Skip to main content

Table 1 FTIR peak assignment for okra seed flours, protein isolate and enzymatic hydrolysates

From: Characterization of okra seed flours, protein concentrate, protein isolate and enzymatic hydrolysates

Functional group WF DF PC PI PHP PHC PHT Suggested nutrients Literature range Saguer et al. (2012)
Intermolecular bonded O-H stretching; N-C stretching 3419.90 3419.90 3419.98 3419.98 3417.98 3417.98 3416.05 Protein and poly-hydroxyl compounds 3029–3639 (3334)
CH2 Stretching asymmetric N.D. N.D. N.D. N.D. 2962.76 2964.69 2917.46 Alkane compounds 2960
O-H stretching; CH2 stretching symmetric 2887.53 2892.36 2890.425 2892.36 N.D. N.D. N.D. Methoxy methyl ether compound 2890
N-H stretching 2359.02 2359.02 2360.95 2360.95 2359.02 2359.02 2362.88 Amino acid component 2332–2359 (2344)
C=O stretching of esters 1745.64 1740.64 N.D. N.D. N.D. N.D. N.D. Triglycerides 1763–1712 (1737.5)
C=O stretching, C=N stretching N.D. 1637.62 1637.62 1647.62 N.D. N.D. 1647.62 Protein amide I band 1620–1650 (1635)
N-H bending; C-N, stretching 1541.18 1541.18 1541.18 1541.18 1541.18 1541.18 1541.18 Protein amide II band 1481–1585 (1533)
CH2 bending asymmetric; CH3 bending asymmetric 1456.30 1456.3 1458.23 1456.3 N.D. N.D. N.D. Protein and fats 1425–1477 (1451)
C-O stretching symmetric of COO- groups of carboxylates 1379.22 1384.94 1484.15 1384.94 1404.22 1402.3 1406.15 Carboxylic acid 1357–1423 (1390)
P=O stretching asymmetric; C-N stretching amine 1277.88 1277.88 1278.85 1279.81 1276.92 1286.57 1286.57 Nucleic acid 1191–1356 (1273.5)
C=N stretch (amide III), N.D. N.D. 1159.26 N.D. 1153.47 N.D. N.D. Tertiary amine 1210–1150 (1170)
C=N stretch (amide I), 1066.67 1076.32 1037.74 1065.701 1074.39 1078.24 1056.07 Primary amine 1090–1020 (1055)
C-Cl stretch, 719.47 N.D. 719.47 N.D. N.D. 773.48 N.D. Aliphatic Chloro-compound 800–700 (750)
C-Br stretch 643.28 643.28 643.28 643.28 623.03 613.38 609.53 Aliphatic bromo compounds 700–600 (750)
  1. WF Whole flour, DF Defatted flour, PC Protein concentrate, PI Protein isolate, PHP Pepsin protein hydrolysate, PHC Pancreatin protein hydrolysate, PHT Trypsin protein hydrolysate, ND Not detected; Saguer et al. (2012)