Vb. Galazka et al., CHANGES IN PROTEIN-PROTEIN AND PROTEIN-POLYSACCHARIDE INTERACTIONS INDUCED BY HIGH-PRESSURE, Food chemistry, 57(3), 1996, pp. 393-398
beta-Lactoglobulin and bovine serum albumin (BSA) protein solutions (0
.1%, 0.2% and 2.5%), when subjected to high pressure treatment (800 MP
a for 20 min) at neutral pH, were denatured and some aggregates formed
. The total calorimetric enthalpy of 2.5% solutions of the pressure-tr
eated proteins decreased to virtually zero for both beta-lactoglobulin
and BSA following pressure treatment. Isoelectric focussing patterns
(IEF) indicated that aggregation occurred in both proteins and there w
as a concomitant loss of sulphydryl groups (42% for beta-lactoglobulin
and 55% for BSA), suggesting that protein aggregation after high pres
sure processing was caused, at least in part, by the formation of -S-S
- bridges. The surface hydrophobicity of the two proteins was modified
, increasing (40%) with beta-lactoglobulin and decreasing (41%) with B
SA. Pressure treatment of 1:1 mixtures of BSA and dextran sulphate (DS
) yielded structures with a significant enthalpy. However, addition of
DS to beta-lactoglobulin had little effect on the thermograms, sugges
ting that the DS either protects the protein against pressure induced
unfolding or enables the pressure-denatured protein to regain some sec
ondary structure. Copyright (C) 1996 Elsevier Science Ltd