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Digestate generated from anaerobic digestion (AD) has been widely used as digestate fertilizer (DF) for plant growth, but its application should be comprehensively investigated. This study evaluates the effects of different amounts of DF on crop growth, nutrient use efficiency (NUE), soil properties, and potential negative impacts of DF application (salinity and heavy metals (HMs)) with two different crops (Eggplant and Shanghai cabbage). In eggplant cultivation, the yield increased with the increase of DF amount, and the yield of the DF-680 group was the highest (65.4 t/ha) under the highest fertilizer amount. However, due to high ammonia volatilization loss and excessive application, the NUE of DF was only about half of that of chemical fertilizer (CF). Significantly different from eggplant, the high application amount of DF resulted in yield reduction in Shanghai cabbage cultivation. The yield and NUE of the DF-170 group were the highest, the yield was 46.5 t/ha, and the NUE was more than twice compared to CF. Moreover, DF can raise soil nitrogen storage and alleviate soil acidification caused by fertilization in both batches of cultivation. Nevertheless, the electrical conductivity (EC) value of the soil was increased by 2-3 times, and the long-term application may lead to soil salinization. On the other hand, the increase of DF application elevated the content of copper (Cu), zinc (Zn), and cadmium (Cd) in soil significantly but did not cause HMs contamination in crops and tillage soil. In summary, reasonable application amounts and methods should be considered when applying DF.

Tea flavonoids are widely recognized as critical flavor contributors and crucial health-promoting bioactive compounds, and have long been the focus of research worldwide in food science. The aim of this review paper is to summarize the major progress in tea flavonoid chemistry, their dynamics of constituents and concentrations during tea processing as well as storage, and their health functions studied between 2001 and 2021. Moreover, the utilization of tea flavonoids in the human body has also been discussed for a detailed understanding of their uptake, metabolism, and interaction with the gut microbiota. Many novel tea flavonoids have been identified, including novel A- and B-ring substituted flavan-3-ol derivatives, condensed and oxidized flavan-3-ol derivatives, and glycosylated and methylated flavonoids, and are found to be closely associated with the characteristic color, flavor, and health benefits of tea. Flavoalkaloids exist widely in various teas, particularly 8

In order to investigate the hypolipidaemic and antioxidant effects of various dark teas produced from different post-fermentation using the same raw material, a hyperlipidaemia zebrafish model combined with binding bile salts assay and antioxidant assays were performed in this study. Results showed that the hypolipidaemic effect of dark tea extracts increased significantly (p 0.05) while the antioxidant ability decreased sharply compared with raw material. Particularly, Liupao tea (50%) and Pu-erh tea (48%) showed promising hypolipidaemic potential; however, the antioxidant capacity of Pu-erh tea decreased (31-49%) most dramatically. Besides, the levels of total polyphenols and catechins decreased sharply, but theabrownin, gallic acid, and caffeine increased significantly after post-fermentation. Moreover, the potential mechanisms of regulating hyperlipidaemia by dark tea extracts were discussed. These results suggest that microbial fermentation significantly affects the bioactivity of dark teas, and provide theoretical basis for processing and improving of dark tea products for hyperlipidaemia therapy.