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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Grain Quality and Structure Research » Research » Publications at this Location » Publication #223246

Title: Effect of Frying Conditions and Yeast Fermentation on the Acrylamide Content in You-Tiao, a Traditional Chinese Fried Twisted Dough-roll

item Tilley, Michael - Mike

Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2008
Publication Date: 11/1/2008
Citation: Huang, W., Yu, S., Zou, Q., Tilley, M. 2008. Effect of frying conditions and yeast fermentation on the acrylamide content in you-tiao, a traditional Chinese fried twisted dough-roll. Food Research International. 41:918-923.

Interpretive Summary: In early 2002, the National Food Administration of Sweden reported the presence of high amounts of acrylamide in heat-treated grain and potato-based foods. This finding resulted in worldwide interest, because acrylamide is a potent neurotoxin and has been classified as a probable carcinogen. The highest concentrations of acrylamide are found in fried potato-based products such as French fries and potato chips. Acrylamide is formed through the Maillard reaction when certain sugars are heated in the presence of the amino acid asparagine, both of which are relatively abundant in potatoes and wheat. Factors such as cooking temperature and cooking time affect production of acrylamide. You-tiao is a traditional Chinese fried twisted dough-roll, usually eaten at breakfast. It is inexpensive and enjoyed by all segments of the population. The dough is similar to bread dough that is fermented but it is fried at high temperatures rather than baked. This study determined how the processing conditions affected acrylamide content in you-tiao.

Technical Abstract: Effects of frying temperature, frying time and dough pH on the formation of acrylamide in the processing of you-tiao, a traditional Chinese fried twisted dough-roll, were analyzed using response surface methodology. The results obtained showed that the frying temperature and time had a notable impact on the formation of acrylamide. Dough pH also had a significant effect on the amount of acrylamide resulting in the products. It was demonstrated that lowering the frying temperature to 175 degrees C, prolonging the frying time to 86 seconds, and adjusting the dough pH to 6.0 with citric acid reduced the acrylamide content by 71% in the finished products. The addition of different levels of yeast ranging from 0.1% to 1.2% to the traditional formulation was examined. We found that dough with the addition of 0.8% yeast fermented for one h could significantly reduce the amount of acrylamide formed in the fried twisted dough-roll by 66.7%. An examination of the influence of yeast fermentation on the free asparagine and reducing sugars, revealed that when the reducing sugars reach the maximum content, the acrylamide content was reduced, and the free asparagine was decreased. As a result, the asparagine reduced by yeast fermentation is more important than the rise in reducing sugar in the reduction of acrylamide content in you tiao.