Effects of deep frying on the contents of 3-monochloropropane-1,2-diol, 3-monochloropropane-1,2-diol esters and glycidyl esters in Hash Brown.

• Main Authors: Hsiang-Ying Kuo, 郭湘盈
• Other Authors: 葉安義
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/gb76q9

碩士 === 國立臺灣大學 === 食品科技研究所 === 107 === During thermal processing of food, few heat-induced contaminants are generated such as 3-monochloropropane-1,2-diol esters (3-MCPD esters) and glycidyl esters (GEs). After intestinal hydrolysis, these esters get hydrolyzed to their free forms, 3-MCPD and glycidol, which are toxic. The International Agency for Research on Cancer (IARC) classifies 3-MCPD and glycidol into Group 2B and 2A substances, respectively. The cause of generation of 3-MCPD esters is mainly the removal of fatty acid groups by diglycerides in high temperatures and dehydration in acidic environment in the presence of chloride ions. GEs are generated at high temperatures from mono- and diglycerides by rearrangement through charge migration and these are partially converted to 3-MCPD esters in presence of chloride ions. High-content of 3-MCPD esters and GEs are often found in refined vegetable oils, especially in palm oil. Deep frying is one of the popular methods for the preparation of foodstuff. During deep-frying of food, the loss of moisture causes oil to enter the food along with these heat-induced contaminants which increase the risk of disease in humans. In this study, the 3-MCPD esters and GEs contents in hash browns was investigated at different frying temperatures. In case of exposure to high temperature for a long time, the 3-MCPD esters and GEs contents of hash browns and palm oil have been found to decrease and no 3-MCPD was detected. This indicates that the 3-MCPD gets decomposed slowly with prolonged frying time in an open frying system. Further, it is known that the fat content of the hash brown after frying is affected by the frying temperature and time, hence, its 3-MCDP esters and GEs content increases with the oil absorption. Moreover, as hash brown contains sodium chloride, it supplies the chloride ions as reactants to frying-oil system and proceeds the reaction. The moisture of hash brown evaporates at high temperatures. The hydrolysis increases the content of free fatty acids, monoglycerides and diglycerides and the increase in acidity results in deterioration of oil. Theoretically, the increase in acid value increases the reactivity of 3-MCPD esters, but in the present study, it was found to result in a slower degradation of 3-MCPD esters in palm oil at 200°C. To sum up, this study aims to evaluate the generation and deterioration of heat-induced contaminants in hash brown during frying process. The optimum frying temperature of hash brown was found to be 180℃.