Ultrasound-assisted extraction of Hibiscus rosa-sinensis flower extracts to be utilized as a sustainable ingredient for the development of functional tea

Hibiscus rosa-sinensis flower is gaining attention for their rich nutritional and functional profile, positioning them as promising ingredients for health-oriented functional foods and beverages. However, limited studies have explored their direct application in functional foods and beverages. This study addresses that gap by assessing the nutritional composition, antioxidant potential, and incorporation of H. rosa-sinensis flower extract as a sustainable ingredient in clean-label functional tea formulations. Ultrasound-assisted extraction (20 kHz, 40 °C, 30 min; 1:20 solvent ratio) using various solvents was employed to obtain flower extracts. Functional teas formulations were developed by replacing green tea with flower extract at 25 %, 50 %, 75 %, and 100 % levels. Nutritional analysis of H. rosa-sinensis flower revealed high carbohydrate content (61.50 ± 1.18 %) and ash (3.71 ± 0.29 %), with calcium (1218 ± 26 mg/100 g), and potassium (1109 ± 40 mg/100 g) as dominant minerals. The H. rosa-sinensis flower extract exhibited strong antioxidant properties with total phenolic content (TPC) of 781.77 ± 4.66 mg GAE/100 g, DPPH inhibition activity of 84.72 ± 2.48 %, ABTS activity of 90.01 ± 2.32 %, and FRAP activity of 1654.4 ± 15.62 µg Fe/100 g. In tea formulations, the highest TPC and FRAP activity were in the control that was 100% green tea (429.98 ± 5.16 mg GAE/100 g, 1759.0 ± 4.48 µg Fe/100 g), while 75 % H. rosa-sinensis extract containing functional tea showed the highest DPPH inhibition activity of 70.05 ± 1.48 %, and ABTS activity of 71.79 ± 1.54 %. The sensory analysis indicated that the 50 % H. rosa-sinensis extract containing functional tea had the highest acceptability and optimal color attributes. FTIR analysis confirmed the presence of key functional groups (O-H, C=C), indicating abundant polyphenols and flavonoids. Overall, H. rosa-sinensis flower demonstrated excellent potential as sustainable ingredient for functional food and beverages development, offering improved antioxidant benefits and appealing sensory properties.