Optimization of Freeze-Drying Time and Inulin Concentration for the Lyophilization of Lactiplantibacillus Plantarum Bs25 using Response Surface Methodology

Abstract

Probiotics are microorganisms that offer a wide array of health benefits to the consumer, thus its extensive applications in the food industry. Recent innovations in probiotic food science include the formulation of Lactiplantibacillus-supplemented functional food. In functional food development, optimizing process conditions to maintain probiotic efficiency while minimizing economic costs are of central importance. Currently, the optimization of the freeze-drying procedure of Lactiplantibacillus plantarum BS25, a novel lactic acid bacteria strain isolated in the Philippines, is yet to be explored. On this basis, the optimization of L. plantarum BS25 freeze-drying time and cryoprotectant inulin concentration was done. The Central Composite Design was used to establish the experimental design with 13 points. Freeze-drying yield and storage viability data obtained from experimental runs with different levels of the process variables were subjected to response surface methodology. Freeze-drying time has a significant quadratic effect on freeze-drying yield, and significant quadratic and linear effects on storage viability. Meanwhile, inulin concentration has a significant quadratic effect for both freeze-drying yield and storage viability. Optimal values of the process variables that result in a desirability of 0.949 were determined: (1) freeze-drying time of 6.793 hours and (2) inulin concentration of 0.763 % (w/v). Such process conditions result in a freeze-drying yield and storage viability of 91.58% and 70.41%, respectively. Optimization of other parameters involved in the lyophilization of L. plantarum BS25 should be done in future studies for the successful application of the novel strain as a probiotic. The findings of this study provide information on the application of RSM for the optimization of the freeze-drying procedure of L. plantarum BS25, a novel LAB strain, to maximize its industrial potential.