Enhancement of Hydrophobicity of Fish Skin Gelatin via Molecular Modification with Oxidized Linoleic Acid

Table 1

Functional group assignment on major absorption bands occurring in the infrared spectra of nonoxidized linoleic acid (LA) and oxidized linoleic acid (OLA).

Wavenumber (cm^−1)		Type of vibration and functional group
LA	OLA
3350–3120		Stretching of OH in fatty acid
	3600–3200	Stretching of OH in aldehyde, peroxide coupled with OH of fatty acid
3009	3009	CH stretching of cis-double bond (=CH)
2954	2954	Asymmetric stretching vibration shoulder of the aliphatic CH3 group
2926, 2854	2926, 2854	Asymmetric and symmetric stretching, respectively, of aliphatic CH2 group
—	1745	Stretching vibration of C=O of aldehyde and ester
1715	1715	Stretching of C=O of fatty acid
1654	1654	C=C stretching vibration
1465, 1458	1465, 1458	Bending vibration of aliphatic CH2, CH3, respectively
1420	1420	Rocking vibration of CH bonds of cis-distributed olefins
	1238, 1175–1055	Stretching vibration of C-O ester groups
	1180	C-O-O vibration of hydroperoxide
	990–980	Bending of C-O of ester overlapping with CH bending of trans-double bond
975	975	Bending of C-O of acid
723	723	Overlapping of the CH2 rocking vibration and the out-of-plane vibration of cis-distributed olefins
680	680	CH bending of cis-double bond