A total of 50 apple samples belonging to 6 apple varieties were hand picked from different orchards in 5 counties of Shaanxi province of China in 2010 (Table 1) Four of these counties (Liquan, Xunyi, Youngshou, and Chunhua) are within the PDO region. It should be noted that apple orchards chosen for juice production lie within a radius of lower or equal to 120 km. Apple samples were picked on the commercial harvest date. Twenty apples per sample were pressed to juice and used for the analysis of soluble solids content and titratable acidity (Table 1). Soluble solids content was determined with a hand-held refractometer (Atago, Tokyo, Japan). Titratable acidity was determined by titrating 10 ml of juice with 0.1 N NaOH to pH 8.1 using 1 phenolphthalein as an indicator. After collection apples were stored in a refrigerator at +4 wk before analysis. Approximately 3 kg of apples were washed and cored. Apple juice was obtained by squeezing the prepared apples with a juicer. Excessive pulp and foam were removed from the juice by a 100-mesh filter. The juice sample(200 ml) was transferred into a glass vessel containing 0.2 g ascorbic acid and 4 g NaCl. The ascorbic acid and NaCl were added to prevent enzymatic browning. All the samples were analyzed in triplicate.