Evaluation of the water binding properties of meat binders, substitutes and extenders by different physical and chemical methods.

Abstract

From investigations concerning water binding capacity measured by an improved Baumann technique, differential scanning calorimetry, nitrogen solubility, moisture sorption isotherms, specific surface area, and specific volume of powdered proteinaceous materials proposed as binders and/or substitutes in frankfurter-type sausages it has been concluded, that in water uptake on the Baumann apparatus activation energies comparable to diffusion processes and enzymic reactions and not comparable to chemical reactions are favoured. Water taken up on the Baumann apparatus predominantly is freezable, that is free and only physical bound water. Powdered proteinaceous materials do not take up water discontinuously by strictly limited surface areas and perforations. At first the geometrical surface is completely wetted. Not till then water will be bound by capillary effects. Thus only up to a certain degree of moistening (aw 0.92) the more water is bound, the lower the material's solubility. Afterwards solubility, capillary suction pressure and swelling (increasing pore space) will compete.