Abstract
Processing beverages containing high concentrations of globular proteins represents a technological challenge due to their instability during heating caused by protein aggregation and gelation. Aggregation of whey protein mixtures was investigated in aqueous model systems at pH 3.5, 4.0, and 4.5 at heating conditions resembling conventional industrial treatment (90 °C for 30 s). The extent of aggregation progressively decreased moving away from the pI. Protein aggregates became smaller
and had a more open structure compared to higher pH values. Significant loss of protein dispersibility occurred at pH 4.0 and 4.5 above the denaturation T of whey protein (~70 °C), at which aggregation was caused by intermolecular hydrophobic interactions. Accessible thiol groups were detected in the heat-treated systems, with a higher intensity at higher pH and increasing extent of aggregation. Intermolecular -S-S- bonding played only a minor role in the aggregation at all conditions studied.
Original language | English |
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Pages (from-to) | 733-741 |
Journal | Journal of Agricultural and Food Chemistry |
Volume | 62 |
DOIs | |
Publication status | Published - 2014 |
Keywords
- bovine beta-lactoglobulin
- disulfide bonds
- interchange reactions
- thermal-denaturation
- alpha-lactalbumin
- particulate gels
- induced gelation
- ionic-strength
- ph 2
- solubility