Cold Storage Properties and Lipid-Lowering Efficacy of Black Tea Superfine Powder with Different Particle Sizes

In order to explore the cold storage properties and lipid-lowering efficacy of black tea superfine powder with different particle sizes, in this study, the physicochemical properties and lipid-lowering capacity of black tea superfine powders with particle sizes of 26.116 (about 600 mesh), 9.612 (about 1600 mesh) and 4.338 μm (about 3600 mesh) were evaluated after refrigerated storage at 4 ℃ for 180 days. The results showed that the contents of tea polyphenols (18.17%) and thearubigins (11.82%) were significantly (P < 0.05) higher in the 600-mesh tea powder than in the 1600-mesh (17.36% and 10.76%, respectively) and 3600-mesh (16.93% and 10.42%, respectively) ones after cold storage, while the content of theabrownines (3.96%) was significantly (P < 0.05) lower than that in the 1600-mesh (4.67%) and 3600-mesh (4.89%) tea powders. In addition, all the three tea powders significantly inhibited pancreatic lipase activity with half-maximum inhibitory concentration (IC₅₀) values of 560.672–591.521 μg/mL and significantly improved body mass (392.5–396.3 g) and the serum levels of total cholesterol (1.756–2.052 mmol/L), triglycerides (3.611–4.308 mmol/L), low-density lipoprotein cholesterol (3.004–3.097 mmol/L) and high-density lipoprotein cholesterol (1.268–1.456 mmol/L) in obese rats after 35 days of gavage, with no significant differences being observed among these tea powders (P > 0.05). In summary, larger particle size of black tea superfine powder in the range of 600–3600 mesh are beneficial to maintain its chemical components during cold storage, and have similar lipid-lowering effects in obese rats.