This research paper delves into the effects of noni juice concentration, fermentation temperature, and incubation time on the physicochemical and sensory properties of noni juice-fortified yogurt. The study found that increasing the concentration of noni juice leads to higher acidity in the yogurt, resulting in a decrease in pH, total soluble solids content, and syneresis. The optimal concentration for achieving the desired physical and sensory qualities is 3%. Incubation time and temperature were also found to significantly influence the yogurt’s pH, acidity, total soluble solids content, and syneresis, with higher incubation time and temperature consistently producing higher-quality yogurt. The best incubation time and temperature for noni juice-fortified yogurt were determined to be 10 h at 42oC. Therefore, the research suggests that adding 3% Bestone noni juice and incubating for 10 h at 42oC using the starter culture powder Yogourmet can lead to the production of consistently high-quality noni juice-fortified yogurt, which is of significant relevance and importance to the dairy and fermentation industries.

Introduction
Materials and Methods
    Materials
    Yogurt formulation and processing
    Physicochemical properties of noni juice and yogurt
    Total phenolic content (TPC)
    Syneresis of yogurt
    Lactic acid bacteria (LAB)
    Sensory evaluation
    Data analysis
Results and Discussion
    Properties of noni juice
    Effect of noni juice addition on yogurt’s sensory quality
    Effect of incubation time and temperature on physicochemical properties and lactic acid bacteria of yogurt
    Effect of incubation time and temperature on sensory qualities of yogurt
Conclusion
Acknowledgements
References
Author Information

• Hong Tran Thi Kim(Department of Chemical Engineering-Environment, University of Technology and Education, The University of Da Nang)
• Linh Tran Thi Ngoc(Department of Chemical Engineering-Environment, University of Technology and Education, The University of Da Nang)
• Toan Nguyen-Sy(Department of Chemical Engineering-Environment, University of Technology and Education, The University of Da Nang)
• Trang Nguyen Huu Phuoc(Department of Chemical Engineering-Environment, University of Technology and Education, The University of Da Nang) Corresponding author