Abstract
When plastic films having a high gas-barrier property are used for tea packaging, the packages often shrink on storage. This shrinkage is thought to be due to the consumption of oxygene in the package by tea. Then, the oxygene consumption by tea was examined under the various conditions of storage.
Pulverized samples of green tea whose moisture contents were low (2.9-3.3%)and high (6.2-6.4%) were canned and stored at different temperatures. Oxygene concentrations in the head space of the can were gas-chromatographically determined after the different periods of storage. The rate of the oxygene consumption increased with the rise of temperature, and the quantities of oxygene absorbed by 100 g of the tea were calculated to be 0.11, 0.30, 0.58 and 1.44 ml/day at 5, 15, 25 and 40°C, respectively. The rate also increased by 10-30% under the condition of the higher moisture content.
The oxygene consumptions by both unpolished rice and popped rice, which are materials of Genmai-cha, were also examined in a similar manner as tea. Popped rice absorbed roughly as much oxygene as tea, but unpolished rice did only one-third as much oxygene as popped rice in the ten days' storage.
