and textural improvement of fermented plant-based products. A wide variety of plant-based substrates (i.e., bases) with different compositions are currently being studied [1; 8] with the goal of mimicking the functionality of dairy milk. Soybean has dominated for the past decades [1; 9], but the portfolio of plant-based raw materials for plant-based fermented products has expanded into other legumes, nuts, seeds, pseudocereals, and cereals [2]. Soy [2; 3; 10], oat [11], and coconut [12] are some of the most popular substrates due to their nutritional value and/or their physicochemical properties. Soy milk has the highest protein content among all plant-based milks (2.5-3.1 g per 100 mL [13]), and its amino acid profile resembles the one from bovine milk [14]. It contains lower saturated and higher mono- and polyunsaturated fat content than dairy milk [13]. However, storage globulins in soy are considered to be allergens [15], one of the reasons for consumer rejection. Soybeans also contain a high amount of galactooligosaccharides (GOSs), mainly raffinose and stachyose [16]. They are considered non-digestible oligosaccharides (NDOs) due to an absence of a galactosidase in human intestine [17]. For this reason, soy has gained bad reputation for generating bloating and gastrointestinal disorders [16]. Fermentation with lactobacilli has been proven to metabolize soy oligosaccharides [18]. Acidification of commercial soy drinks down to pH 3.5 after 48 h of fermentation at 37 \({}^{\circ}\)C has been reported [19]. Fermentation also contributes to the rheological characteristics of soy-based gels, as shown in numerous studies [20; 21]. Soy protein gelation is the main feature in fermented soy gels [22] and it is affected by different factors, such as globulin (ZS and 11S) ratios [23] in protein-polysaccharide blends and molecular weight of polysaccharides [22]. In addition, gelation of soy proteins can also be induced by enzymes. Transplantaminase induced soy protein gelation for plant-based yogurt with encapsulated probiotics [24]. Previous studies suggested that soy protein could have a similar isoelectric point to casein [25; 26] and its high gelation potential [22] could be influenced by its endogenous peptidases. [27]. Moreover, combinations of bacterial strains could influence soy gels rheological properties. For instance, higher viscosity was observed with binary cultures fermentation, specifically with a combination of L. acidophilus and L. plantarum [25]. Fermented soy is associated with a characteristic beauty flavor caused by lipid oxidation products (mostly pentanal and n-hexanal [28]). This limits its acceptance in accidental cultures. However, this can be overcome using different methods, such as pulse electrification or lipoxygenase treatment [29]. Oats have lately gained popularity due to their high nutritional value [30]. Their dietary fibers, specifically soluble fibers \(\beta\)-glucans found in the endosperm cell walls, are considered prebiotics. They serve as feed for the intestinal microflora, promoting bacterial growth during fermentation [31]. \(\beta\)-glucans also contribute to a regulation of satiety levels [32] and act as thickening agents, increasing product viscosity [33] and avoiding the addition of other functional ingredients or stabilizers [34]. Oat groats contain 15-20% protein [35] with a complete amino acid profile with almost all essential amino acids exceeding human requirements except for lysine and threonine [35]. Oat protein digestibility is generally high [36]. However, commercial oat-based milks present a protein deficiency (\(<\)1 g per 100 mL of product) [3]. This questions their suitability as a substrate for yogurt- and cheese-like products, since proteins are an essential factor for texture formation in fermented materials [22; 27]. Nevertheless, this can be solved with protein supplementation or by preparing a matrix from an oat concentrate.