Pressurized low polarity water extraction of saponins from cow cockle seed

Pressurized low polarity water (PLPW) extraction of cow cockle seed was carried out to determine the effect of extraction conditions (temperature (125–175 °C), time (15–180 min)), and sample pre-treatment on saponin yield and composition. Accelerated solvent extractions (ASE) and ultrasonic extractions (USE) using water, methanol and ethanol (50%, 80%, 100%) were also carried out to determine the effect of extraction solvent and method on saponin recovery. A higher saponin yield was obtained by ASE compared to USE using pure and aqueous ethanol and methanol. The highest saponin yield, which was obtained by ASE using 80% ethanol, was used to calculate saponin recoveries. The saponin yield of PLPW extracts increased with extraction temperature and time. While only 33.2 wt% of total saponins was extracted from ground seeds at 125 °C in 3 h, 60.2 wt% was recovered in the first 15 min at 175 °C. Total extraction (1 h) of whole seeds yielded more saponins than ground seeds at 125–160 °C. Saponin concentration of the extracts was affected by the extraction solvent and method, sample pre-treatment and to a lesser extent by the time and temperature of PLPW extraction. The highest saponin concentration of PLPW extract was obtained at 125 °C using whole seeds (12%). The saponin composition of water extracts differed from that of aqueous ethanol and methanol extracts.