Gac (Momordica Cochinchinensis Spreng or Muricia Cochinchinensis Spreng) is an indigenous fruit of Vietnam, commonly used as a colourant in traditional dishes. Recent studies showed that this fruit had a high carotenoid content, especially lycopene and β-carotene. These carotenoids are currently in high demand as they are natural antioxidants to prevent and treat cancers. Over the last ten years some new products from Gac fruit have been found on the market but the cultivation and consumption of the fruit is still limited. Gac is harvested seasonally and the post harvest processing has not been well developed. To make the best use of the valuable substances in Gac, this project investigated some processing methods to make Gac powder and developed the product quality analyses, potentially applicable to local small-scale manufacture. In order to evaluate the efficiency of the Gac powder process and some of the most important qualities of the Gac powder products, the analytical methods to determine lycopene and β-carotene were developed and validated in this project. The new HPLC-based method included a liquid-liquid extraction, followed by a solid phase extraction before the analysis. Both newly- developed HPLC and SP methods exhibited a high extraction yield, good recovery and reproducibility. Compared with the HPLC, the SP method gives higher mean values and standard deviations, but it is quicker, simpler, less expensive and still reliable for industrial applications due to the use of less toxic solvents. The production of powder from Gac fruit included two main stages: seed removal and aril dehydration. Derived from the same drying operation, the enzymatic-treated Gac powder had a lower carotenoid content compared to the heat-treated powder. The Gac powder produced by the freeze-drying method had the highest carotenoid level and brightest colour. Finally the orange-red Gac powder with high carotenoid content was added to some foods as a colorant and nutrient supplement to illustrate its applications. The colours of foods were significantly improved and the carotenoid contents were increased after processing, indicating a potential market for the Gac powder. / Master of Science (Hons)
| Identifer | oai:union.ndltd.org:ADTP/182447 |
| Date | January 2007 |
| Creators | Tran, Thao Hoang, University of Western Sydney, College of Health and Science, Centre for Plant and Food Science |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
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