A Novel Body Weight-loss Promoting Oil Prepared with Vegetable Protein

Abstract

It has been reported that oil thermally processed with wheat gluten (gluten oil) exhibited safe weight-loss promoting effects in animal experiments. However, as the oil has a high color index, and its chemical properties and smell differ from those of fresh oil, it is uncertain if the oil will find market acceptance. In order to resolve the issue, frying oil was heated with soybean protein under reduced pressure (soybean protein oil), resulting in a product with an appearance, chemical properties and smell comparable to those of fresh oil. This improved oil was mixed (7 wt%) with powdered AIN93G no fat, defined standard diet and fed to 10-week-old Wistar rats ad libitum. The experimental rats grew normally, ingesting the same amount as that of the control rats; however, there was a negative correlation between body weight increases and fecal weight increases. After the 12-week feeding period, all the rats were sacrificed to obtain blood and organs. In the experimental group, liver weight, retroperitoneal fat tissue weight and serum triacylglycerol (TG) levels decreased significantly. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and histological analysis supported the safety of the improved oil. In conclusion, it was found that soybean protein oil inhibited body weight increases without any adverse effects in animal experiments. The oil holds promise as a novel dieting oil that steadily decreases body weight at an appropriate rate.Key words: soybean protein, weight-loss promoting, fecal weight, serum triacylglycerol level, retroperitoneal fat tissueCorrespondence to: Nagao Totani, Department of Nutritional Physiology, Faculty of Nutrition, Kobe-Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe, 651-2180 JAPAN E-mail: totani@nutr.kobegakuin.ac.jp Accepted September 19, 2009 (received for review May 30, 2009 One liter of fresh frying oil (Fuji Oil Co., Ltd., Osaka, Japan) was heated at 180 and 5 Torr for 10 h in a 2-L four-neck round-bottom flask under stirring with 1wt% soybean protein. Oil heated with protein was filtered over filter paper under reduced pressure (soybean protein oil) and employed for an animal experiment. Oil AnalysesPeroxide value (POV), carbonyl value (COV), acid value (AV), iodine value (IV) and Lovibond color were measured according to the Japan Oil Chemists' Society's Standard Methods for the Analysis of Fats, Oils, and Related Materials. The content of polar compounds (PC) was analyzed by a PC Tester, 3M, Saint-Ouen l'Aumone, France 3) . Triacyglycerol contents (TG) were determined by applying samples on Chromarods followed by development in a solvent mixture, hexane/diethyl ether/acetic acid, 50:10:1 v/v/v, and quantification with Iatroscan MK-6s, Iatron Laboratories, Inc., Tokyo, Japan. After esterification of oil with diazomethane for possible free fatty acids and then with sodium methoxide for triacylglycerol, oil was analyzed by Shimadzu GC-2010 gas chromatograph equipped with 60-m SP TM -2340 capillary column of 0.25 mm bore, Supelco, St. Lo...

The Mechanism of Weight-Loss Promoting Effects of Oil Heated with Vegetable Protein

“…It was reported that oil heated with soybean protein under reduced pressure, followed by fi ltration of the protein soy oil , accelerated gastrointestinal tract content transfer 2 . Furthermore, the content in the colon was actively excreted, ending up with remarkable weight-loss even though amounts ingested were constant 3 .…”

“…We have reported that a soy oil-containing experimental diet fat-free AIN93G containing oil thermally processed with soybean protein followed by fi ltration inhibited body weight increases and increased fecal excretion without any adverse effects when given ad libitum to male Wistar rats for 12 weeks 3,13 . When thermal processing is conducted in the presence of air, in the preparation of weight-loss promoting oil, the contribution of oxidized polymers in the oil cannot be ignored in assessing its effects.…”

“…But a large amount of feces seems to mean a large excretion of unabsorbed nutrition according to the report by Unno et al 22 that male Wistar rats showed reduced body weight gains by feeding a diet containing tea catechin, and excreted increased amounts of feces containing increased amounts of carbohydrate, lipids and protein. The infl uence of increased amounts of continuous excretion on body weight and serum neutral lipid levels should be substantial 3 .…”

“…Triacyglycerol contents TG were determined by applying samples on Chromarods followed by development in a solvent mixture, hexane/diethyl ether/acetic acid, 50:10:1 v/v/v, and quantification with Iatroscan MK-6s, Iatron Laboratories, Inc., Tokyo, Japan. Fatty acid composition of fresh and soy oils was determined by GC as follows 3 : myristic acid 0. …”

Effects of Oil Thermally Processed with Vegetable Protein on Gastrointestinal Tract Content Transfer

“…All the dieting oils, excluding Olestra ® , are subjected to hydrolysis and absorption in the small bowel; Olestra ® is not hydrolyzed by lipase, but excreted. The soy oil described above is a simple triacylglycerol, but probably contains a small amount of substances formed from components in soybean protein and oil during heating, and reduced body, liver and retroperitoneal fat tissue weights and serum TG levels in a 12-week animal experiment 12) . The oil did not result in deterioration of appetite but increased normal fecal excretion, leading to the assumption that there was reduced digestion and/or absorption of the diet.…”