In recent years, scientific interest in the development of non‐dairy‐based functional foods is increasing progressively and the fermentation of cereals, legumes, fruits and vegetable‐based foods is becoming an important scientific research topic for the production of new probiotic products. In particular, legumes represent a possible alternative to protein foods from animal origins and an adequate fermentation substrate as they contain high amount of nutrients, such as proteins, carbohydrates, fibres, vitamins, and minerals, which are all useful to the growth and metabolic activity of certain microorganisms. This work focuses on the feasibility of developing a dry legume‐based functional product using a fermentation process carried out on a 10% w/v navy bean suspension, in a lab‐scale stirred batch reactor. After soaking and cooking dried navy beans, the fermentation tests performed on the resulting medium using Lactobacillus paracasei CBA L74 showed a maximum bacterial count of 109 CFU/mL after 20 hours and a maximum lactic acid concentration of 1.9 g/L after 16 hours of process time. A freeze‐drying process was performed on the fermented bean suspension, showing a 2‐log microbial reduction and a bacterial viability in the resulting probiotic powder of 3.7 × 108 CFU/g.

Cereals are becoming interesting substrates to be fermented to obtain new functional foods. For this reason, an enzymatic pretreatment of a wheat flour suspension using amylase was investigated in order to guarantee the feasibility to ferment a cereal‐based substrate at a solid content higher than that used in past experimentations. Trials with and without amylase pretreatment, using a 52% w/v wheat flour water suspension, were carried out to evaluate the fermentation feasibility; mixing tests with a food dye were performed to verify the suspension homogeneity. The pretreated suspension, whose starch was hydrolyzed for about 80% by α‐amylase, was then fermented (37°C, 24h) by Lactobacillus paracasei CBA‐L74. Starting from pH value 5.75, microbial concentration 1.89 × 106 CFU/ml and lactic acid 0 mg/L, final values of 3.93, 3 × 108 CFU/ml and 6,251 mg/L were found after 24 hr of fermentation. The untreated suspension went to gelation and was impossible to ferment because its consistency was like a dough and the mixing system was not suitable to ensure mixing. Practical applications The aim of the present study was the handling and the fermentation of cereal‐based substrate at high solid content (52% w/v), through a preliminary amylase pretreatment. The fermentation of such a solid content could guarantee the production of a greater quantity of solid fermented matrix and this could considerably reduce drying times with greater productivity at a low cost.

Studies of the ability of probiotics to ferment cereal flours are necessary to obtain products with enhanced nutritional value. In this study, Lactobacillus paracasei CBA-L74 was used to ferment cereal aqueous mixtures containing both oat (7.5% w/v) and rice flours (7.5% w/v), with and without glucose, to understand whether glucose addition could have any effect on growth and metabolism. Viability, pH, metabolites production during fermentation (24 h, 37 °C) and substrates reduction were analysed. The strain showed good growth in the cereal aqueous mixture both with and without glucose addition, but suspensions prepared with glucose showed the best results. A bacterial concentration of 7 log CFU mL −1 , a pH value of 4.70 and lactic acid production of 1250 mg L −1 were achieved when fermentation was performed without glucose addition, while in the presence of glucose, a t 24 bacterial growth of 8 log CFU mL −1 was reached, with a pH value of 3.11 and lactic acid production of 6050 mg L −1 .

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