February 1, 2015 Thesis Open Access

Shimelis Shumi

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  <identifier identifierType="DOI">10.20372/nadre:2349</identifier>
  <creators>
    <creator>
      <creatorName>Shimelis Shumi</creatorName>
    </creator>
  </creators>
  <titles>
    <title>Optimization and characterization of antioxidant activity from green tea (Camellia sinensis) and evaluation of its preservative effect</title>
  </titles>
  <publisher>Zenodo</publisher>
  <publicationYear>2015</publicationYear>
  <dates>
    <date dateType="Issued">2015-02-01</date>
  </dates>
  <resourceType resourceTypeGeneral="Text">Thesis</resourceType>
  <alternateIdentifiers>
    <alternateIdentifier alternateIdentifierType="url">https://nadre.ethernet.edu.et/record/2349</alternateIdentifier>
  </alternateIdentifiers>
  <relatedIdentifiers>
    <relatedIdentifier relatedIdentifierType="DOI" relationType="IsVersionOf">10.20372/nadre:2348</relatedIdentifier>
    <relatedIdentifier relatedIdentifierType="URL" relationType="IsPartOf">https://nadre.ethernet.edu.et/communities/aau</relatedIdentifier>
    <relatedIdentifier relatedIdentifierType="URL" relationType="IsPartOf">https://nadre.ethernet.edu.et/communities/zenodo</relatedIdentifier>
  </relatedIdentifiers>
  <rightsList>
    <rights rightsURI="http://www.opendefinition.org/licenses/cc-by">Creative Commons Attribution</rights>
    <rights rightsURI="info:eu-repo/semantics/openAccess">Open Access</rights>
  </rightsList>
  <descriptions>
    <description descriptionType="Abstract">&lt;p&gt;The study was conducted with the aim of optimizing and characterizing antioxidant activity of&lt;br&gt;
Camellia sinensis and evaluating its preservative effect on Niger seed and Soybean oils.&lt;br&gt;
Camellia was prepared by investigating the effect of distilled water concentrations of 100, 150,&lt;br&gt;
and 200ml, extraction temperature 80, 85 and 90 ℃ and contact time of 10, 35 and 60 min on its&lt;br&gt;
antioxidant activity and extract yield. Based on ANOVA analysis, extraction parameters have&lt;br&gt;
significant positive effect (P&amp;lt;0.05) on Camellia antioxidant activity and its extract yield. The&lt;br&gt;
best levels of extraction parameters for higher antioxidant activity and extract yield were&lt;br&gt;
distilled water concentration of 200ml for 60min at 90 ℃. As DPPH free radical scavenging&lt;br&gt;
activity results shown the highest antioxidant activity of Camellia was 96.1%. On the other hand&lt;br&gt;
extraction parameters (solvent concentrations, extraction temperature &amp;amp; contact time) were&lt;br&gt;
optimized. The best extraction conditions were 200ml, 88 ℃ and 35 min and the results were&lt;br&gt;
yield (79.850%) and Antioxidant activity (96.9810%). The preservative effect of Camellia was&lt;br&gt;
also studied by performing Free Fatty Acids, Peroxide Value/Acid value on Niger seed and&lt;br&gt;
Soybean oils. In the study, all samples were treated with 0, 1 and 2ml levels of Camellia extract&lt;br&gt;
and analysis were conducted on weekly basis. Compared to Camellia extract containing Niger&lt;br&gt;
seed and Soybean oils, control sample showed higher Free Fatty Acid and Peroxide Values in&lt;br&gt;
each storage weeks.&lt;/p&gt;</description>
  </descriptions>
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