- Title
- Recovering and encapsulating carotenoids from the peel of gac fruit (Momordica cochinchinensis Spreng)
- Creator
- Hoang, Van Chuyen
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2018
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Gac fruit (Momordica cochinchinensis Spreng.) is a rich source of carotenoids for the manufacture of powder, oil and capsules for food, cosmetic and pharmaceutical uses. Currently, only the aril of the Gac fruit is processed and the peel, like the other components, is discarded although it contains high level of carotenoids. Thus, if these carotenoids can be extracted effectively, the peel might become a potential source of these carotenoids and add value to what is otherwise a waste product. This research aimed at: 1) investigating the effects of different drying and treatment conditions for the preservation of carotenoids and antioxidant capacity in Gac peel ; 2) determining optimal conditions for recovering carotenoids and antioxidant capacity from the dried peel ; and 3) identifying optimal conditions for encapsulating the extracted carotenoids in order to increase the storage stability of the carotenoids. The results showed that the pretreatment of Gac peel with ascorbic acid combined with hot air drying at 70°C led to the highest retention of β-carotene, lycopene, lutein, total carotenoid and antioxidant capacity in the dried Gac peel. For the extraction of the dried peel, ethyl acetate was the most suitable solvent for the concurrent extraction of carotenoids and antioxidant capacity. The maximum carotenoid yield of 271 mg/100g DW was achieved by the conventional extraction carried out at 40.7°C for 150 minutes with a ratio of 80:1 of solvent volume to solid weight (mL/g). The optimisation of the ultrasound-assisted extraction of Gac peel determined that 50°C and 250 W were the optimal temperature and ultrasonic power for the extraction with the present sample size (0.5 gram of Gac peel with 40mL of solvent). The extraction at optimal conditions resulted in a significant higher antioxidant capacity yield (822 µM TE/100g DW), shorter extraction time (76 minutes) and a comparable carotenoid extraction yield (269 mg/100g DW) compared to the conventional extraction of Gac peel. The carotenoids recovered in oil from Gac peel were successfully encapsulated by a mixture of whey protein concentrate and gum arabic (7:3, w/w) as the wall material using a spray dryer. The encapsulated powder obtained from the emulsion containing 24.5% total solids with the ratio of 3:10 (w/w) of the carotenoid-rich oil to the wall material showed the highest retention of total carotenoid and antioxidant capacity. The optimal inlet temperature and feeding rate of the emulsion were 160°C and 180mL/h, respectively. A 6-month storage study on the stability of carotenoids observed a significant higher retention of total carotenoid in the encapsulated powder compared to that in the non-encapsulated oil containing carotenoids from Gac peel. In conclusion, carotenoids and antioxidant capacity from Gac peel can be recovered successfully from Gac peel. The encapsulated carotenoids from Gac peel could be preserved for long storage and may be used for the carotenoid fortification of foods, cosmetic and medicines. Thus, Gac peel is suggested to be used as a natural source of carotenoids instead of being regarded as a waste from Gac processing.
- Subject
- gac fruit; peel; carotenoid; extraction; encapsulation; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1390685
- Identifier
- uon:33110
- Rights
- Copyright 2018 Van Chuyen Hoang
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 6 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 412 KB | Adobe Acrobat PDF | View Details Download |