Added protein, meat, detection

Saz and Marina [148] published a comprehensive review on HPLC methods and their developments to characterize soybean proteins and to analyze soybean proteins in meals. In the case of soybean derived products, a number of papers dealing with cultivar identification [149,150], quantification of soybean proteins [151-154], detection of adulteration with bovine milk proteins [151,155-158], and characterization of commercial soybean products on the basis of their chromatographic protein profile [159,160] have been published in the last years. Other studies deal with the analysis of soybean proteins added to meat [161-165], dairy [151,165-167], and bakery products [156,163,168,169]. The same research group developed perfusion RP-HPLC methods for very rapid separation of maize proteins (3.4 min) and characterization of commercial maize products using multivariate analysis [170], and for the characterization of European and North American inbred and hybrid maize lines [171]. 

Extensive proteolysis of a protein often results in the formation of bitter peptides ( ). Therefore, a compromise between high protein yield and low bitterness has to be found when choosing the DH-value at which the hydrolysis reaction should be terminated. For the present process a DH-value of about 10% seems to be a reasonable value. The termination is performed by acid inactivation of the enzyme and the acid used should be chosen in accordance with the desired organoleptic characteristics of the final hydrolysate. A totally non-bitter product can be produced by use of an organic acid like malic or citric acid. Due to the masking effects of such acids, absolutely no bitterness can be detected even when the taste evaluation is performed at neutral pH. Such products are found most suitable for soft drinks. However, when inorganic acids, e.g. hydrochloric or phosphoric acids are used, a slight bitterness may be detected in the pure hydrolysate. However, when evaluated in for instance a meat product, no bitterness at all can be tasted even when the hydrolysate is added up to a proportion of 1 3 of hydrolyzed protein to meat protein. 

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