Microencapsulation of bacteria: A review of different technologies and their impact on the probiotic effects

Highlights

• The article summarizes the most important and new technologies applied in probiotic encapsulation.

• An overview of the materials used in these technologies is given, paying special attention to advantages and disadvantages.

• Our work is the first time that a review described the results obtained using encapsulated probiotic in various pathologies.

Abstract

Probiotic based products are associated with many health benefits. However, the main problem is the low survival of these microorganisms in food products and in gastrointestinal tract. Providing probiotics with a physical barrier is an efficient approach to protect microorganisms and to deliver them into the gut. In our opinion, microencapsulation is one of the most efficient methods, and has been under especial consideration and investigation. However, there are still many challenges to overcome with respect to the microencapsulation process. This review focuses mainly on the methodological approach of probiotic encapsulation including materials and results obtained using encapsulated probiotic in food matrices and different pathologies in animal models.

Industrial relevance

The inclusion of probiotics into food matrices is one of the most challenging lines of research in food technology. Probiotics in general, and some strains in particular, have a low resistance to different environmental conditions, such as oxygen, light or temperature. Thus, the protection and isolation of the microorganism from the food matrix and the environmental condition are crucial for the development of new probiotic food. In this sense, microencapsulation has gained an increasing interest, since it has been demonstrated that it could protect the bacteria not only during its production process but also during its incorporation into the food matrix, also with protective effects during storage. In conclusion, microencapsulation is of great interest since it could allow a wider application of probiotics in the food market, actually restricted to fresh or powder products.

Introduction

Probiotics are described by the World Health Organization (WHO) as “live organism, which when administered in adequate amounts confer health benefits to the host” (FAO/WHO, 2001). In this sense, probiotics have shown in some studies, to be effective in the treatment of several intestinal disorders and to have an impact on the immune system (Kurmann & Rasic, 1991). Considering that these microorganisms are mainly consumed orally, it would be reasonable to believe that its beneficial effects would be mainly apparent in these intestinal pathologies. However, their modulatory effects on systemic immune response may lead to positive effects in systemic disorders such as allergy (Majamaa & Isolauri, 1997) or inflammatory diseases (Malchow, 1997) and they also have demonstrated a beneficial effect in the treatment of vaginitis (Reid, 2000).

The most used probiotic microorganisms are Lactobacillus and Bifidobacteria strains (Solanki et al., 2013). However, other species, such as Escherichia coli and Bacillus cereus have also been used to achieve the same objectives, together with some yeast, mainly Saccharomyces cerevisiae (Burgain, Gaiani, Linder, & Scher, 2011). Some of these species have been incorporated in foods converting them in functional food (Champagne, Gardner, & Roy, 2005). These kinds of aliments are defined as modified food or food ingredient that provides a health benefit beyond satisfying traditional nutrient requirements (Sanders, 1998).

To produce these beneficial effects in health, probiotics have to be able to survive and multiply in the host. In this respect, probiotics should be metabolically stable and active in the product, survive passage through the stomach and reach the intestine in large amounts (Sanz, 2007). However, several factors have been reported to affect the viability of probiotics, including pH, hydrogen peroxide, oxygen, storage temperature, among others (Shah, Lankaputhra, Britz, & Kyle, 1995). Different approaches that increase the resistance of these sensitive microorganisms against adverse conditions have been proposed, including appropriate selection of acid and bile resistant strains, use of oxygen-impermeable containers, two-step fermentation, stress adaptation, incorporation of micronutrients such as peptides and amino acids, and microencapsulation (Sarkar, 2010).

The last option, microencapsulation, is one of the most efficient methods, and has been under especial consideration and investigation. Microencapsulation can be defined as the process in which cells are retained within an encapsulating membrane to reduce cell injury or cell lost, in a way that result in appropriate microorganism release in the gut (Sultana et al., 2000). Some benefits of microencapsulation of cells include: protection from bacteriophages and detrimental factors increasing survival during freeze drying, freezing and storage and converting them into a powder form easier to use, since it enhances their homogeneous distribution throughout the product (Mortazavian, Razavi, Ehsani, & Sohrabvandi, 2007).

Given the importance of microencapsulation, the aim of this article is to review the techniques for the microencapsulation of probiotics, as well as the components used during encapsulation, and its advantages. In addition, we analyze the effect of encapsulated probiotic in food and in some diseases.