Soy protein isolate-maltodextrin maillard conjugate-based emulsion delivery systems for enhancing the stability and bioaccessibility of lutein | |
| Author | Nuntarat Boonlao |
| Call Number | AIT Diss no.FB-23-01 |
| Subject(s) | Soy proteins Bioavailability Dextrins--Health aspects |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of doctor of Philosophy in Food Engineering and Bioprocess Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Currently, most people spend time average of 7 h per day on digital devices in which the digital screen is a source of high-energy blue light. Long-term exposure to this light can increase the risk of eye disorders by damaging the retina. Lutein is a carotenoid pigment found in the human retina, specifically in the macula tissue. Accumulating lutein in this area can protect the retina from blue and UV light, thus preventing the onset of retinal disorders and other chronic diseases, such as cardiovascular disease. Although lutein can be obtained through daily diets, its bioavailability is poor (less than 10-15%) due to low water solubility and susceptibility to degradation during food processing and gastrointestinal conditions. Additionally, the applications of lutein in the food industry are limited. To overcome these obstacles, encapsulation techniques using micro- and nanocarriers could be a potential strategy to design a delivery system for lutein. Emulsion-based delivery systems have received much attention as potential delivery vehicles for lipophilic bioactive compounds, particularly oil-in-water emulsion systems. There has been increasing demand for clean label food ingredients, and as a result, proteins and polysaccharides have been extensively used as emulsifiers instead of synthetic emulsifiers like Polysorbate (Tween). As a consequent, the present study aimed to develop lutein-loaded emulsion-based delivery systems stabilized by protein-polysaccharide conjugates to enhance the stability and bioaccessibility of lutein. Firstly, Maillard conjugation was conducted and the influences of Maillard reaction conditions on the functionalities of conjugates were evaluated. Maillard conjugation was carried out between soy protein isolate (SPI) and maltodextrin (MD) at different SPI-to-MD ratio at 1:2, 1:1, and 2:1 (w/w) via dry heat-induced Maillard reaction (60 ºC, 0-9 days) or wet heat-induced Maillard reaction (90 ºC, 0-120 min). The dry heat-induced Maillard conjugates with the mass ratio of SPI-to-MD at 1:1 profoundly improved the emulsifying properties of the conjugates. Secondly, the influence of dry heat-induced Maillard conjugates at different incubation time (1, 3, 5, and 7 days) on the physicochemical stability of oil-in-water emulsion was investigated. The emulsion stabilized by SPI-MD conjugate incubated for 1 day (MRP-1) exhibited better stability against different NaCl concentrations, pH variations, thermal treatments, freeze-thaw processes, and during storage. Finally, the MRP-1 was used to prepare three kinds of emulsion-based delivery systems for the encapsulation of lutein, including lutein-loaded SPI-MD conjugate nanoemulsion (LSMC-NE), lutein-loaded SPI-MD conjugate nanostructured lipid carrier (LSMC-NLC) and lutein-loaded SPI-MD conjugate solid lipid nanoparticle (LSMC-SLN). The lipid nanoparticles were fabricated by hot homogenization-ultrasonication method. The particle size of the lipid nanoparticles without ultrasonication was approximately 3.5 μm and the particle size decreased to 210-270 nm after being ultrasonicated for 15 min. The physicochemical stability and in vitro digestion of lutein-loaded lipid nanoparticles stabilized by SPI-MD conjugate were evaluated. LSMC-NLC exhibited better storage stability with no change in particle size observed during the 45-day period. Encapsulation within the lipid nanoparticle was found to retard the chemical degradation of lutein during storage and thermal processing, although lutein degradation was more pronounced in the SLN systems. The bioaccessibility of lutein was enhanced from 14.9% for non-encapsulated lutein to 30.7-34.9% for encapsulated form. The produced solid-lipid particles were shown to have improved storage stability and can potentially be used to fortify a variety of dairy products to increase their overall nutritional benefits. Consequently, this study provided valuable insight for designing the lipid nanocarriers for lipophilic active compounds using a natural emulsifier. |
| Year | 2023 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Anal, Anil Kumar |
| Examination Committee(s) | Loc Thai Nguyen;Bora, Tanujjal |
| Scholarship Donor(s) | Royal Thai Government Fellowship;Thailand Graduate Institute of Science and Technology;Asian Institute of Technology Fellowship |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2023 |