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Co-microencapsulation of Probiotic Bacteria and DHA Fatty Acid; Optimization and Evaluation of the Viability of Probiotic and Oxidative Stability of DHA during Gastrointestinal Tract

Vaziri, Asma Sadat | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51207 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Alemzadeh, Iran; Vossoughi, Manouchehr
  7. Abstract:
  8. Due to the increased public awareness about the role of food on health, an increased interest of consuming fortified food has grown rapidly. Probiotic bacteria and DHA poly-unsaturated fatty acid are two major bioactive ingredients becoming increasingly popular in food fortification industry due to their beneficial effects. However, high susceptibility of probiotic bacteria during production, maintenance and digestion in acidic and enzymatic conditions of gastrointestinal tract results in decreasing the survivability and therefore reducing health effects in body. Besides, having multiple double bonds in the structure of DHA fatty acid leads to oxidative degradation that produces volatile aldehydes and ketones leading the formation of unpleasant odor and flavor and ultimately decrease the nutritional value. One of the most promising methods for maintaining the vitality of probiotics and oxidative stability of DHA fatty acid is microencapsulation. The aim of this study was to develop a new microencapsulation system that can embedded probiotic bacteria and DHA at the same time and protecting them from environmental and digestion conditions. This research showed that co-microencapsulation of these two nutrients not only provides the potential benefits of both of them simultaneously, but also improves the viability of probiotic microorganism. At first, a novel bio-composite comprise of sodium alginate, pectin and gelatin was prepared and the microencapsulation procedure was carried out by Ca-alginate, ionotropic-gelation method. Optimal composition of bio-composite was obtained by performing 13 experiments based on maximizing viability of cells after 6 hours exposure to SGI conditions, designed using mixture design method using design expert software. Polymers and optimized bio-composite were characterized using SEM, XRD and FTIR analysis. Then viability of both microencapsulated and co-microencapsulated of probiotic bacteria within the optimized composite under the gastrointestinal conditions was curved. Moreover, swelling behavior of microcapsules was investigated. Based on the results, optimized bio-composite consisted of 1.059% alginate, 0.549% pectin and 0.392% gelatin, besides providing high encapsulation efficiency (98.425%), could also significantly improve the viability of cells (86.66%) during SGJ conditions in contrast to non-encapsulating cells (50.36%). In the next step, DHA and probiotic were co-microencapsulated. Encapsulation of DHA alone (70.78%) and together with probiotic (69.37%) were examined. co-microcapsules of probiotic bacteria showed significantly higher encapsulation efficiency (100%) and viability (90.027%) compared to single microcapsules. Chromatogram curves of microencapsulated DHA during the process and exposure to SGJ showed higher oxidative stability in the presence of probiotic. Though, the bio-composite co-microcapsules synthesized can be used as a new protective system and carrier in fortified foods industry increasing the stability and vitality of probiotics and DHA-rich oils
  9. Keywords:
  10. Sodium Alginate ; Pectin ; Gelatin ; Probiotic ; Bio-Composite ; Lactobacillus Plantarum Bacteria ; Docosahexaenoic Acid (DHA) Fatty Acid

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