Effect of temperature on evolution of free amino acid and biogenic amine contents during storage of Azeitao cheese

Abstract

A study on the evolution of free amino acids and biogenic amines in Azeitao cheese during 4 weeks at different temperatures of storage (4 and 25 degreesC) was performed. Free amino acids and biogenic amines were determined by RP-HPLC with visible detection, following extraction from the cheese and derivatization with dabsyl chloride. The method presented a linear relation between peak area and concentration from 2-200 mg/l. The detection limit value was less than 1.5 mg/l. The average repeatability was less than 4%. The major free amino acids were proline, valine, isoleucine and leucine and the major amines were tyramine, cadaverine and histamine. Room temperature (25 degreesC) promoted a significant increase of the contents of valine, leucine, tyramine and putrescine, expressed as g/kg of dry matter. These two free amino acids and two biogenic amines may serve as indicators of temperatures changes in ripened cheese.