Potential Analysis of Lactobacillus plantarum-Fermented Red Dragon Fruit Juice as Synbiotic Powder via Spray Drying Mochamad Nurcholis1*, Esa Firdausa1, Siti Narsito Wulan1, Feronika Heppy Sriherfyna1, Ella Saparianti1, Jaya Mahar Maligan1, Aniswatul Khamidah2
1 Department of Food Science and Biotechnology, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, Indonesia
2 Research Center for Food Technology and Processing, National Research and Innovation Agency Republic of Indonesia, Playen, Gunung Kidul, Yogyakarta, Indonesia
*corresponding author: cholis_federer[at]ub.ac.id
Abstract
Enhancing the functional properties of probiotics can be achieved through the incorporation of prebiotics. Red dragon fruit or Hylocereus polyrhizus, abundantly produced in East Java, is a rich source of fructooligosaccharides or FOS, a prebiotic substrate readily fermented by Lactobacillus spp., particularly Lactobacillus plantarum, which is commonly found in spontaneous fruit- and vegetable-based fermentations. The combination of probiotics and prebiotics yields synbiotic products. However, fermented foods face stability challenges, necessitating preservation techniques that extend shelf life while maintaining viable bacterial counts. Spray drying offers a promising approach for producing stable synbiotic powders.
This study aimed to evaluate the FOS fermentation of L. plantarum in red dragon fruit juice and compare the characteristics of the synbiotic in both liquid and powder forms. The experiment was conducted in two stages, characterization of synbiotic juice and evaluation of spray-dried synbiotic powder. The optimal treatment, determined using the Zeleny method, was obtained from a mixed substrate of fruit peel and pulp fermented for 72 h. The best formulation exhibited total LAB counts of 8.60 log CFU per mL, total titratable acidity of 1.306 percent, pH of 3.247, L value of 32.167, a value of 34.544, and b value of 1.933. Antibacterial activity was evidenced by inhibition zones of 4.133 mm against Escherichia coli and 5.900 mm against Staphylococcus aureus. Physicochemical and microbiological changes during processing were generally characterized by quality reduction, except for LAB viability. GC-MS analysis confirmed the presence of short-chain fatty acids or SCFAs such as propanoic and pentanoic acids, meeting synbiotic criteria.
