Nutritional Value and Safety in Mice of Proteins and Their Admixtures with Carbohydrates and Vitamin C after Heating

Abstract

When a nutritionally complete basal diet containing 10% protein from casein was supplemented with 20% protein from unheated casein, wheat gluten or soy protein isolate, weanling mice exhibited significantly increased weight gains. In contrast, weight gains were markedly reduced compared to those with the basal diet; that is, growth was inhibited, when the supplement was soy protein or gluten that had been heated at 200 or 215 degrees C for 72 min in the dry state to stimulate crust baking. Addition of various carbohydrates to the gluten during heating prevented such growth inhibition. After heating with sodium ascorbate (but not L-ascorbic acid), soy protein (at 200 degrees C) and gluten (at 215 degrees C) completely prevented growth when added to the basal diet. Growth inhibition also occurred with a heated casein-ascorbate mixture, but was less than with the other proteins. The extent of growth inhibition increased sharply with temperature of heating in the range 180-215 degrees C and with sodium ascorbate concentration in the range 1-20%. Possible physical and chemical changes during heating of protein-ascorbate mixtures are discussed, as are possible mechanisms for the growth inhibition.

Nutritional Value of Proteins from Different Food Sources. A Review

“…Effect of pH and Heat. Food can deteriorate during processing and storage due to both enzymatic and Maillard-type reactions of primary amino groups with reducing sugars and other enzymatic and nonenzymatic browning reactions with nonreducing carbohydrates (Ebersdobler et al, 1991;Friedman and Molnar-Perl, 1990;Friedman et al, 1987;Kratzer et al, 1990;Oste et al, 1991;Ziderman et al, 1989). High pH induces racemization of L-amino acid residues to D-isomers Gumbmann, 1984a,b, 1989) and formation of cross-linked amino acids such as lysinoalanine (Friedman and Pearce, 1989;Friedman et al, 1982a).…”

Behavior of Escherichia coli Bacteria in Whey Protein Concentrate and Corn Meal during Twin Screw Extrusion Processing at different Temperatures

“…Food ingredients developed by this extrusion have improved texture with enhanced physical properties including ex-vivo or in-vivo functionality [5]. Texturization of proteins by extrusion processing occurs at temperatures ranging from 50 to 100°C at short residence times of approximately 2 min [6]. However, information of this processing treatment on the survival and viability loss of microbial organisms present on treated food items is limited.…”

Texturized Dairy Proteins

“…An extruder is one device used to accomplish texturization of proteins through the actions of its internal rotating screws pressing the protein against the fixed heated barrel walls, and forcing the molten protein mass through a restriction die that aligns the protein mass in the direction of rotational flow. Extrusion texturization of proteins can occur at temperatures ranging from 50 to 100 °C and at short residence times (< 2 min), far below the range of thermochemical denaturation conditions for other proteins, for instance, wheat glutens in dry heat from about 200 to 215 °C for 72 min (Friedman and others 1987), or collagen in moist heat below 120 °C for 30 min (Meyer and others 2005).…”