Browsing by Author "Kannangara, Sagarika Dilpushpi"

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An analysis of regional variations in the physicochemical properties of Cocos nucifera L. var. nana across Sri Lanka
(2024) Pavalakumar, Dayani; Undugoda, Lanka Jeewanie Samarakoon; Thambugala, Kasun Madhusanka; Manage, Pathmalal Marakkale; Ruwani, Nilushi Nugara; Kannangara, Sagarika Dilpushpi; Rajapaksha, Suranga M.
This study explores the intriguing regional disparities in the characteristics of green dwarf tender coconut water (Cocos nucifera L. var. nana) in Sri Lanka. Physicochemical parameters of coconut water subjected to a comprehensive analysis following standard AOAC methods. The prevalent sugar types in the samples were identifed as fructose and glucose, with a minute amount of sucrose using High-Performance Liquid Chromatography (HPLC). Notably, regional diferences in sugar profles were observed during the analysis. Kurunegala samples exhibited signifcantly higher levels of total soluble solids (5.98±0.12°Brix), along with elevated total sugar (70.13±5.06 mg mL−1), total reducing sugar (68.53±5.57 mg mL−1), glucose (39.65±6.10 mg mL−1), and fructose (37.65±7.12 mg mL−1), while Colombo samples demonstrated the least values. Regarding pH values, Colombo samples exhibited a signifcantly lower value (4.87±0.10). Furthermore, a significant quantity of macro minerals such as calcium, sodium, potassium, and magnesium, along with trace minerals like iron and zinc, were identifed. Fourier-transform infrared spectroscopy analysis indicated the presence of functional groups from simple sugars and phenolic compounds as major chemical bonds for all regions. Principal Component Analysis was performed considering the Electronic Nose (E-nose) data, revealing distinctive volatile profle clusters for Kurunegala and Colombo samples. Moreover, sensory evaluations confrmed Kurunegala as the most preferred, while Colombo was ranked as the least preferred in terms of organoleptic characteristics. These fndings underscore the critical importance of regional variations in the nutritional content and sensory attributes of coconut water, which play a pivotal role in infuencing customer preferences.
Evaluating the Probiotic Profile, Antioxidant Properties, and Safety of Indigenous Lactobacillus spp. Inhabiting Fermented Green Tender Coconut Water
(2024) Pavalakumar, Dayani; Undugoda, Lanka Jeewanie Samarakoon; Gunathunga, Chathuri Jayamalie; Manage, Pathmalal Marakkale; Ruwani, Nilushi Nugara; Kannangara, Sagarika Dilpushpi; Lankasena, Bentotage Nalaka Samantha
This study isolated and characterized four indigenous lactic acid bacterial strains from naturally fermented green tender coco-nut water: Lactiplantibacillus plantarum CWJ3, Lacticaseibacillus casei CWM15, Lacticaseibacillus paracasei CWKu14, and Lacticaseibacillus rhamnosus CWKu-12. Notably, among the isolates, Lact. plantarum CWJ3 showed exceptional acid tolerance, with the highest survival rate of 37.34% at pH 2.0 after 1 h, indicating its higher resistance against acidic gastric conditions. However, all strains exhibited robust resistance to bile salts, phenols, and NaCl, with survival rates exceeding 80% at given concentrations. Their optimal growth at 37 °C and survival at 20 °C and 45 °C underscored adaptability to diverse environmental conditions. Additionally, all strains showed sustainable survival rates in artifcial saliva and simulated gastrointestinal juices, with Lact. plantarum CWJ3 exhibiting signifcantly higher survival rate (70.66%) in simulated gastric juice compared to other strains. Adherence properties were particularly noteworthy, especially in Lact. rhamnosus CWKu-12, which demonstrated the highest hydrophobicity, coaggregation with pathogens and autoaggregation, among the strains. The production of exopolysaccharides, particularly by Lact. plantarum CWJ3, enhanced their potential for gut colonization and bioflm formation. Various in vitro antioxidative assays using spectrophotometric methods revealed the signifcant activity of Lact. plantarum CWJ3, while antimicrobial testing highlighted its efcacy against selected foodborne pathogens. Safety assessments confrmed the absence of biogenic amine production, hemolytic, DNase, and gelatinase activities, as well as the ability to hydrolase the bile salt. Furthermore, these non-dairy probiotics exhibited characteristics comparable to dairy derived probiotics, demonstrating their potential suitability in developing novel probiotic-rich foods and functional products.
Quorum sensing capability of wine microbial consortium involved in spontaneous fermentation of regional wine production
(2023) Thivijan, Sathivel; Undugoda, Lanka Jeewanie Samarakoon; Nugara, Ruwani Nilushi; Manage, Pathmalal Marakkale; Thambulugala, Kasun Madhusanka; Kannangara, Sagarika Dilpushpi
Quorum sensing (QS) is an intercellular communication process in which wine microbial consortium collectively adapts their metabolism by secreting quorum sensing molecules (QSM) into their environment. These QSMs continuously diffuse into the medium until approaching the threshold level, which stimulates the microbial cell population. Moreover, these molecules bind with their target sensory proteins and stimulate the transcription and translation of genes responsible for aromatic alcohol production. The research findings revealed that ARO genes regulate the synthesis of quorum sensing molecules like tyrosol, 2-phenylethanol, and tryptophol. For instance, ARO8, ARO9, and ARO10 present in Saccharomyces cerevisiae are the significant genes regulating the above QSMs and other aromatic alcohols, which determine the organoleptic qualities of wine. Another essential gene that affects the quality of wine is FLO11. Hence, different grape cultivars harbor different types of wine fermenting microbes with unique quorum sensing systems, leading to the unique organoleptic qualities in regional wine. Since we could still find the quorum sensing system of S. cerevisiae, this may open avenues to conduct much research to discover the unique quorum sensing systems of different wine microbes. These findings will lead to novel wine starter cultures with many specific genes developed through recombinant DNA technology. Therefore, this review focuses on quorum sensing of wine microbial consortium involved in the fermentation process of spontaneous wine fermentation through the chemistry of QSMs and how these signaling processes are genetically manipulated. Furthermore, this focus reviews the organoleptic quality development of regional wine products due to different quorum sensing abilities.