Fermentation is a simple, low-cost, and versatile process that can be used to transform many food products, both solid and liquid. Fermented foods can be considered as “foods made through desired microbial growth and enzymatic conversions of food components” [1]. The fermentation activity of those microorganisms, including bacteria, fungi, and yeast, leads to several changes in sensory and technological characteristics of foods. The fermentation process is also useful to obtain diverse health and nutritional benefits. However, this process has been primarily used for preserving food by preventing the proliferation of undesirable microorganisms and by the inhibitory effect of the organic acids produced in the process [2].

The elaboration of fermented foods and beverages is inherent to the human diet, and each region of the world has its specific products. According to some authors, records of food fermentation date back more than 6000 years [3]. Fermented foods and beverages have been consumed for a long time by different civilizations and by various social classes [4]. Some well-known examples are beer, wine, and bread production, of which there are ancient archaeological records. Motivation to consume these products varies within communities; for example, native populations tend to choose fermented foods and beverages due to medical, dietary, or spiritual motives [5], whereas residents of industrialized areas consume them due to nutritional benefits and not for religious reasons. Some people follow specific trends, such as the “slow food” movement and the tendency to consume foods perceived as “more natural” ^[6][7][6,7]. In these cases, fermentation is attractive, since it is a slow process and appears to be a “natural” method in the eyes of consumers [8]. The sensory aspects of fermented foods and beverages can be attractive to other customers.

A broad classification divides the fermentation process according to the participating microorganisms as bacterial or yeast and mold fermentation. The first can be further divided into alkaline or lactic acid fermentation. Lactic acid bacteria (LAB) are responsible for lactic acid fermentation and can be classified into homolactic and heterolactic groups, according to the pathway used to ferment the sugars. Homolactic bacteria operate through glycolysis, using glucose as a carbon source, and produce only lactic acid. The heterolactic group decomposes glucose not only in lactic acid, but also in significant amounts of ethanol, acetate, propionate, and carbon dioxide, using other pathways besides glycolysis [9].

Morphological and physiological characterization of LAB describe them as gram-positive, acid tolerant, meso-aerophillic, non-spore forming, catalase negative, and morphologically either rod-shaped (bacilli) or spherical (cocci) bacteria that produce lactic acid as the major end product of carbohydrate fermentation [10].

LAB are one of the most widely used microorganisms for fermented foods. Because of their capacity to produce lactic acid and other compounds, they contribute to extending the shelf life of products, improving the nutritional profile of ingredients, and modifying certain physicochemical characteristics of the food (including a decrease in pH). They are considered GRAS (generally recognized as safe) substances. The US Food and Drug Administration (FDA) classifies food ingredients according to the GRAS label, which identifies those substances that are “generally recognized, among qualified experts, as having been adequately demonstrated to be safe under the conditions of its intended use” [11]. One of the best-known applications of LAB is the production of fermented dairy foods. However, LAB can grow correctly in different food matrices including fruits, vegetables, and grains ^[12][13][14][12,13,14], and a wide variety of strains have been isolated from various indigenous fermented foods and beverages [15].

All regions of the world have traditional fermented foods and beverages that are part of their culture. Asian countries have a vast tradition in this subject, possessing in their culture a large number of different foods and typical drinks, some of them well-known worldwide (e.g., kimchi, kombucha, miso, tempeh, soy sauce) ^[16][17][18][16,17,18]. Other parts of the world have their typical fermented foods and beverages, such as beer, wine, cider, yogurt, kefir, or sauerkraut in Europe. Different ingredients used for traditional fermented foods led to developing a diversity of microorganisms, including a variety of LAB [19]. These ingredients and bacteria are typical of each geographical area and contribute to the development of distinctive characteristics, such as typical textures and flavors ^[19][20][19,20].

2. Fermented Foods and Beverages of Latin America

Latin American countries have a long history of people who have elaborated fermented foods and beverages over the years from certain typical ingredients of the continent. According to some authors, a large variety of fermented foods and beverages in Latin America come from native inhabitants that traditionally elaborate these kinds of products using empirical information [5]. Among these populations, fermentation was and is still used mainly as a food preservation method. To elaborate fermented foods and beverages, microorganisms can be added on purpose (as starter cultures) or unintentionally (naturally present in the food). In most cases of native populations, fermented foods and beverages are produced through spontaneous fermentation, considering the process involves different unknown microorganisms present not only in the ingredients but also in the atmosphere or in different materials used during their elaboration [2]. Ingredients used to produce traditional fermented foods and beverages in Latin American countries include cereals (like maize), animal products (meats from beef, lamb, llama, or guanaco, and cheese), certain tubers, fruits, and vegetables ^[5][21][5,22]. It is common for different countries to prepare similar fermented products, sometimes under different names with small variations. This includes changes in elaboration steps or the use of region-specific seasonings. Teachings on how to produce fermented foods and beverages were commonly transferred from generation to generation, and subsequently, loss of information often occurred. The production of these foods was adapted due to the geographic and seasonal availability of ingredients. Due to these factors, different recipes and ways of preparation have come about ^[5][8][5,8]. A big part of the solid fermented foods consumed in Latin America are made with typical ingredients of the region and are part of the culture of the native communities. However, other fermented foods produced in this region were introduced by European immigration, such as cheeses and dried sausages, and are commonly consumed. ReThis searchersction will focus on those products prepared with traditional ingredients of Latin America, leaving aside those fermented foods resulting from immigration. Traditional Latin American beverages include alcoholic and non-alcoholic products, whose recipes are passed from generation to generation. People often consume alcoholic beverages for religious or spiritual purposes, whereas recreational motives are probably the main reason in industrialized populations. Some authors suggest that most of the fermented beverages elaborated by American natives involve the use of LAB ^[22][23][23,24]. Studies show both bacteria and yeast are commonly used in the elaboration of fermented beverages ^[23][24]. In such cases, these two microorganisms have a symbiotic relationship, stimulating each other’s growth. In fermented beverages, the development of LAB is probably augmented by the substances produced by yeast, while the latter is stimulated by the production of acid generated by the bacteria [5]. The variety of fermented beverages in Latin America is wide and many of them are prepared using cassava (Manihot esculenta) or corn (Zea mays) as a substrate ^[22][23]. A large part of them are alcoholic beverages and have an important role in these cultures Although the ethanol in fermented beverages is mainly due to the presence of yeasts (and these are not the object of study in the present review), they coexist with LAB, some of these bacteria being heterofermentative with the ability of producing ethanol. Fermentation time and alcohol content of traditional beverages varies significantly among products and also according to the country. This is the case of chicha, a general name for a drink consumed in different areas of Latin America. Every region that produces it, has its own variations in substrates, alcohol content, and form of elaboration ^[24][25]. Alcohol amount can change according to the fermentation time of the beverage. Inhabitants of Brazilian tribes can wait up to 5 days before consuming caxiri, a drink based on cassava, corn, and sweet potato, in order to have a product with a high alcoholic content. The main bacteria genera described as being part of this kind of product include Lacticaseibacillus, Lactiplantibacillus, Lactobacillus, Limosilactobacillus, Leuconostoc, Streptococcus, and Weisella among others. It is common that sweet potato is used as an inoculum. Inhabitants of some native populations can chew this ingredient, and the obtained product serves as an inoculum for some beverages, including calugi, caium, and chicha ^[21][22]. Starch from the substrates used for fermentation is transformed into fermentable sugars by the action of this inoculum containing amylase enzyme and microorganisms [5].

3. Nutritional Profile and Health Benefits of Traditional Fermented Foods and Beverages of Latin America

As mentioned in other sections, the fermentation process provides several technological, sensory, and nutritional changes to the ingredients used as substrates, and one of the main reasons to consume fermented foods and beverages are the health benefits that come along with them. Functional foods are those that provide a health benefit beyond basic nutrition ^[25][47], and foodstuffs obtained by LAB fermentation represent a large part of functional foods [16]. Fermented foods continue to be staple meals for certain native inhabitants of Latin America, so it can be assumed that these products represent an important energy source and provide various essential nutrients in the diet of these people [5]. Some of the main modifications produced by LAB in the nutritional profile of food ingredients during fermentation include improving their digestibility and increasing the macro and micronutrient content. It is known that several raw foods are indigestible to the human organism or are not sensory acceptable without proper processing (e.g., wheat, barley, corn). Fermentation can help in the production of adequate edible foods and beverages prepared with these ingredients ^[16][26][16,48]. Such are the cases of wheat, a cereal that can be transformed into bread, and malted barley, which is turned into beer. Lactic acid fermentation represents a useful alternative for people having lactose intolerance, since some of them can consume fermented milk products (e.g., yogurts, cheese) without reporting undesirable effects ^[26][48]. TAs can be seen in Section 2, the majority of ingredients used in Latin America to produce fermented products are sources of carbohydrates, including oligosaccharides that are non-digestible to humans ^[27][28][49,50]. When fermentation occurs, these carbohydrates are used by microorganisms as energy source, and this leads to an increase in food digestibility [5]. The production of fermented foods and beverages can increase the protein and amino acid content compared to raw ingredients [5], and LAB can produce peptides with biological activity ^[29][46]. Regarding minerals and vitamins, fermentation can be a key tool to increase their bioavailability. Certain anti-nutritional factors (i.e., phytates, oxalates, tannins) present in raw foodstuffs can be reduced by fermentation, increasing the bioavailability of minerals such as Ca, Fe, and Zn that would be otherwise quenched by these anti-nutrients [5]. In addition, LAB fermentation leads to a process of microbial biosynthesis, which in turn enhances the levels of certain vitamins, including vitamins of the B-group ^[30][51], and lactic acid, one of the main compounds produced during fermentation by LAB, has the potential to enhance the bioavailability of certain minerals and vitamins ^[31][52]. Nutritional improvements produced by LAB on raw food ingredients are summarized in Figure 1. The health effects of consuming fermented foods or beverages are diverse and affect various organic systems ^[32][53]. According to different authors, improvements in gastrointestinal, hepatic, and cardiovascular disorders are among the benefits obtained by the intake of these products. In addition, they could help in the prevention of pathologies such as obesity, diabetes, hypertension, osteoporosis, and certain allergies or intolerances ^[13][33][34][13,54,55]. Additionally, fermented products can be labeled as probiotics. It is important to clarify that not all foods and beverages elaborated through fermentation are considered probiotics. This term is limited to those cases when an established health benefit conferred by well-defined and characterized live microorganisms is demonstrated ^[35][56]. Non-viable microorganisms that confer a health benefit to the consumer (including parabiotics) are a matter of current research works, as after the application of standardized killing methods (e.g., heat, high pressure, ultraviolet, irradiation, sonication, drying, acid, pH changes), they can exert health benefits (e.g., inhibition of pathogens, immunomodulation, mucosal protection, among others) ^[36][57]. The fact that fermented foods provide a wide variety of health benefits may be useful for food industries seeking to attract consumers through health, functional, and nutraceutical labeling [13]. As mentioned, fermentation is used as a food preservation process, making it useful for those looking to conserve their food without the use of synthetic preservatives. However, certain health benefits of native fermented foods may still be unknown due to the fact that many foods contain unidentified but possibly very valuable strains [13]. In this sense, it is necessary to continue the investigations regarding these strains.