METHODS FOR DETECTION AND DETERMINATION OF VEGETABLE PROTEINS IN MEAT-PRODUCTS

Soy protein is the vegetable protein that is most frequently used in meat products. Accordingly, detection and determination procedures have mainly been focused on soy proteins. Cereal proteins received far less attention analytically, let alone the less conventional vegetable proteins. Every method published has only a limited applicability, determined by both the type of soy preparation concerned and the heat processing of the sample. The methods may be divided into five categories. 1. Chemical methods are based on analysis of tracer substances accompanying the soy proteins by nature. Their specificity is rather low; other vegetable proteins may contain the same substances. Soy flour, concentrates and texturates respond quantitatively, and sometimes even qualitatively, different. The methods are almost useless for isolated soy proteins. 2. Microscopic methods may allow rapid detection of soy products except isolates. They may be used for quantitation purposes. However, representative results will only be secured at the expense of time and labor. 3. Electrophoresis methods rely on the recognizability of soy protein bands in the pherogram pattern. Field of application and specificity are satisfactory. Efficient media enable complete solubilization of soy protein from meat products, if not severely heat-processed. 4. Immunochemical methods, although very sensitive and specific, are only suitable for detection purposes, provided the sample temperature did not exceed 100 C during processing. This holds, of course, only true if the soy produced used is not excessively heated during preparation. 5. Methods based on amino acid composition or sequence are based on computer matching of the amino acid pattern of the meat product sample with those of varying mixtures of all proteins that could be contained in the sample. © 1979 The American Oil Chemists' Society.