Influence of heat treatment on carnosine, anserine and free amino acid composition of beef broth and its role in flavour development

In an attempt to determine the most important free amino acids (FAAs) in th e development of the flavour of beef broths, the amino acid compositions of beef broths prepared at different temperatures and cooking times, with fla vours of different intensities, were studied. From our data, broths obtaine d at temperatures above 75 degrees C and cooking times longer than 120 min had significantly lower levels of most of the FAAs studied (P < 0.05). Stat istical analysis of the sensorial and analytical data (principal component analysis, chi-square analysis) permitted the different FAAs to be grouped i n relation to the flavour. There was a significant association between elev ated levels of glutamic acid, asparagine (P < 0.01), lysine and methionine (P < 0.05) and the development of beef broth flavour. However, this was inv ersely related to levels of cysteine, proline, serine, M-histadine, tyrosin e, valine, arginine and aspartic acid whereas reduced levels of beta-alanin e, asparagine, tyrosine, threonine, methionine, cysteine, leucine, isoleuci ne, tryptophan, glutamic acid, histidine, lysine and phenylalanine were ass ociated with sapid properties not characteristic of beef broths (astringent , warmed-over flavours). A significant correlation (P < 0.01) between senso ry evaluation and carnosine and anserine levels was also observed.