Aroma degradation is a pivotal technical challenge restricting the development of tea beverages. Addressing the aroma stability is a pressing issue for the tea beverage industry. In this study, the effect of roasting raw materials on the formation of retort odor in green tea beverages was assessed using chemometrics and sensory evaluation. The results found that roasting could significantly reduce the concentration of specific retort odorants including theaspirane (0.260 → 0 μg/L) and linalool (−31.30 %), while significantly promoting the accumulation of Maillard reaction products including 3-ethyl-2,5-dimethylpyrazine (0 → 0.800 μg/L), 2-acetylfuran (0 → 0.104 μg/L), and norisoprenoids including α -ionone (0 → 0.059 μg/L), β -cyclocitral (28.57 %), β -ionone (82.46 %) ( p < 0.05). Sensory evaluation results indicated that moderate roasting (5 min) effectively reduced the intensity of retort odor in green tea beverages while maintaining high overall acceptability. The study provides a theoretical basis for flavor regulation in the tea beverage industry.
Processing is an indispensable technology in the preparation of Spirulina platensis ( S. platensis ). The key odorants in liquids, muds, and powders from S. platensis (NM and GZ) were characterized. A total of 90 odorants were identified and 41 odorants were sniffed with the flavor dilution (FD) factors ranging from 1 to 729. Among them, nonanal, decanal, d -limonene, β -cyclocitral, and β -ionone with FD factors ≥1 were detected in S. platensis during the whole processing stages. In addition, heptanal, ( E , E )-2,4-nonadienal, trans -4,5-epoxy-( E )-2-decenal, 1-hepten-3-one, isophorone, 3-ethyl-2,5-dimethylpyrazine, and α -ionone exhibited higher odor activity values in powders; β -myrcene, methional, and S -methyl methanethiosulphonate were key odorants in muds; while trans -3-penten-2-ol was key odorant in liquids. Besides, the GZ-mud presented stronger earthy and fishy odor than NM - mud. S. platensis powders have the stronger grassy odor, roasted odor, and marine odor than S. platensis muds. Overall, drying process promotes the formation of aldehydes, heterocyclic compounds, and terpenoids.