Formation and distribution of (E,E)-2,4-decadienal in deep-fried dough sticks under different conditions

(E,E)-2,4-Decadienal is an important product of deep-frying systems and is regarded as a health hazard. The present study investigated the formation of (E,E)-2,4-decadienal in deep-fried dough sticks under different conditions, including types of deep-frying oils, deep-frying temperature, and dough composition. In addition, the correlation between (E,E)-2,4-decadienal formation and deep-frying conditions was analyzed. The results showed that the (E,E)-2,4-decadienal content in the deep-frying system was related to the linoleic acid level in the deep-frying oils. Furthermore, adding 6% soy protein isolate to the dough considerably suppressed the formation of (E,E)-2,4-decadienal in the deep-frying system, resulting in the lowest content at 43.52 mg kg^–1. The highest (E,E)-2,4-decadienal content in the deep-frying system (64.65 mg kg^–1) was observed when a dough with a moisture content of 38% was used. The results of the correlation analysis revealed a strong association between the (E,E)-2,4-decadienal content in the deep-fried dough sticks and their oil absorption capacity. The (E,E)-2,4-decadienal content increased with higher oil content in the deep-fried dough sticks. Therefore, suppressing the oil absorption of deep-fried dough sticks is an important approach for controlling (E,E)-2,4-decadienal content.

Practical applications: As one kind of traditional deep-fried foods in China, deep-fried dough sticks attracted the attention of consumers because of its desirable flavor and texture. Thus, it is crucial to improve its safety and quality. As is known, (E,E)-2,4-decadienal is harmful to health, and it is the main aldehyde component in the deep-frying system. Herein, it is important to improve the safety of deep-fried dough sticks while suppressing the formation of (E,E)-2,4-decadienal in deep-frying system and reducing the content of (E,E)-2,4-decadienal in deep-fried dough sticks. On the one hand, the use of deep-frying oils with lower level of linoleic acid could limit the formation of (E,E)-2,4-decadienal in deep-frying system, which could also be achieved with the addition of protein into the dough. On the other hand, suppressing the oil uptake ability of deep-fried dough sticks is an important approach to limit the level of (E,E)-2,4-decadienal in deep-fried dough sticks.