Production and Characterization of Custard Apple Seed Extract for its Possible Application as Bio-pesticide
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Date
2019-06
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Addis Ababa University
Abstract
The intensive use of synthetic pesticide has undeniably resulted in adverse and sometimes
irreparable effects on the environment including human health. Therefore, alternative pest
management strategies are desired. Natural pesticides have proven potential for pest management
and they are being used throughout the world. To this effect, this thesis investigated the production
and characterization of locally available custard apple seed extract for its possible application as
natural pesticide using ethanol (97%) as a solvent. The raw seed moisture content, fat content, ash
and organic matter content were determined properly. The extraction parameters were extraction
time, temperature and ethanol to custard apple seed ratio. A maximum of 12.63 % total extraction
yield of pesticide was achieved at the optimal conditions of 4h, 50 and 7:1 v/w of extraction time,
temperature and ethanol to CAS ratio respectively. The individual and interaction effect of these
parameters on the yield of oil was studied and optimum conditions were established by using RSM of
Box-Behnken method of Design Expert 7.0.0 software. The characteristics of CAS extract were then
evaluated using different analytical methods. Specific gravity, flash point, water solubility, pH value
and TVOCs were analyzed with respective methods. The FT-IR analysis indicates presence of C=O
group of the unsaturated lactone group. The GC-MS result shows that the presence of uvaricin,
annonacin and squamocin. From the statistical analysis method, all the three factors had an impact
on the yield directly and extraction time with temperature, extraction time with ethanol to CAS ratio,
temperature with ethanol to CAS ratio had also a significant effect on the yield. Using model
optimization of the factors were found the optimum points of extraction time (3.99hr), temperature
(49.92 ) and ethanol to CAS ratio (7.04:1 v/w) with 12.63 % yield of product. Generally, the results
found in this study showed that CAS extract seems to be a viable alternative option for the
production of the natural pesticide.
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Keywords
Natural pesticides, Custard apple seed, Uvaricin, Annonacin, quamocin, RSM