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Open Access Research

Crosslinking with transglutaminase does not change metabolic effects of sodium caseinate in model beverage in healthy young individuals

Kristiina R Juvonen1*, Martina E Lille2, David E Laaksonen34, Hannu M Mykkänen1, Leo K Niskanen56, Karl-Heinz Herzig78, Kaisa S Poutanen12 and Leila J Karhunen1

Author Affiliations

1 Food and Health Research Centre, Department of Clinical Nutrition, Institute of Public Health and Clinical Nutrition, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland

2 VTT Technical Research Centre of Finland, 02150, Espoo, Finland

3 Department of Medicine, Kuopio University Hospital, 70211, Kuopio, Finland

4 Institute of Biomedicine, Physiology, University of Eastern Finland, 70211, Kuopio, Finland

5 Department of Medicine, Central Hospital Central Finland, 70460, Jyväskylä, Finland

6 University of Eastern Finland, 70211, Kuopio, Finland

7 Department of Psychiatry, Kuopio University Hospital, 70211, Kuopio, Finland

8 Institute of Biomedicine, Division of Physiology and Biocenter of Oulu, Oulu University, 90014, Oulu, Finland

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Nutrition Journal 2012, 11:35  doi:10.1186/1475-2891-11-35

Published: 1 June 2012

Abstract

Background

Postprandial metabolic and appetitive responses of proteins are dependent on protein source and processing technique prior to ingestion. Studies on the postprandial effects of enzymatic crosslinking of milk proteins are sparse. Our aim was to study the effect of transglutaminase (TG)-induced crosslinking of sodium caseinate on postprandial metabolic and appetite responses. Whey protein was included as reference protein.

Methods

Thirteen healthy individuals (23.3 ± 1.1 y, BMI 21.7 ± 0.4 kg/m2) participated in a single-blind crossover design experiment in which the subjects consumed three different isovolumic (500 g) pourable beverages containing either sodium caseinate (Cas, 29 g), TG-treated sodium caseinate (Cas-TG, 29 g) or whey protein (Wh, 30 g) in a randomized order. Blood samples were collected at baseline and for 4 h postprandially for the determination of plasma glucose, insulin and amino acid (AA) concentrations. Gastric emptying (GE) was measured using the 13 C-breath test method. Appetite was assessed using visual analogue scales.

Results

All examined postprandial responses were comparable with Cas and Cas-TG. The protein type used in the beverages was reflected as differences in plasma AA concentrations between Wh and Cas, but there were no differences in plasma glucose or insulin responses. A tendency for faster GE rate after Wh was detected. Appetite ratings or subsequent energy intake did not differ among the protein beverages.

Conclusions

Our results indicate that the metabolic responses of enzymatically crosslinked and native sodium caseinate in a liquid matrix are comparable, suggesting similar digestion and absorption rates and first pass metabolism despite the structural modification of Cas-TG.

Keywords:
Caseinate; Whey protein; Crosslinking; Postprandial; Glucose; Insulin; Amino acids; Appetite