Investigating particle‐size‐induced changes in composition, physical, rheological, and bioactive properties of black tea powder

Abstract

BACKGROUND: People brew tea to drink an infusion that only contains 25% water-soluble constituents, leading to most of the insoluble materials being wasted. Tea powder could be drunk directly by mixing with water without producing any waste. Tea powder can also be used as a natural additive to improve the flavour and taste in beverages and foods. Much detailed information on the particle properties of tea powder is required with its increasing consumption. The aim of this study was to investigate the effects of particle size ranging from median diameter D 50 = 4.32 to 26.59 ∼m on the composition, physical, rheological, and bioactive properties of black tea powder. RESULTS:The results indicate that large powder sizes had high bulk density and flowability, whereas small powder sizes possessed good swelling ability and wettability. The contents of water extract, total polyphenols, crude fibre, catechins, and thearubigins reduced with a decrease in particle size. To change the particle size and concentration could adjust the elastic modulus and the viscous modulus of the black tea powder suspension. Moreover, black tea powder with small particle size could regulate blood lipids in a hyperlipidaemic rat model by lowering triacylglycerols and elevating high-density lipoprotein cholesterol, whereas large particles presented an advantage in reducing body weight. CONCLUSION: Our investigation extended the knowledge of commercial black tea powder in composition, physical, rheological, and bioactive properties. These results lay the foundation for future exploration of the use of tea powder in the food industry.

Effect of superfine grinding on the physico‐chemical and antioxidant properties ofCistanche deserticolapowders

“…The particle size distribution of the C. deserticola powders was analyzed using a LS13320 steam laser diffraction particle size analyzer (Beckman Coulter, Inc, USA). The span of particle size distribution was calculated with Equation (1) (Zhu et al, 2022): where D 90 , D 50 , and D 10 are the particle size of the equivalent volume at 90%, 50%, and 10% additive volume.…”

“…Xi et al (2016) also found that Astragalus ultrafine powder could boost the immune response in chickens. Zhu et al (2022) reported that black tea ultrafine powder expressed a good bioactivity on reducing triglyceride and promoting high-density lipoprotein in rat model with hyperlipidemia. The wheat bran superfine powder had good dispersibility and solubility, so that it can be handily used in food (He et al, 2018).…”

Fast Pyrolysis of Tea Waste under a Hydrogen-Rich Atmosphere: A Study on Nitrogen Evolution and Green Ammonia Production

“…According to the Food and Agriculture Organization of the United Nations, the output of tea around the world was 7.02 million tons in 2020, of which China accounted for 42%. However, over 90% of tea was disposed of after the brewing process, leading to a significant increase in the production of tea waste. , It is noteworthy that tea waste is enriched with nitrogen functionalities (amino acids and caffeine) and has a much higher content of nitrogen (about 5%) than conventional biomass or coal (about 1%). , Therefore, unreasonable disposal of tea waste may probably lead to nitrogen pollution like harmful NO x emissions and water eutrophication. , Therefore, it is highly desirable to search for an effective method for the resource utilization of tea waste while alleviating the environmental load.…”

“…18 Tea is widely consumed as the most popular drink without alcohol because of its desirable flavors and various health benefits. 22 According to the Food and Agriculture Organization of the United Nations, the output of tea around the world was 7.02 million tons in 2020, of which China accounted for 42%. However, over 90% of tea was disposed of after the brewing process, leading to a significant increase in the production of tea waste.…”

“…However, over 90% of tea was disposed of after the brewing process, leading to a significant increase in the production of tea waste. 22,23 It is noteworthy that tea waste is enriched with nitrogen functionalities (amino acids and caffeine) 24 and has a much higher content of nitrogen (about 5%) than conventional biomass or coal (about 1%). 25,26 Therefore, unreasonable disposal of tea waste may probably lead to nitrogen pollution like harmful NO x emissions and water eutrophication.…”