Abstract
Over the past decade, probiotics have gone from been special health supplements to widely incorporated components in many foods and nutrition products. This has led to more careful checks of their safety, viability, and functional performance under realistic processing and consumption conditions. Within lactic acid bacteria, Limosilactobacillus reuteri (formerly Lactobacillus reuteri) has been extensively investigated for its immunomodulatory, antimicrobial, anti-inflammatory, antioxidant, and metabolic properties as demonstrated across multiple in vivo and in vitro experimental models. Despite these functional attributes, its viability during food processing and gastrointestinal transit remains strongly influenced by the strain and the characteristics of the delivery matrix; as a result, encapsulation is an essential strategy to preserve cellular integrity and functionality.
The present review examines the functional properties of Limosilactobacillus reuteri (L. reuteri or LR) strains alongside the technological approaches used for their encapsulation. Current encapsulation approaches, including ionic gelation, extrusion, electrospray, and spray drying combined with biopolymers to improve encapsulation efficiency and survival of strains such as DSM 17938 and DSM 20016, are discussed with emphasis on their applicability to probiotic delivery and the formulation of functional foods with potential to improve gastrointestinal health, modulate inflammation, and enhance metabolic functions. In addition to strain-specific functional activities, this review examines how coating material, processing method, and strain affect release kinetics, functional activities, and viability. However, data on the stability of encapsulated L. reuteri during industrial processing, storage, and health claim validation under regulatory frameworks remain limited. Future research should address these challenges to support the use of L. reuteri in functional foods and therapeutic products.
Introduction
The growing demand of foods that provide health benefits has accelerated the development of formulations fortified with probiotic microorganisms (Damián et al. 2022; Das et al. 2016). Within this group, strains of Limosilactobacillus reuteri have garnered sufficient interest due to their specific functions, such as immunomodulation, production of antimicrobial metabolites, for example, reuterin, reduction of total cholesterol and triglycerides, inhibition of Helicobacter pylori, and their ability to colonize different host niches.
Despite its multiple benefits, the application of L. reuteri in food matrices remains complex, as the microorganism is sensitive to food processing conditions, for example, heating, dehydration, and oxygen exposure, but also to gastrointestinal challenges such as pH, bile salts, and digestive enzymes (Algaithi et al. 2022). These limitations tend to reduce the viability and functional activity of L. reuteri, compromising its efficacy when administered through food matrices.
In this sense, encapsulation has emerged as a key strategy to improve the stability, survival, and targeted release of L. reuteri, both in food and throughout the gastrointestinal tract (Anal and Singh 2007; Cook et al. 2012). Several studies have explored the use of different coating materials, for example, alginate, pectin, proteins, starch, and polysaccharides, as well as different encapsulation methods such as extrusion, emulsification, ionic gelation, electrospraying, coacervation, and spray drying, with the aim of improving probiotic functionality (Algaithi et al. 2022; Rokka and Rantamaki 2010; Nazzarro et al. 2012).
However, despite the increasing number of experimental studies, literature still presents several gaps in this area. Nowadays, most research focuses on the individual strains, isolated functional activity, or specific encapsulation approaches, without adequately integrating how strain-dependent characteristics align with encapsulation design or how these interactions may be translated into technological performance in real word food systems (Gbassi and Vandamme 2012; Rokka and Rantamaki 2010). According to the above, this review aims to integrate current knowledge on the functional properties of L. reuteri with the role of encapsulation strategies in preserving its viability during processing and gastrointestinal transit, considering how strain characteristics, encapsulation methods and coating materials impact functional activity and technological viability in food matrices.
1.1 Background on Probiotics and Viability in Food Systems
Globally, there has been an increasing interest in foods that provide health-promoting benefits beyond basic nutrition, along with a growing demand for transparency regarding ingredients, additives, and the inclusion of functional components such as probiotic microorganisms. In this context, various validation approaches such as standardizer in vitro gastric digestion models have been developed to assess digestibility, bioaccessibility, stability, and release of nutrients and bioactive compounds. These methodologies have been extensively used to assess the survival and stability of probiotic microorganisms under simulated gastrointestinal conditions, thereby providing valuable insights into the challenges associated with their incorporation into food matrices (Brodkorb et al. 2019; Minekus et al. 2014).
A fundamental requirement for probiotics to exert their intended physiological effects is their capacity to reach the intestine in sufficient numbers while maintaining viability during food processing, storage, and gastrointestinal transit (FAO/WHO 2002; Tripathi and Giri 2014). However, exposure to heat, mechanical stress, oxygen, moisture, acidity, and bile salts can substantially decrease cell survival. Consequently, preserving probiotic viability remains one of the major technological challenges in the development of functional foods (Tripathi and Giri 2014).
1.2 State of the Art on Encapsulated Limosilactobacillus reuteri
Among the assorted genera used in probiotic applications, it can be found Lactobacillus and Bifidobacterium; however, L. reuteri stands out due to its unique biological and functional properties (Algaithi et al. 2022). Particularly, LR is an intestinal symbiont that can colonize gastrointestinal tract in various mammals, including humans. It is tolerant to gastric acidity and bile, but also produces many of the essential compounds responsible for gut health (Liu et al. 2016; Yu et al. 2023).
Nevertheless, in recent decades, there has been a considerable decrease in the presence of L. reuteri in humans, which have been correlated with an increase in the incidence of inflammatory diseases (e.g., ulcerative colitis, Crohn’s disease, and indeterminate colitis). For the above, research works attending the development of functional foods, particularly those containing probiotic strains, are imperative for addressing some of the public health issues mentioned.
Over the past decade, research on L. reuteri encapsulation has expanded substantially, motivated by the need to enhance cell survival during food processing, storage, and gastrointestinal transit (Anal and Singh 2007; De Prisco and Mauriello 2016; Tripathi and Giri 2014). Various encapsulation materials, such as alginate, pectin, starch derivatives, chitosan, whey proteins, mucilage, inulin, and multilayer coatings, have been investigated alongside methods including extrusion, emulsification, ionic gelation, spray drying, and electrospraying (Anal and Singh 2007; De Prisco and Mauriello 2016). While these approaches have consistently demonstrated improvements in viability; the extent of protection is highly dependent on the chemical composition of the wall material, capsule structure, drying conditions, and strain-specific physiological characteristics.
A key challenge in current research is the strain-dependent response of L. reuteri. Strains such as DSM 17938, DSM 20016, CRL 1324, ATCC 55730, and others show significant differences in acid–bile tolerance, adhesion, exopolysaccharide (EPS) production, reuterin synthesis, and dehydration sensitivity (Britton et al. 2014; Mu et al. 2018a; Walter et al. 2011). Despite these differences, many studies assess encapsulation effects on specific functions without directly linking these outcomes to material selection or capsule architecture. This limits the ability to establish structure–function relationships or identify optimal material–strain combinations (De Prisco and Mauriello 2016; Tripathi and Giri 2014).
Although previous reviews have explored either the probiotic activity or encapsulation strategies of L. reuteri, only a few numbers of they have provided an integrated analysis that connects specific strains, coating materials, encapsulation methods, and their technological and health-related implications. Most existing reviews either focus narrowly on clinical aspects or provide general overviews of probiotic encapsulation without discriminating against bacterial species or materials. Table 1 addresses gaps in the general overview by providing an integrative comparison of representative encapsulation strategies for L. reuteri. It organizes studies by wall material and processing technique, and highlights encapsulation efficiency (EE), postprocessing viability, gastrointestinal survival, and functional performance.
This integrative comparison in EE (Table 1) highlights the relationships between structure and function, showing how capsule architecture, polymer composition (wall material), and processing strategy can have a direct influence on L. reuteri viability, EE release behavior, and functional performance across different studies.
Current research on L. reuteri underscores the need to integrate strain physiology, wall material properties, technological outcomes, and functional performance. This review examines encapsulation studies involving L. reuteri, focusing on how strain-dependent physiological characteristics affect EE, survival during processing and storage, and release under gastrointestinal conditions. It synthesizes evidence from various strains, materials, and encapsulation methods to identify new relationships across different food structures and functions (Figure 1).
Figure 1. Limosilactobacillus reuteri strains in food matrices.
This framework links encapsulation design variables, such as the chemical composition of the coating material, encapsulation size, mechanical properties and process conditions, with strain-dependent physiological characteristics, including EPS production and tolerance to gastric and intestinal acidity. This relationship clarifies outcome metrics, including the viability of encapsulated microorganisms and their stability during processing, storage and exposure to gastrointestinal stress. Figure 2 illustrates a structure–function approach for interpreting the selection of coating materials, encapsulation methods and processing conditions to maintain performance and functionality in food matrices.
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Berenice, L. E., B.-F.Rigoberto, C.-M.Abraham, M. N.Yoliztli, and R.Minerva. 2026. “Encapsulation and Functional Activity of Lactobacillus reuteri Strains: Advances, Challenges, and Perspectives.” Comprehensive Reviews in Food Science and Food Safety25, no. 2: e70412. https://doi.org/10.1111/1541-4337.70412
