Portal appearance of duodenal 14C-lysine injections in rats fed heat treated full-fat soybeans

• Published in: Nutrition research (New York, N.Y.) Vol. 12; no. 8; pp. 965 - 974
• Main Authors: Marty, Bruno J., Barthakur, Nayana N., Chavez, Eduardo R.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.08.1992; Elsevier Science
• Subjects: Biological and medical sciences; Food industries; Fruit and vegetable industries; Full-fat soybean; Fundamental and applied biological sciences. Psychology; Heat treatment; Rat; Rat; Full-fat soybean; Heat treatment; Nutrition; Rodentia; Gut; Maillard reaction; Foodstuff; Soybean; Torrefaction; Vertebrata; Mammalia; Absorption; Lysine; Manufacturing process; Aminoacid; Extrusion
• ISSN: 0271-5317; 1879-0739
• DOI: 10.1016/S0271-5317(05)80581-0

An in vivo study was conducted to determine if commercial extrusion (Ex) or roasting (Ro) of full-fat soybeans (FFSB) would influence the rate and total amount of lysine absorption in young male Sprague Dawley rats. Portal appearance of duodenal 14C-lysine injections were measured in rats under general anaesthesia. Rate of 14C-lysine absorption as well as total 14C-lysine absorption had a tendency (p<0.09 and .14, respectively) to be lower in rats fed Ex compared to Ro FFSB. This apparent contradiction with literature reports which suggest a higher nutritional value of Ex compared to Ro FFSB can only reasonably be explained by distinctive absorption of free and peptide bound amino acids. An increased proportion of heat induced peptides resistant to luminal digestion and a concomitant lower concentration of free lysine from Ro FFSB would reduce the competition with 14C-lysine for absorptive carrier processes through the enterocytes. The rate of absorption of 14C-lysine from casein fed rats was similar to that of FFSB fed rats (p>0.83). In the later total absorption was lower (p<0.04) but peak 14C-lysine disappearance from the intestinal lumen was reached faster (p<0.001).