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

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 relevanceThe 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.     

Encapsulation of probiotic living cells: From laboratory scale to industrial applications

In the recent past, there has been a rising interest in producing functional foods containing encapsulated probiotic bacteria. According to their perceived health benefits, probiotics have been incorporated into a range of dairy products but the major current challenge is to market new probiotic foods. In the research sector, many studies have been reported using dairy products like cheese, yogurt and ice cream as food carrier, and non-dairy products like meat, fruits, cereals, chocolate, etc. However, in the commercial sector only few products containing encapsulated probiotic cells can be found. Nutraceuticals are another important vector for probiotics already developed by several companies in a capsule or a tablet form. The review compiles the technologies used to encapsulate the cells in order to keep them alive and the food matrices used in the research and commercial sector for delivery to the consumer.     

Invited review: Application of omics tools to understanding probiotic functionality

The human gut microbiota comprises autochthonous species that colonize and reside at high levels permanently and allochthonous species that originate from another source and are transient residents of the human gut. The interactions between bacteria and the human host can be classified as a continuum from symbiosis and commensalism (mutualism) to pathogenesis. Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Recent advances in omics tools and sequencing techniques have furthered our understanding of probiotic functionality and the specific interactions between probiotics and their human hosts. Although it is known that not all probiotics use the same mechanisms to confer benefits on hosts, some specific mechanisms of action have been revealed through omic investigations. These include competitive exclusion, bacteriocin-mediated protection against intestinal pathogens, intimate interactions with mucin and the intestinal epithelium, and modulation of the immune system. The ability to examine fully sequenced and annotated genomes has greatly accelerated the application of genetic approaches to elucidate many important functional roles of probiotic microbes.     

In vitro analysis of probiotic strain combinations to inhibit pathogen adhesion to human intestinal mucus

Competition with pathogens for adhesion and colonization of the mucosal surfaces are possible protective mechanisms of probiotics. In this study we evaluated the ability of commercial strains (Lactobacillus rhamnosus GG, L. rhamnosus LC705, B. breve 99 and Propionibacterium freudenreichii ssp. shermanii JS) each strain alone and in different combinations to inhibit, displace and compete with selected pathogens in order to test the influence of the presence of the other probiotic in the adhesion pathogens to immobilized mucus. The ability to inhibit the adhesion or to displace adhered pathogens was variable depending on both the probiotic combination and the pathogen tested. Our results demonstrate that different probiotic combinations were able to enhance the inhibition percentages to pathogen adhesion to intestinal mucus. All probiotic combinations tested in this study showed inhibition abilities against pathogen infection with values which were over 40% for some pathogens tested. Combinations had specific properties and inhibition abilities against some or all of the tested pathogens. These results suggest that combinations of probiotics strains could be useful and more effective in inhibition of pathogen adhesion. The inhibition and displacement profiles were very different suggesting that different mechanisms are implied in both processes. Selection of new probiotic combinations should be conducted for specific target pathogens or pathogen associated microbiota aberrancies.     

Probiotics interaction with foodborne pathogens: a potential alternative to antibiotics and future challenges

Abstract

Antibiotics are a key tool used nowadays in health care industry to fight against bacterial infections; however, repeated antibiotic use or misuses, have led to bacterial resistance, causing significant threats for many people with common bacterial infections. The use of probiotics to enhance gastrointestinal health has been proposed for many years. In recent years, there has been an increasing interest in the use of probiotic bacteria as alternatives for antibiotics for preventing or treating various intestinal infections. Several important underlying mechanisms responsible for the antagonistic effects of probiotics on different microorganisms include: (1) competitive exclusion for adhesion sites and nutritional sources; (2) secretion of antimicrobial substances; (3) enhancement of intestinal barrier function; and (4) immunomodulation. However, their mode of action is not very well understood and therefore a clearer understanding of these mechanisms is necessitated. This will enable appropriate probiotic strains to be selected for particular applications and may reveal new probiotic functions. The goal of this review was to highlight some studies from literature describing the probiotic interaction with several major foodborne pathogens, as well as explore the mechanisms for such probiotic-pathogen interaction. The review will conclude by presenting future perspective and challenges of probiotic application in food products.     

益生菌发酵乳低温酸性双重胁迫致益生菌损伤 机制的研究进展

益生菌是一类对宿主有益的活性微生物,是定植于人体肠道、生殖系统内,能产生确切健康功效从而改善宿主微生态平衡、发挥有益作用的活性有益微生物的总称。近年,有关益生菌发酵乳中低温酸性双胁迫致益生菌的损伤,发酵乳中益生菌活性的保护,以及组学技术推动下的菌株损伤相关代谢研究取得了一定进展。本文综述了益生菌低温酸性双胁迫下损伤应激和保护机制、菌株特性对发酵乳风味和质量的影响及益生菌发酵乳冷藏过程低温酸性双重胁迫下菌体活性的保护策略,为研究影响益生菌发酵乳中益生菌存活能力、菌体细胞膜特性及代谢酶活性的因素,明确益生菌发酵乳基质中益生菌低温酸性双胁迫损伤的分子机制,建立益生菌发酵乳加工和贮藏过程中益生菌的保护策略提供参考,也为未来改善益生菌发酵乳的功效和品质提供了科学依据。     

Incorporation of probiotic bacteria in whey cheese: decreasing the risk of microbial contamination

For dairy products that are consumed fresh, contamination by spoilage microorganisms and pathogens from the environment is a major concern. Contamination has been associated with a number of outbreaks of foodborne illnesses; however, consistent data pertaining to the microbial safety of whey cheeses specifically have not been reported. Hence, the goals of this research effort were (i) to manufacture a probiotic whey cheese with Bifidobacterium animalis and Lactobacillus casei and (ii) to assess the antimicrobial activity of these probiotics against a set of foodborne pathogens (Listeria innocua, Salmonella Enteritidis, and Staphylococcus aureus) and food spoilage microorganisms (Pseudomonas aeruginosa and Escherichia coli). Three ranges of these microbial contaminants were used for inoculation of cheeses: 10(3) to 10(4), 10(4) to 10(6), and 10(6) to 10(8) CFU/g. Inoculation in plain culture medium served as a control. The inhibition produced by the probiotics was calculated, and the major effect was found to be bacteriostatic. In specific cases, full inhibition was observed, i.e., by B. animalis against P. aeruginosa and by L. casei against Salmonella Enteritidis and L. innocua. Conversely, the least inhibition was detected for L. casei against P. aeruginosa. Our results suggest that use of these probiotic strains can extend the shelf life of whey cheeses and make them safer by delaying or preventing growth of common contaminant bacteria.     

益生菌的功效与潜在危害

过去20年里,益生菌被广泛应用于食品中,尤其是发酵乳品中。在筛选益生菌时,其安全性、功能性和加工特性是必须考虑的方面。益生菌对免疫活性宿主是有益的,但是对免疫缺陷宿主,却可能产生危害。一些益生菌与条件感染有关,并且还有传递抗抗生素基因的危险。     

Probiotics: towards demonstrating efficacy

PROBDEMO, a multi-centre European research project, began in 1996 with the aim of demonstrating that probiotic micro-organisms can positively effect human health in rigorously conducted human clinical studies. These studies, now completed, have shown that some probiotics can influence the composition of the intestinal microbiota and modulate the host immune system with measurable benefits to health, including the control of atopic eczema in infants with food allergy. Considerable promise was also demonstrated for the use of selected probiotics in controlling inflammatory bowel disease, and infections in children and the elderly. The scientific approaches to selecting and evaluating probiotics that were demonstrated in the PROBDEMO project provide a model for food manufacturers to move further towards demonstrating efficacy for their probiotic products.     

Probiotics in Goat Milk Products: Delivery Capacity and Ability to Improve Sensory Attributes

Dairy foods, particularly those of bovine origin, are the predominant vehicles for delivery of probiotic bacteria. Caprine (goat) milk also possesses potential for successful delivery of probiotics, and despite its less appealing flavor in some products, the use of goat milk as a probiotic carrier has rapidly increased over the last decade. This review reports on the diversity, applicability, and potential of using probiotics to enhance the sensory properties of goat milk and goat milk‐based products. A brief conceptual introduction to probiotic microorganisms is followed by an account of the unique physicochemical, nutritive, and beneficial aspects of goat milk, emphasizing its advantages as a probiotic carrier. The sensory properties of probiotic‐enriched goat milk products are also discussed. The maintenance of probiotic viability and desirable physicochemical characteristics in goat milk products over shelf life is possible. However, the unpleasant sensory features of some goat milk products remain a major disadvantage that hinder its wider utilization. Nevertheless, certain measures such as fortification with selected probiotic strains, inclusion of fruit pulps and popular flavor compounds, and production of commonly consumed tailor‐made goat milk‐based products have potential to overcome this limitation. In particular, certain probiotic bacteria release volatile compounds as a result of their metabolism, which are known to play a major role in the aroma profile and sensory aspects of the final products.     

Non-dairy probiotic products

There is evidence documenting the beneficial health effects of probiotic microorganisms. Also, many studies have reported that the best matrices to deliver probiotic are dairy fermented products. However, recently several raw materials have been extensively investigated to determine if they are suitable substrates to produce novel non-dairy probiotic microorganisms, and it has been found that traditional fermented foods may contain viable probiotic microorganisms. Numerous such examples can be found in the text. Therefore, the aim of this review was to investigate the utilization of probiotics in new and traditional non-dairy products with probiotic potential. It was found that while cereals have been extensively investigated to develop new probiotic foods; further research about the probiotic beneficial effects of traditional fermented products is needed.     

Probiotication of foods: A focus on microencapsulation tool

BackgroundWith almost thirty years of application in field of probiotics, microencapsulation is becoming an important technology for sustaining cell viability during food production, storage and consumption as well as for the development of new probiotic food carriers. Potentiality of microcapsules in protecting probiotics along human digestive tract seems to be well established. Instead, the inclusion of probiotics into foods, also in microencapsulated form, poses still many challenges for the retention of their viability, being food intrinsic and extrinsic factors crucial for this item.Scope and approachWe collect the relevant literature concerning the use of microencapsulation for the inclusion of probiotics in traditional food vehicles such as milk derivatives and in novel food carriers that were grouped in bakery, meat, fruit and vegetable. Furthermore we intent to highlight within different food categories the main factors that act in challenging probiotics viability and functionality. What we aim is to establish how microencapsulation is effectively promising in the research and development of innovative probiotic foods.Key findings and conclusionsDespite the relevant improvements toward the broadening of probiotic food products and categories, additional efforts have to be attempted. For this purpose, development of easy to use, stable and cheap probiotic microcapsules could be an important key for industrial spreading of microcapsules. Also the monitoring of cell stability along the entire food production including a real storage period as well as the assessment of encapsulated probiotic metabolism are some topics that require additional investigations.     

Horizontal gene transfer in the gut: Is it a risk?

The human gastro-intestinal microbiota involves the highest concentration of microorganisms in the human body and contains both probiotic and pathogenic bacteria. The co-presence of these different bacteria may lead to the occurrence of the so-called horizontal gene transfer (HGT) between these microorganisms. This phenomenon has been shown to allow the transfer of genes encoding virulence traits and antimicrobial drug resistance from pathogenic bacteria to other non-pathogenic strains, which highlighted its significance to human health. It could be envisaged that HGT may occur between pathogenic and probiotic bacteria in the gut, where pathogens could receive genetic elements from probiotics that enhance the pathogen’s colonization in the gut. HGT may also allow for the acquisition of virulence genes by probiotics from neighboring gut pathogens. Pertinent literature on HGT events within gut microbiota is controversial and the present paper aims to critically address this aspect. In light of an increased production of probiotics-containing foods, addressing HGT would be a vital act to ensure food safety.     

Citrus flavonoid represses Salmonella pathogenicity island 1 and motility in S. Typhimurium LT2

Most of the current commercial probiotic strains have not been selected for specific applications, but rather on the basis of their technological potential for use in diverse applications. Therefore, by selecting them from appropriate sources, depending on the target population, it is likely that better performing strains may be identified. Few strains have been specifically selected for human neonates, where the applications of probiotics may have a great positive impact. Breast-milk constitutes an interesting source of potentially probiotic bifidobacteria for inclusion in infant formulas and foods targeted to both pre-term and full-term infants. In this study six Bifidobacterium strains isolated from breast-milk were phenotypically and genotypically characterised according to international guidelines for probiotics. In addition, different in vitro tests were used to assess the safety and probiotic potential of the strains. Although clinical data would be needed before drawing any conclusion on the probiotic properties of the strains, our results indicate that some of them may have probiotic potential for their inclusion in products targeting infants.     

Functional foods as carriers for SYNBIO®, a probiotic bacteria combination

The popularity of functional foods continues to increase as consumers desire flavorful foods that will fulfil their health needs. Among these foods, probiotics may exert positive effects on the composition of gut microbiota and overall health. However, in order to be beneficial, the bacterial cultures have to remain live and active at the time of consumption. The aim of this study was to develop new probiotic food products, such as seasoned cheeses, salami, chocolate and ice-cream with a final probiotic concentration of approximately 10?CFU/daily dose of Lactobacillus rhamnosus IMC 501? and Lactobacillus paracasei IMC 502? mixed 1:1 (SYNBIO?). The survival and viability of probiotics were determined during the foods shelf-life. The values of viable probiotic bacteria of all dairy and non-dairy foods were between 10? and 10?CFU/g of food at the end of the shelf-life and for some of them the values were maintained even after the expiry date. Based on the results of the current study, all the dairy ("Caciotta" cheese, "Pecorino" cheese, "Büscion" Swiss cheese and "Fiordilatte" ice-cream) and non-dairy ("Ciauscolo" salami, Larded salami, Swiss small salami, milk chocolate, dark chocolate, organic jam and chocolate mousse) food products studied would be excellent vehicles to deliver the probiotic health effects because of the high viability of probiotics during the shelf-life of foods and in some cases even after their expiry date.     

潜在益生乳酸菌分离和鉴定研究进展

利用益生菌提高人类健康水平是当前营养健康领域最具前景的方向之一。乳酸菌是食品中常用的益生菌,迄今为止,联合国粮食及农业组织（FAO）和世界卫生组织（WHO）推荐仅从人的胃肠道分离的乳酸菌可在食品中使用。而越来越多的研究从食品来源中分离出具有益生功能的菌株以扩大益生菌的选择范围。随着分子生物学和检测分析等技术的发展,基质辅助激光解吸电离-飞行时间质谱（MALDI-TOF MS）、全基因组测序、实时荧光定量聚合酶链式反应（RT-FQ-PCR）等技术可以鉴定到亚种及菌株水平上的益生菌。鉴于分离鉴定技术是益生菌安全规范应用的先决条件,该文综述了近年来针对潜在益生乳酸菌有效分离和鉴定技术的研究进展,以期为我国益生乳酸菌自主开发利用提供借鉴。     

益生菌干酪成熟过程中微生态变化的研究进展

随着人们健康意识及对益生菌产品需求的增强,有关益生菌干酪的研究和加工也不断增多。益生菌干酪在成熟过程中,由于受到益生菌的作用,干酪会发生一系列复杂的微生态理化反应,从而影响到产品的风味、质构、安全性和功能性等特性。本文重点综述了益生菌干酪在成熟过程中微生态变化的研究进展,包括益生菌在干酪基质中的存活、益生菌干酪在益生菌作用下发生的理化特性变化以及组学方法在益生菌干酪中的应用等,以期为提升干酪加工技术水平、推动益生菌干酪产品的研制以及促进我国干酪产业的发展提供参考。     

Probiotic fermentation of plant based products: possibilities and opportunities

Functional foods are claimed to have several health-specific advantages. In addition to their basic nutritive value, they contain a proper balance of ingredients which help in the prevention and treatment of illnesses and diseases. Within this category, products containing lactic acid bacteria or probiotics are increasingly gaining importance. The recognition of the beneficial effects of dairy products containing probiotics has been well established. The allergy to dairy products, lactose intolerance, and cholesterol content are the major drawbacks related to the use of fermented dairy products for a large percentage of consumers. Modern consumers are increasingly interested in their personal health, and expect the food that they eat to be healthy or even capable of preventing illness. Because of this, probiotic food products made out of fermentation of cereals and fruits and vegetables is receiving attention from the scientific world as well as consumers and constitutes the major part of this review. The use of mathematical models for the probiotic fermentation will help in reducing the time and effort involved in the optimization of the probiotic fermentation process. We have tried to summarize the developments in the use of mathematical models for probiotic fermentation. Future technological prospects exist in innovations which represent solutions for the stability and viability problems of probiotics in new food environments. Current research on novel probiotic formulations and microencapsulation technologies exploiting biological carrier and barrier materials has also been discussed.     

Probiotics,prebiotics, and microencapsulation: A review

The development of a suitable technology for the production of probiotics is a key research for industrial production, which should take into account the viability and the stability of the organisms involved. Microbial criteria, stress tolerance during processing, and storage of the product constitute the basis for the production of probiotics. Generally, the bacteria belonging to the genera Lactobacillus and Bifidobacterium have been used as probiotics. Based on their positive qualities, probiotic bacteria are widely used in the production of food. Interest in the incorporation of the probiotic bacteria into other products apart from dairy products has been increasing and represents a great challenge. The recognition of dose delivery systems for probiotic bacteria has also resulted in research efforts aimed at developing probiotic food outside the dairy sector. Producing probiotic juices has been considered more in the recent years, due to an increased concern in personal health of consumers. This review focuses on probiotics, prebiotics, and the microencapsulation of living cells.     

The Comparison of Food and Supplement as Probiotic Delivery Vehicles

Probiotics are live bacteria which have frequently been reported to be beneficial in preventing a wide range of diseases as well as playing a major role in treating the existing ailments. Thus far, a variety of probiotic products have been developed which can be categorized into two groups: probiotic foods and supplements. Both foods and supplements have been able to confer the health benefits claimed for them. However, it is not known which one can be clinically more efficient, and to the best of our knowledge, until now no research has been conducted to investigate this issue. The present review aims to discuss this matter, based on the evidence available in the literature. To do so, articles indexed in PubMed and ScienceDirect between 2000 and 2011 were reviewed. The articles included the clinical trials in which either foods or supplements were used to administer the probiotics to either patients suffering from different diseases or healthy subjects. Although both foods and supplements seem to have been efficient carriers for the beneficial bacteria, to generally promote public health in communities, probiotic foods appear to be preferred to probiotic supplements.