Production of Bio-Improved Butter with Lactic Acid Bacteria Isolated from Traditional Cheese Matrix and Eye Fluid

This study aimed to investigate the effects of Levilactobacillus brevis, Lacticaseibacillus paracasei, and Lacticaseibacillus rhamnosus strains isolated from Mihalic cheese, also known as “weeping cheese”, on fermentation kinetics, microbial viability, and textural and aromatic properties of the butter matrix. The effects of the isolates were determined on acidification kinetics (Vmax, Tvmax, pHvmax), viability proportion index (VPI), textural parameters (firmness, work of shear, stickiness, work of adhesion), and volatile aroma compounds (GC-MS) formation. This study found that the BLR sample containing Lacticaseibacillus rhamnosus maintained its limited viability under acidic stress conditions despite its high fermentation rate and low pHvmax values. The BLP sample containing Lacticaseibacillus paracasei exhibited high viability due to its low acidification rate and limited pH change. Determining the chemical classes to which the aroma compounds in the BLP sample belonged revealed a composition rich in fatty acids. The BLB sample containing Levilactobacillus brevis produced a high ΔpH value and an aroma profile rich in aldehyde compounds. Examination of the macro-structural properties of the butter samples revealed that the sample containing Lacticaseibacillus rhamnosus, similar to the control sample (BMC), was more compact and rigid during storage. In contrast, samples containing Lacticaseibacillus paracasei and Levilactobacillus brevis had a softer/spreadable texture. These findings demonstrate the potential of lactic acid bacteria isolates from the traditional Mihalic cheese microbiota as biological catalysts for the development/improvement of texture, aroma, and sensory quality in high-fat dairy products and for the industrial production of products modified to meet consumer preferences.