Substitution of Casein by [beta]-Casein or of Whey Protein Isolate by [alpha]-Lactalbumin Does Not Affect Mineral Balance in Growing Rats1

• Published in: The Journal of nutrition Vol. 135; no. 6; p. 1438
• Main Authors: Peter Van Dael, Kastenmayer, Peter, Clough, Jennifer, Andrée-Rose Jarret
• Format: Journal Article
• Language: English
• Published: Bethesda American Institute of Nutrition 01.06.2005
• Subjects: Animal care; Dietary minerals; Milk; Proteins; Rodents
• ISSN: 0022-3166; 1541-6100

Bovine milk protein fractions that enable modification of the protein composition and amino acid profile of infant formulas to mimic those of human milk have recently become available. To determine the effects on protein quality and mineral bioavailability of replacing casein by β-casein and of whey protein isolate by α-lactalbumin, 4 groups of growing rats were fed for 3 wk diets containing 10% protein as 1) casein (control); 2) β-casein; 3) casein:whey (40:60); or 4) β-casein:α-lactalbumin (40:60). Protein quality, determined as protein efficiency ratio (PER), net protein utilization (NPU), biological value (BV) and protein digestibility (PD), as well as body weight gain, were higher (P < 0.05) with consumption of the whey-adapted diets [casein:whey (40:60); β-casein:α-lactalbumin (40:60)] compared with the casein diets (casein; β-casein); however, there were no differences between the 2 casein diets or between the 2 whey-adapted diets. Apparent absorption of minerals (Ca, P, Fe, Zn) from the whey-adapted diets was higher than that from the casein diets (P < 0.05); but again, no differences were observed when casein or whey protein isolate were replaced by β-casein or α-lactalbumin, respectively. Thus, substitution of casein by β-casein or of whey protein isolate by α-lactalbumin does not affect protein quality or mineral bioavailability as determined in growing rats. [PUBLICATION ABSTRACT]