iPURSE 2019
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Browsing iPURSE 2019 by Subject "Antioxidant"
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- ItemDetecting of sugar adulteration in black tea and its impact on quality parameters(University of Peradeniya, 2019-09-12) Wedagedara, H. M.; Wanigasuriya, W. A. G. I.; Nissanka, S. P.; Mohotti, A. J.; Mendis, B. E. P.; Botheju, W. S.Ceylon tea is considered as the world’s finest black tea, in terms of quality. However, the issue of tea being adulterated with sugar has been prevalent for some time. Sugar adulteration is basically done to enhance the colour properties of tea in order to fetch higher prices. Therefore, development of a simple method to detect sugar adulteration in tea is timely needed. Hence, this study was conducted to develop a rapid method to detect sugar adulteration in black tea and to evaluate the quality parameters in sugar adulterated black tea. Three batches of black tea samples were prepared from TRI 2025 clone grown at St Coombs Estate, Sri Lanka, by adding different sugar levels of 0 g, 2 g, 4 g, 8 g, and 16 g per 1kg (Trial 1), and 0 g, 10 g, 20 g and 30 g per 1kg (Trial 2) of withered tea leaves, during the 1ˢᵗ rolling, using a miniature environment control manufacturing (ECM) system. Sugar adulteration in black tea cannot be identified by using both quantitative and qualitative Benedict’s test, Strip method and Sensory evaluation technique. Phenol-sulfuric method and anthrone method showed increasing pattern of spectrophotometer reading with increasing of adulterated sugar levels in black tea. Sugar adulterated black tea samples showed reduction in antioxidant and total phenolic contents compared to the sugar unadulterated black tea samples. There was also no significant difference between moisture content with increasing sugar levels (p>0.05). But there was an increasing pattern in moisture content in all sugar adulterated levels when storage time is increased. Phenol-sulfuric method and anthrone method can be recommended to detect sugar adulteration. Sugar is a constituent which naturally occurs in tea brew. Hence baseline data for inherent sugar content should be established for different seasons and regions.
- ItemDetermination of antioxidant properties of blossoms of banana (musa acuminata) varieties available in Jaffna district(University of Peradeniya, 2019-09-12) Theepana, Y.; Sarathadevi, R.; Subajini, S.Banana blossom is a by-product of banana cultivation and is a rich source of antioxidants. The aim of this study was to evaluate and compare the antioxidant properties of blossoms of fourvarieties of banana (Itharai, Kathali, Monthan and Kappal). Fresh banana blossoms were collected from four Divisional Secretariat Divisions (Chankanai, Atchuvely, Neerveli and Karaveddy) of the Jaffna District, Sri Lanka. Banana blossoms were cut and soaked in anti-browning solution (0.3% citric acid) for 30 minutes. After draining, composite sample was prepared by mixing the blossoms of the same variety collected from different areas. Samples were macerated and prepared samples (3 g) were extracted using 60 mL of solvent (either ethanol (70%, v/v) or methanol (70%, v/v)) by shaking at 200 rpm at ambient conditions for 2, 4 and 6 h. Dry extracts obtained after evaporation of solvent were used to analyze antioxidant properties by determining total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacity (AC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Efficiency of extraction of antioxidant significantly (p<0.05) increased with increasing extraction duration. Compared with methanol extract, ethanol extract exhibited high antioxidant properties. Itharai exhibited significantly (p<0.05) highest total phenolic content (142.45±12 mg gallic acid equivalent/g dry matter), whereas, Monthan showed highest total flavonoid content (68.85±1.2 mg catechin equivalent/g dry matter). Highest antioxidant capacity (309.7±5 mg ascorbic acid equivalent/g dry matter) and highest DPPH radical scavenging activity (IC50 value, 0.049±0.004 mg/mL) were exhibited by Kathali and Kappal, respectively. This study concludes that extracts of four varieties of banana blossom used in this study are potent sources of natural antioxidants
- ItemRoot cause analysis of high microbial count in moringa (moringa oleifera) powder and developing a method to enhance its microbial quality for the export market(University of Peradeniya, 2019-09-12) Hettiarachchi, H. A. D. L.; Rathnayaka, R. M. S. U. K.Sri Lanka produces a range of superfoods using Moringa which is highly susceptible to microbial contamination. The objectives of this study were to investigate the root causes for the high microbial contamination in Moringa powder and to develop a method to enhance microbiological quality to meet export standards. Initially root cause analysis was performed using cause and effect diagram. Three sets of water samples from the direct pipeline and the temporary storage tank, and three sets of leaf samples from each processing were randomly collected and subjected to total plate count (TPC), coliform and yeast and molds analyzes. The maximum sodium hypochlorite (NaOCl) concentration used for the washing process in an organic Moringa production was calculated by measuring the residual chlorine content using the sodium thiosulfate titration method. Various methods were developed by adding NaOCl washing process to eliminate the identified root causes and then a series of samples were prepared. Three sets of Moringa powder from each developed methods have been used to analyze the antioxidant activity with Folin-Ciocalteu assay and measured the physicochemical properties. The results were compared with already prepared dried gamma treated Moringa powder. Accordingly, fresh Moringa leaves contain high initial coliform, yeast & mold and TPC as 181 x10 ⁴ CFU/ml, 41 x 10 ⁴ CFU/ml and 250 x 10 ⁵ CFU/ml, respectively. The major root causes were poor hygienic practices, lack of inspection and improper manufacturing practices. It was concluded that the new method; washing up fresh leaves with 50 ppm sodium hypochlorite, sun drying until the moisture level of fresh leaves in the farm drops to 40%, steam blanching at the processing plant, Oven drying of Moringa leaves until the moisture level is reduced to 10%, grinding and further drying of powder at 55 ⁰C for 30 minutes, has enhanced the microbial quality to the desired levels, while retaining maximum physicochemical properties such as ash, fat, protein, fiber values as 4.73±0.02 g, 3.01±0.26 g, 20.80±0.72 g, 16.86±0.07 g respectively thus making the powder suitable for the export market.
- ItemStudy on the effect of heat sterilization on bioactivity of flacourtia indica (Burm.f.) merr. (Uguressa) and flacourtia inermis roxb. (Lovi) fruit juices(University of Peradeniya, 2019-09-12) Shamika, D. G. H.; Dissanayake, D.; Perumpuli, B.; Kumar, N. S.; Jayasinghe, L.Though underutilized, Flacourtia indica Roxb. (Lovi) and Flacourtia inermis (Burm.f.) Merr. (Uguressa) of the family Flacourtiaceae are a rich source of biologically active compounds such as phenolics, anthocyanins and hydroxybenzyl alcohol glycosides. Thermal sterilization can be used to increase the shelf life of fruit juices for a considerable period. However, during sterilization, nutritional and bioactive properties can be changed either adversely or favorably. Hence, the current study was focused on the effect of thermal sterilization at 121 ⁰C for 20 minutes, on bioactivity of extracts obtained from sterilized and fresh fruit juice of two fruits. Antioxidant activity was determined using 1-diphenyl-2-picryl-hydrazyl activity (DPPH) radical scavenging power assay which was expressed in IC₅₀. Total phenolic content (TPC) was determined by Folin ciocalteu method and α-amylase enzyme inhibitory activity was determined by Dinitrosalicylic Acid (DNSA) method which was also expressed in IC₅₀ values. Extracts obtained from sterilized juice of F. indica shows the highest DPPH radical scavenging activity (IC₅₀ 51.49 ±0.6 ppm). The highest TPC value was recorded in the sterilized juice of F. indica (85.35±4.9 mg of gallic acid/g of extract). Thus, antioxidant activities of extracts obtained from the sterilized juice of F. indica has increased with the sterilization. This may be due to hydrolysis of polyphenols in both species. The α-amylase inhibitory activity of all the crude extracts was found to be significantly less than that of Acarbose (IC₅₀ 19.85 ppm), which is commonly identified as clinical drug for hyperglycemia. However, α-amylase inhibitory activity of the juice of both fruits was further reduced upon sterilization. Possible reason may be the α-amylase inhibitory activity might have related to heat liable compound. In conclusion, consuming the thermally sterilized juice of F. inermis and F. indica will provide benefits in human diets as a rich source of natural antioxidant and phenolic compounds. However, α-amylase inhibitory activity of the juice of both fruits was further reduced upon sterilization.