Roasting and packaging in nitrogen atmosphere protect almond var. Guara against lipid oxidation

Abstract

The effect of packaging in nitrogen (N₂) atmosphere or in air on the quality of peeled and roasted almond var. Guara during storage for 20 weeks at 20 °C ± 1 °C and 65-70% relative humidity (RH) was studied. No changes in the sugar, fat, protein or fiber contents were observed during the storage period nor in color. Only the lipid fraction showed significant changes with the kind of packaging atmosphere. The composition of fatty acids remained unchanged during the 5 month storage in all the samples. Packaging in N₂ atmosphere was seen to have a protective effect against the accumulation of conjugated dienes (CD) in peeled almonds, while in roasted almonds, the protective effect was lower and even nil by the end of storage. The contrary effect was observed for the ultraviolet (UV; K₂₇₀) index which increased more slowly in the roasted samples packaged in N₂, while in peeled samples it reached the same levels at the end of storage regardless of the packaging atmosphere. No effect of the packaging atmosphere was observed on the evolution of the peroxide value in the tested samples (peeled or roasted almonds). None of these changes in the lipid fraction was reflected in the final sensory quality of the samples and the taster panel found no changes in the sensory quality in any case.