Hu Zhao,Xiaopu Shi,Cheng Shen,Caifeng Chen,Jiyuan Liu,Changqing Qu
Toon bud is rich in polyphenols and flavonoids, which not only have nutritional value but also have health benefits. However, the molecular mechanisms of flavonoid accumulation during storage remain unclear. In our report, small RNA libraries from toon buds were synthesized after three storage period (0, 3, and 5 days) at 4 °C. Overall, 303 homologous sequences with known microRNA (conserved miRNAs homology) and 19 putative novel miRNAs were obtained using Illumina sequencing technology. Furthermore, the potential target unigenes of these miRNAs were predicted. Of the predicted miRNAs and their target unigenes, 17 conserved miRNAs and their target unigenes were confirmed by quantitative real-time PCR (qRT-PCR). Exactly 11 miRNAs involved in the flavonoid pathway and 6 miRNAs targeting transcription factors displayed significant correlation with flavonoid accumulation in toon buds. The findings will be helpful for better understanding flavonoid accumulation in toon buds during storage.
Sulfur-containing compounds are responsible for the aroma of Toona sinensis shoot (TS). In this study, vacuum-freeze-drying (VFD), microwave-drying (MD), and hot-air-drying at 100 and 40 °C (HAD100 and HAD40, respectively), were applied to dehydrate perishable TS for preservation. VFD-TS retained most aroma of fresh/raw TS after rehydration. The content of sulfur-containing compounds reached to 118.00 µg/g with leading by methyl thiirane, ( E,E )/( E,Z )/( Z,Z )-bis-(1-propenyl) disulfides, and ( Z )/( E )-2-mercapto-3,4-dimethyl-2,3-dihydrothiophenes accounting for 86.33 %. They were undetected in the rehydrated MD-TS and HAD100-TS, as the indigenous enzymes in TS were deactivated under their dehydration conditions. Interestingly, the sulfur-containing compounds was restored by 77.47 % after the TS was treated by gamma-glutamyl transferase (GGT). Thus, the release of sulfur-containing compounds from TS could depend on GGT reaction. It was different from alliaceous vegetables relying on alliinase reaction. The results revealed the aroma formation in TS and provided an approach to enhance the aroma of TS dried by different methods.
危险品化学品经营许可证（带存储）