Temperature-dependent growth kinetics of Lacticaseibacillus rhamnosus GG in oat-based milk alternative

Zuzana Matejčeková ^*, Tamara Čmiková ^a, Pavel Ačai ^b, Ľubomír Valík

Department of Nutrition and Food Quality Assessment, Institute of Food Science and Nutrition, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 812 37 Bratislava, Slovakia
^a Department of Food Technology, Institute of Food Sciences and Nutrition, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 812 37 Bratislava, Slovakia
^b Department of Food Technology, Institute of Food Sciences and Nutrition, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 812 37 Bratislava, Slovakia

E-mail: ^* zuzana.matejcekova@stuba.sk

Abstract: The microbial growth responses of probiotic Lacticaseibacillus rhamnosus GG with well-documented health effects were studied in an oat-based milk alternative in a biokinetic temperature range of 8 to 44 °C. The applied Baranyi model (with a fixed parameter value h₀ = 0.407) fitted the growth data well, as shown by the goodness of fit measures (R² = 0.995; RMSE = 0.153) for the total experimental data set (n = 245). Using the initial inoculations of 2.7 ±0.1 log CFU.ml^-1, the maximal population density (MPD) of 8.3 ±0.4 log CFU.ml^-1 was reached in stationary phase in the temperature range from 12 to 37 °C. Slightly lower MPDs were recorded at the higher temperatures 40 and 44 °C, while at 8 °C only increase in 1 log was reached. Thus, the MPD 3.7 log CFU.ml^-1 was only estimated. Based on the experiments, the highest specific growth rate (µ_max) of 0.800 h^-1 and the shortest lag phase (λ) of 0.51 h were observed at 40 °C. The Ratkowsky modified square root model (mSQRT) was used in the secondary modelling for µ_max values and the following cardinal parameters, the minimum and maximum temperature, were determined: T_min = 4.2 °C; T_max = 47.8 °C. As drinks of plant origin are produced in large volumes, the production of their fermented varieties will appear in a short time. This is why providing parameters on kinetic behaviour of L. rhamnosus GG might be essential for industrial process design and further scale up of fermented dairy-free matrice with a probiotic potential.

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Acta Chimica Slovaca, Vol. 18, No. 1, 2025, pp. 24—31, DOI: 10.2478/acs-2025-0003

© 2025 Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava