Microencapsulation Of Probiotics

Microencapsulation of probiotics using hydrocolloids is now an established method for ensuring their survival and even for accurate dosing into products (Anal and Singh, 2007). The encapsulation process is a promising technique for protecting probiotics against adverse conditions to which these microorganisms can be exposed (Anal and Singh, 2007; Mokarram et al., 2009). In many instances it is the only method for ensuring the survival of a probiotic in the stomach and gut.

Several studies have been carried out investigating the protective role of this technique. Microencapsulation can be employed via extrusion and emulsion techniques. The emulsion technique is a method for encapsulation of probiotic bacteria in capsules smaller than 1 mm.

The daily intake of probiotic bacteria should exceed 10⁶ living bacteria per milliliter or per gram of the product (Aragon-Alegro et al., 2007). Probiotics are living bacteria that are sensitive, almost to the point of being super delicate to product conditions such as high acidity, acidic pH, presence of digestive enzymes, molecular oxygen, heat treatment, hydrogen peroxide, and SCFAs (short-chain fatty acids) to name a few conditions.

Maintaining levels of a probiotic in any product is problematic. Encapsulation should allow for accurate dosing of these particular levels. A good example concerns the viability Lactobacillus acidophilus in a healthy synbiotic corn-based snack (Castillo-Escandón et al., 2023) . 

Lactobacilli show better resistance to a low pH and a better adaptation to milk and other foods than other probiotic bacteria. Their encapsulation simply adds to that benefit.

If you want to know more about the different microencapsulation methods then refer to reviews by Frakolaki et al., (2021).

Alginate Is Ideal For Microencapsulation Of Probiotics

Alginate is possible the most popular microencapsulation material as it is cheap and a water-soluble anionic biopolymer. It is a natural heteropolysaccharide composed of D-mannuronic and L-guluronic acid residues joined linearly by (1-4) glycosides linkages (Mokarram et al., 2009). It is sourced from marine algae especially seaweeds. A number of jellies using alginate have been prepared, stabilised by calcium until they dissolve in the gut. This is an effective way of releasing the encapsulated contents into the intestine and in some cases can be designed to be released in the upper intestine.

Ding and Shah (2008) assessed the pH changes occurring in orange and apple juices containing eight strains of probiotics in free and encapsulated forms. They found that irrespective of the bacterial strain, samples containing protected probiotics with sodium alginate have a more stable environment during storage.

To improve the stability of alginate microcapsules and to decrease the loss of encapsulated material such as a probiotic, the alginate microcapsules are coated with polycationic polymers such as chitosan and poly-L-lysine (Lee et al., 2004; Koo et al., 2001). A membrane is created as a result of strong bonding between the carboxylic groups on the alginate molecule and amine groups from the chitosan part (Lee et al., 2004).

A combination of calcium alginates with the addition of prebiotics such as inulin or fructooligosaccharides improves the viability of the probiotic and also helps in the formation of the integrated structures of capsules (Narra et al., 2012). Mokkaram (2009) found that L. acidophilus and L. rhamnosus exposed to simulated gastric juice without pepsin had a higher viability when encapsulated in calcium alginate with a double coating of sodium alginate. Zanjani et al., (2017) microencapsulated Lactobacillus casei ATCC 39392 and Bifidobacterium adolescentis ATCC 15703 in calcium alginate beads with wheat, rice and high-amylose corn (Hylon VII) starches along with chitosan and poly L-lysine coatings. They examined the survival of the probiotics in ice-cream for 100 days at −30 °C. Microencapsulation coupled with a coating of chitosan and poly L-lysine as mentioned earlier helped the probiotics to survive.

The optimum alginate concentration was established for Lactobacillus casei Shirota which is the Yakult microorganism using a Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) approach. The beads obtained with extrusion better protected the probiotic cells than the beads prepared by emulsification. The optimum alginate level was between 2 and 2.5% (Gul and Dervisoglu, 2017).

Lactobacillus rhamnosus GG (LGG) was embedded in a cross-linked soy protein isolate (SPI) using transglutaminase (TGase) (Li et al., 2016). This microencapsulated preparation was evaluated in a model gut intestine (pH 2.5 or 3.6), intestinal juice (0.3 or 2% bile salts) and a yogurt. In both cases the microencapsulated bacteria survived well enough to be considered a viable alternative to the use of alginate or other polysaccharide gelation methods.

Frakolaki et al., (2022) immobilized Bifidobacterium animalis by encapsulation for use in yogurt production. It protected the microorganism during emulsification and extrusion. Again, alginate based encapsulating blends containing 2% w/v sodium alginate and 11% v/v glycerol (AG) or 1% carrageenan (AC), and/or 2% w/v inulin, were tried. The emulsification method produced a higher yield of 95% minimum compared to 77% minimum when the extrusion method was used. The viability of the encapsulated bacteria after 30 days storage was up to 6.9 log cfu/g.

In the same year, Sharma et al., (2022) found encapsulated B. longum cells survived longer in storage than free cells when added to milk. The cells were encapsulated using spray-drying.

In another example, we mentioned earlier that inulin can be added to enhance the growth and viability of probiotic bacteria. It is not only an effective prebiotic but makes for an excellent agent for changing texture in foods like yogurt. It is also used to encapsulate probiotic bacteria such as the Lactobacilli and meant they had a higher viability than if they had been used to ferment milk without the addition of the fibre (Krasaekoopt & Watcharapoka, 2014).

In 2023, Castillo-Escandón et al., showed how L. acidophilus was protected on the surface of a churrito,  a corn-based snack using an agave fructan-alginate. The addition of legume protein improved the nutritional profile. The synbiotic (bacteria plus prebiotic) was incorporated into a surface coating of an edible film matrix. The addition of agave fructans extended bacteria longevity by reducing probiotic loss during drying and storage. Fructans are shown from previous work to be good probiotic protecting agents.

Most of the encapsulated probiotics must survive through the upper and lower intestine before coming to the harsh environment of the colon. It is here in these murky regions that they are needed to help manage various gastrointestinal disorders such as ulcerative colitis. The bacterial strain Lactiplantibacillus plantarum LM-20, is well suited to aiding treatment of this gut inflammatory condition (Lopes et al., 2023).

In 2025, de Paula Antunes et al., produced cereal bars  enriched with Bacillus clausii and Bacillus coagulans. Cereal bars are dry matrices ideal for sporulated bacteria such as these bacilli. Spores are highly resistant to all sorts of processing conditions (Soares et al., 2023).

References

Anal, A.K., Singh, H. (2007) Recent advances in microencapsulation of probiotics for industrial applications and targeted delivery. Trends Food Sci. Technol. 18 pp. 240–251.

Aragon-Alegro, L.C., Alarcon Alegro, J.H., Roberta Cardarelli, H., Chih Chiu, M., Isay Saad, S.M. (2007) Potentially probiotic and synbiotic chocolate mousse. LWT- Food Sci. Technol. 40 pp. 669–675

Castillo-Escandón, V., Montfort, G. R. C., Rubio, A. R. I., Marszalek, J. E., Subiría-Cueto, R., & Michel, S. F. (2023). Development of healthy synbiotic corn-based snack: Nutritional composition and effect of agave fructan-alginate coating on survival of Lactobacillus acidophilus. Journal of Cereal Science, 114, 103777 (Article).

de Paula Antunes, D. J., de Almeida Costa, N., Martins, M. L., Benevenuto, W. C. A. D. N., Talma, S. V., Campos, A. N. D. R., & Martins, E. M. F. (2025). Healthy cereal bar enriched with probiotic Bacillus: bromatological characterization, probiotic viability, consumer acceptance, and gastrointestinal resistance in vitro. International Journal of Food Science and Technology, 60(1), vvae070.

Ding, W. and Shah, N.P. (2008) Survival of free and microencapsulated probiotic bacteria in orange and apple juices. Int. Food Res. J. 15, pp. 219–232.

Donthidi, A., Tester, R.F. and Aidoo, K.E. (2010) Effect of lecithin and starch on alginate-encapsulated probiotic bacteria. J. Microencapsul. 27, pp. 67–77

Frakolaki, G., Giannou, V., Kekos, D., & Tzia, C. (2021). A review of the microencapsulation techniques for the incorporation of probiotic bacteria in functional foods. Critical Reviews in Food Science and Nutrition, 61(9), pp. 1515-1536.

Frakolaki, G.; Kekes, T.; Lympaki, F.; Giannou, V.; Tzia, C. (2022) Use of Encapsulated Bifidobacterium animalis subsp. lactis through Extrusion or Emulsification for the Production of Probiotic Yogurt. J. Food Process Eng. 2022, 45, e13792 (Article)

Gul, O., Dervisoglu, M. Application of multicriteria decision technique to determine optimum sodium alginate concentration for microencapsulation of Lactobacillus casei Shirota by extrusion and emulsification. J. Food Process Eng. 40:e12481. Article 

Koo, S., Cho, Y., Huh, C., Baek, Y., Park, J. (2001) Improvement of the stability of Lactobacillus casei YIT 9018 by microencapsulation using alginate and chitosan. J. Microbiol. Biotechn. 11 pp. 376–383

Krasaekoopt, W., Bhandari, B., Deeth, H.C. (2006) Survival of probiotics encapsulated in chitosan-coated alginate beads in yoghurt from UHT- and conventionally treated milk during storage. LWT- Food Sci. Technol. 39 pp. 177–183.

Krasaekoopt, W., & Watcharapoka, S. (2014). Effect of addition of inulin and galactooligosaccharide on the survival of microencapsulated probiotics in alginate beads coated with chitosan in simulated digestive system, yogurt and fruit juice. LWT-Food Science and Technology, 57(2), pp. 761-766 (Article).

Lee, J.S., Cha, D.S., Park, H.J. (2004) Survival of Freeze-Dried Lactobacillus bulgaricus KFRI 673 in Chitosan-Coated Calcium Alginate Microparticles. J. Agr. Food Chem. 52 pp. 7300–7305

Li, C., Wang, C.-L., Sun, Y., Li, A.-L., Liu, F. and Meng, X.-C. (2016), Microencapsulation of Lactobacillus rhamnosus GG by Transglutaminase Cross-Linked Soy Protein Isolate to Improve Survival in Simulated Gastrointestinal Conditions and Yoghurt. Journal of Food Science, 81: M1726–M1734. Article

Lopes, S. A., Roque-Borda, C. A., Duarte, J. L., Di Filippo, L. D., Borges Cardoso, V. M., Pavan, F. R., … & Meneguin, A. B. (2023). Delivery strategies of probiotics from nano-and Microparticles: trends in the treatment of inflammatory bowel disease—an overview. Pharmaceutics, 15(11), 2600.

Mokarram, R.R., Mortazavi, S.A., Najafi, M.B.H., Shahidi, F. (2009) The influence of multi stage alginate coating on survivability of potential probiotic bacteria in simulated gastric and intestinal juice. Food Res. Int. 42 pp. 1040–1045

Narra, K., Dhanalekshmi, U., Rangaraj, G., Raja, D., Senthil Kumar, C., Neelakanta Reddy, P., Baran Mandal, A. (2012) Effect of formulation variables on rifampicin loaded alginate beads. Iran J. Pharm. Res. Summer; 11(3) pp. 715-21

Sharma, R., Rashidinejad, A., & Jafari, S. M. (2022). Application of spray dried encapsulated probiotics in functional food formulations. Food and Bioprocess Technology, 15(10), pp. 2135-2154.

Soares, M. B., Almada, C. N., Pereira, E. P., Ferreira, B. M., Balthazar, C. F., Khorshidian, N., … & Sant’Ana, A. S. (2023). Sporeforming probiotic bacteria: Characteristics, health benefits, and technological aspects for their applications in foods and beverages. Trends in Food Science & Technology, 138, pp. 453-469.

Zanjani, M.A.K., Ehsani, M.R., Ghiassi Tarzi, B., Sharifan, A. (2017) Promoting Lactobacillus casei and Bifidobacterium adolescentis survival by microencapsulation with different starches and chitosan and poly L-lysine coatings in ice cream. J. Food Process Preserv. 00:e13318. Article