Effect of Cooking on the Contents of a-Chaconine and α-Solanine in Potatoes

Abstract

The decrease in α-chaconine (CHA) and a-solanine (SOL), toxic glycoalkaloids in potatoes, during cooking by three procedures was investigated. Raw or cooked potato samples (2 g) were extracted twice with 5% acetic acid solution. The extract was purified on Sep-pak C18and CHA and SOL contents were determined by high performance liquid chromatography. Recoveries of CHA and SOL from raw potatoes were 96.5% and 98.2%, respectively and those from cooked potatoes were 96.2% and 96.7%, respectively. It was found that 93.9% of CHA and 95.9% of SOL remained in potatoes after boiling. These values indicate that boiling is ineffective as a means to decrease the alkaloids. Alkaloid content was reduced by microwaving by 15% in each case. In the case of deep-frying, their contents varied according to the temperature. At 150°, both alkaloids showed no decrease, and at 170°, the potatoes showed a large variation in residual alkaloids. At 210°, however, the alkaloids were partially decomposed; after 10 minutes’ heating, 64.9% of CHA and 59.7% of SOL remained. It was suggested that the critical temperature for the decomposition of both alkaloids in potatoes may be around 170°C. In this study, relatively high stability of CHA and SOL in potatoes under normal home cooking conditions was confirmed. © 1990, Japanese Society for Food Hygiene and Safety. All rights reserved.