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Item Thermal stability of phenolic compounds in coconut cake and its stabilizing effect on stripped sunflower oil(Faculty of Graduate Studies, University of Kelaniya, 2015) Prasadani, W.C.; Jayawardena, B.M.; Seneviratne, K.N.Coconut cake possesses phenolic compounds which are antioxidatively active in chemical and food model systems. However, the thermal stability of these phenolic compounds has not yet been investigated. In this study, the thermal stability of phenolic compounds in coconut cake (PCCC) was compared with that of synthetic antioxidants, butylated hydroxy toluene (BHT), butylated hydroxy anisole (BHA) and tert butyl hydroxy quinone (TBHQ) using two food model systems. PCCC were extracted using ethanol:water (70:30 v/v) and the phenolic concentration was determined using the Folin-Dennis method. Thermal stability was tested by heating PCCC and other synthetic antioxidants at 180 oC up to two hours. In 30 min intervals, the activity of heated antioxidants were tested by evaluating their ability to inhibit thiobarbituric acid reactive substances (TBARS) formation in egg yolk emulsion (EYEM). The percentage inhibition of TBARS formation was calculated against a control EYEM sample prepared without added antioxidants. Protective effect of antioxidants on stripped sunflower oil (SSO) was also evaluated. For this purpose, PCCC and synthetic antioxidants were heat treated at 180 oC for two hours and these antioxidants were incorporated into SSO. The induction time (IT) of SSO was determined at 100 oC in the Rancimat apparatus. The percentage inhibition of TBARS formation in EYEM by BHT, BHA, TBHQ and PCCC decreased with heating time and the percentage inhibition of all antioxidants decreased below 40 % after two hours of heating at 180 C. However, at 30 min of heating, inhibition percentage of TBARS formation by PCCC (72±4 %) and TBHQ (68±2 %) is considerably higher compared to BHT (54±2 %) and BHA (42±2%). The IT of SSO varied in the order, control (1.85±0.14 h) < BHT (2.06±0.08 h) < BHA (2.14±0.06 h) < PCCC (2.18±0.03 h) < TBHQ (2.44±0.10 h). The results of these experiments suggest that PCCC can be used to stabilize foods under high temperature cooking conditions.Item Efficacy of phenolic compounds of coconut cake on oxidative stability of pork(Book of Abstracts, Annual Research Symposium 2014, 2014) Prasadani, W.C.; Seneviratne, N.A.K.P.J.; Jayawardena, B.M.Antioxidant efficacy of different concentrations of phenolic compounds of coconut cake (PCCC) was determined using pork as a food model system. The extracts of PCCC were prepared using ethanol: water (70:30 v/v) and the antioxidant activity of the extracts on formation of thiobarbituric acid reactive substances (TBARS) was evaluated using a spectrophotometric method. Malondialdehyde, a secondary product of the oxidation of polyunsaturated fatty acids reacts with thiobarbituric acid and yield a pinkish red chromogen with an absorbance maximum at 532 nm. The effect of PCCC at 50, 100 and 200 ?g/g meat was compared with that of butylated hydroxy toluene (BHT) 200 ?g/ g and tert butylated hydroquinone (TBHQ) 200 ?g/ g. The extracts were effective in inhibiting the oxidation of pork in comparison with the control with no added phenolic extracts which showed the highest TBARS values during the storage period. At the end of day 5 of storage the inhibition percentage of TBARS are 26 � 9, 35� 7, 54� 4, 54� 4 and 56� 5 for TBHQ, BHT, PCCC 50, PCCC 100 and PCCC 200 respectively. PCCC were effective in suppressing the formation of TBARS in the employed system and their activity is higher than that of BHT and TBHQ. Coconut cake may be considered as a cheap potential source of phenolic compounds effective in stabilizing lipid foods.