High pressure-low temperature processing of food proteins.
High pressure-low temperature (HP-LT) processing is of interest in the food field in view of: (i) obtaining a "cold" pasteurisation effect, the level of microbial inactivation being higher after pressurisation at low or sub-zero than at ambient temperature; (ii) limiting the negative impact of atmospheric pressure freezing on food structures. The specific effects of freezing by fast pressure release on the formation of ice I crystals have been investigated on oil in water emulsions stabilized by proteins, and protein gels, showing the formation of a high number of small ice nuclei compared to the long needle-shaped crystals obtained by conventional freezing at 0.1 MPa. It was therefore of interest to study the effects of HP-LT processing on unfolding or dissociation/aggregation phenomena in food proteins, in view of minimizing or controlling structural changes and aggregation reactions, and/or of improving protein functional properties. In the present studies, the effects of HP-LT have been investigated on protein models such as (i) beta-lactoglobulin, i.e., a whey protein with a well known 3-D structure, and (ii) casein micelles, i.e., the main milk protein components, the supramolecular structure of which is not fully elucidated. The effects of HP-LT processing was studied up to 300 MPa at low or sub-zero temperatures and after pressure release, or up to 200 MPa by UV spectroscopy under pressure, allowing to follow reversible structural changes. Pressurisation of approximately 2% beta-lactoglobulin solutions up to 300 MPa at low/subzero temperatures minimizes aggregation reactions, as measured after pressure release. In parallel, such low temperature treatments enhanced the size reduction of casein micelles.
Dumay
Eliane
E
Equipe de Biochimie et Technologie Alimentaires, UMR 1208, Département Agro-Ressources et Procédés Biologiques, Université Montpellier II, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France. e.dumay@univ-montp2.fr
Picart
Laetitia
L
Regnault
Stéphanie
S
Thiebaud
Maryse
M
D000818:Animals; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D005519:Food Preservation; D005615:Freezing; D008894:Milk Proteins / Q000737:chemistry*; D011312:Pressure; D011506:Proteins / Q000737:chemistry
D008894:Milk Proteins; D011506:Proteins