Oxidative stability parameters and sensory properties of in-shell Stuart pecans [Carya illinoinensis (Wangenh.) K.Koch] stored at different temperatures under non-accelerated conditions

The main goal of the present work was to determine the oxidative stability of Stuart pecans stored at different temperatures throughout 300 days (approximately 10 months post-harvest). In-shell pecans were stored at 2 degrees C and 20 degrees C at 65 % relative humidity and the oxidative stability was evaluated at 60 days intervals. At 20 degrees C, lipid oxidation markers were significantly higher than at 2 degrees C. Kinetic of oxidation showed significant changes after 210 days of storage with hexanal and pentanal levels 10-fold higher at 20 degrees C than at 2 degrees C, leading to development of rancid and bitter taste with the significant loss of typical flavour and sweetness. Low storage temperature helped lower the levels of oxidative markers but did not avoid the rise of oxidation. Fatty acids and alpha-tocopherol did not change throughout storage, but gamma- tocopherol showed a 12 % and 24 % decrease when pecans were stored for 300 days at 2 degrees C and 20 degrees C respectively. The Principal component analysis showed a clear correlation between hexanal and pentanal and the appearance of bitter and rancid taste in nuts along with the storage time. Aldehydes resulted in a suitable non-destructive marker of pecans stability and quality. Therefore, refrigeration of in-shell pecans reduced the oxidation and its sensory consequences.

Automated summary

The research discovered that lipid oxidation markers of Stuart pecans stored at 20 degrees C were significantly higher than those stored at 2 degrees C. After storage for 210 days, levels of hexanal and pentanal increased, leading to the development of rancid and bitter taste in pecans, with a significant loss of typical flavor and sweetness. While low storage temperature helped reduce the levels of oxidative markers, it could not completely prevent oxidation.