Preparation, characterization and antioxidant activities of derivatives of exopolysaccharide from Lactobacillus helveticus MB2-1.

Affiliation

College of Food Science and Technology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, PR China; Key Laboratory of Agro-Products Processing, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China. Electronic address: [Email]

Abstract

In this study, different derivatives of exopolysaccharides (EPS-2) from Lactobacillus helveticus MB2-1 including acetylated EPS-2 (A-EPS-2), carboxymethyl EPS-2 (C-EPS-2), sulfated EPS-2 (S-EPS-2) and phosphorylated EPS-2 (P-EPS-2) were prepared. Furthermore, the structure, physicochemical properties and antioxidant activities of EPS-2 and its derivatives were compared. The introduction of different chemical groups was confirmed using Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectrogram, and the degrees of substitution (DS) for A-EPS-2, C-EPS-2, S-EPS-2 and P-EPS-2 were 0.439, 0.526, 0.625 and 0.432, respectively. Among four derivatives, the particle size distribution of A-EPS-2, C-EPS-2 and P-EPS-2 was in accordance with the molecular weight (Mw) distribution. Besides, the results of scanning electron micrograph, thermogravimetric analysis and differential scanning calorimetry indicated the surface morphology and thermal behavior of EPS-2 had greatly changed after modification. Notably, several derivatives especially S-EPS-2 exhibited improved antioxidant activities when compared with EPS-2, implying the derivatives of EPS-2 might have wide applications as antioxidants in food industry.

Keywords

Antioxidant,Derivatives,Exopolysaccharides,Lactobacillus helveticus MB2-1,Physicochemical properties,Structure,

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