Browsing by Author "Ellepola, V.P."

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    Effect of Gamma Irradiation on Physicochemical and Microbiological Properties of Ceylon Black Pepper (Piper nigrum L.)
    (Uva Wellassa University of Sri Lanka, 2020) Shanika, W.W.B.; Madurakanthi, A.A.G.; Perera, G.A.A R.; Ellepola, V.P.
    Ceylon black pepper (Piper nigrum L.), commonly known as the “King of Spices”, has dominated the international spice market due to its high piperine content, strong aroma, and rich flavor. Ceylon black pepper is highly susceptible to contamination with different types of microorganisms. This study focused on evaluating the effects of different doses of gamma irradiation on physicochemical and microbial properties of Ceylon black pepper. Samples were collected from a particular exporter in the western province, Sri Lanka. The collected samples were irradiated at five different doses (0, 5, 10, 20, and 30 kGy) by using an industrial Co-60 gamma irradiator. Treated samples were analyzed for water activity (Water activity meter -Novasina LabMATER), moisture content (Moisture analyzer -MRS 120-3), antioxidant activity (DPPH assay method), total polyphenol content (Folin ciocalteu reagent method), flavonoid content (Colorimetric method) and volatile content (GC-MS). Total plate count and yeast and mold counts of these samples were enumerated. This experiment was repeated thrice. Irradiation dose did not affect significantly (p<0.05) on the tested physicochemical properties of Ceylon black pepper. All tested irradiation doses were capable of reducing total plate count and yeast and mold count significantly (p<0.00) as compared to the control. Therefore, it can be concluded that irradiation with 5 kGy dose will ensure the microbial quality of Ceylon black pepper while preserving its original physicochemical properties. Keywords: Ceylon black pepper, Gamma irradiation, Dose, Microbial safety
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    Effect of Osmotic Dehydration on Quality of Green Chili Powder
    (Uva Wellassa University of Sri Lanka, 2019) Dissanayake, W.D.M.R.R.; Fernando, H.R.P.; Ellepola, V.P.; Wijesinghe, W.A.J.P.
    Green chili (Capsicum annuum L.) is commercially grown as a spice crop. Rapid changes in post-harvest quality and the price fluctuation are the main problems facing green chili industry in Sri Lanka. In this study, concentration of chlorophyll a, b and total chlorophyll, moisture content, water solubility, rehydration time, ascorbic acid content (2, 6-dichlorophenol-indophenol method), total phenolic content (Folin-Ciocalteau method), total antioxidant activity (DPPH method), total plate count and yeast and mold count of osmotic (5% NaCl) and non-osmotic dehydrated green chili powder samples (Variety MI 2) were investigated. To investigate the consumer preference, a sensory evaluation was done. Low moisture (4.00%), higher total antioxidants concentration (4.26 ×10ˉ4 kg Lˉ¹), ascorbic acid concentration (9.04 × 10ˉ4 kg Lˉ¹), rehydration time (8.25 s) and low total plate count were observed in osmotic dehydrated green chili powder when compared with the non-osmotic samples. Best green color with high chlorophyll a (2.39 × 10ˉ6 kg Lˉ¹), b (4.50 × 10ˉ6 kg Lˉ¹) and total chlorophyll (6.88 × 10ˉ6 kg Lˉ¹), high water solubility index (3.94%), total phenolic content (1.52 × 10ˉ4 kg kgˉ¹) and low yeast and mold count were exhibited in non-osmotic dehydrated green chili powder samples. There was significant difference between osmotic and non-osmotic samples of all above parameters except the ascorbic acid content. In the sensory evaluation, non-osmotic samples obtained the higher ranks for color, taste, aroma, texture and mouth feel. The osmotic dehydrated product obtained the highest score for overall acceptability. However, the osmotic dehydration technique is the most favorable for commercial level green chili powder production due to their good physicochemical and nutritional characteristics.
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    Isolation of Colourants from Crude Green Tea Extracts as a Substitute for Commercially Available Synthetic Food Colourants
    (Uva Wellassa University of Sri Lanka, 2021) Liyanage, S.P.; Lochana, E.A.L.; Ellepola, V.P.; Wijesinghe, W.A.J.P.
    A natural food colour is any dye, pigment or any other substance obtained from a natural source. The demand for natural food colours in the international market is increasing rapidly due to the increasing public awareness on the harmful effects of synthetic food colourants. Hence this study was aimed at isolating food colourants using green tea based refuse tea and dust grade as a value added product. Accordingly, colour extraction of refuse tea (8 % moisture, 5.58 % ash, 15.51 % crude fiber, 2.06 % fat and 19.68 % protein) and green tea dust (6.06 % moisture, 5.63 % ash, 14.55 % crude fiber, 2.07 % fat and 15.57 % protein) was initially done by sonication and simple water bath techniques. The most desirable samples were then selected based on the colour intensity values (b*) and absorbance values. The selected samples were stabilized with 3 % carrageenan which converted the filtrate into a gel. The stability of the colourants was studied against pH, concentration and time-temperature combinations. The consumer preference for the products were studied using a structured sensory evaluation. According to the results yellowness (5 Y8/10 to 5 Y8/12) could be expected in 3 to 4 pH range in refuse tea based colourant and yellowness (5 Y8/6 to 5 Y8/10) could be expected in 3 to 6 pH range in the green tea dust based colourant. It was observed that with the increase of the temperature darkness of the colourant significantly rises, especially from 60 ºC and above, which resulted in a hue approximated to caramel black. Both colourants showed yellow hues from 0.3 to 2 % v/v concentration level. Moreover both colourants are having considerable levels of polyphenol content ,antioxidant activity and caffeine content, which contribute to human health promotion. Therefore, it can be inferred that developing colourants using crude green tea extract to be sustainable and safe alternative for synthetic colourants used in the food industry. Keywords: Dust; Extraction ; Green tea; Natural food colour; Refuse tea
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    Nutritional, Physicochemical and Sensory Properties of Embul Banana (Musa acuminata AAB) Snack Developed using Vacuum Dehydration
    (Uva Wellassa University of Sri Lanka, 2019) Chandrasiri, M.H.T.K.; Hettiarachchi, D.N.; Ellepola, V.P.; Wijesinghe, W.A.J.P.
    A great potential exists for Embul Banana (Musa acuminata AAB) value added products due to its limited preservation methods and proven health benefits. This study focused on development of Embul banana snacks using vacuum dehydration. Vacuum dehydrated Embul banana snacks were packed using 300 µ High Density Polypropylene bags and stored in a cool and dry place for two months. Proximate composition of the final product was determined using AOAC methods. As microbiological properties total plate count, yeast and mold count and Escherichia coli were checked during the storage. Sensory data obtained monthly by 9-point hedonic scale were analyzed using Kruskal Wallis non parametric test in MINITAB 16. Developed snack sample contained 0.87±0.005% moisture, 5.2±0.01% crude fiber, 0.3±0.01% free fat, 15.4±0.01% protein, and 3.2±0.01% ash. Sensory evaluation revealed that there were no significant changes (P > 0.05) in any sensory attribute (color, aroma, taste, mouth feel, texture and overall acceptability) throughout the storage period. Physicochemical properties such as pH, firmness, total soluble solids, moisture% and ascorbic acid content of the final product were 5.12±0.005, 4.26±0.50 Kg, 6.0±0.0%, 0.87±0.005% and 10.79±0.005 mg 100g-1, respectively. Total phenolic content determined by Folin-Ciocalteau method for the final product was 281.86±1.18 mg GAE 100g-1 while IC50 value determined from the DPPH radical scavenging assay for the final product was 234.06±1.03 mg mL-1. Total plate count was less than 101 CFU g-1 while yeast and mold counts were less than 103 CFU g-1 which ensures that the product is within the international limits stipulated by World Health Organization. E. coli were not detected even after two months. Developed vacuum dehydrated Embul banana snacks can be safely stored under room temperature for two months.
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    Value Addition to off Grade Tea by Incorporating Tea Aroma
    (Uva Wellassa University of Sri Lanka, 2015) Ellepola, V.P.
    In each step of tea manufacturing process various chemical compounds are developed owing to enzymatic and non-enzymatic reactions. Considerable amount of volatile compounds which formed up to fermentation process are lost during drying. An experiment was conducted to study how to make use of, amount of volatiles formed during fermentation process of tea to enhance the organoleptic attributes of off grade tea. Experiment was conducted during June to July at Rozella tea factory, Watawala. After extracting aromatic volatiles from fermented tea dhools, aromatic volatile concentration of the extract was enhanced. The developed concentrated aromatic liquid sample was then used to add value to off grade tea. Developed tea samples were then subjected to the sensory evaluation consisting of a panel of seven professional tea tasters. After the sensory evaluation moisture content of the developed teas were recorded. Finally considering both moisture content and sensory results, best treatment was selected. Off grade tea incorporated with 1% of non-concentrated volatile sample and, 2% of concentrated volatile sample were identified as the best treatments. Samples developed using the concentrated volatile sample manifested a significant improvement of the organoleptic traits of the tea over the non-concentrated treatment. Treatments had a significant impact on the development of aroma, flavor and quality traits. Hence, the study proves that resupplying of volatile compounds to off grade tea is found to be a good approach to add value to off grade tea. Key words- Tea Aroma, Tea off grades, Volatile compounds, Value addition
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    Value Addition to Off Grade Tea by Incorporating Tea Aroma
    (Uva Wellassa University of Sri Lanka, 2016) Ellepola, V.P.; Premathilake, K.G.; De Silva, P.D.P.M.P.; Chitty, A.
    Considerable amount of volatile compounds which formed up to fermentation process are lost during drying. An experiment was conducted to study how to make use of, amount of volatiles formed during fermentation process of tea to enhance the organoleptic attributes of off grade tea. Experiment was conducted at Rozella tea factory, Watawala. After extracting aromatic volatiles from fermented tea dhools, concentration of the extract, was enhanced. The developed treatment was then used to add value to off grade tea and sensory evaluation was conducted. Then moisture content of the developed teas were recorded. Off grade tea incorporated with 1% of non-concentrated volatile sample and, 0.5 % of concentrated volatile sample were identified as the best treatments. Treatments had a significant impact on the development of aroma, flavour and quality traits. Hence, the study proves that resupplying of volatile compounds to off grade tea is found to be a good approach to add value to offgrade tea. Keywords: Tea Aroma, Tea off grades, Volatile compounds, Value addition