Free amino acid (mg/L)
Control
pH 3
pH 4
pH 5
pH 6
pH 7
pH 8
pH 9
Leucine 1.57 110.18 225.35 93.66 27.02 15.74 6.56 1.31
Phenylalanine 0 78.30 120.92 49.56 14.21 8.92 3.63 0.99
Valine 0 34.91 72.40 34.68 10.78 6.79 4.45 14.06
Alanine 0 29.76 63.61 28.87 9.80 7.48 5.52 10.69
Isoleucine 0 22.82 57.19 27.02 6.30 3.94 2.36 0.26
Tyrosine 0.72 28.99 52.55 27.90 8.70 6.89 3.62 0.36
Arginine 1.39 8.36 39.02 31.01 10.80 14.28 13.94 3.83
Methionine 0.30 21.49 38.50 22.38 5.37 4.77 2.69 0.30
Threonine 0 12.86 38.36 18.11 0 2.62 1.67 0
Proline 0 11.28 35.92 13.82 4.37 0 0 0
Glutamic acid 0.29 19.42 34.72 13.54 2.65 1.77 1.77 5.89
Lysine 0 6.72 34.21 25.44 9.65 9.94 8.48 0.88
Serine 0.42 12.19 30.27 16.18 4.83 3.15 2.10 2.10
Glycine 0.90 7.51 22.67 10.06 3.00 2.40 2.40 7.51
Histidine 0 0 2.79 2.79 0.93 0.93 0.62 0
Total free amino acids 5.59 404.79 868.48 415.02 118.41 89.62 59.81 48.18
Total free amino acids/total proteins (%) 0.06 4.21 9.04 4.32 1.24 0.93 0.62 0.50
TCA−NSI (%) 3.95 31.18 41.47 38.67 29.52 16.32 10.71 4.67
TCA-soluble peptides (%) 3.89 26.97 32.43 34.35 28.28 15.39 10.09 4.17