**7. Postbiotic**

"Postbiotics" is known to be a new term in the biotic field, and therefore, they are still not common to the public. Therefore, in contrast to pre- and probiotics, it has, however, become more challenging to get a consensus on the true definition of postbiotics in the available literature. Nevertheless, Tsilingiri and Rescigno [74] defined postbiotics as any chemical released/created by the metabolic activity of a bacterium that directly or indirectly benefits the host. Postbiotics were also described by Blazheva et al. [6] as "a preparation of inanimate microbes and their constituents which is beneficial to the health of the host." Postbiotics are therefore functional bioactive substances that are created in a matrix during fermentation and are employed to support the health of individuals [6]. Several of the suggested health benefits

#### *Lactic Acid Bacteria: Review on the Potential Delivery System as an Effective Probiotic DOI: http://dx.doi.org/10.5772/intechopen.111776*

of probiotic, prebiotic, and synbiotic additions depend on the possible production of short-chain fatty acids and components such as microbial fractions, functional proteins, secreted polysaccharides, extracellular polysaccharides, cell lysates, teichoic acid, peptidoglycan-derived muropeptides, and pili-type structures [75–77]. These understandings contributed to a reappreciation of food fermentation and gave rise to the theory of postbiotics. Postbiotics can also be described as functional fermentation chemicals, such as the ones mentioned above, that can be combined with dietary elements to enhance health [64]. Paraprobiotics and fermented infant formulas (FIFs) are two examples of postbiotics that are frequently mentioned. These days, the term "paraprobiotics," also known as "ghost probiotics," "non-viable probiotics," or "inactivated probiotics," is frequently used to refer to nonviable or inactivated microbial cells that, when provided in adequate proportions, benefit the host [64], whereas FIFs are baby or follow-on formulae that have been fermented with lactic acid-producing or other bacteria and often do not contain living bacteria [64]. The potential for postbiotics to boost the effectiveness of active microorganisms or transform them into useful components is possible. Additionally, postbiotics get around the technical difficulties of maximizing colonization and preserving the viability and stability of the microorganisms at high doses in the product. Postbiotics can also be employed in circumstances where it is more difficult to regulate and maintain the conditions for manufacture and storage, such as in underdeveloped nations [64]. Additionally, it has been suggested that using postbiotics in critically ill patients, young children, and premature newborns may be a desirable substitute for other "-biotics" [78]. Food, microbiology, and customized medicine may become even more intertwined according to the postbiotics idea [64].

In general, all substances created because of microbial fermentation might be "postbiotics." Additionally, the concept of these postbiotics is often established on the concept that these microbiotas release a variety of metabolites during/after fermentation, and these metabolites impact positive effects on the health of humans. In addition to treating various types of diarrheas, postbiotic consumption in healthy people has been shown to improve general health and alleviate the symptoms of a variety of illnesses, including atopic dermatitis in adults and colic in newborns. Numerous studies have shown that postbiotics can have clinically significant effects as well as immunomodulatory effects. In addition, postbiotics also have antioxidant, anti-inflammatory, and anticancer capabilities [79]. Postbiotics have some significant functions, which include boosting active microorganisms to work more effectively or transforming them into useful components. This might perhaps speed up the transport of active substances to the intended location in the gut and extend the shelf life of these chemicals [80].

Postbiotics may also impart several benefits in food safety, and one of the advantages of adding probiotics to food is that they interact with pathogenic bacteria, which may inhibit pathogen growth by competing with them for resources such as nutrients or by secreting antimicrobial compounds [81]. Probiotic bacteria generate antimicrobial compounds known as postbiotics, which have the potential to play a significant role in food safety by preventing the development of pathogens in food and enhancing consumer health. Numerous bioactive metabolites, including organic acids, short-chain fatty acids, carbohydrates, antimicrobial peptides, enzymes, vitamins, cofactors, immune-signaling compounds, etc., are present in postbiotics made from LAB [82, 83]. In almost every study pertaining to food safety, the authors created a CFS solution that contained biological compounds produced by target bacteria and employed as postbiotics. Several LAB strains can be thought of as probiotics, and

their postbiotic products frequently provide consumers with similar or complementary health benefits [84]. To enhance the technical qualities and lengthen the shelf life of foods, LAB has been widely employed, whether as the primary starter or as the secondary starter [22]. Postbiotics have several qualities that distinguish them from probiotics and make them important components. For instance, postbiotics have advantages over parent bacterial live cells in that they have a longer shelf life, safer structures, cannot spread antibiotic resistance, do not produce biogenic amines (BA), are simple to use and store, are stable in a wide range of pH and temperature, and have broad-spectrum antimicrobial activity [22, 85]. The difficulty in using live starter cultures directly in food products is ensuring that they will grow and survive in a variety of food matrices and settings. In this regard, the direct addition of a postbiotic mixture or individual postbiotic prevents unfavorable interactions between live primary and adjunct starters for antimicrobial purposes [86]; however, there are some challenges in the use of individual postbiotic of starters and protective cultures. Despite the high expense of bacteriocin separation and purification, antimicrobial metabolites have a restricted spectrum, making it possible for infections that have been treated with some of them, such as bacteriocins, to acquire resistance. In addition to a postbiotics mixture's excellent heat stability, food may fully benefit from its broad-spectrum antibacterial activity and the synergistic interactions between organic acids and other metabolites. Individual postbiotics perform a variety of well-known and newly discovered food safety roles, such as food biopreservation and packaging, control, and elimination of the biofilm of foodborne pathogens, biodegradation of dangerous chemical contaminants (such as mycotoxins, pesticides, and BAs), and much more. According to Moradi et al. [22], the kind of target microbe or pollutant, the concentration and method of administration, and the properties of the food matrix all affect how effective postbiotics are in food systems.

### **7.1 Antioxidants potential of probiotics and postbiotics**
