Effect of packaging and storage temperature on shelled pecan chemical quality indicators and their impact on consumer acceptance

Abstract

Raw, shelled ‘Western Schley’ and ‘Stuart’ pecans were stored for 24 months at 8, 23, and 32 ^°C in cardboard cartons, vacuum pack bags, and modified atmosphere (MAP) bags flushed with nitrogen gas, at 65 % RH. The oxidative stability was assessed by peroxide values (PVs) and free fatty acids (%FFAs), while HS-SPME-GC-FID was used to measure the changes in the concentrations of secondary lipid oxidation compounds, and consumer panels were used to assess pecan acceptability. FFAs and concentrations of secondary lipid oxidation compounds were observed to be significantly higher in ‘Stuart’ pecans than in ‘Western Schley’ pecans over the 24-mo storage period. Samples stored in cartons tended to degrade quicker, while only 1 sample was rejected in MAP packaging. Five of the 6 samples that were rejected by 24 mo were stored at 32 °C. Storage in MAP bags at 8 or 23 °C provided greatest protection. No one chemical marker clearly predicted product failure. Multivariate analyses suggested that consumer rejection was most associated with %FFA, octanal, hexanal and 1-hexanol. These were driven by higher temperature, longer time, storage in cartons and ‘Stuart’ cultivars.