Beef broth flavour: relation of components with the flavour developed at different cooking temperatures

The components of broths obtained at different cooking temperatures (from 5 5 degrees C to boiling under reflux) have been related, through regression analysis, with their sensorial evaluation. An increase in cooking temperatu re led to a significant rise (P less than or equal to 0.05) in the concentr ation of nitrogen in peptides of molecular weight higher than 600 Da (HPPN, higher than 600 Da peptidic nitrogen), nitrogen in non-amino acid substanc es of less than 600 Da (SNAN, small. non-amino acid nitrogen compounds), cr eatinine, inosine 5'-monophosphate (IMP) and adenosine 5'-monophosphate (AM P) in beef broths. The levels of SNAN, IMP, AMP, guanosine 5'-monophosphate (GMP) and creatine showed a positive and significant relation (P less than or equal to 0.01) with the sensorial evaluation. Simple linear regression analysis showed that the beef broth flavour is inversely related to the pro tein nitrogen (PN) concentration. Multiple linear regression analysis sugge sted that flavour properties of beef broths were more influenced by the EMP concentration than the GIMP and AMP concentration and that SNAN is more im portant than HPPN. Significant correlations (P less than or equal to 0.01) established between D-ribose content, sensorial evaluation and amino acid n itrogen (AN) concentration suggested that besides amino acids and free suga rs, substances from the earlier steps of Maillard reactions are involved in the obtention of suitable beef broth flavour at 85 degrees C. Nevertheless , the development of off-flavours at cooking temperatures higher than 95 de grees C, especially warmed-over flavour (WOF), suggests that it is advisabl e to restrict the reactions that occur at high temperatures. (C) 2000 Socie ty of Chemical Industry.