الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Only 65% of the shrimp is edible. The remainder is discarded as inedible waste (cephalothoraxes and exoskeleton). Over the years,
techniques have been developed for the exploitation and recovery of
these by-products in valuable biopolymers (Ferrer et. al, 1996;
Benhamou and Evelo, 1996). Shrimp by-products have been
identified as an animal protein source of great potential; also, as an
important source of chitin (Shahidi and Synowiecki, 1991). Chitin
and its deacetylated derivative, chitosan, have unique properties,
which make them useful for a variety of applications (Sandford,
1989; Synowiecki and Al-Khateeb, 1997 and Amanatidou et. al.,
2000).
6.1. Chemical composition of crude shrimp shell.
This research aims to take advantage of shrimp shells, the
chemical composition of crude shrimp shells were determined to
identify the various components of this waste. The results showed that
the total ash content of crude shrimp shell was 44.96% ,% total protein
was 36.63%, while the fat content was 4.85% and fiber content was
6.18 %, meanwhile the content of carbohydrates was 7.38 % (on a dry
weight basis).
6.2. Factors affect demineralization: -
Using of 2 M HCL gave the best results in the disposal of ash as
they reduced 91.98% of ash content, where the reduction rate in both
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1M and 3M HCL concentrations were 86.76%, 86.58%, respectively.
The acid treatment at 45°C gave the best results in disposing of ash
(98.2%) and treatment with HCL for 2hr gave the best ash disposal
(94.40%).
6.3. Factors affect Deproteinization.
The effect of different factors (NaOH concentration -
temperature - time) on the removal of protein (deproteinization) from
crude shrimp shell were carried out. The results showed that 1M
NaOH gave the highest elimination of total protein (63.93%).
Deproteinization at 75°C gave the highest elimination of total protein
(72.63%), while the reduction rate was 62.28%, 60.84%, 65.21% for
the process carried out at 45°C, 60°C, 90°C, respectively. The best
deproteinization time was 4 hours which eliminate 68.40% of the total
protein content while the lowest reduction rate was obtained after
treating the shell for 1 hr.
The proximate composition of the shrimp shell chitin
demineralized by 2M HCL for 2hr at 45°C and then Deprotienized at
1M NaoH for 4 hr at 75 °C was 0.42% ash , 2.07% protein, 1.07 %
fat, 29.41 % fibers and 67.03 % carbohydrates.
6.4. Factors affect deacetylation process (chitosan production).
Optimum Deacetylation condition (NaOH concentration,
temperature and treatment time) were evaluated for the shrimp shell
chitin produced via the previously defined optimum demineralization
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(2M HCL, 45°C and 2 hr) and deptotenizetion (2M NaOH, 75°C and
4hr) condition. The results showed that the concentration of 40%
NaOH gave the best results in converting chitin to chitosan as they %
DD (75.83), while it was 49.87% for the shrimp chitin treated with
10% NaOH. The temperature of 90 °C gave the best % DD (82.76%).
The extraction time (1-2 hours) gave the best impact in the conversion
of chitin into chitosan (85.35%, 86.67%, respectively).
The proximate composition of the shrimp shell chitosan
deacetylated by 40% NaoH for 2hr at 90 °C was 0.26% ash, 1.23%
protein, 0.54% total fat, 33.60% total crude fiber and 64.18%
carbohydrates.
It was also degree of acetylation (% D.D) with a study of some
functional properties of the chitosan product such as the water binning
capacity(WBC), fat binding capacity (FBC) and % solubility in shrimp
shell chitosan produced were 521.64%, 405.65% and 55.65%.
6.5. Application of Shrimp Chitosan as a natural antioxidant and
edible coating.
6.5.1. Using of shrimp shell chitosan to prolong cup cake shelf life.
Different Chitosan concentration (0.5, 1, 1.5, 2, and 2.5%) was
used to prepare cake. The effect of chitosan concentration on sensory
and physical properties of cake as well as chemical characteristics
(acidity, acid and peroxide value) of the extracted oil was carried out
during storage of cake at room temperature for 30 day.
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The cake produced without chitosan had the highest overall
acceptability (86.19%), followed by that prepared by 2% chitosan
(77.88) then that prepared with 2.5 % chitosan (71.10%). The same
trend was observed in the cake stored for 30 days.
Adding of 1% shrimp shell chitosan improved the weight loss by
(17.51%). While, addition of 2% shrimp shell chitosan had no
significant affect (P>0.05) compared with control (85.52). Cup cake
prepared with 0.5%, 1%, 1.5% and 2% shrimp shell chitosan
significantly (P ≤0.05) improved total volume.
No significant (p>0.05) deference were observed in peroxide
value (meq O2/ kg oil) of oil extracted from unstored cup cake
prepared with 0.5% shrimp shell chitosan (0.78 meq O2/ kg oil)
compared with control (0.81 meq O2/ kg oil). While, adding of shrimp
shell chitosan by 1%, 1.5%, 2% and 2.5% significantly (p≤0.05)
reduced the peroxide value of fresh cup cake oil by 20.98%, 21.22%,
17.28% and 27.16%, respectively. Concentration of 2% shrimp shell
chitosan had a higher antioxidant activity than 0.5%, 1%, 1.5% and
2.5% chitosan concentrations. Generally, peroxide value of cup cake
increased significantly (p≤0.05) by increasing the storage period.
No significant (p>0.05) deference were observed in acid value
of oil extracted from unstored cup cake prepared with 1%, 1.5%, 2%
and 2.5% shrimp shell chitosan (0.38, 0.32, 0.28, and 0.39 mg
KOH/100gm oil, respectively) compared with control (0.32 mg
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KOH/100gm oil). While, adding of 0.5% shrimp shell chitosan
significantly (p≤0.05) reduced the acid value of cup cake oil by 9.37%
compared with control. Oil extracted from cup cake prepared with 2%
shrimp chitosan had the lowest (p≤0.05) acid value compared with the
other concentrations (even 2.5% shrimp chitosan). Acid value of oil
extracted from stored cup cake increased significantly (p≤0.05) by
increasing the storage time. On the other side, No significant (p>0.05)
deference were observed in acidity (%) of oil extracted from unstored
cup cake prepared with 0.5%, 1%, 1.5%, 2% and 2.5% shrimp
chitosan (0.15%. 0.20%, 0.18%, 0.14% and 0.19%, respectively)
compared with control (0.17%). While, adding of different
concentration of shrimp chitosan had no effect (p>0.05) on cup cake
oil acidity compared with control. These results comply with the result
of antioxidant activity indicated that 2% shrimp shell chitosan solution
had the highest antioxidant activity.
6.6. Using shrimp shell chitosan as edible coating to prolong shelf
life of strawberry.
6.6.1. Using of Chitosan as edible coating for strawberry fruits.
Fresh strawberry fruits coated by 1.5% shrimp shell chitosan
solution had a lower (p>0.05) titratable acidity (0.72%) compared with
the fresh uncoated fruits (0.84%). Mean while, the fresh strawberry
coated with other concentrations (0.5%, 1%, and 2% shrimp chitosan
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solution) had significantly (p≤0.05) lower acidity compared with
uncoated fruits.
No significant (p>0.05) effect were detected in the fresh
strawberry fruits coated by 1.5% shrimp shell chitosan solution (49.25
mg/100gm) compared with the fresh un coated fruits (48.75
mg/100gm). Mean while, the fresh strawberry coated with other
concentrations (0.5%, 1%, and 2% shrimp shell chitosan solution) had
significant (p≤0.05) lower than Vit C (46.37, 46.60 and 47.45
mg/100gm, respectively) compared with uncoated fruits. T.S.S didn’t
affect (p>0.05) during storage of coated strawberry up to 10 days. No
significant (p>0.05) deference in hardness, pH and total soluble solids
(T.S.S) between uncoated and fruits coated with deferent chitosan
concentration.
Our results revealed that improvements in shelf-life of tomatoes
fruits can be achieved by using good quality raw products, special care
during handling and use of coating by 1.5%% shrimp shell chitosans
film.
6.6.2. Using of Chitosan as edible coating for tomatoes fruits.
No difference in vitamin C (p>0.05) were detected in the fresh
tomatoes fruits coated by 0.5% shrimp shell chitosan solution (37.47
mg/ 100 gm) compared with the fresh un coated fruits (34.84 mg/100
gm). Mean while, the fresh tomato coated with other concentrations
(1%, 1.5%, and 2% shrimp chitosan solution, had significantl.