Evaluation of cell recovery protocols of Lactococcus lactis GV103, microencapsulated

Microencapsulation of probiotics is an effective strategy to increase cell stability in the face of technological processes and gastrointestinal conditions. However, the verification of the viability of these cells depends directly on the recovery protocol chosen, since the release of the bacteria from the matrix can interfere with the results. Thus, the objective of this study was to evaluate the methods of verifying the viability of the potentially probiotic strain Lactococcus lactis GV103, microencapsulated in a vegetable fat matrix associated with lyophilized gum arabic emulsion, in the face of protocols with and without active rupture of the capsules. Two protocols were tested for quantification; where Protocol 1 consisted of rehydration in 0.1% peptone water, with incubation at 37 °C for 10 minutes followed by vigorous agitation in a vortex, without application of rupture agents,  Protocol 2 used 2% sodium citrate (pH 7.0) as a release agent, associated with incubation at 42-44°C. Subsequently, serial dilutions were performed in 0.1% peptone water and surface plating counting, with Man, Rogosa and Sharpe agar (MRS), incubated at 37°C for 48 hours. The results showed that Protocol 1 had the highest counts, being 9.27 log CFU/mL, indicating that rehydration was sufficient to release the microencapsulated cells without causing significant damage. Protocol 2 had lower counts than the previous protocol, being 8.62 log CFU/mL, suggesting that more complex methods do not necessarily result in better cell recovery, and may even compromise bacterial viability. When choosing a protocol, consideration should be given not only to the efficiency of capsule rupture but also to the preservation of probiotic cell integrity. The conclusion is that the peptone water rehydration protocol combined with mechanical agitation (Protocol 1) was the most appropriate method for verifying the viability of Lactococcus lactis GV103 microencapsulated in vegetable fat and gum arabic emulsion, providing superior results to protocols involving chemical rupture.