title: Reactions of chlorogenic acid and quercetin with a soy protein isolate--influence on the in vivo food protein quality in rats.
abstract: Plant phenolic compounds are known to interact with proteins producing changes in the food (e. g., biological value (BV), color, taste). Therefore, the in vivo relevance, especially, of covalent phenol-protein reactions on protein quality was studied in a rat bioassay. The rats were fed protein derivatives at a 10% protein level. Soy proteins were derivatized with chlorogenic acid and quercetin (derivatization levels: 0.056 and 0.28 mmol phenolic compound/gram protein). Analysis of nitrogen in diets, urine, and fecal samples as well as the distribution of amino acids were determined. Depending on the degree of derivatization, the rats fed with soy-protein derivatives showed an increased excretion of fecal and urinary nitrogen. As a result, true nitrogen digestibility, BV, and net protein utilization were adversely affected. Protein digestibility corrected amino acid score was decreased for lysine, tryptophan, and sulfur containing amino acids.
authors.affiliation: Department of Food Analysis, Institute of Food Technology and Food Chemistry, Technical University of Berlin, TIB 4/3-1, Gustav Meyer Allee 25, D-13355 Berlin, Germany. Sascha.Rohn@TU-Berlin.de
authors.forename: Sascha
authors.initials: S
authors.lastname: Rohn
authors.forename: Klaus J
authors.initials: KJ
authors.lastname: Petzke
authors.forename: Harshadrai M
authors.initials: HM
authors.lastname: Rawel
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kroll
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight; D002726:Chlorogenic Acid / Q000737:chemistry*; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000032:analysis / Q000378:metabolism; D004063:Digestion; D004435:Eating; D008297:Male; D009584:Nitrogen / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine; D011786:Quality Control; D011794:Quercetin / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D030262:Soybean Proteins / Q000008:administration & dosage* / Q000737:chemistry* / Q000378:metabolism; D014886:Weaning
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D030262:Soybean Proteins; D002726:Chlorogenic Acid; D011794:Quercetin; D009584:Nitrogen