Ultrasound-assisted isolation of mucilaginous hydrocolloids from Salvia macrosiphon seeds and studying their functional properties

•Hydrocolloids were isolated from Salvia macrosiphon seeds by ultrasound, successfully.•Yield of ultrasound-assisted isolation method was higher than conventional method.•Ultrasound power and time had significant effects on rheological properties.•Ultrasound power and time had significant effect on chemical compositions.

Time and energy consuming centrifugation and purification steps have been reported as the main challenges for isolation of high quality hydrocolloids from mucilaginous seeds in commercial production. Ultrasound-assisted isolation of mucilaginous hydrocolloids from Salvia macrosiphon seeds as an innovative technology was performed successfully. After determination of optimum swelling condition, mucilaginous hydrocolloids samples were isolated using ultrasonic system under different ultrasound conditions (i.e., time, 1–20 min, temperature, 5–60 °C and ultrasound power (30–150 W)) and their physicochemical characteristics were studied in terms of yield, lightness, chemical composition, rheological properties and intrinsic viscosity in comparison with the conventional method. Ultrasound method increased yield, lightness and purity, in particular protein content, of the isolated hydrocolloids. Rheological measurements showed that increase of the intensity of ultrasound causes a decrease in consistency coefficient and an increase in the flow behavior index and thus hydrocolloid solutions tend to show more Newtonian behavior. The critical concentrations of S. macrosiphon seed gum isolated with the conventional method and the strongest ultrasonic treatment were 0.06 and 0.2 g/dl, respectively. Ultrasound showed to be a suitable method to isolate hydrocolloids from S. macrosiphon seeds.Industrial relevanceIsolation of mucilaginous hydrocolloids from seeds is a major challenge for commercializing these promising hydrocolloids. Using power ultrasound, isolation of hydrocolloid from S. macrosiphon mucilaginous seeds was performed, successfully. Ultrasound is able to scrape swelled mucilage layers of the seeds layer by layer. In the conventional method during high shear application some parts of the seed cores are crushed that would require extra separation steps such as high speed centrifugation. However, with ultrasound method seed cores are not broken down, therefore no centrifugation step is needed.