Spirulina (Arthrospira) platensis is a cyanobacterium that offers numerous health benefits, making it a potential ingredient for functional foods. However, its distinct microalgal aroma and taste can limit consumer acceptance. This study aimed to characterize S. platensis fermented by Lactobacillus paracasei and Lactobacillus plantarum Dad-13, and to evaluate the characteristics of the optimum fermentation treatment. Fermentation was conducted at 37 °C for 0, 24, 48, and 72 h. The fermented S. platensis was characterized based on lactic acid bacteria (LAB) count, pH, titratable acidity (TA), antioxidant activity, and metabolite profiles. Fermentation with either L. paracasei or L. plantarum Dad-13 for 48 h yielded better results than the other treatments, producing optimal LAB counts, pH, titratable acidity, and IC50 values for antioxidant activity. The antioxidant activities of both fermented spirulina variants were classified as strong, with IC50 values of 53.17 ppm and 61.15 ppm, respectively, while exhibiting distinct candidate metabolite compositions. Furthermore, the liquid fermented spirulina by L. paracasei was successfully formulated into a jelly product containing 4.8% dietary fiber and a LAB count of 6.79 log CFU/g.
Keywords: antioxidant, characterization, lactic acid bacteria, Spirulina sp.