Abstract:

A mixture of green tea and water (1:30, m/V) was treated for 10 min by ultra-high pressure (UHP) of 100, 200 and 300 MPa at room temperature to study the effect of UHP treatment on quality of green tea juice using the sample obtained with interval shaking at normal pressure (0.1 MPa) as a control. The results indicated that the UHP treatments of 100, 200 and 300 MPa resulted in a marked increase in leaching rate of polyphenols and free amino acids by 52% － 78% and 26%－ 39%, respectively, and a decrease in water-soluble sugar by 11% － 24% and in residual peroxidase (POD) activity by 5% － 47% compared with the control; the UHP-treated green tea juice had deeper yellow-green color than the control.

Key words: ultra-high pressure treatment, green tea juice, quality