Studies on genetic variants of alpha-lactalbumin and beta-lactoglobulin from milk of native Portuguese ovine and caprine breeds

• Type: Article in International Scientific Journal
• Date: 1999

Authors

Pintado, ME (Author) Other; F. Xavier Malcata (Author) Other

Journal

Title: International Journal of Food Science and Technology

Vol. 34 No. 4

Pages: 245-252

ISSN: 0950-5423

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 7 Citations

Scopus - 7 Citations

Other information

Authenticus ID: P-001-46V

DOI: 10.1046/j.1365-2621.1999.00258.x

Abstract (EN): alpha-Lactalbumin (alpha-La) and beta-lactoglobulin (beta-Lg) fractions were obtained from Portuguese native breeds of ewes and goats by preparative gel filtration and further purified by ion exchange; their genetic variants were characterized by isolectric focusing, and beta-Lg isolated was further characterized by differential scanning calorimetry. Separation of beta-Lg and alpha-La by molecular exclusion from native whey was relatively easy, whereas beta-Lg from both breeds accounted for a single peak via ion exchange under various gradients of NaCl. Isoelectric focusing has indicated that alpha-La from ovine and caprine wheys appears as a single variant in each case, as well as beta-Lg from caprine whey; however, beta-Lg from ovine whey appears as two peaks, tentatively denoted as beta-Lg A and B. Further comparison with bovine whey made it possible to rank whey proteins by increasing value of pi as follows: bovine beta-Lg A, bovine alpha-La, bovine beta-Lg B, ovine and caprine alpha-La, ovine beta-Lg A, and finally ovine beta-Lg B and caprine beta-Lg. beta-Lg from goat's whey showed the highest onset temperature of denaturation in the presence (78-97 degrees C) or absence (90-100 degrees C) of NaCl for every pH tested; when NaCl was present, a good correlation between pi and onset temperature of denaturation was obtained for pH values in the range 3.5-7.0.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8