Enhancing the Functional and Sensory Properties of Yogurt with Red Fruit Oil (Pandanus conoideus L.): Antioxidant and α-Glucosidase Inhibitory Activities

Abstract

Red fruit oil (Pandanus conoideus L.) is rich in bioactive compounds with antioxidant and antidiabetic activity. However, its application in food remains limited due to its unfavorable taste and aroma. Meanwhile, yogurt is a widely consumed fermented dairy product known for its distinctive physical and sensory characteristics. This study aimed to evaluate the effect of red fruit oil addition on the physical properties, sensory quality, bioactive compound content, antioxidant activity, and α-glucosidase inhibitory activity of yogurt. Four formulations (F0, F1, F2 and F3) were prepared by adding red fruit oil at levels of 0%, 5%, 10% and 15%, respectively. Parameters analyzed included pH, viscosity, titratable acidity (TA), color, hedonic test, QDA, antioxidant activity (CUPRAC), total flavonoid and phenolic contents, and in vitro α-glucosidase inhibition. Yogurt without red fruit oil (F0) showed antioxidant activity of 130.99 ± 7.48 μmol TE/g, flavonoid content of 20.04 ± 0.95 mg QE/g, phenolic content of 24.08 ± 0.36 mg GAE/g, and α-glucosidase inhibition of 64.46 ± 1.56%. The addition of 10% red fruit oil (F2) significantly increased these values to 369.47 μmol TE/g, 29.00 ± 0.62 mg QE/g, 155.54 ± 0.95 mg GAE/g, and 78.08 ± 0.37%, respectively. The addition of the oil also improved the sensory perception of red fruit oil itself, making it more organoleptically acceptable. F2 exhibited a balance between biological functionality and sensory acceptance, with an overall liking score of 5.38 ± 1.7 and the highest color score of 7.30 ± 1.4. These findings support the potential of red fruit oil yogurt as a functional food with antioxidant and antidiabetic effects.

HIGHLIGHTS

• Addition of red fruit oil (Pandanus conoideus) significantly enhanced the antioxidant capacity of yogurt.
• Yogurt enriched with red fruit oil showed increased levels of bioactive compounds (phenolics, flavonoids, and carotenoids).
• Functional enrichment improved health-promoting potential, particularly in inhibiting α-glucosidase activity.
• Sensory evaluation indicated that red fruit oil affected color, aroma, and flavor, with moderate acceptability at optimal concentrations.
• The study demonstrates the potential of red fruit oil as a natural functional ingredient for yogurt innovation.

GRAPHICAL ABSTRACT