Fermentation of Sapodilla juice with <i>Lactobacillus acidophilus</i> : Fermentation kinetics and evaluation of functional properties

Nowadays, probiotic-enriched fruit drinks are one of the most demanding products in the global market. In line with this trend, lactic acid bacteria are commonly used in these industries primarily due to their beneficial effects on health and ability to improve food quality. This study evaluated the adaptability and suitability of the Lactobacillus acidophilus (LA 14) strain for fermenting Sapodilla juice, monitoring its effect on viable cells during storage conditions, and the juice's phytochemical, antioxidant, enzyme inhibitory, and sensorial properties. As per the results, after a 48-h fermentation, the probiotic cell counts reached 9.08 log CFU/mL with enhanced acidity from 0.28 to 0.80 mg/L and a subsequent decrease in juice pH from 5.21 to 3.84. Lactic acid fermentation also increased the levels of phytochemicals substantially in the juice which in turn translated to a notable increase in its antioxidant potential, as measured by DPPH and ferric reducing antioxidant power assays. Furthermore, the fermented juice demonstrated significantly improved α-amylase inhibition activity and garnered greater overall consumer acceptance compared to the nonfermented one. Although a 30% decline of microbial cells was observed during cold storage, the counts were above 6 log CFU/mL. These findings suggest that lactic acid fermentation can be an excellent method for improving the storage stability, functional, and sensorial qualities of Sapodilla juice, leading to the development of new functional probiotic beverages to meet growing market demand. PRACTICAL APPLICATION: Sapodilla (Manilkara zapota L.) has a reputation as a highly nutritious fruit, but its perishability and underutilization hold major concerns. This study seeks a noble way to preserve and utilize this fruit to develop a functional probiotic beverage. The finding will help to better understand the potential of the Lactobacillus acidophilus strain to ferment and improve different functional properties of Sapodilla fruit juice for more efficient industrial applications.