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Detection of pH 4.6 insoluble beta-lactoglobulin in heat-treated milk and Mozzarella cheese
No full textDifferent protein aggregates including beta-lactoglobulin (beta-lg) were detected in the pH 4.6 insoluble fraction recovered from actual heat-treated milk samples by gel electrophoresis and immunoblotting. A competitive enzyme-linked immunosorbent assay (ELISA) using anti-beta-lg polyclonal antibodies was developed to analyze the beta-lg partition in the protein fractions obtained upon acidification of both milk and Mozzarella cheese at pH 4.6. According to ELISA determinations, nearly 90% of the pH 4.6 soluble beta-lg included in raw milk was found in the pH 4.6 insoluble fraction of ultrahigh temperature (UHT)-treated milk. As concerns Mozzarella cheese analysis, ELISA results indicated that about 36% of the total beta-lg milk content was transferred from pasteurized milk to Mozzarella cheese, whereas less than 0.5% was transferred from raw milk. The pH 4.6 insoluble beta-lg proved to be a suitable indicator of the intensity of the heat treatment applied to milk. The ELISA-based detection of this parameter was suggested for quality control of both drinking milk and raw milk cheese
Authentication of dairy products by immunochemical methods: a review
No full textAntibody-based techniques for the assessment of authenticity of dairy products are reviewed in this paper. Because of the inherent complexity of the protein and peptide fractions from milk and even more so from cheese, the use of immunoreagents which are more selective than polyclonal antibodies is usually required for the assaying dairy authenticity by immunochemical methods. Significant advances in this area have been achieved over the last decade thanks to advances in the antipeptide antibody technology, based on the use of properly designed peptides which mimick specified protein substructures as model antigens. Tailor-made antibodies have been developped either for the detection of single protein components or for recognizing protein adducts created by the technological processes employed. Different reagent configurations and immunoassay formats have been devised for a number of analytical applications relevant to the quality control of dairy products, ranging from the monitoring of molecular markers to the tracing of technological processes applied to milk for cheese-making
Occurrence of major whey proteins in the pH 4.6 insoluble protein fraction from UHT-treated milk
No full textA clear picture of the protein rearrangement in milk following UHT-treatment was drawn by a comparative
analysis of the pH 4.6 soluble protein fraction (SPF) and the pH 4.6 insoluble protein fraction (IPF) recovered from raw and
UHT-treated milk samples. The two protein fractions were analyzed by mono- or bidimensional gel electrophoresis under
reducing and nonreducing conditions, and protein bands were identified by specific immunostaining. Results showed that bovine
serum albumin, β-lactoglobulin, and, to a lesser extent, α-lactalbumin coprecipitated with caseins in UHT-treated milk samples at
pH 4.6. These proteins were almost exclusively involved in high molecular weight aggregates held together by disulfide bonds.
Partition of α-lactalbumin and bovine serum albumin in the protein fractions obtained upon acidification of milk at pH 4.6 was
evaluated by competitive immunoassays. The ELISA-based results suggested the possibility of using pH 4.6 insoluble α-
lactalbumin and bovine serum albumin, in addition to pH 4.6 insoluble β-lactoglobulin, as indicators of the intensity of the heat
treatment applied to milk
Detection of plasmin-mediated beta-casein hydrolysis in milk and cheese through immunochemical techniques
No full textDetection of plasmin-mediated beta-casein hydrolysis in milk and cheese through immunochemical techniques
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