physicochemical and functional properties of crawfish chitosan as ...

CHAPTER 4
RESULTS AND DISCUSSION
Results of the proximate analysis and physicochemical properties of various chitosan
samples are presented in Tables 2-7.
4.1 Yield
Yield was calculated as the dry weight of chitosan obtained from 400-600 g of dried
crawfish shell powder. Chitosan yield ranged from 16.7-18.8%. The highest yields were obtained
from DMPAC, followed by DCMPA, DMCPA, DPMCA (control) and DMPCA.
Table 2 - Crawfish Chitosan Production Yield (dry weight basis)
Sample Yield (%)
DCMPA
DMCPA
DMPCA
DMPAC
DPMCA (control)
DAPMC
41
18.3
17.8
16.7
18.8
16.8
0.34
Results (Table 2) showed that the DMPCA had the lowest yield (16.7%), but was not
different from the control DPMCA (16.8%). Brzeski (1982) reported about 14 % yield of
chitosan from krill and 18.6% from prawn waste (Alimuniar and Zainuddin, 1992). The % yield
of chitosan obtained (16.7-18.8%, Table 2) is lower than that (approximately 23%) of chitin
reported in the literature (No and Meyers, 1989). This is due to loss of sample mass/weight from
excessive removal of acetyl groups from the polymer during deacetylation (i.e. the conversion of
chitin to chitosan). On the other hand, the yield of DAPMC was 0.34% which was quite an
insignificant amount. Therefore, only five samples were considered for further analysis.
From this study, when chitosan process begins with deacetylation (DA), very poor yield
(0.34%) was obtained due to depolymerization of the chitosan polymer. Depolymerization is the