Powdered water kefir: Effect of spray drying and lyophilization on physical, physicochemical, and microbiological properties

Abstract

This study addresses the challenge of optimizing powdered water kefir's fermentation and preservation processes to enhance its physical-chemical, microbiological, and technological characteristics. The main objective was to determine the best fermentation conditions and evaluate the efficacy of different drying methods. The optimal fermentation conditions were 5 % kefir grains, 10 % brown sugar, and an incubation temperature of 25 °C. Remarkably, the microbiological analysis revealed high abundances of Zymomonas mobilis (grains: 94.31 % and beverage: 91.68 %), Sporolactobacillus spathodeae (grains: 3.00 % and beverage: 5.42 %), and Liquorilactobacillus satsumensis (grains: 1.47 % and beverage: 0.62 %) among bacteria, and Lachancea fermentati (grains: 95.54 % and beverage: 67.53 %), Wickerhamomyces anomalus (grains: 3.00 % and beverage: 26.77 %) among fungi. The study innovatively demonstrates that lyophilization preserves the viability of these microorganisms, making it a promising method for producing stable, probiotic-rich powdered kefir. Although spray drying resulted in a logarithmic reduction of 3 logs CFU/g, it maintained sufficient microorganism counts, proving its viability as an alternative drying method. These methods retain the ideal physical-chemical properties and expand the accessibility and practical applications of water kefir. This research underscores the potential for powdered water kefir to deliver health benefits conveniently and versatilely, paving the way for broader industrial and academic applications.