Abstract
We examined the change in the content of pectic substances in tea leaves during the steaming of green tea. In four cultivars of tea leaves, water-soluble pectin (WSP) content increased with steaming time, whereas the dilute hydrochloric acid soluble pectin (HSP) content remained almost constant. A β-elimination reaction proceeds throughout the steaming process, so it was postulated that some water-insoluble forms of pectin in HSP convert to a water-soluble form via β-elimination degradation with increasing steaming time. When tea leaves were steamed, pectin fractions with a molecular weight of 1,100 × 103 were degraded from water-insoluble HSP and eluted as WSP. Additionally, as steaming time increased, the fraction of smaller molecular weight pectin increased.
