Browsing by Author "Senanayake, C.M."

Now showing 1 - 9 of 9

Antioxidant activities in extracts of five plant sources on stabilization of stripped sunflower oil and egg yolk homogenate
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Senanayake, C.M.; Seneviratne, K.N.
out to evaluate the antioxidant potential of five natural sources namely, coconut cake (A), Psidium guajava L. leaf (Guava) (B), Psidium guineense Sw. leaf (Ambul guava) (C), rice bran (D) and sesame cake (E) in both chemical and food model systems (stripped sunflower oil and egg yolk homogenate). Phenolic substances from the test plant materials were extracted using ethanol:water (70:30) solvent system. Total phenolic content (TPC) was determined using Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE) per kilogram of sample. Antioxidant activities of extracts and butylated hydroxytoluene (BHT) were evaluated using deoxyribose degradation assay after adjusting the concentration to 30 μg mL-1. Antioxidant activities of phenolic extracts on stripped (antioxidant free) sunflower oil were determined by comparing the induction time (IT) using the Rancimat Apparatus at 100 0C. Effect of phenolic antioxidants on the inhibition of thiobarbituric acid reactive substances (TBARS) formation was evaluated using egg yolk homogenate as the food model system. Results of TPC as GAE vary in the order, C (195.25±9.56 g/kg) > B (68.83±3.74 g/kg) > D (4.14±0.46 g/kg) > E (2.11±0.29 g/kg) > A (0.77±0.03 g/kg). Phenolic extract of C showed a significantly (p<0.05) higher percentage inhibition of deoxyribose degradation (76.5±1.5 %) than other phenolic extracts and BHT. Inhibition percentages obtained for A, B, D, E and BHT were 39.5±1.4 %, 71.0±2.7 %, 46.1±3.1 %, 42.1±2.5 % and 32.6±2.1 % respectively. Results of IT of stripped sunflower oil and inhibition % of TBARS formation were stated in Table 1.
Antioxidant activities of phenolic extracts of guava leaf, coconut cake, rice bran and sesame cake obtained using subcritical water and ethanol: water (70:30 v/v)
(Faculty of Graduate Studies, University of Kelaniya, 2015) Senanayake, C.M.; Jayawardena, B.M.; Senavirathne, K.N.
Antioxidant and Nutritional Properties of Domestic and Commercial Coconut Milk Preparations
(International Journal of Food Science, 2020) Karunasiri, A.N.; Gunawardane, M.; Senanayake, C.M.; Jayathilaka, N.; Senevirathne, K.N.
The aqueous extract of scraped coconut kernel is known as coconut milk. Coconut milk preparations are also commercially available in the form of desiccated powders or liquids. While these various coconut milk preparations are heavily used in cooking in the Asian countries as a major source of dietary fat, limited studies have been conducted on their chemical and nutritional composition. In this study, we have determined the chemical composition and nutritional effects of both domestic preparations of coconut milk and the commercially available counterparts. The results indicate that the phenolic compounds of all coconut milk preparations provide protection against oxidative damage on lipids and inhibit oxidative damage of both proteins and DNA. The lipid profiles are not significantly affected by the consumption of the three coconut milk preparations despite their different fat contents.
Determination of thermal stabilities of guava leaf, coconut cake, rice bran and sesame cake extracts
(Sri Lanka Association for the Advancement of Science, 2015) Senanayake, C.M.; Seneviratne, K.N.; Jayawardena, B.M.; Prasadani, W.C.
Effect of Repeated Heating on The Oxidative Degradation of White Coconut Oil and Soy Bean Oil
(Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Senanayake, C.M.; Jayathilaka, N.; Seneviratne, K.N.
Repeated heating of cooking oils is a common practice used mainly to save the cost in food preparations. The aim of the present study was to investigative the effect of repeated heating on the oxidative degradation of frying oils (white coconut oil and soy bean oil). Initially, fresh potatoes were peeled off and sliced into uniform thickness (4×0.3×0.3 cm3). Sliced potatoes (batches of 25 g) were fried in 100 mL portions of white coconut oil (WCO) and soy bean oil (SO) separately at 180±5 °C for 10 minutes. The oils were reused for 2 more frying cycles over a span of 3 days (1 frying cycle per day). In each day, an amount of fresh oil was added to make the volume of frying oil in to 100 mL. After each frying cycle, oil samples were collected from the frying pan and by extraction of fat with n-hexane from potato chips. Level of oxidation of frying oils and lipid extracted from potato chips were assessed by measuring the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Table 01 states the results of PV and TBARS. Both PV and TBARS of frying oils and lipid extracted from potato chips increased as the number of frying cycles were increased (Table 01). Fried SO (FSO) and lipid extracted from potato chips fried in SO (PSO) showed higher PV and TBARS values than that of fried WCO (FWCO) and lipid extracted from potato chips fried in WCO (PWCO) in every frying cycle (Table 01).
Ethanolic extract of rice bran: a thermally stable preservative for edible oils and cake
(2022) Seneviratne, K.P.; Anjali, N.V.P.; Senanayake, C.M.
The purpose of this study was to evaluate the thermal stability of the rice bran extract (RBE) and analyze the effect of RBE on the shelf-life of sunflower oil and the quality characteristics and shelf-life of baked cake. The thermal stability of RBE was evaluated by a Rancimat test using sunflower oil. Properties such as moisture content, porosity, crumb density and pore area of cakes baked with RBE and the synthetic antioxidant butylated hydroxytoluene (BHT) were compared. Sensory properties such as taste, aroma, texture, color and overall acceptability of the cake samples were compared using a sensory panel test. The shelf-life of the cakes was evaluated by microbial counts and chemical methods. Thermally treated RBE and BHT for 2 h at 180 °C retained 75% of their initial capacity in protecting sunflower oil while RBE had a significantly higher protection factor (p < 0.05). Cakes baked with RBE received higher scores for taste, color and overall acceptability compared to control or BHT-added cake. BHT-added cake and RBE-added cake exceeded the aerobic plate count (APC) and yeast and mold count (YMC) on days 11 and 13 respectively, while the control cakes without added antioxidants exceeded the APC and YMC on day 7. Both BHT- and RBE-added cakes maintained hexanal levels below 5 mg/kg over 28 days while the control cake exceeded this level on day 21. The results suggest that RBE can be used as a natural food additive to improve the quality and shelf-life of baked foods and edible oils.
Nutritional Effect of Consumption of Domestic and Commercially Available Coconut Milk Preparations in Wistar Rats.
(In: Proceedings of the International Postgraduate Research Conference 2017 (IPRC – 2017), Faculty of Graduate Studies, University of Kelaniya, Sri Lanka., 2017) Senanayake, C.M.; Seneviratne, K.N.; Jayathilaka, N.; Ekanayaka, S.
The use of both domestic coconut milk (CM) preparations and commerciallyavailable CM preparations in cooking has become popular. The present study involves evaluating In vivo effect of domestic CM prepared by blending (BCM), commercially available powdered CM (PCM) and liquid CM (LCM) on serum lipid profiles and serum antioxidant capacity using Wistar rats. Seven weeks old male Wistar rats were randomly assigned into treatment groups. Control group was fed with a semisynthetic diet recommended by WHO. Second, third and fourth groups were fed with semi synthetic diet which contains 12 mL BCM, PCM or LCM per kg of feed respectively. Blood was drawn on day before feeding experimental diets (Day 0), 30 days, 90 days, 120 days and 150 days after feeding experimental diets. Serum total cholesterol (TC), high density lipoprotein (HDL) and triglycerides (TG) were analyzed using a test kit. Low density lipoprotein (LDL) was determined using Friedewald equation. Antioxidant activity of serum was determined by ABTS assay and DPPH radical scavenging assay. TC levels of all groups were significantly (p<0.05) increased after 150 days of feeding compared to their day 0 levels. TC levels (mg/dL) of rats fed with BCM (80±4), PCM (80±5) and LCM (81±3) were similar to control group (77±7). However, rats fed with LCM showed a statistically significant (p<0.05) increase in TC compared to control group. Although, TG levels of CM diet groups indicated significant (p<0.05) increase on day 150 compared to their day 0 levels, these levels were similar to that of control group. Both HDL and LDL levels of CM diet groups remained same compared to control group at day 150. All CM diet groups showed a significantly (p<0.05) increased activity on day 150 compared to their day 0 levels.CM fat contains nearly 90 % saturated fat. However, majority of the saturated fat in CM fatis composed of short and medium chain fatty acids, which are beneficial to health. As such, adding CM to diet did not affect average levels of serum TC, LDL and TG of Wistar rats suggesting that none of the CM preparations under investigation contribute to detrimental changes in lipid profiles. All CM preparations, on the other hand, appear to increase serum antioxidant activity which may contribute in retarding oxidative damage to biomolecules. Financial assistance from National Research Council (12-012) and University Research Grant (RP/03/02/06/05/2015) areacknowledged.
Phenolic extracts of the leaves of Psidium guineense Sw. improve the shelf life of sunflower oil and baked cake and antioxidant status of Wistar rats
(J Food Biochem, 2018) Senanayake, C.M.; Hapugaswatta, H.; Jayathilaka, N.; Seneviratne, K.N.
The potential of the ethanolic extract of Psidium guineense Sw. leaves (PGLE) to protect food from oxidation was evaluated using sunflower oil and baked cake as food models. The nutritional quality of PGLE was evaluated by feeding Wistar rats with PGLE for 150 days. Psidium guineense Sw. leaves contain 195.25 ± 9.56 mg g–1 phenolic substances, 51% of which are o‐diphenols. Protection factor, the ability of Psidium guineense Sw. leaves to protect sunflower oil against oxidation (1.82 ± 0.13), was not significantly affected by heat treatment compared to BHT. Formation of oxidation products, peroxide and hexanal in PGLE‐ and BHT‐added cake was significantly lower (<5 ppm over 28 days) compared to control with no added antioxidants. Therefore, addition of PGLE improved the shelf life of sunflower oil and oxidative stability of baked cake. PGLE also improves the serum antioxidant capacity and inhibits lipid and protein oxidation in Wistar rats. Practical applications PGLE is a rich source of phenolic substances. Due to high antioxidant activity, pleasant sensory quality and high thermal stability, PGLE can be used to improve the shelf life of baked cake and edible oils. As PGLE also improves serum and plasma antioxidant properties without causing any toxicity, nutritional food supplements can be developed based on PGLE.
Protective Effect of Coconut Oil Meal Phenolic Antioxidants against Macromolecular Damage: In Vitro and In Vivo Study
(Journal of Chemistry, 2020) Karunasiri, A.N.; Senanayake, C.M.; Hapugaswatta, H.; Jayathilaka, N.; Seneviratne, K.N.
Coconut oil meal, a cheap by-product of coconut oil production, is a rich source of phenolic antioxidants. Many age-related diseases are caused by reactive oxygen species- (ROS-) induced damage to macromolecules such as lipids, proteins, and DNA. In the present study, the protective effect of the phenolic extract of coconut oil meal (CMPE) against macromolecular oxidative damage was evaluated using in vitro and in vivo models. Sunflower oil, bovine serum albumin (BSA), and plasmid DNA were used in the in vitro study, and thiobarbituric acid reactive substances (TBARS), protein carbonyl, and nicked DNA were evaluated as oxidation products. The inhibitory effect of CMPE against H2O2-induced macromolecular damage was evaluated using cultured HEp-2 cells. The results indicate that CMPE inhibits macromolecular damage both in vitro and in vivo. In addition, CMPE regulates redox status of HEp-2 cells under oxidative stress conditions by maintaining higher reduced glutathione levels. There was no significant difference in the expression of glutathione peroxidase in stressed and unstressed cells suggesting that CMPE regulates the cellular oxidative stress responses without affecting the expression of oxidative stress response genes. Oral feeding of Wistar rats with CMPE improves the serum and plasma antioxidant status without causing any toxic effects.