Captions for figures
Figure 1. Reaction scheme and molecular structures of amino acids used
in the current study
Figure 2. Retention of tocopherols in soybean oil at 180 °C: a) α-, b)
γ-, and c) δ- tocopherols in soybean oil containing 5.5 mM alanine (Ala)
and alanine potassium salt (Ala K), and d) α-, e) γ-, and f) δ-
tocopherols in soybean oil containing 5.5 mM phenylalanine (Phe) and
phenylalanine potassium salt (Phe K). Error bars indicate standard
deviation (n=4). Means not sharing a common letter are significantly
different (P < 0.05).
Figure 3. Synergism of amino acid potassium salts with mixed tocopherols
in comparison with the corresponding amino acids in stripped soybean oil
during heating at 180 °C for 2 h: a) %loss of olefinic protons and b)
%PTAG with L-alanine (Ala) K salt, c) %loss of olefinic protons and d)
%PTAG with L-phenylalanine (Phe) K salt, and e) %loss of olefinic
protons and f) %PTAG with L-proline (Pro) K salt. Error bars
indicate standard deviations.
Means not sharing a common letter are significantly different (P
< 0.05).
Figure 4. Antioxidant activity of amino acids or amino acid salts (5.5
mM) during micro-frying of potato cubes at 180 °C for 8 h: a) % loss of
olefinic protons, b) % loss of bisallylic protons, and c) %
polymerized triacylglycerols (PTAG). Error bars indicate standard
deviations (n = 3). Means not
sharing a common letter are significantly different (P <
0.05).
Table 1. Antioxidant activity of 5.5 mM amino acid, amino acid sodium
salt, or amino acid potassium salt in soybean oil during 8-h heating at
180 °C.