Abstract:
The aromatic quality of concentrated peach puree was significantly influenced by different processing stages. To improve product quality, it is vital to elucidate the patterns of aroma evolution at each processing stage. Flavoromics combined with chemometrics were used to clarify the stage and differential aroma-active components of peach puree after commercial crushing, centrifugation, concentration and sterilization. A total of 89 volatile components were determined in the peach puree throughout the four stages. Among them, 15 volatiles, with relative odor activity value (rOAV) ≥ 1, were defined as the key aroma-active components:
γ-decalactone, ethyl butyrate, ethyl isovalerate, isoamyl acetate, hexyl acetate, (Z)-3-hexenyl acetate, hexanal, octanal, (E,Z)-2,6-nonadienal, 1-hexanol, benzyl alcohol, damascenone, isovaleric acid, theaspirane, and 2-acetyl-1-pyrrolidine. Specifically, 11, 8, 4 and 2 key aroma-active components were identified in the crushed, centrifuged, concentrated and sterilised peach puree, respectively. Furthermore, principal component analysis (PCA) revealed that the concentration step was identified as the crucial stage responsible for the changes and deterioration of the aroma quality in peach purees. Compared to the peach puree after crushing, fruity esters and green alcohols in the peach puree after concentration decreased by 100.00% and 97.95%, respectively. In addition, four differential aroma-active compounds were screened out using variable influence on projection (VIP) analyses to distinguish peach puree across processing stages: leaf acetate (fruity, VIP: 1.16), 1-hexanol (green/floral, VIP: 1.82), benzyl alcohol (floral, VIP: 2.41), and isovaleric acid (rancid, VIP: 1.93). The concentration-induced changes in these compounds contributed significantly to the loss of the characteristic peach aroma at the concentration stage. Hence, concentration is the key stage that caused the undesirable changes in key aromas during continuous production of peach puree. This study provides a theoretical basis for peach puree processing enterprises to produce products with highly preserved characteristic aromas through the optimization of concentration technologies.