Encapsulation of Lactobacillus acidophilus in solid lipid microparticles via cryomilling

Microencapsulation of Lactobacillus reuteri by Emulsion Technique and Evaluation of Microparticle Properties and Bacterial Viability Under Storage, Processing, and Digestive System Conditions

In this research, the emulsification method was used to encapsulate Lactobacillus reuteri in microparticles of whey protein concentrate (WPC) at different levels (1%, 2%, and 4%) and gum Arabic (GA) at three levels (0/5%, 1%, and 1/5%) and a constant level of sunflower oil (5%). The results showed that emulsions with higher quantities of wall materials exhibited better encapsulation efficiency (67%/57%) and preservation ability at different temperatures, different pH, and presence of 1% bile salt. During the storage time, the droplet size of the emulsion increased more than two times (from 2.2 to 4.6 μm) and the absolute zeta potential of the optimal emulsion decreased (from -19/63 to -16/76 mV). Encapsulating Lactobacillus reuteri in the stabilized emulsion with the highest concentration of wall material improved the cells' protection during storage. The study also observed a decline in the number of primary encapsulated live cells in the gastrointestinal tract (from 4/32 to 3/58 Log CFU/mL) after 90 days of storage. In the case of the nonencapsulated sample, the initial live population decreased from 2.8 to 1 Log CFU/mL after 90 days of storage. The electron microscope images showed that the emulsions became unstable after 30, 60, and 90 days of storage, but the microbial cells were still visible in the continuous phase. Overall, encapsulating Lactobacillus reuteri using emulsification technique can preserve the probiotics during storage and "in vitro" gastrointestinal digestion.

Oral responsive delivery systems for probiotics targeting the intestinal tract

The increasing prevalence of health issues, driven by sedentary lifestyles and unhealthy diets in modern society, has led to a growing demand for natural dietary supplements to support overall health and well-being. Probiotic dietary supplements have garnered widespread recognition for their potential health benefits. However, their efficacy is often hindered by the hostile conditions of the gastrointestinal tract. To surmount this challenge, biomaterial-based microencapsulation techniques have been extensively employed to shield probiotics from the harsh environments of stomach acid and bile salts, facilitating their precise delivery to the colon for optimal nutritional effects. With consideration of the distinctive gastrointestinal tract milieu, probiotic delivery systems have been categorized into pH-responsive release, enzyme-responsive release, redox-responsive release and pressure-triggered release systems. These responsive delivery systems have not only demonstrated improved probiotic survival rates in the stomach, but also successful release in the intestines, facilitating enhanced adhesion and colonization of probiotics within the gut. Consequently, these responsive delivery systems contribute to the effectiveness of probiotic supplementation in intervening with gastrointestinal diseases. This review provides a comprehensive overview of the diverse oral responsive delivery systems tailored for probiotics targeting the intestinal tract. Furthermore, the review critically examines the limitations and future prospects of these approaches. This review offers valuable guidance for the effective delivery of probiotics to the intestinal tract, enhancing the potential of probiotics as dietary supplements to promote gastrointestinal health and well-being. © 2024 Society of Chemical Industry.

Novel Encapsulation Approaches in the Functional Food Industry: With a Focus on Probiotic Cells and Bioactive Compounds

Bioactive substances can enhance host health by modulating biological reactions, but their absorption and utilization by the body are crucial for positive effects. Encapsulation of probiotics is rapidly advancing in food science, with new approaches such as 3D printing, spray-drying, microfluidics, and cryomilling. Co-encapsulation with bioactives presents a cost-effective and successful approach to delivering probiotic components to specific colon areas, improving viability and bioactivity. However, the exact method by which bioactive chemicals enhance probiotic survivability remains uncertain. Co-crystallization as an emerging encapsulation method improves the physical characteristics of active components. It transforms the structure of sucrose into uneven agglomerated crystals, creating a porous network to protect active ingredients. Likewise, electrohydrodynamic techniques are used to generate fibers with diverse properties, protecting bioactive compounds from harsh circumstances at ambient temperature. Electrohydrodynamic procedures are highly adaptable, uncomplicated, and easily expandable, resulting in enhanced product quality and functionality across various food domains. Furthermore, food byproducts offer nutritional benefits and technical potential, aligning with circular economy principles to minimize environmental impact and promote economic growth. Hence, industrialized nations can capitalize on the growing demand for functional foods by incorporating these developments into their traditional cuisine and partnering with businesses to enhance manufacturing and production processes.

Release profile of amino acids encapsulated in solid lipid particles during in vitro oro-gastrointestinal digestion

Some amino acids are known to mediate immune responses through gut microbiota metabolism in both humans and monogastric animals. However, through the diet, most free amino acids are absorbed in the small intestine and only a small quantity reaches the microbiota-rich colon. To enhance microbial metabolism of amino acids and their potential health benefits, encapsulation strategies are developed for their protection and delivery to the colon. So far, the main encapsulation systems for amino acids are based on solid lipid particles, but their fate within the digestive tract has never been fully clarified. In this study, we investigated the release of various amino acids (branched-chain amino acid mixture, or lysine, or tryptophan) loaded in solid lipid particles during in vitro oro-gastrointestinal digestion mimicking the piglet. The loaded solid lipid particles were fully characterized for their composition, thermal behavior, molecular structure, crystalline state, surface morphology, and particle size distribution. Moreover, we investigated the effect of particle size by sieving solid lipid particles into two non-overlapping size fractions. We found that amino acid release was high during the gastric phase of digestion, mainly controlled by physical parameters, namely particle size and crystalline state including surface morphology. Large particle size and/or smooth ordered particle indeed led to slower and lower release. Although lipid hydrolysis was significant during the intestinal phase of digestion, the impact of the crystalline state and surface morphology was also observed in the absence of enzymes, pointing to a dominant water/solute diffusion mechanism through these porous solid lipid particles.

The encapsulation strategy to improve the survival of probiotics for food application: From rough multicellular to single-cell surface engineering and microbial mediation

The application of probiotics is limited by the loss of survival due to food processing, storage, and gastrointestinal tract. Encapsulation is a key technology for overcoming these challenges. The review focuses on the latest progress in probiotic encapsulation since 2020, especially precision engineering on microbial surfaces and microbial-mediated role. Currently, the encapsulation materials include polysaccharides and proteins, followed by lipids, which is a traditional mainstream trend, while novel plant extracts and polyphenols are on the rise. Other natural materials and processing by-products are also involved. The encapsulation types are divided into rough multicellular encapsulation, precise single-cell encapsulation, and microbial-mediated encapsulation. Recent emerging techniques include cryomilling, 3D printing, spray-drying with a three-fluid coaxial nozzle, and microfluidic. Encapsulated probiotics applied in food is an upward trend in which "classic probiotic foods" (yogurt, cheese, butter, chocolate, etc.) are dominated, supplemented by "novel probiotic foods" (tea, peanut butter, and various dry-based foods). Future efforts mainly include the effect of novel encapsulation materials on probiotics in the gut, encapsulation strategy oriented by microbial enthusiasm and precise encapsulation, development of novel techniques that consider both cost and efficiency, and co-encapsulation of multiple strains. In conclusion, encapsulation provides a strong impetus for the food application of probiotics.