Supplementary material

Investigation of Micellization and Vesiculation of Conjugated Linoleic Acid by Means of Self-Assembling and Self-Crosslinking

Ye Fan, Yun Fang *, Lin Ma, Hang Jiang

The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education; School of Chemical and Material Engineering, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122 Jiangsu, People’s Republic of China. Tel.: +86 510 85917920 Fax: +86 510 85917920

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Characterization of CLA

Infrared spectroscopy (IR) was performed on a FTLA2000-104 infrared spectrometer (ABB Bomem Co. Ltd., Canada). UV spectrum was measured on a Persee T6 UV-Vis spectroscopy (Beijing Pgeneral Co. Ltd.) using ethanol as solvent. 1H NMR spectrum was recorded with a 400 MHz Avance III NMR spectrometer (Bruker, Germany). GC analysis was carried out with a FULI 9790 gas chromatograph (Fuli analytical instrument Co. Ltd.) equipped with PEG 20000 capillary column and FID detector.

The peaks of 3015 cm-1, 1709 cm-1, and 1654 cm-1 were attributed to stretching vibration of =CH, C=O and C=C, respectively. Compared to LA, the out-of-plane bending vibration bands at 946 cm-1 and 982 cm-1 were corresponded to trans-, cis- CLA and cis-, trans- CLA, indicating the presence of conjugated double bond [1] (Fig. S1a). The characteristic absorption peak of conjugated double bond at 234 nm [2] appeared in UV spectrum (Fig. S1b). 1H NMR (CDCl3, ppm) δ: 5.68 (m, 4 H), 2.34 (t, 2 H), 2.12 (q, 4 H), 1.63 (m, 2 H), 1.32 (m, 16 H), 0.89 (t, 3 H). In comparison with LA, the peak at 2.05 ppm assigned to hydrogen of C11 in LA molecule disappeared (Fig. S1c, d).

Fig. S1. FT-IR spectra (a) of LA and CLA, UV spectrum (b) of CLA, and 1H NMR spectra of LA (c) and CLA (d)

GC spectra of methyl esters derived from fatty acid mixture of safflower oil (a), urea inclusion enriched LA (b) and produced CLA (c) are shown in Fig. S2. Based on the comprehension of safflower oil and taking isolated fatty acids as standards, the peaks appeared in Fig. S2a at retention time of 4.549, 7.103, 7.616 and 8.849 min were corresponded to palmitic acid, stearic acid, oleic acid (OA) and LA, and the content of them by means of area normalization method were 6.4 %, 2.7 %, 17.1 % and 72.4 %, respectively. The peak at retention time of 9.420 min was assigned to LA, and the purity of enriched LA was up to 97.6 % (Fig. S2b). The peaks between 11.224 min and 12.974 min were referred to isomers of CLA and the percentage of CLA was 96.0 %, while the peaks at retention time of 7.945 min and 8.928 min were corresponded to OA and LA, respectively (Fig. S2c).

Fig. S2. GC spectra of methyl esters derived from fatty acid mixture of safflower oil (a),

urea inclusion enriched LA (b) and produced CLA (c)

References

1. Kadamne JV, Castrodale CL, Proctor A (2011) Measurement of conjugated linoleic acid (CLA) in CLA-rich potato chips by ATR-FTIR Spectroscopy. J Agr Food Chem 59: 2190-2196

2. Liu X, Li H, Chen Y, Cao Y (2012) Method for Screening of Bacterial Strains Biosynthesizing Specific Conjugated Linoleic Acid Isomers. J Agr Food Chem 60: 9705-9710