Effect of Different Packaging Materials on the Quality of Toona sinensis Powder Analyzed by Gas Chromatography-Ion Mobility Spectrometry Combined with Multivariate Statistical Analysis

To extend its shelf life, vacuum freeze-dried Toona sinensis (VFDTS) powder was packaged in sealed polyethylene (PE) bags, sealed aluminum foil bags, composite vacuum bags, or aluminum foil vacuum bags. Changes in the sensory quality, moisture content, color, flavor components and total bacterial count of VFDTS powder were monitored during storage under accelerated conditions at (55 ± 1) ℃ and (40 ± 3)% relative humidity (RH). The results showed that VFDTS powder packaged in sealed PE bags exhibited severe moisture absorption and browning with prolonged storage time, and the total bacterial count significantly increased. On the other hand, the moisture content, color and total bacterial count of the powder stored in aluminum foil vacuum bags remained substantially unchanged. A total of 56 volatile compounds were identified in VFDTS powder stored in the different packaging systems, including 13 alcohols, 11 aldehydes, 3 acids, 3 terpenes, 7 ketones, 9 esters, one ether, 2 sulfur compounds, 3 alkanes, and 4 heterocycles. Principal component analysis (PCA) of the volatile compounds showed clear separation among VFDTS powder samples stored in the 4 packaging systems. Based on variable importance in projection (VIP > 1) from orthogonal partial least squares discriminant analysis (OPLS-DA), a total of 14 differential volatile compounds were selected, and their clustering heatmaps could be used to effectively classify the samples in different packaging systems. The samples in aluminum foil vacuum bags had the best quality, followed by sealed aluminum foil bags and composite vacuum bags, while the greatest changes in moisture, color, flavor and microbiological quality were observed in VFDTS powder in sealed PE bags during storage.