Abstract

The evolution of non-protein-nitrogen (NPN), total and free amino acids in reduced fat Cheddar cheese, prepared by formulated milk for Cheddar cheese with optimized texture, using a single and mixture of adjunct starter cultures during storage was studied. The concentrations of NPN, free and total amino acids were significantly affected by the type of microorganism present and the storage time. The total concentration of free amino acids (TFAA) and NPN in reduced fat cheeses inoculated with adjunct starter culture were higher than full fat control cheese without any adjunct starter culture. Also, higher level of TFAA and NPN were observed in reduced fat cheeses made with single culture of Lactobacillus helveticus. The concentration of glutamine, methionine and leucine as major precursors and contributors to sapid taste and flavor compound in reduced fat cheeses made with single culture of L. helveticus were higher than reduced fat Cheddar cheeses inoculated withLactobacillus casei and Streptococcus thermophilus, and even higher than full fat control cheese made with usual mesophilic starter culture.

Key words: Cheddar cheese, amino acid, non-protein-nitrogen, adjunct starter culture, xanthan gum.

Abbreviation

NPN, Non-protein-nitrogen; TFAA, total of free amino acids.