Article Modeling of lactic acid fermentation of soy formulation with Lactobacillus plantarum HM1 Zuzana Matejc ˇekova ´ 1 , Elena Dujmic ´ 2 , Denisa Lipta ´kova ´ 3 and L ˇ ubomı ´r Valı ´k 1 Abstract Lactic acid bacteria alone or with special adjunct probiotic strains are inevitable for the preparation of various specific functional foods. Moreover, because of their growth and metabolism, the final products are preserved for a certain time. Thus, growth dynamics of the lactic acid bacteria of the Fresco DVS 1010 culture (Lactococcus lactis spp. lactis, Lactococcus lactis spp. cremoris, Streptococcus salivarius spp. thermophilus) during liquid-state fermentation of soya mashes and pH values within the process were analyzed in this study. Although milk is the most typical growth medium for the lactic acid bacteria, presumable viable counts of Fresco culture reached levels 10 9 CFU ml 1 after 8 h, representing 2–3 log increase in comparison to initial state (specific growth rates ranged from 1.06 to 1.64 h 1 ). After 21 days of storage period, the pH levels in the products were reduced to 4.50–4.70, representing a decrease of about 1.5–1.7 units. All prepared soybean products contained detectable amounts of raffinose-series oligosaccharides (0.25–0.68 g per 100 g) that were reduced in average by about 30.5% during period of 21 days. Keywords Soya, fermentation, Lactobacillus plantarum, predictive microbiology, raffinose-series oligosaccharides Date received: 10 April 2018; accepted: 3 September 2018 INTRODUCTION Due to consumer’s demands for healthier foods, the industry is directing development of new products toward the area of functional foods. The concept of functional foods includes foods or food ingredients exerting health benefits beyond the traditional nutrients (Ogunremi et al., 2015). Research in the area of func- tional foods has moved progressively toward develop- ment of dietary supplementation, introducing the concept of probiotics and prebiotics that may affect gut microbial composition (Charalampopoulos et al., 2002; Hasler, 2002). Worldwide, the dairy sector that is strongly linked to probiotics represents for nearly 33% of the broad market (Champagne et al., 2009). This may be a great opportunity for nondairy food and beverage probiotics sector with a diversity of new products expected in the future. Previously, studies are being done to demon- strate that cereals are suitable substrates for the growth of certain probiotic bacteria (Angelov et al., 2006; Kedia et al., 2007; Matejcˇekova´ et al., 2017). Nevertheless, fruit juices, desserts, and legume-based products can also be used featuring probiotics (Petrula´ kova´ and Valı´k, 2015). The soybean plant (Glycine max), as one of the most important crops 1 Department of Nutrition and Food Quality Assessment, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovakia 2 Department of Biochemical Engineering, Faculty of Technology and Biotechnology, University of Zagreb, Pierottijeva, Croatia 3 State Institute for Drug Control, Bratislava, Slovakia Corresponding author: Zuzana Matejc ˇekova ´, Department of Nutrition and Food Quality Assessment, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinske ´ho 9, Bratislava 812 37, Slovakia. Email: matejcekovaz@gmail.com Food Science and Technology International 25(2) 141–149 ! The Author(s) 2018 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1082013218803257 journals.sagepub.com/home/fst