Extraction of watermelon seed proteins with enhanced functional properties using ultrasound

Watermelon seed is the potential source of value-added proteins, oils, and carbohydrates. The present study evaluates the extraction, and functional properties of watermelon seed protein (WMSP) obtained by ultrasound-assisted extraction (UAE) method from watermelon seed (WMS). The optimization of various operating parameters, such as pH (9), WMS powder to solvent ratio (1:50 w/v), temperature (30 +/- 2 degrees C), ultrasound power (90 W), frequency (25 kHz), and duty cycle (75%) has been carried out. The extraction yield obtained was 87% and the extraction time was lowered down to 9 min from 120 min of conventional batch extraction. It contains all essential amino acids in an adequate amount required for adults as per FAO/WHO guidelines while for 2-5 years old children, the content of valine and isoleucine are above the required range. Methionine and lysine contents are adequate for both children and adults. Functional properties of ultrasonic extracted proteins were found superior to conventionally extracted proteins.