Browsing by Author "Hapuarachchi, C.D."

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Comparison of fatty acid composition and antioxidant properties of virgin coconut oil and traditional coconut oil
(2010) Hapuarachchi, C.D.
ABSTRACT: The major quality parameters (peroxide value, acid value, iodine value and saponification value) of coconut oil were determined using reported methods. Both traditional coconut oils (TCO1, TCO2 and TCO3) and virgin coconut oils (VC01, VC02 and VC03) gave different results for quality parameters (Acid value and peroxide value) which were prepared using different endosperm components. The peroxide value of TCO 3 was found to have the lowest value compared to other oils and the lowest acid value was observed in VCO 2. Individual fatty acid analyses of traditional coconut oil, virgin coconut oil and commercial coconut (CCO) were done using gas chromatography. The phenolic composition and antioxidant potential were determined and compared in TCO, VCO and CCO. The objective of this study was to investigate how processing method, temperature and components of the endosperm of coconut affected the yields of phenolic substances and the antioxidant capacity of coconut oil. Total phenolic content of TCO and VCO was determined by the Folin-Denis procedure and expressed as acid equivalents. The total phenol content in TCO varied from 66 - 305 mg/kg and in VCO the above value varied from 62 - 66 mg/kg . In addition, antioxidant activities were tested by using 2,2-diphenyl-l-picryhydrazyl (DPPH) free radical scavenging assay, deoxyribose assay and ferric-reducing antioxidant power. Polyphenol fraction from TCO was found to have the highest inhibitory effect on radical scavenging activity and reducing power compared to that from the other two oils. Individual phenolic compounds present in the nonsaponifiable fraction of coconut oils were identified and quantified by Reverse Phase HPLC with UV detection. The phenolic compounds were identified comparing the retention time of authentic standards. Then the phenolic compounds were quantified by using calibration curves Effect of polyphenol fraction isolated from TCO, VCO and CCO were tested for the ability to maintain physiological antioxidant levels. Coconut oil mixed meals were fed to Wistar rats for 84 days and after the experimental period, Trolox Equivalent Antioxidant Capacity (TEAC) of erum of rats were compared. TEAC value was determined by the ABTS [2,2/-azinobis (3-ethylbenzothiazoneline-6-sulfonic acid)] assay using the Trolox as a standard compound. The results of the experiment showed that the diet containing TCO, had the highest level of TEAC value and the value significantly increased and stabilized with the time. Phenolic compounds and antioxidant activity of coconut cake (poonac) was also investigated. TCO shows excellent antioxidant properties due to the rich phenolic fraction of TCO. The nutritional quality of other coconut oil cans also improved by incorporation of phenolic substances in to coconut oil from coconut cake. The study indicated better antioxidant activities of coconut cake extracts compared to BHT. Enriched coconut oil was prepared using coconut cake and copra oil and this oil effectively enhanced the total antioxidant capacity of the blood serum of Wistar rats. The total phenol contents in coconut oils significantly correlated with TEAC values.
Comparison of the in vivo antioxidant activity of traditional coconut oil, virgin coconut oil and soya oil
(Sri Lanka Association for the Advancement of Science, 2008) Seneviratne, K.N.; Ekanayake, S.; Hapuarachchi, C.D.
When the nutritional quality of cooking oils is considered, it is extremely important to evaluate the contribution of cooking oils to the antioxidant activity in blood. In the present study, the in vivo antioxidant potentials of three cooking oils are compared. Male Wistar rats were fed with a special diet containing traditional coconut oil (TCO, prepared by boiling coconut milk), virgin coconut oil (VCO) and soya oil (SO). The effect of the consumption of these oils on the total antioxidant activity in blood serum was analyzed and compared. The decolorization of ABTS•+ (radical cation of 2,2'-azinobis-(3-ethylbenzothiazoline- 6-sulfonic acid) was used as a measure of antioxidant activity and the antioxidant activity was expressed as trolox equivalent antioxidant capacity (TEAC).
Comparison of the Phenolic-dependant antioxidant properties of coconut oil extracted under cold and hot conditions
(Food Chemistry, 2008) Senevirathne, K.N.; Hapuarachchi, C.D.; Ekanayake, S.
Improving the nutritional quality of coconut oil by incorporating phenolic substances of coconut cake
(Sri Lanka Association for the Advancement of Science, 2009) Seneviratne, K.N.; Hapuarachchi, C.D.; Ekanayake, S.
Phenolic content and antioxidant activity of virgin coconut oil and other coconut oils
(Sri Lanka Association for the Advancement of Science, 2006) Seneviratne, K.N.; Hapuarachchi, C.D.
Radical Scavenging Activity of Phenolic Compounds of Coconut Cake
(University of Kelaniya, 2007) Seneviratne, K.N.; Hapuarachchi, C.D.
2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical has been widely used to evaluate the free radical scavenging activity of natural antioxidants. Antioxidants react with DPPH radical, which is a stable free radical and convert it to 2,2-diphenyl-1-picryl hydrazine. The degree of discoloration indicates the scavenging activity of antioxidant extracts. In the present study, phenolic compounds of coconut cake were extracted using methanol : water (80 : 20 v/v) and the radical scavenging activities of the phenolic extracts and butylhydoxytolucne (BHT) against DPPH radical were determined spectrophotometrically in order to compare the antioxidant potential of the phenolic extracts of coconut cake. The change in color from deep violet to light yellow was measured at 515 nm using a UV /Visible spectrophotometer. Radical scavenging activity of the phenolic extracts was expressed as the percentage inhibition with respect to a control with no added phenolic extract. Total phenol concentrations of the phenolic extracts measured by Folin-Denis colorimetric method were adjusted to a range of concentrations by suitable dilutions of the extracts with the methanol water solvent system. A similar concentration series was also prepared by suitable dilutions of BHT. Figure 1 compares the DPPH radical scavenging activity of the phenolic extracts of coconut cake with that of BHT. Figure 1. 100- 90 ~ 80 " 70 5 so "' ~ 50 .5 ;f. 40 30 20 ' 10' 0 ; DPPH radical scavenging activities of the phenolic extracts of coconut cake and BHT -.-Coconut cake extract 25 50 75 100 Concentration of the extract or BHT (mg/ L) There is lot of interest in recent times about the suitable alternatives for synthetic antioxidants. The above results indicate that the phenolic extracts of coconut cake are potential candidates for nontoxic natural antioxidants.