Gluten Binds Cytotoxic Compounds Generated in Heated Frying Oil

Abstract

Male Wistar rats, age 10 weeks, were fed for 11 weeks a commercial powdered diet (no fat) containing 7 wt% fresh frying oil and 0.1 wt% gluten heated in oil at 180 for 10 h followed by filtration. The animals appeared to grow normally and had the same serum levels of glucose, triacylglycerol, phospholipids, and cholesterol as those of a control group fed a diet containing 7 wt% fresh oil. However, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were significantly higher in the test group, and many dark-red patches due to bleeding were observed on the livers of this group. In contrast, rats fed for 11 weeks a diet containing 7 wt% of oil obtained by filtration after the heating described above did not show any damage to the liver or kidneys and showed no gross symptoms. Rats fed a diet containing 7 wt% fresh frying oil and 0.1 wt% gluten heated in a tube at 180 for 10 h did not show any differences from the control group. Analyses of low-molecular-weight compounds in the filtered oil revealed that gluten obviously reduced the level of all the low-molecular-weight compounds (except ethanol) of the oil heated at 180 for 10 h. Thus, it was suggested that gluten reacted with/adsorbed thermally oxidized oil/decomposition products and kept the cytotoxic low-molecular-weight compounds in the chemical structure even after filtration.

Cytotoxic Compounds Generated in Heated Oil and Assimilation of Oil in Wistar Rats

“…It is important to moderate appetite. Gluten heated without addition of oil did not result in cytotoxicity, but led to increased daily ingestion 5) , thus suggesting that oil was not essential to maintain appetite.…”

“…The amount of oil excreted from the three groups tended to decrease as the amount of oil ingested also decreased 5) (…”

“…We thus proposed that low-molecular-weight compounds formed during frying are responsible for the cytotoxicity of deteriorated oil. In addition, it was reported 5) that these low-molecular-weight compounds bound with gluten during heating, and the gluten complex resulted in severe organ damage in rats while oil filtered from a heated mixture of oil and gluten did not show any adverse effects on rats 6) ; diets containing oil heated with amino acids, wheat starch or sucrose showed cytotoxicity in animal experiments.…”

“…The presence of GHIO and HG had no significant effect on feed efficiency. Thus, thermally processed gluten appears to be unrelated with the efficiency, although it promoted slight increases in appetite and body weight 5) .…”

“…This suggests that the batter coating of fried products contains proteins bound to low-molecular-weight products. On the other hand, heated gluten can stimulate the appetite, and food ingestion and body weight in rats tends to increase 5) .…”