title: Moisture-induced aggregation of alpha-lactalbumin: effects of temperature, cations, and pH.
abstract: Alpha-lactalbumin is an important dairy protein ingredient, and has been widely used in high-protein foods such as infant formula and nutritional bars for its nutritional and functional properties. The purpose of this study was to investigate the moisture-induced aggregation of alpha-lactalbumin in premixed protein dough model systems, and to illustrate the effects of temperature, cations, and pH on the progress of protein aggregation. Our results suggested that storage temperature was a critical factor for protein aggregation in model systems, and the formation of protein aggregates became faster with increases in storage temperature. Calcium significantly improved the thermal stability of alpha-lactalbumin and slowed down the formation of protein aggregates. The increases in pH accelerated the aggregation of alpha-lactalbumin. Our results also suggested that the formation of intermolecular disulfide bonds together with noncovalent interactions are the main mechanisms resulting in the moisture-induced aggregation of alpha-lactalbumin in model systems.
  
  
  CONCLUSIONS
  Alpha-lactalbumin is an important dairy protein ingredient, and has been widely used in high-protein foods such as infant formula and nutritional bars for its nutritional and functional properties. Our results suggested low storage temperature, the presence of calcium and low pH condition can make high-protein food products containing alpha-lactalbumin more stable.
authors.affiliation: State Key Lab. of Food Science & Technology, School of Food Science & Technology, Jiangnan Univ., Wuxi, Jiangsu Province 214122, China.
authors.forename: Dasong
authors.initials: D
authors.lastname: Liu
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Liu
authors.forename: Theodore P
authors.initials: TP
authors.lastname: Labuza
mesh_terms: D001059:Apoproteins / Q000737:chemistry; D001939:Bread / Q000032:analysis*; D002118:Calcium / Q000032:analysis; D002122:Calcium Chloride / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D005520:Food Preservatives / Q000737:chemistry*; D061353:Food Storage; D005527:Food, Fortified / Q000032:analysis; D006358:Hot Temperature / Q000009:adverse effects; D006863:Hydrogen-Ion Concentration; D007768:Lactalbumin / Q000737:chemistry*; D008274:Magnesium / Q000032:analysis; D015636:Magnesium Chloride / Q000737:chemistry*; D008956:Models, Chemical; D008970:Molecular Weight; D009994:Osmolar Concentration; D011489:Protein Denaturation / Q000187:drug effects; D012995:Solubility; D013997:Time Factors; D014867:Water / Q000032:analysis / Q000737:chemistry*
chemical_list: D001059:Apoproteins; D005520:Food Preservatives; C041966:apo-alpha-lactalbumin; D015636:Magnesium Chloride; D014867:Water; D007768:Lactalbumin; D008274:Magnesium; D002122:Calcium Chloride; D002118:Calcium