The Mulberry Juice Fermented by Lactiplantibacillus plantarum O21: The Functional Ingredient in the Formulations of Fruity Jellies Based on Different Gelling Agents

This study aimed to investigate the effects of adding probiotics, prebiotics, and different types of jelly agents on a few key quality attributes of potentially functional mulberry jellies throughout a 10-day storage period at 4 °C. Mullbery juice was separately fermented at 37 °C for 24 h using Lactiplantibacillus plantarum O21; it was a favorable matrix for the proliferation of probiotics. Lactic acid fermentation positively affected the total anthocyanin concentration of investigated products. Also, antioxidant capacities of mulberry juices were improved by L. plantarum O21 fermentation. The results showed that the applied prebiotic–inulin addition and agar–agar addition, as a gelling agent in recipes of potentially functional mulberry jellies, were proved to be beneficial technological solutions, both in fresh and stored products, and obtained an appropriate, high number of LAB bacteria, good sensory quality, and beneficial antioxidant properties.