Plant-based probiotic foods: current state and future trends

Abstract

Abstract

Plant-based probiotic foods (PBPFs) have recently become a notable choice for many consumers. While less recognized than dairy products, these foods offer efficient alternatives for individuals with lactose intolerance, vegans, or those aiming for more sustainable dietary practices. Traditional fermented PBPFs, such as kimchi, sauerkraut, and kombucha, are part of cultures from different countries and have gained more significant popularity in recent years globally due to their peculiar flavors and health benefits. However, new plant-based probiotic products have also been studied and made available to consumers of the growing demand in this sector. Therefore, this review discusses trends in plant-based probiotic production, known benefits, and characteristics. Challenges currently faced in manufacturing, distribution, marketing, consumer acceptance, and legislation are also discussed.

Graphical abstract

Introduction

Fermented food production has probably begun as a means to preserve food better; however, in this microbial process, several health-beneficial compounds are produced during the fermentation process, such as bioactive peptides and exopolysaccharides (Mukherjee et al., 2024). Probiotics found in foods and drinks contain a variety of beneficial bacteria that have been an integral part of eating habits throughout human history. However, their importance for human health has been better understood recently (Khan Laghari et al., 2023; Zommiti et al., 2020). Throughout history, in many countries, the connection between the consumption of fermented foods and longevity has been partially linked to consuming diets rich in microorganisms. However, it is essential to note that these foods were predominantly consumed by individuals with more straightforward and modest lifestyles (Mackowiak, 2013). Nowadays, several probiotic-rich foods are widely available in the market, such as dairy-based cheese, fermented milk, and yogurts (Küçükgöz and Trząskowska, 2022).

Table 1 comprehensively compares plant-based and dairy-based probiotic foods, focusing on nutritional composition, health benefits, environmental impact, allergen potential, and sustainability practices. Plant-based probiotic foods (PBPFs) are those derived from plant sources and contain live microorganisms that confer health benefits when consumed (da Cruz Nascimento et al., 2024). These foods are typically rich in fiber, vitamins (e.g., vitamin C, vitamin K), and minerals (e.g., iron, magnesium), supporting gut health, aiding digestion, and contributing to overall well-being (Slavin and Lloyd, 2012). One notable difference highlighted is the nutritional composition: plant-based probiotic foods are typically rich in fiber, vitamins, and minerals, while dairy-based options are rich in protein, calcium, and B vitamins (Górska-Warsewicz et al., 2019). Additionally, plant-based probiotic foods often have a lower environmental footprint. They suit individuals with lactose intolerance or dairy allergies, whereas dairy-based options may pose allergen risks due to lactoalbumin content (Plamada et al., 2023). Sustainability practices also differ, with plant-based options often sourced from sustainable agricultural practices such as organic farming, promoting biodiversity and soil health. In contrast, dairy-based probiotic foods are derived from dairy sources and contain live microorganisms, often rich in protein, calcium, and B vitamins (e.g., vitamin B12). They support gut health, aid digestion, and may enhance immune function. Both probiotic foods offer unique nutritional profiles and health benefits tailored to different dietary preferences and needs.

Table 1.

Comprehensive comparative analysis: plant-based vs. dairy-based probiotic foods—nutrition, health, environmental impact, and additional considerations

Aspect	Plant-based probiotic foods	Dairy-based probiotic foods
Nutritional composition	Typically rich in fiber, vitamins (e.g., vitamin C, vitamin K), and minerals (e.g., iron, magnesium). It may contain a variety of plant proteins	Rich in protein, calcium, and B vitamins (e.g., vitamin B12). It may contain lactose
Health benefits	It supports gut health, aids digestion, and contributes to overall well-being. It may also offer anti-inflammatory properties and promote heart health	Supports gut health, aids in digestion, and may enhance immune function. It may help alleviate lactose intolerance symptoms and promote bone health
Environmental impact	Generally lower environmental footprint due to reduced greenhouse gas emissions and land use than animal agriculture. It may require less water and produce less waste	Often associated with higher environmental impact due to methane emissions from cattle and intensive farming practices. It may require significant land, water, and feed resources
Allergen potential	These products are generally free from common allergens like dairy, suitable for those with lactose intolerance or dairy allergies, but may still contain allergens like nuts or soy, depending on the formulation	Contains lactoalbumin, a common allergenic protein found in dairy, which can trigger allergic reactions in individuals with dairy allergies
Sustainability practices	Often sourced from sustainable agricultural practices, including organic farming and regenerative agriculture. It may support biodiversity and soil health	Practices vary widely, but some dairy producers implement sustainable initiatives such as reduced water usage and methane capture systems

Although the benefits of probiotics have traditionally been associated with the digestive system, their potential is more comprehensive, contributing to improving the health of various organs in the body. Figure 1 illustrates the broad impact of probiotics on overall health beyond traditional associations with digestive health. The use of these microorganisms is beneficial in studies with mice and humans, providing advantages such as stress reduction (Merkouris et al., 2024), skin improvement (Gao et al., 2023), balance in hormonal levels (Szydłowska et al., 2021), enhancement of the immune system (Mazziotta et al., 2023), and reduction of abdominal fat (Álvarez-Arraño and Martín-Peláez, 2021).

Fig. 1.

Health benefits observed following probiotic intake: insights from studies conducted in human and mice models

Several reports have attributed health benefits to probiotic consumption due to a better balance of microorganisms in the gastrointestinal tract and the intestinal microbiota as the microbial-poor diets may disrupt the intestinal balance, a condition known as dysbiosis occurs, leading to several diseases related to gut malfunction (de Salis et al., 2022), such as irritable bowel syndrome (IBS) and type 2 diabetes (Liaqat et al., 2023). The beneficial bacteria and yeast present in the probiotics have been found to play essential roles in the human gut microbiome ecosystem, as shown in Table 2. For example, Lactobacillus plantarum can compete with pathogens like Salmonella for adhesion sites, mitigating the effects of infections (Potočnjak et al., 2017). Also, Bifidobacterium lactis and Lactobacillus acidophilus produce acids, such as lactic, which form a non-propitious environment for pathogens proliferation, boosting the immune system. Some research has also reported some new benefits of these probiotics. Studies have shown that Bifidobacterium infantis can alleviate symptoms of irritable bowel syndrome (Ruiz et al., 2017). Lactobacillus rhamnosus can reduce the risk of eczema in children when given to pregnant or lactating individuals (Szajewska and Horvath, 2018). Additionally, Lactobacillus helveticus and Bifidobacterium longum may have mood-regulating and anxiety-reducing effects (de Carvalho et al., 2023), and Lactobacillus acidophilus has also shown potential in preventing respiratory infections (Khan Laghari et al., 2023) (Fig. 2).

Table 2.

Probiotic microorganisms, main foods where they are present, and health benefits verified in commercial products

Microorganism	Species/strain	Common Sources	Verified benefits	Commercial products and country of origin	References
Lactic acid bacteria	Lactobacillus acidophilus	Yogurt, fermented dairy products	Digestive health, vaginal health, possible reduction in cholesterol	DanActive (USA), Yakult (Japan)	Khorshidi et al. (2021)
	Lactobacillus rhamnosus GG	Fermented dairy, probiotic drinks	Prevention and treatment of gastrointestinal infections and diarrhea, skin health	Culturelle (USA), Danimals (USA)	Łopusiewicz et al. (2021)
	Lactobacillus casei Shirota	Fermented milk, cheeses	Immune system support, digestive health	Yakult (Japan)	Zhang et al. (2020)
	Lactobacillus reuteri	Dairy products	Digestive health, oral health	BioGaia (Sweden)	Semenikhina et al. (2018)
Bifidobacteria	Bifidobacterium bifidum	Yogurt, fermented dairy	Digestive health, support against harmful bacteria	Align (USA)	Kamel et al. (2021)
	Bifidobacterium longum	Cereals, infant formulas	Reduces gastrointestinal discomfort caused by stress	TruBiotics (USA), PureBiotics (USA)	Duman et al. (2021)
	Bifidobacterium breve	Some dairy products	Digestive health, skin health	Mutaflor (Germany)	Matsuoka et al. (2018)
Saccharomyces	Saccharomyces boulardii	Fermented milk, cheeses	Prevention of antibiotic-associated diarrhea, treatment of various forms of diarrhea	Florastor (France)	Moré and Vandenplas (2018)
Streptococcus	Streptococcus thermophilus	Yogurt, cheese	Digestive health may improve lactose digestion	Activia (Spain)	Yamauchi et al. (2023)
Bacillus	Bacillus coagulans	Various probiotic supplements	Digestive health, irritable bowel syndrome	Digestive Advantage (USA), Sustenex (USA)	Maity et al. (2021)
Propionibacterium	Propionibacterium freudenreichii	Swiss cheese, specific dairy	Limited data, some suggest it can be beneficial for bowel movements	Few specific commercial products, usually in cheese blends, as Emmental (Switzerland)	Cheng et al. (2018)

Fig. 2.

Popular plant-based probiotics appreciated by several cultures worldwide

Most foods industrially enriched with probiotics are of animal origin, especially dairy foods like yogurt or fermented milk. However, due to restrictive diets and growing health concerns, there has been a notable trend towards PBPFs, which generally do not contain lactose and have a lower environmental impact. During fermentation, simpler sugars, like lactose, are broken down into organic acids, mainly lactic acid (LA). In contrast to dairy products, fruits contain glucose, sucrose, and fructose as their primary sugars, which are converted into pyruvate and LA through a process facilitated by the enzyme D- or L-lactate dehydrogenase. This conversion is significant because it transforms one mole of glucose into two moles of LA and two ATP through the fermentation of microorganisms (Raj et al., 2022) (Fig. 3).

Fig. 3.

Step-by-step standard procurement of plant-based raw materials for producing probiotics

In this context, probiotic foods’ benefits appear to align with those of a plant-based diet. In addition to PBPFs having the same health benefits as dairy probiotics, they are rich in fiber and support better digestion and a balanced microbiota. Research suggests that diets rich in vegetables, fruits, legumes, and whole grains are correlated with a reduced risk of chronic diseases such as heart disease, type 2 diabetes, and certain types of cancer (Cena and Calder, 2020; Mellendick et al., 2018). Also, on the environmental sustainability front, animal ethics and the substantial contribution of animal production, particularly livestock farming, to greenhouse gas emissions, deforestation, and biodiversity loss (Rust et al., 2020) have been decisive in including PBPFs in the daily diet over dairy-based ones.

This review article discusses current probiotic trends in plant-based foods, integrating new scientific, nutritional, environmental, technological, and market subjects. It will discuss the new technologies for better production and extension of shelf-life of the market position of PBPFs in comparison to dairy-based ones. The health benefits of these probiotics and their mechanisms of action in the human body will also be discussed. Additionally, it covers potential issues such as the loss of bacterial viability, undesired fermentations, and changes in sensory characteristics affecting product quality and consumer acceptance. Furthermore, the text seeks to present the potential of PBPFs as microbial active foods with high potential for inclusion in health diets, presenting an alternative for people, especially those with food restrictions, who seek healthy ways of life.

Probiotics microorganisms in foods

Probiotics are consumed by several cultures worldwide. However, the Japanese government originally introduced the concept of a “probiotic food” in the early 1990s, encompassing several microorganisms, such as Lactobacillus casei and Bifidobacterium, especially in yogurt (Almeida et al., 2012). However, due to the biotic characteristics of probiotics, their production must be regulated, and the quality parameters followed. Thus, the current regulatory endorsements for strains like Lactobacillus and Bifidobacterium are some of the most commonly used probiotics due to their safety, being vastly applied in the food industry (Chen et al., 2023; Khan Laghari et al., 2023).

However, before this period, it is expected that fermented food has been consumed through past centuries due to its extended expiration date, nutritional benefits, and unique flavors (Mukherjee et al., 2024). Also, Through fermentative processes occurs the production of beneficial compounds like vitamins and organic acids that improve gut health (Leeuwendaal et al., 2022); the consumption of these foods has been perceived as health-improving by several consumers (O’Mahony et al., 2023). This process may also assist in the digestion of some sugars, such as lactose, into more easily digestible forms, improving the food’s nutritional value (Almeida et al., 2012), reducing the risk of several diseases (Emília et al., 2018; Khan Laghari et al., 2023; Lv et al., 2023) and be a standard diet in some good-health centenary population (Ayala et al., 2017; Mackowiak, 2013).

One of the most common probiotic foods is yogurt, which is usually rich in Lactobacillus and Bifidobacterium and is dairy-based, which causes its exclusion from the dietary habits of lactose intolerant and vegan people. However, other probiotics, especially plant-based ones, such as kimchi, kombucha, and sauerkraut, are also rich in beneficial bacteria while not being restricted for some diets (Dimidi et al., 2019). These plant-based probiotics, although not as much present in the daily life of Western society as dairy-based ones, are well-appreciated and historically consumed in Asian countries, being related to the high longevity and well-posed cardiovascular systems of those country’s populations, such as Japan and Korea (Ayala et al., 2017; Dimidi et al., 2019).

Plant-based probiotic foods

The production of plant-based probiotic foods (PBPFs) offers a new alternative for individuals with restrictive diets who require probiotic benefits (de Carvalho et al., 2023; Polyak et al., 2023). As a result, the scientific community has been focusing on these plant-based bioactive foods, leading to the development of several vegan alternatives to dairy-based ones (Craig et al., 2023; Küçükgöz and Trząskowska, 2022; Vijaya Kumar et al., 2015).

Traditionally, many fermented vegetable-based products have been consumed for millennia worldwide, with nuances involving social and local factors specific to each country. Plant-based probiotics such as kimchi, kombucha, sauerkraut, and sourdough are present in several culinary worldwide, using different vegetal raw materials usually abundant in the region (Table 3), been appreciated by their flavor, nutritional value, and medicinal potential.

Table 3.

Traditional plant-based fermented foods with probiotic potential

Food	Plant raw material	Other ingredients	Main microorganisms	Largest consumers	References
Sauerkraut	Cabbage	Salt, sometimes caraway seeds	Lactobacillus	Germany, Poland, Czech Republic	Wang et al. (2022a)
Kimchi	Napa cabbage, Korean radishes	Garlic, ginger, red chili peppers, fish sauce or shrimp paste, scallions	Lactobacillus kimchii, Lactobacillus brevis	South Korea, China, Japan	Jang et al. (2019)
Pickles	Cucumbers	Vinegar, salt, dill, garlic	Lactobacillus plantarum, Lactobacillus brevis	United States, Russia, India	Zhou et al. (2021)
Kombucha	Tea	Sugar	Acetobacter xylinum, Saccharomyces	China, United States, Australia	Ojo and de Smidt (2023)
Poi	Taro root	–	Lactobacillus poi	Hawaii (USA), Samoa, Tahiti	Brown and Valiere (2004)
Kvass	Rye Bread	Water, sugar, raisins	Lactobacillus brevis, Saccharomyces cerevisiae	Russia, Ukraine, Belarus	Wang et al. (2022b)
Tibicos	Water and sugar	–	Lactobacillus, Streptococcus, Pediococcus, Leuconostoc, Saccharomyces	Mexico, Central America, and parts of South America	Romero-Luna et al. (2020)
Sourdough Bread	Flour and water	–	Saccharomyces cerevisiae, Lactobacillus	United States, France, Italy	Jin et al. (2021)

The fermentation of vegetal foods was first utilized for preservation, intending to extend the storage period of foods (Mukherjee et al., 2024). The fermentation of grains and other vegetables, on the other hand, enhances levels of B vitamins, especially riboflavin (B2), niacin (B3), and folate (B9) (Melini et al., 2019). Thus stabilizing the vitamin levels in the organism, aiding the prevention of several neurological diseases, such as Wernicke’ = s encephalopathy, depression, beriberi, seizures, subacute combined degeneration of the spinal cord, or peripheral neuropathy (Calderón‐Ospina and Nava‐Mesa, 2020).

Sauerkraut, for example, a plant-based probiotic highly consumed in Central European gastronomy, especially in Germany and Poland, is a product of cabbage fermentation, a process predominantly by Lactobacillus species, producing organic acids through the metabolization of sugars present in the raw material, altering flavors, prolonging its shelf life and producing B vitamins, such as folate (B9) and riboflavin (B2), and other healthy components such as isothiocyanates and glycosylates (Martinez‐Villaluenga et al., 2009; Sharma et al., 2020; Wang et al., 2021; Yang et al., 2018). These compounds also have anti-inflammatory and anticancer properties, possibly by modulating specific cellular pathways and exhibiting antioxidant activity, which counteracts the damaging effects of free radicals (Ejtahed et al., 2012; Sharma et al., 2020). Kimchi is a well-known plant-based probiotic that originated in Korea and has gained popularity worldwide. The dish is made from Napa cabbage, Korean radishes, and various sauces. After adding the ingredients, the mixture is fermented for several days by a combination of Lactobacillus, Leuconostoc, and Weissella. Similar to sauerkraut, these microorganisms metabolize the vegetable sugars, resulting in the production of organic acids that preserve and enhance the unique flavor of the cabbage (Dimidi et al., 2019; Song et al., 2021; Yoon et al., 2000).

Pickles are significant in various cuisines globally, notably in the United States, Russia, and India. Among the variety of vegetables employed for pickling, cucumbers stand out as the most traditional choice. The fermentation process for pickle production hinges primarily on naturally occurring lactic acid bacteria, notably Lactobacillus plantarum and Lactobacillus brevis (Ji et al., 2013). As these bacteria metabolize the carbohydrates in cucumbers, they generate lactic acid, imparting the characteristic tangy flavor and creating an environment hostile to the proliferation of pathogens and spoilage microorganisms. Additionally, the probiotic content of pickles holds potential health benefits, such as regulating blood sugar levels and exhibiting anti-cancer properties (Markowiak and Śliżewska, 2017). Moreover, the fiber fraction inherent in pickles and their probiotic content fosters a healthy gut microbiota, which bears far-reaching implications for overall health, from mental well-being to metabolic regulation (Bell et al., 2018). Furthermore, pickles are a notable source of essential vitamins, particularly B-complex vitamins like riboflavin, niacin, and thiamine (Hrubša et al., 2022). Additionally, pickles contain various bioactive compounds, including antioxidants, that are essential for combating oxidative stress in the body (Moskwa et al., 2023; Shang et al., 2022).

Kombucha is a type of probiotic drink that originated in China. It is made by fermenting sweet tea to create a tart and fizzy beverage. During the fermentation process, Kombucha develops several vitamins, including B1 (thiamine), B2 (riboflavin), B6 (pyridoxine), and B12 (cobalamin) (Bishop et al., 2022a). Also, producing organic acids, such as acetic, gluconic, and glucuronic acids, confers the beverage with the characteristic sourness and has potential detoxifying properties (Bishop et al., 2022a; Selvaraj and Gurumurthy, 2023). D-glucaric acid has been associated with hepatic detoxification, aiding in the binding and subsequent excretion of potentially harmful compounds (Ayyadurai et al., 2023). Kombucha also contains antioxidants, such as ascorbic acid, gluconic acid, and polyphenol, which combat reactive oxygen species, mitigating oxidative stress and potentially aiding against certain degenerative diseases, such as atherosclerosis (Toledo-Ibelles and Mas-Oliva, 2018) and Alzheimer’s disease (Franco et al., 2023).

The consumption of plant-based beverages has also increased due to health benefits such as lower cholesterol, reduced inflammation, decreased risk of chronic diseases, and a growing number of people with lactose intolerance or milk protein allergies (Craig et al., 2023; Xiao et al., 2023). Many fruits may be used in the production of probiotic juices include pineapple (Nurmita Aziz et al., 2023), sugarcane (Islam et al., 2023), mango (Mousanejadi et al., 2023), apple (Wu et al., 2023), orange (Barik et al., 2023), banana (Akter et al., 2022), cherry (Gao et al., 2022) and tomato (Goderska et al., 2022).

Fruit juices are also promising for delivering probiotic bacteria as they are rich in carbohydrates, minerals, fiber, fructooligosaccharides (FOS), inulin, and vitamins. They are a suitable medium for maintaining high viability even after exposure to the stomach’s highly acidic environment (Lillo-Pérez et al., 2021). The probiotic incorporation into juices may increase the product’s shelf life from 7 days to 4 weeks, depending on factors such as initial count, temperature, time, bacteria strain, and substrate (Aspri et al., 2020; Subhashree and Kavita, 2019).

Foods like sauerkraut, kimchi, pickles, or kombucha, widely consumed around the world, are rich in essential vitamins (such as B-complex vitamins and vitamin C) and bioactive, antioxidant compounds, promoting intestinal health, mental well-being, and metabolic regulation. However, some studies have reported that excessive consumption of these microorganisms can pose potential health risks, including gastrointestinal discomfort, especially in individuals with compromised health conditions. As indicated by Barretto et al. (2024), unsupervised use of these supplements can result in inadequate doses, leading to treatment inefficacy or even overdose. Additionally, when included in compounded formulations, the risk of administration or dosage errors increases, compromising treatment efficacy and safety. These authors reviewed the use of dietary supplements by children and adolescents, concluding that their use has increased but is often not prescribed by healthcare professionals. Unsupervised use can lead to inadequate doses and risks of overdose, especially in complex formulations. They emphasize the importance of medical guidance regarding the risks and benefits of supplements.

Table 4 enumerates some recent advancements in probiotic fruit juice production. The analysis focused on several juices and their compatibility with different probiotic strains, considering factors such as fermentation, storage, and cell viability.

Table 4.

Comparison of probiotic viability and fermentative characteristics in various juices

Type of juice	Probiotic microorganisms	Juice characteristics	Fermentation	Storage conditions	Cell viability in juice after storage	Cell viability in juice after gastric juice	References
Marang juice (Artocarpus odoratissimus)	Lacticaseibacillus paracasei	> 10° Brix and pH 3.84	Initial viable cell counts of 103 CFU/mL/4 °C for 30 days	4 °C for 30 days	> 108 CFU/mL	> 107 CFU/mL	Calumba et al. (2023)
Mango (Mangifera indica)	Lactobacillus plantarum	> 12° Brix and pH 4.0	30 ºC/48 h	–	> 108 CFU/mL	–	Hoang et al. (2023)
Sorrel + Pineapple (varying proportions including 50:50)	Lacticaseibacillus paracasei	Formulated from dried calyxes of Hibiscus sabdariffa L. and fresh pineapple. pH 3.7	Initial viable cell counts of > 1010 CFU/mL	30 °C for 30 days and 4 °C for 30 days	> 10 CFU/mL at 30 °C  > 104 CFU/mL at 4 °C		Marius et al. (2023)
Beetroot (Beta vulgaris)	Lactobacillus plantarum	Beetroot juice fermented with prebiotic carriers (inulin, oligofructose, Nutriose®) and maltodextrin	Applied at 2% m/v with starter cultures (109 CFU/mL). Fermentation was conducted at 35 °C	–			Brzezowska et al. (2023)
Apple (Malus domestica)	Lactobacillus plantarum and Lactobacillus acidophilus	Apple Juice with phenolic content and antioxidant capacities during refrigeration. Specific changes to chlorogenic acid, ester, and ketone	pH adjusted to 5.0. Inoculated with probiotics to final counts of 107 CFU/mL. Incubated at 37 °C for 48 h	Stored at 4 °C for 28 days	Decreased by 2.1 (Lp90) and 1.6 (La85) log CFU/mL during refrigerated storage	> 106 CFU/mL	Wu et al. (2023)
Broccoli (Brassica oleracea)	Pediococcus pentosaceus	pH 5.8	37 °C for 36 h	During fermentation, samples were collected and stored at − 20 °C until analysis	> 107 CFU/mL	–	Park et al. (2023)
Orange juice	Lactobacillus acidophilus	pH 3.5	–	Stored at 4 °C for 21 days	> 107 CFU/mL	–	Kardooni et al. (2023)
Parmentiera acuelata juice	L. plantarum subsp. plantarum; L. paracasei subsp. paracasei	TSS: 11% (RS: 9%); Titratable acid: 0.16% (citric) and 0.25% (lactic)	Initial pH: 4.0; 72–120 h fermentation resulted in pH change to between 3.28 and 3.35, titrable acid of up to 0.69%	4–6 °C	L. plantarum 1.36 × 109 cell/mL, L. paracasei 4.94 × 108 cel/mL	–	Lara-Cervantes et al. (2022)

The emergence of plant-based probiotic foods provides a promising alternative for individuals with dietary restrictions, offering significant health benefits. Traditional fermented vegetable-based products, such as kimchi and sauerkraut, have been consumed for centuries across cultures, contributing to both flavor diversity and nutritional value. Furthermore, pickles, kombucha, and probiotic fruit juices represent modern adaptations of these ancient practices, offering convenient and healthful options for consumers seeking gut-friendly choices.

Health and nutritional benefits

Probiotics have been proven to provide numerous vital health benefits. These benefits mainly stem from the maintenance of a healthy balance of gut microbiota (Craig et al., 2021; Márquez-Morales et al., 2021; De Oliveira et al., 2023), which minimizes disease risks and alleviates disease symptoms, such as those from irritable bowel syndrome (IBS) (Satish Kumar et al., 2022). Probiotics also enhance the body’s immune response, making it more effective in fighting infections (Al-Ghazzewi and Tester, 2014; Lee et al., 2017). A study by Wei et al. (2024) explored the potential of fermented tomatoes to combat obesity in mice with a high-fat diet. The results showed that mice fed with fermented probiotic tomato (Live Fermented Tomato—LFT) significantly reduced body weight gain by over 40% compared to the high-fat diet group after nine weeks of administration. This suggests that Live Fermented Tomato significantly impacted weight reduction, indicating potential benefits in body weight management. In addition, fermented tomatoes had a notable effect on the intestinal microbiome of mice. It inhibited the growth of bacterial genera associated with obesity, such as Clostridium and Olsenella, while promoting the development of beneficial genera, such as Roseburia and Coprococcus. These changes in the microbiota were correlated with reductions in body weight and adverse biochemical indicators.

Certain types of probiotics can improve nutrient absorption by the body, thereby increasing the bioavailability of nutrients (Sheridan et al., 2014). Probiotics can also produce substances that prevent the growth of harmful bacteria, lowering the risk of infections (Khan Laghari et al., 2023). They can positively impact metabolic processes, reducing the likelihood of obesity (Laue et al., 2023) and type 2 diabetes (Li et al., 2016). Table 5 summarizes the main probiotic microorganisms, highlighting their proven benefits and examples of commercial products manufactured using these strains.

Table 5.

Probiotic microorganisms and their diverse health benefits: insights from clinical studies

Health benefits	Microorganisms	Source	Essays	References
Prevents infections in the respiratory tract	Bifidobacterium, L. acidophilus	Commercial product (Ecotec™)	Patients hospitalized with severe respiratory infections	Khan Laghari et al. (2023)
Reduction of in-hospital deaths of myocardial infarcted patients	B. longum, L. acidophilus, E. faecalis	Triple viable capsule (Shanghai Xinyi Pharmaceutical Co.)	Reduction of mortality of infarcted patients caused by intestinal disorder	Chen et al. (2023)
Reduction of abdominal fat	L. fermentum	Commercial strains provided from Centro Sperimentale del latte, Italy)	Treatment of overweight patients with metabolic syndrome	Laue et al. (2023)
Reduction of stress	L. paracasei, L. plantarum, L. brevis	Fermented drink (Aguamiel)	Reduction of stress in students by consumption of fermented beverage	Márquez-Morales et al. (2021)
Hormonal balance	B. bifidum, B. lactis, L. acidophilus, L. brevis, L.casei, L.salivarius, L. lactis	Sanprobe® Barrier	Hormonal balance of perminopausal and postmenopausal women	Szydłowska et al. (2021)
Treatment of encephalopathy	C. butyricum, B. infantis	Sanprobe® Barrier	Patients with HBV-induced liver cirrhosis	Xia et al. (2018)
Improvement of immunity system	L. paracasei ssp. paracasei, B. animalis ssp. lactis, L. plantarum	Dairy yogurt	Blood analysis of patients consuming probiotic yogurt every day	Lee et al. (2017)
Improves skin health	B. bifidum, L. acidophilus, L. casei, L. salivarius	Probiotik® Pur	Treatment of children with atopic dermatitis	Yeşilova et al. (2012)
Aliviates constipation in late pregnancy	Probio M8 and Probio M9	Probio-M8/M9	Sows in late gestation	Ma et al. (2023)
Treatment of liver injuries	L. plantarum	Several sources	Treatment of mice with D-galactose-induced aging	Xia et al. (2024)
Treatment of intestinal inflammations	L. plantarum	Pasteurized milk	Treatment of mice with acute and tracolimus colitis	Emília et al. (2018)
Treatment of osteoporosis	L. paracasei, L. plantarum	Commercial strains provided from the Food Industry Resource and Development Institute (Taiwan)	Treatment of ovariectomized-induced oteoporosis	Yang et al. (2020)
Alleviates constipation	L. plantarum	Commercial strains provided from China Center For Type Culture Collection (China)	Treatment of carbon-induced constipations in mice	Ma et al. (2023)
Anti-Alzheimer	L. plantarum	Commercial strains provided from IMTech (India)	Treatment of Alzheimer’s disease induced mice	Nimgampalle (2017)
Hypoglycemic activity	L. plantarum	Commercial strains CCFN0236	Type II diabetes mice	Li et al. (2016)

Combining probiotics with plant-based foods can enhance digestive processes and overall health, leveraging the synergistic effect of probiotics with the abundant fiber in plant foods (Kechagia et al., 2013). Whole grains, including oats and barley, have diverse fibers such as cellulose, hemicellulose, and beta-glucans. Probiotics ferment these fibers to yield short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate, which are fundamental in fortifying the intestinal mucosa and mitigating inflammation (Tosh and Bordenave, 2020).

Inherent anti-nutrients often impede the absorption of minerals from plant-based foods. For example, while spinach is calcium-rich, its oxalate content can inhibit calcium absorption (Melse-Boonstra, 2020; Petroski and Minich, 2020). However, fermentation is a valuable method to increase mineral bioavailability, which degrades anti-nutritional compounds like phytates. Consequently, fermented legumes such as lentils and chickpeas promote enhanced assimilation of minerals like iron and zinc compared to their non-fermented counterparts (Gupta et al., 2015; Nkhata et al., 2018). Fermenting grains, such as in sourdough bread, and vegetables, like in fermented carrot sticks, increase mineral accessibility. For instance, the fermentation of beans, rich in iron but with phytate inhibitors, can be optimized using specific probiotics to reduce anti-nutrient content, facilitating mineral assimilation and improving sensory attributes (Lopez et al., 2003; Samtiya et al., 2021; Sokrab et al., 2014; Xiang et al., 2019).

Several probiotic strains, including Lactobacillus reuteri and Lactobacillus fermentum, synthesize B-complex vitamins, boosting the nutrient profile of plant-derived foods (Latif et al., 2023). This endogenous production by probiotics synergistically enhances the benefits of plant foods; these ubiquitous compounds of plants, such as antioxidants, fiber, and phytochemicals, combat free radicals, mitigating oxidative stress and cellular damage, thereby promoting overall health and well-being (Tosh and Bordenave, 2020). Probiotics may also reduce the propagation of harmful bacteria (Raheem et al., 2021). Moreover, the phytochemicals in many vegetables enhance the immune response and exhibit anti-inflammatory properties (Park et al., 2023; Rahaman et al., 2023). Integrating these nutrients with probiotics yields a synergistic benefit for immune health (Lillo-Pérez et al., 2021).

The gut-brain axis, a subject of increasing research focus promoted by probiotics, may be presented as a benefit of balanced probiotic consumption (Carabotti et al., 2015). By promoting a healthy intestinal environment that supports communication with the brain, incorporating such dietary elements can optimize the gut-brain axis, potentially offering cognitive benefits (Filosa et al., 2018; Liu et al., 2023; Verduci et al., 2020).

Moreover, naturally rich in antimicrobial compounds like allicin, plant foods like garlic can strengthen this defensive barrier (Ding et al., 2023; Sasi et al., 2021). Thus, a combined dietary intake of such plant foods and probiotics can bolster the body’s defense (Banerjee et al., 2023; Tegegne and Kebede, 2022). Finally, by producing organic acids and flavor-enhancing compounds, probiotics improve fermented products’ palatability and nutritional quality, aligning with consumer preferences for nutritious and flavorful options (Parvez et al., 2006; Soemarie et al., 2021).

Plant-based probiotics offer a promising avenue for enhancing gut health and overall well-being. A study conducted by Abdel Tawab et al. (2023) investigated traditional fermented foods sold in Egyptian markets to identify potential probiotics. The products analyzed were soy sausage, whole soy, and pickles, which contained lactic acid bacteria (LAB) strains with probiotic properties. Four strains were identified: Enterococcus faecium, Enterococcus lactis, Enterococcus massiliensis, and Lactiplantibacillus plantarum. Enterococcus massiliensis, isolated from soy sausage, demonstrated broad therapeutic potential, including resistance to bile salts and extreme pH conditions crucial for gastrointestinal survival. These strains also exhibited resistance to high salt concentrations and significant antimicrobial activity. Importantly, they were safe for consumption, showing no hemolysis in sheep erythrocytes and proving safe in rat experiments. These strains also displayed significant antioxidant activity, highlighting their therapeutic value.

While in vitro studies provide valuable insights, human clinical trials have also demonstrated the efficacy of plant-based probiotics (Juntunen et al., 2001). For probiotics to be considered adequate, they must survive the harsh conditions of the digestive system, including gastric acidity, digestive enzymes, bile toxicity, competition with intestinal flora, peristalsis, and antimicrobial agents. The concentration of probiotics necessary for efficacy is often cited as 10⁶ to 10⁷ colony-forming units per milliliter (CFU/mL) or higher. This ensures viable microorganisms reach the intestine after traversing the gastrointestinal tract (Lee and Bak, 2011). Thus, plant-based probiotics offer a promising avenue for improving gut health and overall wellness, supported by scientific research and clinical evidence.

Synthesis of plant-based probiotics

The production of PBPFs, such as sauerkraut, kimchi, kombucha, pickles, and probiotic juices, involve distinct fermentative processes, each with its specific characteristics. These processes can occur either in solid or liquid substrate fermentation. Foods like sauerkraut and kimchi undergo solid substrate fermentation, where the vegetable is chopped and submerged in a saline solution. Salinity is a limiting factor in controlling unwanted microorganisms’ growth and promoting probiotic strains’ development in this process. Kombucha and probiotic beverages undergo liquid substrate fermentation, where sweetened tea or fruit/vegetable juice is a substrate for microbial activity (Siddiqui et al., 2023). These processes usually occur in hermetic or semi-hermetic containers to prevent contamination by external microorganisms. Regardless of the fermentation type, the probiotics in the foods degrade complex nutrients into simpler compounds during fermentation. This produces metabolites, such as organic acids, enzymes, and other bioactive compounds, contributing to these foods’ flavor, aroma, and nutritional characteristics. During fermentation, various parameters are controlled to optimize the growth and activity of these microorganisms, including temperature, pH, oxygen presence, fermentation time, and contamination control (Chong et al., 2023; Xiang et al., 2019).

Each food has its specificities regarding these parameters, and precise control is essential to ensure the viability of probiotics and the quality of the final product. For example, sauerkraut, obtained by fermenting chopped cabbage in water and salt, undergoes fermentation at an ideal temperature ranging between 18 and 22 °C, with a pH maintained between 3.6 and 4.0. Oxygen presence is not required as the process is predominantly anaerobic, with predominant microorganisms like Lactobacillus and Pediococcus naturally present in the raw material. The salt concentration in the fermentation solution is essential as it inhibits contaminating microorganisms and enhances the texture of cabbage, typically around 2 to 2.5% (w/w). During fermentation, lactic acid (up to 2% w/w) and acetic acid (up to 0.5% w/w) are produced, which are the primary acids responsible for the flavor and preservation of sauerkraut. The fermentation time varies from 1 to 4 weeks, depending on fermentation conditions and final product requirements (Jansone et al., 2022; Wang et al., 2024; Wiander and Palva, 2008).

In the kimchi fermentation process, the ideal temperature ranges between 10 and 15 °C, with pH maintained between 4.2 and 4.5. Similar to sauerkraut, kimchi is fermented predominantly under anaerobic conditions, with microorganisms like Lactobacillus and Pediococcus naturally present in the vegetables used. During fermentation, lactic acid and acetic acid are produced, contributing to flavor and preservation. The average concentration of these acids varies, usually between 0.5 and 1.5% (w/w) for lactic acid and between 0.2 and 0.5% (w/w) for acetic acid. The salt concentration in the fermentation solution is generally around 2 to 3% (w/w) (Choi et al., 2018). Industrial fermentation time for kimchi may vary, being precisely controlled to ensure consistency and quality of the final product. However, on average, the fermentation process ranges from days to weeks, depending on the specific process used by the company and desired product characteristics.

During kombucha fermentation, the ideal temperature ranges between 24 and 30 °C, with pH maintained between 2.5 and 3.5 (Cohen et al., 2023). Similar to sauerkraut and kimchi, kombucha fermentation occurs in an anaerobic environment, although there may be a small amount of oxygen present due to exposure to air during the process. Microorganisms like Acetobacter, Brettanomyces, Saccharomyces, and various other strains are crucial in fermentation. While yeast metabolizes the sugar in the tea, it produces ethyl alcohol and carbon dioxide through anaerobic fermentation. Subsequently, Acetobacter bacteria oxidize alcohol to form acetic acid, responsible for kombucha’s characteristic flavor (Bishop et al., 2022b). Some bacteria, such as Lactobacillus and Bifidobacterium species, are considered probiotics, contributing to intestinal health when consumed. The initial sugar concentration in the fermented tea may vary depending on the recipe but is usually between 5 and 15% (w/v). The average ethanol concentration in ready-to-consume kombucha usually ranges between 0.5 and 2% (v/v), although variations may vary depending on the fermentation process and ingredients used (Bishop et al., 2022b; Jayabalan et al., 2014; Kim et al., 2020). This process can be carried out in a static culture or controlled aeration. Although limited oxygen presence can be tolerated, it is essential to minimize air exposure to avoid contamination by contaminating microorganisms. Kombucha fermentation time varies from 7 to 14 days, depending on fermentation conditions and desired flavor, being controlled to ensure consistency and quality of the final product (Vitas et al., 2019).

For pickle preparation, especially with cucumbers, carrots, onions, and cauliflower, the ideal fermentation temperature ranges between 18 and 22 °C, with a pH below 4.0. Similar to sauerkraut, kimchi, and kombucha, fermentation occurs under anaerobic conditions. Microorganisms responsible for this process, such as Lactobacillus, Leuconostoc, and Pediococcus, are naturally found on the surface of the vegetables used, forming part of the natural microbiota of these foods (Alan, 2019). Thus, commercial inoculants are not required. The salt concentration, usually between 2 and 5% (w/w), controls the growth of unwanted microorganisms. The fermentation time can also vary from a few days to weeks, depending on the vegetable and desired flavor, as acetic acid and lactic acid are produced, giving the characteristic flavor and preserving the vegetables. Fermentation is carried out in airtight containers to minimize oxygen exposure.

Probiotic vegetable beverages, as mentioned, are produced by fermenting fruit or vegetable juices (Yang et al., 2018). The ideal temperature for producing these beverages ranges between 18 and 25 °C. The pH must be maintained between 3.5 and 4.5 to ensure an environment conducive to the growth of probiotic microorganisms. To initiate the fermentation process, specific strains are added as inoculum, such as Lactobacillus, Bifidobacterium, Streptococcus, and other lactic acid bacteria, at a concentration usually between 10⁶ to 10⁸ colony-forming units (CFU) per mL (Garcia et al., 2018). During fermentation, other organic acids, such as acetic acid and citric acid, are produced in varying amounts, usually around 0.1% to 0.5% (w/w) for acetic acid and 0.05% to 0.2% (w/w) for citric acid (Patelski et al., 2024). Bioactive metabolites, such as polyphenols, B-complex vitamins, digestive enzymes, and prebiotics, are also synthesized. These compounds can improve digestion, strengthen the immune system, and promote intestinal health (Popova et al., 2024). Additional parameters, such as fermentation time (which can range from 24 to 72 h), agitation or mixing during the process, post-fermentation storage conditions (usually refrigerated at 4 °C), residual sugar content (typically below 2%), and monitoring of microbiological activity (since microorganisms must be viable at the time of consumption), are essential to ensure the quality and consistency of the final product (Mantzourani et al., 2020).

Plant-based probiotics and sustainability

In recent years, the adoption of plant-based diets has risen, driven by health considerations and increasing consumer awareness of the environmental implications of dietary choices (Küçükgöz and Trząskowska, 2022; Polyak et al., 2023). When analyzing the global food industry, the difference between the environmental impact of foods of animal origin and plant origin foods is significant (Polyak et al., 2023). Also, as a primary source of greenhouse gas emissions, agriculture has significantly contributed to climate change (Cederberg et al., 2011), and the production of foods of animal origin, such as meat and dairy products, imposes a substantial environmental burden.

Plant-based foods require significantly less land and generate fewer greenhouse gas emissions (Polyak et al., 2023). Also, concerning water usage, producing 1 kg of beef requires approximately 15,000 L, whereas producing the same amount of beans requires only about 2000 L (Rodrigues Junior and Dziedzic, 2021). Even the roughly 5000 L of water required to produce 1 kg of soybeans is still significantly less than that needed for beef, highlighting the efficiency of plant production regarding water resources (de Albuquerque Nunes et al., 2021). This disparity in water use is particularly concerning given the growing water crises in various regions worldwide, such as the Brazilian semi-arid region (Morante-Carballo et al., 2022).

Another example of negative environmental impact is the effluents generated by dairy factories. They have a high organic load due to the presence of components such as lactose, proteins, and other milk residues (Küçükgöz and Trząskowska, 2022). When inadequately treated, they can harm whole aquatic ecosystems through anaerobic decomposition that depletes oxygen from water bodies. Also, intensive agriculture affects our atmosphere and directly impacts biodiversity (Ortiz et al., 2021). Farm runoff, containing waste and agrochemicals, can flow into rivers, creating dead zones in areas like the Gulf of Mexico, where marine life is drastically reduced (Tallis et al., 2019; Xu et al., 2022). More sustainable farming practices linked to a plant-based diet, such as syntropic farming, which integrates various plants within the same space, can help maintain soil fertility, increase water retention capacity, and reduce erosion (O’Donoghue et al., 2022).

Within this context, producing plant-based probiotic foods to replace traditional fermented animal-based foods partially appears to be a promising alternative that addresses many of these environmental problems. In terms of production, these foods require significantly fewer resources (Küçükgöz and Trząskowska, 2022; Polyak et al., 2023). Growing plant substrates for probiotics, such as grains and legumes, is less water and land-intensive and has lower greenhouse gas emissions. Also, they are not associated with the effluent challenges found in dairy production (Senanayake et al., 2023).

In addition to issues related to pollution, opting for probiotic products from plant sources also reflects a growing consumer awareness of sustainability. These foods generally have a smaller carbon footprint, less impact on land use, and less contribution to land degradation and biodiversity loss. These foods are tangible solutions to the ecological challenges associated with food production (Serra-Majem et al., 2020).

Market trends in plant-based probiotic foods

Examining the historical period of 2017–2021, the global plant-based probiotics market demonstrated a Compound Annual Growth Rate (CAGR) of 5.1%, according to a detailed industry analysis by Fact.MR is a leading market research and competitive intelligence provider. The sector is predicted to have achieved a valuation of US$ 890.1 million in 2022, and it is on track to show an accelerated growth of 6.7% CAGR in the next decade (Fact. MR, 2023). This growth is expected to drive the market to reach US$ 1.7 billion by the end of 2032. In the current and short-term period (2022 Q2 to 2025), consumer awareness of the health benefits and disease mitigation potential of PBPFs is predicted to increase significantly, which is likely to drive market expansion in the short term. At a medium-term scale (2025–2028), the market for plant-based probiotics is set to be fueled by an even further increase in awareness, rising disposable incomes, and improved quality of life. Concurrently, higher consumer spending and an expansion in product logistics and distribution due to the ongoing optimization of manufacturing activities in the food and beverage industry are also expected to drive the market expansion. In the longer term (2028–2032), investments by key market players in Research and Development (R&D) activities to develop efficient plant-based probiotics are expected to play a significant role in this expansion.

Several examples of probiotic plant-based foods have been arising in the worldwide market. Probiotic foods in the US include Bacillus coagulans-infused kombucha, fermented raw and energy bars, cashew-based yogurts, fermented potato chips, and sauerkraut with different probiotic sources (Herkenhoff et al., 2023; Yang et al., 2019). The Canadian company Lightlife primarily focuses on plant-based proteins and has some fermented products, including Lactobacillus fermentum. In the UK, Biona is a substantial market player in this area with fermented pickles and sauerkraut, rich in Lactobacillus casei. Biotiful Dairy has also launched similar products, such as plant-based kefirs and probiotic smoothies containing Bifidobacterium lactis. Zuivelhoeve manufactures coconut-based probiotic yogurts in the Netherlands using a mix of Bifidobacterium and Lactobacillus. Japan’s Morinaga stands out with its “Aloe Yogurt”, a plant-based yogurt made primarily of aloe vera, a component known for its health benefits, and enriched with Bifidobacterium breve (Al-Taif et al., 2022). South Korea’s Pulmuone keeps the tradition alive with its kimchi options, which frequently contain Lactobacillus sakei. Australia’s Peace, Love & Vegetables brand offers superkrauts enhanced with Lactobacillus acidophilus and other flavors. In South America, Brazil presents “A Tal da Castanha”, which has diversified the market with cashew nut-based yogurts rich in Lactobacillus paracasei and Lactobacillus rhamnosus, providing a tropical alternative to traditional yogurt based on a raw material that is widely available locally.

The market for plant-based probiotics has a promising future, with higher revenues expected due to the growing awareness of gut health and increased adoption of plant-based diets (Alcorta et al., 2021; Markowiak and Śliżewska, 2017; Polyak et al., 2023). As the demand for these products increases, there is a great potential for them to become standard choices among consumers. To achieve widespread acceptance in the future, it is essential to communicate the benefits, flavor, and texture science innovations more transparently and develop consistent consumer education initiatives.

Challenges and opportunities in the plant-based probiotic food sector

The field of plant-based probiotic food is rapidly growing and holds significant potential to become a significant part of the food industry. However, research efforts, industry innovations, and government policies must address several challenges to improve market value and feasibility.

The heavy global reliance on soy for producing PBPFs is a significant concern due to its relatively high carbon footprint compared to similar vegetable crops. The soy production is associated with approximately 0.8 kg of CO₂-equivalent emissions/kg of soy that can be traced back to land-use changes, deforestation, transportation, and other energy-intensive agricultural practices (Escobar et al., 2020). Additionally, soy poses risks of allergenicity and contributes to deforestation, particularly in regions like Brazil, where a 300% increase in demand over the past decade has led to half of the recent deforestation (De Maria et al., 2020).

Finding alternatives to soy-based plant-based foods is essential to moderate the environmental impact of heavy reliance on soy production. While soy is a prevalent ingredient in many plant-based products, its drawbacks, such as allergenicity risk and contribution to deforestation, highlight the need for diversification in plant sources. Exploring and promoting alternative vegetable crops with lower carbon footprints and less environmental impact can help alleviate pressure on soy production and reduce deforestation rates. Additionally, investing in research and development to identify and optimize cultivation practices for underutilized crops can expand the range of available plant-based ingredients, providing consumers with more sustainable options while fostering biodiversity and environmental conservation.

More advanced applied research will also be essential for improvement in probiotic efficiency. For example, encapsulation techniques can be utilized to protect probiotics from the harsh conditions of the digestive system. Microencapsulation, involving a protective coating made of alginate or gelatin, shields the probiotics, ensuring their survival until they reach the intestines, where they can exert their health benefits (Etchepare et al., 2015). Continued research and technological advancements are needed to refine existing methods and develop new ones, optimize strains, explore alternative growth substrates, and create additional encapsulation strategies to meet the demands of the probiotics market.

Also, due to traditional beliefs, probiotic foods derived from plant sources are not yet widely accepted globally. Many consumers may not be familiar with these new options or even question their benefits. Nearly half of U.S. consumers are interested in probiotic products, but a quarter are still unsure about their specific benefits (Latif et al., 2023). As mentioned, education and awareness are crucial (Pimentel et al., 2021). Consumers, in general, are unaware of studies (Küçükgöz and Trząskowska, 2022; Shori and Al Zahrani, 2022) that demonstrate that plant-based probiotics in sauerkraut or kimchi offer benefits similar to those of probiotics derived from dairy products concerning intestinal health. In-depth education campaigns that highlight such research can override the initial skepticism observed.

Furthermore, in many markets globally, the higher price of plant-based probiotic products, due to their specialized production process and often organic ingredients, can deter a wider acceptance among consumers with lower purchase power (Bryant and Sanctorum, 2021). While the health benefits of probiotics are widely recognized, consumer acceptance is significantly influenced by the sensory experience of probiotic-rich products. Off-flavors, for example, are a common concern in fermented foods that can arise due to metabolic by-products of probiotic bacteria or the fermentation process (Luckow et al., 2006). Consumers have widely reported lower acceptance levels of soya-based foods due to a ‘beany’ aroma and an ‘artificial’ or ‘bland’ taste (Giacalone et al., 2022). Overcoming these off-flavors necessitates research efforts, from meticulous strain selection to more thorough fermentation control to enhance probiotic products’ palatability.

Furthermore, texture and flavor considerations are intricately linked to marketing strategies and cultural perceptions. Effective communication about the diverse strains and their benefits and culturally tailored product formulations can influence and shift consumer preferences (Grumet et al., 2020). The balance between these sensory aspects and the educational component in marketing campaigns becomes crucial for fostering widespread acceptance of probiotics across diverse consumer segments and cultural contexts. Continuous innovation in product development, coupled with strategic marketing approaches, is essential to align the sensory attributes of probiotics with consumer expectations, ultimately enhancing their overall acceptance in the market. More novel PBPFs, such as cashew or coconut-based products, offer different sensory experiences than traditional yogurts. This change may require an adaptation period on the part of consumers (Appiani et al., 2023; Montemurro et al., 2021). Companies like the Forager Project (USA) are already working in this direction, adapting the flavor and texture of their cashew-based yogurts to resemble dairy options.

Additionally, the regulatory landscape for probiotics varies across countries, reflecting diverse approaches to overseeing the marketing and sale of these products. While some countries already have some regulations regarding PBPFs, others have lagged, and the sector still falls under the umbrella of other broader segments (‘beverages’ or ‘dairy products,’ for example). Legislation on fermented, plant-based probiotic products is even more scarce.

The Food and Drug Administration (FDA) oversees probiotics categorized as dietary supplements in the United States, but formal pre-market approval is not required. It is also important to highlight that regulations may vary across states and are subject to State laws, apart from the overarching Federal-level laws. In Regulation 21 CFR 131.200, which defines yogurts, probiotic bacteria are considered additives. Regulations for non-dairy probiotic foods are not always specific. For example, if Kombucha is brewed to contain 0.5% alcoholic content and above, the product is subject to the Federal Alcohol Administration Act, and it may be classified as “beer”.

Abroad, such as in the UK, the Food Standards Agency (FSA) is responsible for the general and country-specific food regulations. Following its relatively recent departure from the EU, the country has been working on its legislation but has retained some previous EU regulations. Using the term “probiotics” is considered a health claim and, therefore, falls under the “Nutrition Law”, partially equivalent to the EU Regulation (EC) 1924/2006. In Europe, the European Food Safety Authority (EFSA) regulates probiotics as food supplements, with stringent criteria for health claims and adherence to general EU regulations (e.g., Regulation (EC) No 178/2002). PBPFs are likely to fall under the regulation for novel foods (Regulation (EU) 2015/2283), especially when health claims are made. Australia, in turn, treats probiotics as ‘therapeutic goods,’ subject to registration and safety standards set by the Therapeutic Goods Administration (TGA). In Brazil, the National Health Surveillance Agency (ANVISA) plays a fundamental role in ensuring that probiotic supplements adhere to safety and quality standards. Probiotic foods and drinks are subject to RDC 241/2018, a regulation complementary to RDC 18/1999, which sets the standards for health claims and functional properties of foods. In China, the China Food and Drug Administration (CFDA) regulates probiotics, and companies must obtain approval before marketing their products.

While it may be challenging for countries around the world to fully agree on legislation governing PBPFs and plant-based fermented beverages in terms of quality and safety, it is essential to establish clear regulations for their production and distribution. This not only ensures consumer safety within individual countries but also fosters more uniform international trade rules and agreements among nations.

The emergence of probiotic foods from plants is an exciting development for those seeking to maintain good health and promote sustainable food practices. The proven health benefits of plant-based probiotics, coupled with growing awareness of the impact of diets on the environment, underscore the importance of this field. However, several challenges exist, including reducing reliance on soy, addressing environmental concerns and allergies, and establishing consistent global regulations. Research should focus on diversifying probiotic sources and improving encapsulation techniques, while education and marketing efforts aim to increase acceptance and sensory appeal. Standardizing regulations is crucial to ensure product safety and facilitate international trade. Collaboration among researchers, industry players, and governments is essential to overcome these obstacles and encourage the growth of plant-based probiotic foods. Despite these challenges, the potential of this sector to promote health and sustainability makes it a promising frontier. By addressing these challenges and raising consumer awareness, plant-based probiotics can promote individual well-being and environmental responsibility in the global food landscape.

The integration of specific probiotics with plant-based foods, resulting in PBPFs, can provide foods that contribute to well-being, including intestinal health and overall physiological balance. As discussed throughout this review, PBPFs are known to enhance nutrient absorption, inhibit the growth of harmful bacteria, and positively impact metabolic processes. Additionally, they contribute to health benefits such as stress reduction, improved skin health, hormonal balance, and immunity, as well as reducing the risk of obesity and type 2 diabetes. Combining probiotics with plant-based foods also improves the nutritional profile and bioavailability of essential nutrients like minerals and B vitamins, leveraging plant-based foods’ antioxidant and anti-inflammatory properties.

The symbiotic relationship between probiotics and plant-based foods also benefits cognitive health by optimizing the gut-brain axis. The inclusion of antimicrobial plant compounds further strengthens the body’s defenses. Probiotics produce organic acids and flavor-enhancing compounds, improving fermented plant-based products’ palatability and nutritional quality and aligning with consumer preferences for nutritious and flavorful options. Clinical evidence supports the effectiveness of plant-based probiotics in promoting intestinal health, positioning them as a viable alternative to traditional animal-based probiotics. Furthermore, the growing market for plant-based probiotics reflects increasing consumer awareness of intestinal health and the benefits of plant-based diets. However, challenges such as regulatory issues and sensory preferences need to be addressed to fully realize the potential of PBPFs.

Despite facing challenges, the combination of plant-based nutrition and probiotics has the potential to improve individual health and promote environmental sustainability. Plant-based foods require fewer natural resources, produce fewer greenhouse gas emissions, and have a lower environmental impact than animal products. They also support sustainable agricultural practices and reduce reliance on finite resources, aligning with long-term environmental conservation goals. Plant-based foods’ health benefits and positive environmental impacts underscore their role in transitioning to a more sustainable and healthier food system. These factors make plant-based foods strong candidates for a healthy diet soon.

Declarations

Conflict of interest

The authors declare that they have no competing interests.