Effects of heat treatment of cow's milk and whey on the nutritional quality and antigenic properties.

Abstract

SUMMARY Recent experiments in guinea-pigs suggest that heat treatment applied during the manufacture of baby milk formulae reduces the immunological sensitising capacity of the cows' milk proteins. This immunological benefit must be weighed against possible damage that heat treatment may cause to the nutritional quality of the products. Severe heat treatment of skimmed milk (121°C for 20 min) destroyed all the vitamin B12, about 60% of the thiamin and vitamin B6, 70% of the ascorbic acid, and about 30% of the folate. Available lysine was reduced by 21 % and lactulose was formed (166 mg/100 ml). Despite extensive denaturation of the whey proteins the milk retained its capacity to sensitise guinea-pigs for systemic anaphylaxis when administered orally. Animals drinking heated milk also produced circulating antibodies to 3-lactoglobulin and casein, although titres were lower than for unheated milk. Unlike skimmed milk, heat-treated diafiltered whey failed to sensitise guinea-pigs orally. It caused the production of trace levels of antibodies in some of the animals, but these were specific for residual casein. We suggest that it may be possible to produce a non-sensitising baby milk without casein based on heat-denatured whey. The nutritional quality could be preserved by removing low molecular weight nutrients before heat treatment and adding back appropriate quantities later.

Negative effect of heat sterilization on the free amino acid concentrations in infant formula

“…High heat has been shown to cause substantial loss of several vitamins, including thiamin, vitamin B6, ascorbate, folate, and vitamin B12. The dehydro form of ascorbate, which is produced on heating milk, is involved in oxidative reactions affecting folate and vitamin B12 (Adrian, 1974;Kilshaw et al, 1982). Other investigators, however, have argued that heat treatment has no serious harmful effects on nutritional value, apart from the destruction of heat-labile vitamins, which can easily be supplemented (Langhendries et al, 1992;Angelino et al, 1999).…”

“…Infant formulas are often heat sterilized in hospitals where water contamination or nosocomial infection is an issue, especially in developing countries and when large quantity of prepared milk is needed daily for nursery and hospitalized infants. However, only a few studies have investigated the effect of heat on the nutritional value of infant formula (Adrian, 1974;Kilshaw et al, 1982;Gerber et al, 1983). High heat has been shown to cause substantial loss of several vitamins, including thiamin, vitamin B6, ascorbate, folate, and vitamin B12.…”

The Application of Membrane Separation Technology in the Dairy Industry

“…Milk is treated with heat to remove microbial cells [49]. However, the heat treatment change the nutritional and flavor profile of the products [50,51]. Membrane separation techniques are operated at low temperature, which remove bacteria effectively without affecting the nutritional and flavor profile.…”

Effects of Sterilization Process on the Physicochemical and Nutritional Properties of Liquid Enteral Formula

“…Because the amino group of amino acids, especially lysine, is blocked by the reducing sugar in the Y. Takeda. et al 574 Maillard reaction (Rufián-Henares et al, 2006;van Boekel, 1998), it is thought that heat treatment affects protein quality (Desrosiers and Savoie, 1991;Kilshaw et al, 1982;Rutherfurd and Moughan, 2005;Sarwar et al, 1988).…”

“…Because the amino group of amino acids, especially lysine, is blocked by the reducing sugar in the Y. Takeda. et al 574 Maillard reaction (Rufián-Henares et al, 2006;van Boekel, 1998), it is thought that heat treatment affects protein quality (Desrosiers and Savoie, 1991;Kilshaw et al, 1982;Rutherfurd and Moughan, 2005;Sarwar et al, 1988).In fact, Sarwar et al (1989) investigated the protein quality of commercial infant formulae manufactured by different production processes in a rat study, and found that the digestibility and protein efficiency ratio of the liquid formula were lower than those of the powder. In contrast, Sarriá et al (2000) investigated the protein quality of various commercial formulae, including a powdered form, an in-bottle-sterilized form and a UHT form, and reported no remarkable differences in product digestibility and protein utilization in rats.…”