title: Effects of Toasting Time on Digestive Hydrolysis of Soluble and Insoluble 00-Rapeseed Meal Proteins.
abstract: Thermal damage to proteins can reduce their nutritional value. The effects of toasting time on the kinetics of hydrolysis, the resulting molecular weight distribution of 00-rapeseed meal (RSM) and the soluble and insoluble protein fractions separated from the RSM were studied. Hydrolysis was performed with pancreatic proteases to representin vitroprotein digestibility. Increasing the toasting time of RSM linearly decreased the rate of protein hydrolysis of RSM and the insoluble protein fractions. The extent of hydrolysis was, on average, 44% higher for the insoluble compared with the soluble protein fraction. In contrast, the rate of protein hydrolysis of the soluble protein fraction was 3-9-fold higher than that of the insoluble protein fraction. The rate of hydrolysis of the insoluble protein fraction linearly decreased by more than 60% when comparing the untoasted to the 120 min toasted RSM. Increasing the toasting time elicited the formation of Maillard reaction products (furosine,Nε-carboxymethyl-lysine andNε-carboxyethyl-lysine) and disulfide bonds in the insoluble protein fraction, which is proposed to explain the reduction in the hydrolysis rate of this fraction. Overall, longer toasting times increased the size of the peptides resulting after hydrolysis of the RSM and the insoluble protein fraction. The hydrolysis kinetics of the soluble and insoluble protein fractions and the proportion of soluble:insoluble proteins in the RSM explain the reduction in the rate of protein hydrolysis observed in the RSM with increasing toasting time.
authors.affiliation: Wageningen Livestock Research, Wageningen, The Netherlands.|Animal Nutrition Group, Wageningen University and Research, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
authors.forename: Sergio
authors.identifier: 0000-0002-0332-6263
authors.initials: S
authors.lastname: Salazar-Villanea
authors.affiliation: Animal Nutrition Group, Wageningen University and Research, P.O. Box 338, 6700 AH Wageningen, The Netherlands.|Agrifirm Innovation Center BV, Royal Dutch Agrifirm Group, Apeldoorn, The Netherlands.
authors.forename: Erik M A M
authors.initials: EMAM
authors.lastname: Bruininx
authors.affiliation: Laboratory of Food Chemistry, Wageningen University and Research, Wageningen, The Netherlands.
authors.forename: Harry
authors.initials: H
authors.lastname: Gruppen
authors.affiliation: CREOL/OLEAD, Pessac, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Carré
authors.affiliation: Terres Inovia, Paris, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Quinsac
authors.affiliation: Animal Nutrition Group, Wageningen University and Research, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
authors.forename: Antonius F B
authors.initials: AFB
authors.lastname: van der Poel
keywords: Hydrolysis rate; Maillard; Protein solubility; Rapeseed meal; Toasting