An interaction between additives x storage time x packaging
method was observed for yellowness (Fig. 3b). A faster increase
in b⁄ values was noted during storage in the air, compared with
vacuum. Differences in b⁄ along the storage period could be related
to the intensity of the oxidation process that takes place during
storage and might tend to increase yellowness of samples by rancidity
(García-Esteban, Ansorena, & Astiasarán, 2004). Differences
between samples were observed only at some stages of storage,
and they did not show a clear trend.