Irradiation technology has been shown to be a possible preservation technology used to prolong the shelf life and provide microbial decontamination of spices. In this study, the molecular mechanisms of the irradiation-induced accumulation of polyphenols in star anise were explored using metabolomics combined with ultra-high-performance liquid chromatography quadrupole-Orbitrap (UHPLC-Q-Orbitrap) high-resolution mass spectrometry. Fifty-six star anise samples from different areas processed with 2–10 kGy doses of irradiation were compared. The effect of post irradiation storage times ranging from 0 to 70 days was also evaluated. A total of 161 metabolites with variable importance on projection greater than 1 were characterized, and significant differences in flavonoid content in star anise were observed after irradiation. Absolute quantification was used for the quantification of distinctive compounds, and the limit of quantitation of the components was 1.90–6.53 μg/kg. The flavonoid content was stable on the 28th day of storage. The average content of flavonoids increased by 2–9 times due to the breaking of glycoside bonds in star anise by irradiation. C 15 H 11 O 7 + m/z 303.13045 and C 3 H 3 O 2 + m/z 71.01276 were defined as the characteristic fragments of flavonoids according to the mechanism of fragmentation. Checking the extraction ion chromatogram (EIC) characteristic fragments allows straightforward screening of untargeted flavonoids.
Xuan Li,Xinye Wu,Jinfeng Bi,Xuan Liu,Xiao Li,Chongting Guo
Polyphenols are closely related to the nutritional value , flavor, and color of dried apple products. In present work, the correlation of polyphenol accumulation with apple slices browning in hot air drying (65 °C, 2 m/s air velocity) process was investigated. Polyphenols composition were distinguished in different apple varieties, among which chlorogenic acid, epicatechin were the most abundant constitutes, accounting for 44.47–75.45 g/100 g, 30.31–35.16 g/100 g of total polyphenols respectively in apple flesh. Browning characteristic distribution of 7 varieties dried apple in PCA analysis model were similar to their fresh counterparts. The average browning degree were 22.31 and 6.72 in dried and fresh apple slices respectively, revealing that hot air drying treatment accelerated and extended the effects of polyphenol enzymatic browning process. High chlorogenic acid and/or catechin content induced redness value ( a* value) variation, while lower total polyphenol content and higher polyphenol diversity mainly induced brightness ( L* value) and yellowness ( b* value) variation in drying process. Specifically, in Fuji apple slices, quercetin-3-O-galactoside significantly correlated to L* variation (r = 0.838, **P < 0.01), while catechin, chlorogenic acid, phlorizin successively contributed to the variation of a* (r = 0.877, 0.906, 0.848, **P < 0.01) and b* (0.919, 0.953, 0.906, **P < 0.01). These results would be the reference for predicting and controlling the color quality of dehydrated apple products by polyphenol content and composition.
危险品化学品经营许可证（带存储）