Extraction and Encapsulation of Bioactive Compounds Employing Novel Technologies

The main objective of this thesis was to investigate the potential of novel extraction techniques to enhance the extraction efficiency and biological functionality of bioactive compounds. The potential of encapsulation to increase the efficacy of these extracted bioactive compounds in food, nutraceutical and pharmaceutical applications was also investigated. Chapter 3 investigated conventional and novel extraction protocols utilizing novel techniques to extract phycobiliproteins (PBPs) from the red microalgae. PBPs were extracted using a cold plasma discharge system (CPDS) and a cold plasma jet system (CPJS) with water as the solvent. CPDS demonstrated superior effectiveness in enhancing extraction yield. CPDS-treated PBPs exhibited the highest antioxidant activities and demonstrated high cytotoxic potential in Caco-2 human colorectal adenocarcinoma cell lines. UAE, MAE, and PEFAE novel technologies, were employed to further enhance the extraction yield of PBPs in Chapter 4. This enhanced extraction yield was achieved through UAE treatment using a 20kHz probe for 10min at 4°C. Significant improvements in the antioxidant activities were also measured. Moreover, PBPs extracts obtained through UAE treatment exhibited no cytotoxic potential in human lung carcinoma and colorectal adenocarcinoma cell lines. In Chapter 5 the potential of MAE and UAE treatments to enhance the extraction yields of phycocyanins (PCs) from Arthrospira platensis were investigated at selected pH levels. The highest extraction yield was obtained from UAE for 15min at 4°C. Highest antioxidant activities were measured in crude PEs extract obtained from 10min UAE treatment. Cytotoxicity analysis revealed that the obtained crude PCs extracts pose minimal cytotoxic risk at concentrations <80µg/mL. Chapter 6 and 7 employed similar protocols for the extraction of proteins, lipids, chlorophylls, total carotenoids and total phenolic compounds from two green microalgae species. The results showed that UAE treatment was the most effective for extraction using these microalgae species. Cytotoxicity analysis of extracts obtained from UAE treatment on colorectal adenocarcinoma cells indicated >75 to 80% cell viability <200µg/mL. Chapters 8 and 9 investigated the extraction of phenolic compounds and proteins from food byproducts The highest extraction yield from buckwheat was obtained from HPPAE for 8min at 400MPa treatment. The highest antioxidant activities measured in crude phenolic extracts were obtained from HPPAE for 8min at 400MPa treatment. From M. charantia seeds, the highest extraction yield of crude proteins was obtained from UAE 30min at 4°C. After isolation and purification, 9.08 ± 0.23g of protein with 82.69 ± 0.78% purity was obtained from 100g of M.charantia seeds on a dry basis. Antidiabetic assays showed significantly antidiabetic higher activity for the purified protein compared to the crude protein . In vitro cytotoxicity analysis showed that concentrations <200µg/mL were non-toxic. Chapter 10 investigated the encapsulation of bioactive pigments using inulin and gum arabic. Microparticles were produced using a nano spray drying technique. Results demonstrated high encapsulation yields, solubility and colour retention for both encapsulated PCs and PEs. The combination of inulin and gum arabic facilitated the formation of smaller encapsulated particles with a homogeneous morphology and higher encapsulation efficiency compared to microparticles prepared with inulin alone. The antioxidant activity of microparticles encapsulated with the combination of inulin and gum arabic exhibited the best performance in case of FEAP assay for PCs and ABTS assay for PEs. In summary, this thesis demonstrated the potential of novel extraction technologies as viable alternatives to CAE. Encapsulation was demonstrated to enhance the stability and functionality of natural colourants.