Undergraduate Theses
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Item Antifungal activities of lemongrass (Cymbopogon citratus) essential oil -B-cyclodextrin inclusion complex incorporated in commercial fish feedsBaure, Jiaren G. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)During the wet season in the Philippines, fish feeds can be contaminated with mycotoxins, affecting fish production. The addition of essential oil (EO) is one of the ways to prevent this, but it is prone to physical and chemical reactions. Thus, this study aims to encapsulate lemongrass essential oil (LGEO) in B-cyclodextrin (B-CD) to produce an inclusion complex (IC) that can be used as an additive in commercial tilapia feeds to prevent or minimize fungal contamination. The inclusion complex was made using the co-precipitation method and was characterized by Fourier Transform Infrared (FTIR) Spectroscopy. The spectrum was similar to that of citral, a major component of lemongrass essential oil that is responsible for inhibiting fungi. The antifungal activities of pure and encapsulated LGEO at varying concentrations against Aspergillus species were carried out by the Agar Well Diffusion assay. Results showed that A. flavus was more susceptible in LGEO and IC compared with A. fumigatus. The tested concentration of EO could inhibit both fungi. However, it would take 50% IC to effectively inhibit the growth of both fungi. The stability of the inclusion complex in commercial fish feeds was also evaluated. The feeds were stored in an area with the appropriate conditions that could promote the growth of molds, such as temperature (>27°C), moisture levels (14%), and relative humidity levels (>70%). The results showed that the encapsulated LGEO was effective in extending the shelf life of the feeds and was best observed at a concentration of 5 g kg-1 IC. The oil remained active for nine days, wherein about 10- 40% of the feeds with 5 g kg-1 IC were covered with molds. On the other hand, about 70-100% of the surface of the feeds with essential oil was contaminated with molds after nine days, which indicated that encapsulation of EO was needed to maintain its effectiveness as an antifungal agent.Item Effects of alginate coating loaded with lemongrass essential oil-cyclodextrin inclusion complex on the postharvest quality of calamansi(Citrus microcarpa)Astorga, Krizzia Anne B. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)Calamansi (Citrus microcarpa) is locally grown in the Philippines and is considered to be an important commodity because of its wide range of uses. Losses of this fruit in the country already reached up to 30% because of postharvest degradation. To address this problem, three coating treatments (1% alginate, 1% alginate loaded with lemongrass essential oil-B-cyclodextrin inclusion complex, and 1% alginate loaded with lemongrass essential oil-hp-B-cyclodextrin inclusion complex) were made for the purpose of examining their potential in the preservation of the postharvest quality of calamansi. Quality parameters such as color and weight loss of calamansi, as well as pH, FTIR spectra, total soluble solids, and titratable acidity of the fruit juice were evaluated in a span of 15 days at room temperature storage. Results show that the prepared edible coatings did not significantly preserve the postharvest quality of calamansi (p > 0.05) as coated samples resulted to earlier appearances of yellow and brown peel color, higher weight loss percentages, pH, and total soluble solids content. Out of the three coating treatments, fruit samples coated with 1% alginate resulted to lower weight loss percentages, pH, TSS, and TA. Fruit samples coated with 1% alginate loaded with lemongrass essential oil-hp-B-cyclodextrin inclusion complex resulted to the highest pH, TSS, and TA, while those coated with 1% alginate loaded with lemongrass essential oil-B-cyclodextrin inclusion complex resulted to the highest weight loss percentages. Data on the titratable acidity weren’t conclusive since the results obtained were not in agreement to the expected outcome. The ineffectiveness of the coatings may be a result of unfavorable storage conditions and incompatibility of the coating materials or formulations on the calamansi.
