Nutritional Caracterisation of Micellar Casein

Overview

There are different types of casein on the market, which differ according to their chemical or physical process of obtaining. The processes will impact structural differences in the macromolecular assembly. The majority of caseins marketed in nutrition are casein in the form of Na caseinate or Ca caseinate. The micellar caseins obtained by membrane filtration (physical process) are more and more used in the nutrition market. The development of casein extraction with different structures on an industrial scale opens up other perspectives for these proteins, particularly in terms of health. The main objective of this project is to study the postprandial kinetics of the plasma concentrations of the essential amino acids of three structurally different types of caseins. The secondary objective is to study the speed of gastric emptying and the nutritional properties of different proteins.

All the participants will give freely their written informed consent before their selection in the study. Each subject will participate in 3 kinetics of 5 hours with a different product test each time, in a randomized order. A wash-out period of at least 7 days will be respected between each kinetics. The products to be tested will be in the form of a powder (25g individual sachet, including 20.1g of protein) which will be reconstituted in 250ml of water and to which 100mg of 13C sodium acetate will be added. For each of the kinetics, blood samples, expires gasses, will be collected at different time during the kinetics. A urinary collection throughout the day of kinetics will also be performed to allow the determination of urinary nitrogen Indirect calorimetry measurements will be performed 45 minutes every hour in the postprandial period and a measurement of 45 minutes will be made when the subject is fasting. Six measurements of indirect calorimetry will be performed for each kinetic. Finally subjects will be asked to evaluate their satiety on a visual analog scale, 15' before taking the product, then every 15' the first hour in the postprandial period and every 30 'from the 2nd hour. The subjects will also have a tolerance questionnaire to complete with each kinetic. At the end of the kinetics, a standardized meal, single menu, consumption ad libitum measured in double weighing will be proposed to the volunteers to evaluate their satiety During the 3 days preceding each kinetics, the protein intake of the subjects will be controlled. The meal of each night in the evening of kinetics will be standardized and identical for each kinetics. The volunteers will complete a food survey on the 3 days of control of their diet that precede each kinetics.