Understanding process parameter-induced variability for physicochemical and sensory metrics of green tea powder

Grinding is an essential process in green tea powder production, which greatly affects the final quality. However, in-depth studies on process parameter-quality correlations are lacking, especially regarding the multiple process parameters induced variability. In this work, the influence of process parameters (ambient temperature, rotational speed, and grinding time) on physicochemical and sensory metrics of green tea powder was investigated with univariate and multivariate analysis. Both rotational speed and grinding time contribute to reducing the particle size and water holding capacity (WHC), and increasing lightness, greenness, and yellowness of green tea powder, while low ambient temperature can help to improve the WHC and flowability. Rotational speed is significantly related to the concentrations of gallic acid, catechin, epigallocatechin gallate, and epigallocatechin gallate ( p  < 0.01). Rotational speed and grinding time are closely related to the final appearance of green tea powder, while temperature is the dominant factor influencing its aroma.