Optimization of ultrasonic-assisted extraction for bioactive compounds in Rubus ellipticus fruits: An important source for nutraceutical and functional foods

Bioactive compounds of Rubus ellipticus fruits are known for their potential in nutraceutical and functional food; however, systematic investigation on optimization of extraction conditions for improving yield is lacking. In the present study, extraction of bioactive compounds was performed using Plackett-Burman (PBD) and Central Composite Design (CCD). Parameters such as solvent to sample ratio, methanol concentration, and extraction temperature significantly (p < 0.05 and p < 0.001) influenced bioactive compounds extraction under linear, quadratic and interactive effects. The model predicted values of bioactive compounds and antioxidant activity were found close to the experimental value signifying the least coefficient of variation. Further, regression analysis showed a high coefficient of determination (R²) and a non-significant lack of fit. High-performance liquid chromatography equipped with a photodiode detector (HPLC- PDA) analysis detected the presence of seven bioactive compounds under optimal extraction conditions, among which catechin was maximum (27.67 mg/g DW). Results showed 35–99 percent improvement in yield to conventional studies and earlier reports on the species. The optimized process can further be upscaled for harnessing maximum benefits of the species in nutraceutical and energy supplement development program at an industrial scale.