DETERMINATION OF THE FACTORS THAT CAUSE BITTERNESS DURING SHELF-LIFE IN WHITE CHEESE PRODUCED USING ULTRAFILTRATED MILK

Abstract

This study aimed to determine the causes of bitterness problems in white cheese produced by ultrafiltration (UF). To investigate the association between the bitterness with the enzyme use or by the starter culture, white cheese was produced using UF-pasteurized and UF-raw milk with two different coagulating enzymes and two starter cultures with different proteolytic activities. Sensory analysis, protein, water-soluble nitrogen, 12% trichloroacetic acid-soluble nitrogen, 5% phosphotungstic acid-soluble nitrogen and acid degree values were determined on day 1, 30, 60 and 90 of the ripening periods. During the ripening process, bitterness was determined in the cheese samples due to proteolysis. The A cheese sample, which was produced using chymosin enzyme and a starter culture with high proteolytic activity, was determined to be the sample with the highest bitterness level in the sensory analyses, SDS-PAGE electrophoresis and HPLC analysis. 72.26% αs-casein hydrolysis was determined in the A cheese sample. According to HPLC results, a high hydrophobic peptide formation was determined with the increase in the area of hydrophobic peptides with a rate of 106% between 40 and 60 minutes.