Screening and optimisation study on antioxidant extracts from selected lamiaceae plants
This thesis deals with screening of antioxidant activity, phenols content and mineral profiles, optimisation of extraction of antioxidants and optimisation of spray drying of boiling extract from the selected Lamiaceae plants. The objective of this thesis was to select the plant materials of the...
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| Format: | Thesis |
| Language: | English |
| Published: |
2010
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| Subjects: | |
| Online Access: | http://umpir.ump.edu.my/id/eprint/2733/ http://umpir.ump.edu.my/id/eprint/2733/1/MOHD_SHAIFUL_AZMAN_B._ABDUL_RAHIM.PDF |
| Summary: | This thesis deals with screening of antioxidant activity, phenols content and
mineral profiles, optimisation of extraction of antioxidants and optimisation of spray
drying of boiling extract from the selected Lamiaceae plants. The objective of this thesis
was to select the plant materials of the selected Lamiaceae species that gave the highest
antioxidant activity, highest phenols content and best mineral profiles. This thesis
presents the optimised levels of experimental variables that gave the highest antioxidant
activity-yield. This thesis also presents the optimum levels of the operational variables
that influence the spray drying of the liquid extract of the Lamiaceae plant. Fresh
Plecranthus amboinicus Lour. Indonesia (PALl) samples were randomly collected from
Jakarta, Indonesia and samples of Plecranthus amboinicus Lour. Malaysia (PALM),
Pogostemon cablin Benth. (PCB), SOlenostemon scutellariodes Benth. Red (SSR) and
Solenostemon scutellariodes Mix Colour (SSMC) were randomly collected from
Kuantan, Malaysia. The extracted samples were assessed using 1,1-diphenyl-2-
picry1hydrazyl (DPPH) free radical scavengiig assay for determination of antioxidant
activity. Folin Ciocalteau method was chosen for total phenols determination, while the
essential minerals were analysed by using atomic absorption spectrometer. The 22
factorial design of experiment was used in the optimisation of extraction of antioxidants
by boiling. The method of Path of Steepest Ascent was used to maximise the
antioxidant activity in the spray dried extract. The obtained results indicated that the
- leaves tissues of PCB samples exhibited the significant 6<0.05) highest antioxidant
activity (63.18%) and highest phenols content (7.64 mg/g fresh weight) while the
highest total minerals content was observed in the PALl leaves (38.41 ppm). For
optimisation of extraction of antioxidant by boiling, the theOretical maximum point has
the boiling temperature (T) at 116.18°C and boiling time duration (t) at 107.81 minutes
which gave an antioxidant activity-yield of 65.153 ' %. The combination of levels of
operational variables where the spray dryer was operated at X1 (temperature) =
177.65°C and X2 (concentration of maltodextrin) = 48.65% gave the highest yield of
antioxidant activity of spray dried extract. This research suggests a chemical basis for
some of the health benefits claimed for in folk medicine and warrant further studies to
develop it as a natural functional food. |
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