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Studies on the electrostatic interactions between β-lactoglobulin and tragacanthin:The first step towards fabrication of biopolymeric micro- and nano-particles
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M Hassandokht Firouz   , P Haratian , R Komeili Fanood , MA Mohammadifar * |
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Abstract: (10684 Views) |
| Background and Objective: Investigation of the colloidal behaviour of protein-polysaccharide systems is becoming increasingly important to provide a foundation for their applications in areas such as production of biopolymer micro-and nano-particles, designing food analogues, and microencapsulation technology. The aim of the present study was to investigate the pH-induced critical transitions during associative phase separation between β-lactoglobulin (BLG) and tragacanthin (T).
Materials and Methods: The formation of electrostatic complexes in BLG/T dispersions (0.3wt.% total concentration BLG:T ratio 2:1) was investigated as a function of pH (2.00-6.00) by spectrophotometry and particle size analysis. In addition, coupling of slow in situ acidification of the blend, with glucono-delta-lacton, and rheometry were used to monitor the structural transitions during the associative phase separation. The influence of salt type and concentration on the formation of micro-particles were also determined.
Results: The formation of soluble complexes started at pH ~5.20, and at pH ~4.85 the aggregation of intrapolymeric complexes occurred, followed by a bulk phase separation at pH ~4.30. The data indicated that coacervation occurred at pH 4.15. Finally, the mixture returned to a mono-phasic system at pH 2.5. Particle size analysis showed that the assembled structures experienced a contraction process upon complexation. Rheometry provided deeper insights into the colloidal behaviour of the system and the results were in good agreement with quiescent pH-induced transitions established by HCl titration. The formation of the micro-particles was strongly salt-dependent.
Conclusion: Under controlled pH conditions, electrostatic interactions between β-lactoglobulin and tragacanthin can be used to form a variety of biopolymer particles. These biopolymeric micro- and nano-particles may be used in the food industry as natural delivery systems or fat-replacers.
Keywords: β-Lactoglobulin, Tragacanthin, Protein-polysaccharide interactions, Associative phase separation, Biopolymer micro-particles |
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| Keywords: β-Lactoglobulin, Tragacanthin, Protein-polysaccharide interactions, Associative phase separation, Biopolymer micro-particles |
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Full-Text [PDF 373 kb]
(2973 Downloads)
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Article type: Research |
Subject:
Food Science
Received: 2013/01/6 | Published: 2013/01/15
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