揉捻 のことです。
詳しくは揉捻を参照してください。
rollingを英語で説明する場合は
Rolling the tea leaves. The main purpose of rolling tea leaves is to damage the cell walls. Tea leaves are twisted and pressed in order to extract the juices that are held inside. The goal is to distribute the moisture evenly on the outside of the leaves. This exposes enzymes to the air, speeding up the process of oxidation. Volatile aromatic compounds are also increased during the rolling step.
Rolling is accomplished in a variety of ways.
あたりでしょうか。もっと良い言い方や間違いがあったらぜひ教えてください。