Ripening day   0 5 10 15 20 Oxalic acid 142.99 ± 3.26d1) 209.43 ± 5.59c 250.10 ± 5.17b 285.90 ± 6.75a 2.21c Phosphoric acid 273.96 ± 5.39a 161.63 ± 3.69c 156.30 ± 4.37c 181.89 ± 4.79b 1.90b Citric acid 1.81 ± 0.04a - 2) - -   Tartaric acid 0.72 ± 0.02e 3.65 ± 0.08d 9.85 ± 0.31c 40.91 ± 1.22a 0.62b Malic acid 2.77 ± 0.06a 1.24 ± 0.03b 0.84 ± 0.02c 0.17 ± 0.00d 0.00e Succinic acid 5.40 ± 0.13c 8.50 ± 0.26a 5.21 ± 0.12c 6.36 ± 0.14b 0.11d Lactic acid 59.53 ± 1.37c 82.79 ± 2.30a 74.09 ± 1.58b 25.74 ± 0.77d 0.07e Formic acid 0.26 ± 0.01e 1.72 ± 0.04d 3.28 ± 0.08c 5.94 ± 0.12a 0.10b Acetic acid 0.76 ± 0.02e 7.77 ± 0.09d 16.19 ± 0.32b 22.19 ± 0.60a 0.29c Total 488.20 ± 12.23c 476.73 ± 9.29c 515.86 ± 13.55b 569.10 ± 11.73a 6.14d

1)Values are means ± SD (n = 3). Values with different superscripts in the same row are significantly different at P<0.05 by Duncan's multiple range test.2) Not detected.

Table 2: Organic acid contents of skate during different ripening periods (mg/100 g).