Functional quality evaluation and shelf life study of synbiotic yacon juice

The research aimed to utilize the prebiotic potential of yacon fruit by preparation of synbiotic yacon juice containing probiotic microorganism Lactobacillus acidophilus (La5) and studying the changes in physicochemical properties during storage. The fresh juice extracted was added with probiotic microorganism and was subjected for storage at refrigerated (4°C) and room condition (25°C) along with control (nonfermented) juice. The viability of probiotic strains in the juice was found to be at the satisfactory level (10⁶ CFU/ml) for 27 and 15 days, respectively, in refrigerated and room condition. Total soluble solid, pH, acidity, bioactive compounds (ascorbic acid, carotenoid content, and total phenol), and antioxidant capacity of the products were evaluated. Total soluble solid of the prepared synbiotic juice stored at refrigerated and nonrefrigerated conditions decreased from 7.8 ± 0.05 to 5.5 ± 0.26 and 5.3 ± 0.10 while the acidity increased from 0.067 ± 0.05 to 0.80 ± 0.06 and 1.02 ± 0.04 after 27 and 15 days of storage, respectively. Similarly, yeast and mold count, total plate count, and the coliform count were determined during the storage period. The low amount of yeast and mold count and absence of coliform in the synbiotic juice even after 27 and 15 days of storage indicated that the synbiotic juice can be continued to be consumed as a normal juice even after the viability decreased below the satisfactory level. Ascorbic acid, phenolic content, and antioxidant activity were higher in fermented juice when compared to control juice stored at the refrigerated conditions for the same period (p < .05). High therapeutic properties and numerous health benefits of yacon, when combined with the health benefits of probiotic bacteria, could lead to the development of commercial beverages with high health and nutritional values.