Relationship between MALDI-TOF Analysis of β-CN f193−209 Concentration and Sensory Evaluation of Bitterness Intensity of Aged Cheddar Cheese

An internal standard method was previously developed to measure the concentration of a synthetic bitter peptide, β-CN f193−209, by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The objective of this study was to evaluate the relationship between β-CN f193−209 concentration in an aqueous extract of aged Cheddar cheese and bitterness intensity of the cheese. Concentrations of β-CN f193−209 in cheese extracts were determined by MALDI-TOF at 0, 120, 180, and 270 days. Trained panels evaluated the bitterness intensity of the cheeses at 180 and 270 days. Correlation coefficients between MALDI and sensory data at 180 and 270 days were 0.803 and 0.554, respectively. The decreased correlation may be due to the presence of other bitter peptides more responsible for bitterness at longer aging or the production of compounds that mask bitterness intensity. Keywords: Bitter peptide; β-CN f193−209; cheese; MALDI; matrix-assisted laser desorption/ionization