Study on Ultrasonic Extraction and Stability of Glucosinolate in Rapeseed Cake

Abstract

This paper performs an ultrasonic-enhanced glucosinolate extraction test with the rapeseed cake as the object and ethanol as the solvent, and compares this method with the conventional one. Based on that, this paper studies the stability of glucosinolate. The result shows that under the optimal conditions (150W acoustic power, 70% ethanol, 4:1 (mL/g) liquid-to-material ratio, 60 °C, and the extraction frequency of 5 times/15 min), the glucosinolate yield can reach 62.1 mg/g. Compared with the conventional method, in order to reach the same yield, the method used in this paper can reduce the required temperature by 20 °C and shorten the extraction time by 40%. Stability test shows that the glucosinolate is sensitive to temperature and pH, more stable below 80 °C and in neutral environments; it degrades faster above 80 °C, and is easy to decompose in acidic and alkaline environments. Under the test conditions, its stability decreases with the increase of acoustical power.