Influence of oxygen concentration on the storage stability of cream powder

The influence of low oxygen concentrations on lipid oxidation during storage of cream powder was studied. The powder was packed with oxygen concentrations of 209 mL/L, 17 mL/L, 8.3 mL/L, 3.4 mL/L, 1.5 mL/L, 0.7 mL/L and 0.6 mL/L and stored in darkness at 30 degrees C for 29 weeks. To follow oxidation, the formation of volatile oxidation products and oxygen consumption were measured. After 7 weeks of storage a significant (P < 0.01) hexanal development was already seen in all the samples, and the hexanal content was directly related to the initial oxygen content, with one exception, the 0.6 mL/L sample, which had a slightly (but not significantly, P > 0.05) higher hexanal content than the 0.7 mL/L sample. There were only small differences in hexanal formation between the samples packed with oxygen concentrations below 3.4 mL/L. This could be due to a more pronounced influence of oxygen diffusion at these low levels of oxygen, leading to a diffusion-controlled oxidation. Other volatiles not produced by lipid oxidation, also increased during storage. The formation of Strecker aldehydes was found to be oxygen-dependent, whereas the formation of 2-alkanones was not. Measurement of oxygen consumption was not sufficient to detect differences in oxidation rate between the samples packed with 17 mL/L oxygen and less.