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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/13

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Keyword: search.filters.keyword.Essential oils

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    Antifungal activities of alginate films incorporated with lemon grass (Cymbopogon citratus) essential oil on sliced bread
    Bronzal, Lucile A. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    The accumulation of non-degradable and non-recyclable waste materials leads researches to venture on biopolymer films which have been regarded as the promising green substitutes of non-biodegradable plastic materials. However, food products can be subjected to contamination by bacteria and fungi. The addition of plant derived essential oil can control microbial contamination of foods by reducing the growth rate of target microorganisms or by inactivating microorganisms by direct or indirect contact. Incorporating antimicrobial compounds into films provides a different way to improve the safety of ready-to-eat foods. In this study, the efficiency of synthesized alginate films incorporated with lemon grass essential oil (LGEO) for antifungal activity on white bread was evaluated. Two sets of film were prepared the (1) LGEO - Ethanol incorporated films and (2) LGEO — β-cyclodextrin inclusion complex films via solution casting method. Furthermore, the FTIR analysis of the generated films was also assessed to identify the functional groups present in the film that facilitates its antifungal property. Experimental results showed that LGEO enhanced the antifungal properties in the films and significantly slowed down the propagation of fungi on white sliced bread. After two weeks of storage, all bread samples packed with various film samples showed fungal growth. It was found out that citral is the main component of essential oil which contributes to the inhibition of fungal growth. The incorporation of LGEO in the film decreased the O-H peak absorbance while the inclusion complex in the film increases the O-H peak absorbance and broad O-H peaks were also obtained.
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    Physicochemical characterization and FTIR Analysis of the essential oil from Almaciga (Agathis philippinensis Warb) gum
    Briones, Kathleen Faith C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-02)
    Almaciga (Agathis philippinensis ) is one of the few conifer timber species endemic to the Philippines. It is highly valued for its resin which is the world- renowned Manila copal (hard resin). Manila copal have been reportedly employed in treating asthma, headaches, myalgia and even arthritis. An ethnomedical documentation of Manila copal usage also reported the utilization of the resin for stomachache, ulcers and dysentery. However, there is only limited literature regarding the Almaciga gum (the softer resin). To provide supplemental data regarding the Almaciga gum, this study was conducted to characterize the physicochemical properties and to identify the major functional groups of the essential oil extracted from its resin. The essential oil was extracted using a makeshift steam distillation set- up with a total yield of 3.20%. The essential oil was found to have a refractive index of 1.4731± 0.0002, a density of 0.8502±0.0039 g/mL, and a specific gravity of 0.8527±0.0039. Odor, color and appearance were evaluated using the organoleptic method. Major functional groups were identified from Fourier Transform - Infrared Spectroscopy (FTIR) which suggested that limonene is the major component.
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    Phytochemical, antioxidant, and antibacterial analysis of essential oils from Zingiber officinale Roscoe(Ginger) and Curcuma long Linn.(Turmeric)
    Alviar, Joseph Noel G. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    This study was conducted to characterize and compare the phytochemistry, antibacterial and antioxidant activities of essential oils extracted from the rhizomes of Zingiber officinale Roscoe (ginger) and Curcuma longa Linn. (turmeric). Percent yields in the steam distillation of ginger and turmeric were 0.42±0.02% and 0.43± 0.02%, respectively. Qualitative phytochemical screening showed that both essential oils are positive for flavonoids, phenols, saponins, terpenoids, tannins, and quinones. Antibacterial activity was tested against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli using 100%, 75%, 50%, and 25% (v/v) essential oil in ethanol with positive control tetracycline and negative control ethanol. It was determined that C. longa did not have antibacterial activity against both bacteria while Z. officinale had “moderately inhibitory” to “strongly inhibitory” activity against S. aureus with zone of inhibition (ZOI) from 17.67±1.53 mm to 23.67±0.58 mm and “weakly inhibitory” to “moderately inhibitory” activity against E. coli (ZOI from 12.33±1.15 mm to 15.67±2.08 mm). The standard antibiotic tetracycline also showed “moderately inhibitory” activity against both S. aureus (ZOl = 19.00±0.89 mm) and E. coli (ZOI = 17.33±1.21 mm). Antioxidant activity was determined by DPPH free radical inhibition. Highest % DPPH free radical inhibition was exhibited by the standard antioxidant ascorbic acid (92.98%), followed by C. longa essential oil (88.74%), and Z. officinale (76.30%).