation of LEO-based systems into industrial food applications.

Freshwater fish represent an underutilized source of bioactive compounds with potential applications in food enrichment and functional food design. This article reviews the current state of knowledge regarding bioactive components derived from freshwater fish, including proteins, amino acids, protein hydrolysates, bioactive peptides, lipids and polyunsaturated fatty acids, polysaccharides, pigments, minerals, vitamins, and other compounds of high functional value. Particular attention is paid to their biological and technological properties and potential applications in food products. Conventional and modern extraction and processing technologies used on an industrial scale are also discussed. Furthermore, the importance of biorefinery as a tool for the comprehensive management of freshwater fish biomass is presented. Available data indicate significant potential for bioactive components derived from freshwater fish, but their wider application requires further research to optimize recovery processes and their use in real food matrices.