Influence of dissolved gases and heat treatments on the oxidative degradation of polyunsaturated fatty acids enriched dairy beverage.
The combined effect of dissolved gas composition and heat treatment on the oxidative degradation of a dairy beverage enriched with 2% linseed oil was studied. The dairy beverage was saturated with air, nitrogen, or a nitrogen/hydrogen mixture (4% hydrogen) before pasteurization or sterilization. Saturation with either nitrogen or a nitrogen/hydrogen mixture decreased the dissolved oxygen concentration in dairy beverages (Delta = 7.7 ppm), and the presence of hydrogen significantly reduced the redox potential (Delta = 287 mV). Heat treatments also reduced the oxygen content and redox potential, sterilization being more effective than pasteurization. Both pasteurization and sterilization induced the oxidative degradation of the beverages. On average, the propanal concentration increased by a factor of 2.3 after pasteurization and by a factor of 6.2 after sterilization. However, during storage, sterilized beverages resisted light-induced oxidation better than unheated or pasteurized beverages. Furthermore, saturation with nitrogen or a nitrogen/hydrogen mixture significantly reduced oxidative degradation and provided some protection against color changes during storage.
Giroux
Hélène J
HJ
Food Research and Development Centre, Agriculture and Agri-Food Canada, 3600 Casavant Boulevard West, Saint-Hyacinthe, Quebec, Canada J2S 8E3.
Acteau
Geneviève
G
Sabik
Hassan
H
Britten
Michel
M
D001628:Beverages / Q000032:analysis*; D003611:Dairy Products / Q000032:analysis*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D005511:Food Handling / Q000379:methods; D006358:Hot Temperature; D006859:Hydrogen / Q000737:chemistry*; D008043:Linseed Oil / Q000032:analysis; D015227:Lipid Peroxidation; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry
D005231:Fatty Acids, Unsaturated; D006859:Hydrogen; D008043:Linseed Oil; D009584:Nitrogen; D010100:Oxygen