Ohmic heating for attenuation of Lactobacillus acidophilus LA-5 in Minas Frescal cheese: probiotic survival, biological activity, and in vitro antimicrobial activity

Abstract

This study evaluated the effect of ohmic heating (OH) at different electric field intensities (4, 6, and 8 V/cm) on the attenuation of Lactobacillus acidophilus LA-5 and its subsequent influence on the quality and functionality of Minas Frescal cheese. Five formulations were manufactured: control without probiotic (C1), with probiotic (7–8 log CFU/g, PROB), and with attenuated cells (OH4, OH8, OH12). Cheeses were evaluated over 14 days for pH, proteolysis, probiotic viability, gastrointestinal survival, metabolite production, functional properties (antioxidant, antihypertensive, antidiabetic), and antimicrobial activity. Attenuation via OH preserved cell viability (>6 log CFU/g) and enhanced proteolysis and functional activities compared to C1 and PROB. Furthermore, it reduced organic acid production, especially at higher intensities (OH8 and OH12). Notably, OH4 maintained moderate antimicrobial comparable to the PROB. These findings demonstrate that OH is a promising strategy for modulating probiotic metabolism while maintaining viability, enhancing bioactivity, and improving the nutritional and functional quality of probiotic cheeses. This approach supports the development of functional dairy products with extended shelf life and health-promoting attributes.