AbstractsBiology & Animal Science

Extraction of β-carotene from carrot pomace using microemulsions and pulsed electric fields

by Shahin Roohinejad

Institution: University of Otago
Year: 0
Keywords: Microemulsions; pulsed electric fields; β-carotene; Cytotoxicity; Extraction; Carrot pomace
Record ID: 1300772
Full text PDF: http://hdl.handle.net/10523/5098


Classical extraction methods, such as low pressure solvent extraction (LPSE) are widely used to obtain hydrophobic bioactive compounds from plant sources. Although LPSE is a simple method, it has limited application in food processing due to most organic solvents being banned for food products extraction, and they are costly, environmentally hazardous, and require expensive disposal procedures. Thus, the use of inexpensive and efficient alternate extraction systems might be suitable to replace the use of LPSE techniques. The objective of this research was to develop a new strategy to extract hydrophobic bioactive compounds from plant materials. The effect of electric field strength and frequency during pulsed electric field (PEF) processing on the extractability of carotenoids in carrots was examined. This study attempted to evaluate the effectiveness of oil-in-water (O/W) microemulsions as a potential alternative to replace the use of organic solvents for extracting β-carotene from carrot pomace. The carotenoids extractability of carrot pomace was improved using PEF processing at different electric field strengths (0.1-1 kV cm-1) and frequencies (5-75 Hz). Electroporation due to PEF treatment at moderate field strengths up to 1 kV cm-1 at 5 Hz improved the extractability of carotenoids in carrot pomace when organic solvents and vegetable oils were used as extraction media. Increasing PEF frequency above 10 Hz at an electric field strength of 1 kV cm-1 did not improve the amount of extracted material. The impact of oil type and fatty acid chain length on the development of food-grade microemulsions for the entrapment of β-carotene was investigated. The microemulsion region of a ternary phase diagram containing short chain monoglycerides was larger than for di- and triglycerides when Tween 80 was used as surfactant. Due to the higher solubilization of monoglycerides compared to other types of lipids studied, β-carotene-loaded O/W microemulsions were developed using medium chain monoglycerides (Capmul MCM), non-ionic surfactant (Tween 80), phosphate buffer, and synthetic β-carotene as the main constituents. Incorporation of β-carotene into the microemulsion affected the structure in terms of size and polydispersity index (PDI), whereas no significant differences in the zeta potential, pH and refractive index values between the blank and β-carotene-loaded microemulsions were observed. Amongst the formulations, the microemulsion contained 30% Capmul MCM oil, 20% Tween 80 and 50% buffer had the highest β-carotene loading with a particle size less than 100 nm. The feasibility of using an O/W microemulsion as the medium to extract natural β-carotene from PEF-treated carrot pomace was further investigated. The optimum carotenoids extraction conditions by O/W microemulsion were determined by means of three levels Box-Behnken experimental design combined with response surface modelling (RSM) and the extraction efficiency was compared to other extraction medium (e.g. organic solvent and oil). Similar to organic solvents…