Novel development of lentil protein + pectin-based vitamin delivery systems using high-intensity ultrasound and supercritical carbon dioxide technologies
Creators: Mekala, Srujana
Publisher: name: University of Alberta Library
Year: 2024

<p>The demand for plant-based delivery systems has grown rapidly in recent years. Emerging technologies such as high intensity ultrasound (HIUS) and supercritical CO2 (SC-CO2) drying are promising to develop delivery systems with lentil protein and pectin due to their abundance, biocompatibility, and functionality. Therefore, the main objective of this PhD thesis was to develop lentil protein and pectin colloidal based lipophilic vitamin delivery systems using HIUS and SC-CO2 drying technologies and evaluate the physico-chemical characteristics, encapsulation efficiency and bioaccessibility of the vitamins. <br>
In the first study, oil-in-water emulsion systems were prepared using HIUS technology and the stability of lentil protein concentrate (LPC) and whey protein concentrate (WPC) emulsions were compared. The influence of HIUS treatment at nominal powers (0, 300, 600, 900, and 1200 W) on the LPC-stabilized emulsion properties were evaluated and compared to the emulsion stabilized by WPC. Steric stabilization mechanism was observed for LPC and WPC stabilized emulsions and the interfacial tension results showed the ability of LPC to adsorb into the oil-water interface. The mean droplet diameter of LPC emulsions had significant reduction from 5.44 µm at 0 W nominal power to 2.07 µm at 600 W. However, HIUS process intensification by increasing nominal power up to 1200 W increased, the mean droplet diameter due to the formation of starch and dietary fiber aggregates. Then, to improve the storage stability, emulsion-filled hydrogel systems were developed to encapsulate a vitamin complex (β-carotene, cholecalciferol, α-tocopherol, and ascorbic acid). This second study aimed at investigating the chemical stability of the vitamin complex in LPC – pectin emulsion-filled hydrogel processed by HIUS. The impacts of HIUS nominal power, the addition of xylooligosaccharides (XOS) and ascorbic acid on the physico-chemical and functional properties were evaluated. The maximum retention capacities were observed for gels processed at 900 W for β-carotene and ascorbic acid, and 600 W for cholecalciferol and α-tocopherol after 21 days of storage. <br>
Since the previous study showed the highest retention capacity for β-carotene, ultrasound assisted ethanolic gelation of lentil protein isolate (LPI) and pectin was investigated to load β-carotene in the emulsion gels in the third study. This study investigated the influence of HIUS nominal power, pH, and ethanol concentration on the physico-chemical and functional properties of the LPI-pectin emulsion gels. The HIUS process improved the overall stability by promoting LPI-LPI and LPI-pectin interactions. The β-carotene encapsulation efficiency (78 – 93%) and the bioaccessibility (2 – 50%) were significantly dependant on the HIUS nominal power used. Additionally, the β-carotene loaded emulsion gels were freeze-dried to form aerogels to improve the long-term shelf stability. In the last study, the interaction mechanisms of LPC and pectin gelation in HIUS process and the influence on the physico-chemical characteristics of aerogels formed by SC-CO2 drying were investigated. First, the influence of HIUS nominal power and the biopolymer concentrations on the physico-chemical characteristics of emulsion gels was studied. Then, the emulsion gels were dried using SC-CO2. The emulsion gels formed in this study were thermo-reversible. Low density aerogels (0.0009-0.003 g/mm3) were formed with good textural and swelling capacity that can be explored to form tailor-made vitamin delivery systems. <br>
Overall, the results obtained in this PhD thesis showed that HIUS process and SC-CO2 drying are promising technologies for the development of vitamin delivery systems. Furthermore, the aerogels formed in this study could potentially be used in nutraceuticals and food formulations as fat replacers. </p>