In a centrifuge tube 12 mL of 10% sulfosalicylic acid was added
to 12mL of suan-cai juice and, following oscillation blending, it was centrifuged
at 120,000 g for 15 min. A 1 mLaliquot of the resulting supernatant
was filtered through a 0.22 μmmicropore filter and evaluated in a
High Speed Amino Acid Analyzer (Model Hitachi L-8800).