International Research Symposium on Pure and Applied Sciences (IRSPAS)

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Author: search.filters.author.Liyanage, R.Has files: Yes

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    Determination of polycyclic aromatic hydrocarbons in black tea at different processing stages.
    (4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Sithara, T. A. H.; Marapana, R. A. U. J.; Liyanage, R.; Senanayaka, S.
    Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous organic molecules considered as environmental pollutants, generally enter to the environment during incomplete combustion of organic materials. Various foods have been contaminated from PAHs during preparation, processing or from the environment. The present study was carried out to investigate the occurrence of 16 priority PAHs, in black tea, collected from a tea factory. There were six samples of tea from the same batch and same grade at different processing stages that were analyzed. The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method was followed to prepare samples and the analysis was done by using gas chromatography- mass spectroscopy. The total PAHs contents of fresh tea leaves, withered, rolled, fermented, dried, graded tea were 26631.84, 59716.89, 43517.76, 11584.72, 7151.88, 16726.77 μg/kg respectively. The results showed that the PAHs were high in withering and rolling steps than the other steps and high PAHs count in graded tea than dried black tea. Since the withering, rolling and tea grading steps are carried out close to the unloading bay and machinery, they could be contaminated from smoke of vehicles and factory smoke effluent. The fermented tea showed less PAHs content and that decrement could be due to volatilization and degradation of PAHs during fermentation. The PAHs contamination of tea leaves depend on the manufacturing premises, environmental condition, thermal energy type, dryer type and raw material conditions etc. The majority of detected PAHs in tea samples were of low molecular weights. According to International Agency for Research on Cancer, 2 and 3 ring PAHs were classified into group 2B and 3 according to the carcinogenicity; the agent possibly carcinogenic and not classifiable as to its carcinogenicity to humans respectively. Even though, tea was contaminated from PAHs, these PAHs are not harmful to the human health. Therefore, the consumption of black tea is safe to the humans
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    Effect of boiling and simulated digestion on the total phenol, total flavonoid and antioxidant activity of commonly consumed legumes in Sri Lanka
    (4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Deen, A.; Visvanathan, R.; Rathanayaka, I.; Jayewardene, B. C.; Liyanage, R.
    Legumes are considered as a rich source of proteins, complex carbohydrates (dietary fibers), minerals and vitamins. Owing to the fact, above legumes hold a special place in vegetarian diet. In addition, legumes are gaining attention due to their extraordinary health benefits. These health benefits are attributed to the presence of numerous bioactive compounds in legumes. Antioxidants are one such important bioactive compound present in legumes. However, processing and gastrointestinal digestion may alter the bioavailability of antioxidants in legumes. Hence, this study focuses on the effect of boiling and simulated digestion on the antioxidant capacity, phenolic and flavonoid content of chickpea, mung (MI6), cowpea (Waruni), cowpea (Dawala) and horse gram (Kollu). The raw and boiled legume samples were digested by using synthetic gastrointestinal enzymes (pepsin, pancreatin, bile extract). The total phenol (TP)content and total flavonoid (TF) content in experimental legume samples were assessed using Folin-ciocalteu method and Aluminium chloride colorimetric method, respectively. The antioxidant activity in experimental legume samples were determined using DPPH (2,2-diphenyl -1 –picrylhydrazyl), ABTS (3-ethylbenzothiazoline-6-sulphonic acid) and FRAP (Ferric reducing power) methods. All the experiments were carried out in triplicate and three factor factorial model was used to analyze the data and the level of p≤0.05 was considered significant. According to the results it shows that boiling and simulated digestion modulate the bioavailability of antioxidants and their activity. Among the raw samples, Horse gram (Kollu) showed the highest (p≤0.05) amount of phenolics (20.66±1.58 mg GAE/g), highest (p≤0.05) Fe3+ reducing activity, ABTS and DPPH radical scavenging activity while cowpea (Dawala) showed the lowest amount of phenolics (13.59±0.1 mg GAE/g) and lowest (p≤0.05) antioxidant activity. However, upon boiling, studied legumes showed (p<0.05) a reduced bioavailability of TP, TF content and reduced antioxidant activity. When considering the simulated digested samples, boiled legumes showed a significant increase (p≤0.05) in TF, TP content and antioxidant activity compared to raw samples. In-vitro digested, boiled Mung and horse gram had the highest Fe3+ reducing activity (233.90±13.10 mM/Fe2+ g-1/,233.68±37.82 mM/Fe2+ g-1) and ABTS radical scavenging activity (621.83±16.77 μmolTE/g/, 363.34±10.34 μmolTE/g). Hence, the overall results reveal that the processing and simulated digestion modulate the bioavailability of TF, TP and the antioxidant activity of above five selected legumes. Bioavailability of phenols and flavonoids were high (p≤0.05) in horse gram and mung bean compared to other legumes