Extraction and Characterisation of Bioactive Compounds From New Zealand Black-footed Abalone
There is expanding interest in marine organisms as a source of new bioactive chemicals for development of novel health-promoting products. Marine species account for half of the world’s biodiversity making them a rich source of new chemicals and the largest remaining source of beneficial natural molecules that might be exploited as functional ingredients in various food, cosmetic and pharmaceutical products. Abalone, a marine organism, have believed to provide health benefit with consumption for many years. Recent research has shown that abalone contain physiologically active chemicals with diverse modes of action, including antioxidant, antibacterial, anticancer, anti-hyaluronidase, anti-collagenase activities, and collagen. Thus, this thesis aimed to explore the extraction of bioactive compounds from Zealand black-footed abalone using novel environmentally friendly extraction techniques in order to make it an ideal candidate as a natural active ingredient for health promoting products.
Bioactive compounds were extracted from New Zealand black-footed abalone using subcritical water extraction (SWE), an environmentally friendly extraction technique. Abalone subcritical water extracts are promising sources of bioactive compounds, including antioxidants, glycogen, phenolic compounds, carbohydrates, proteins, and amino acids, based on the overall findings. Furthermore, the findings demonstrate that the efficiency of SWE is affected by temperature, which is a critical factor in demonstrating extraction efficiency. Antioxidant and antiageing properties of bioactive compounds were recovered from wild and farmed black-footed abalone using SWE. The black-footed abalone extracts obtained by SWE, were found to be rich in majority of essential and non-essential amino acids and exhibited broad antioxidant and antiageing properties such as anti-hyaluronidase and anti-collagenase activity without causing significant toxicity at the high doses evaluated. It was also demonstrated that there was a strong correlation between antioxidant, antiageing and total phenolic compounds in both farmed and wild abalone extracts. Consequently black-footed abalone extracts were found as promising sources of novel anti-aging agents due to their high antioxidant, anti-collagenase and anti-hyaluronidase activities that could be incorporated into cosmetics. In addition, collagen type I was isolated from farmed and wild black-footed abalone using ultrasound assisted extraction (UAE) and CO2 water extraction (CO2-WE). Both techniques yield comparable SDS-Page, FTIR, and cytotoxicity results. However, CO2-WE had higher collagen extraction yield, shorter extraction time and used water instead of organic solvent. Therefore, CO2-WE could be an alternative promising technique than UAE with higher sustainability for enhancing the non-toxic extraction efficiency of collagen type I from black-footed abalone with applications in the cosmetic, biomedical, and pharmaceutical industries.
The overall findings of this study, have confirmed the feasibility of using SWE and CO2-WE to produce high-quality abalone extracts from black-footed abalone. This study has also proved that New Zealand black-footed abalone possesses vast unexploited potential to be used to make high value products. This research resulted in a better understanding of the composition and bioactivity of black-footed abalone that can inspire to further research of this native abalone and accordingly, deriving high value products and expand it’s applications.