A facile and effi cient pressing method was developed to separate shrimp head waste into solid and liquid fractions with different ratios.. This step encourages using smaller amounts o[r]
Trang 158 • NHA TRANG UNIVERSITY
A FACILE AND EFFICIENT PRESSING METH OD FOR IMPROVEMENT OF CHITIN PRODUCTION
Nguyen Cong Minh 1 , Pham Thi Dan Phuong 2 , Nguyen Van Hoa 2 , Trang Si Trung, 2,*
Received: 01/8/2016; Revised: 20/9/2016; Accepted: 26/9/2016
ABSTRACT
Shrimp head waste has been used as raw materials for production of chitin and protein hydrolysate In this study, a facile and effi cient pressing method was developed to separate the solid and liquid phases from shrimp heads The different solid/liquid ratios as well as the size of the solid component can be obtained easily
by changing the pressing operating parameters The solid fraction was used to prepare chitin and chitosan This pressing method can save large amount of water and chemicals in the production of chitin and it can be used in the large-scale
Keywords: shrimp head waste, chitin, pressing method, protein hydrolysate
1 Institute of Biotechnology and Environment, Nha Trang University
2 Faculty of Food Technology, Nha Trang University
* Corresponding author: trungts@ntu.edu.vn
I INTRODUCTION
Shrimp head waste is considered as a
source of valuable components including about
6% chitin and 66% protein on the dry basis of
the raw material [4,5,8] In the original form,
chitin is linked to proteins by glycosidic bonds
Therefore, the fabrication of chitin requires
deproteinization process which is commonly
accomplished by using alkali solution However,
it is known that severe alkali treatment results
in degradation of chitin polymer chains
and also reduces the quality of the protein
hydrolysate [9,10]
So far, industrial methods use chemical
processes for preparation of chitin from shrimp
shells involving: (i) grinding; (ii) demineralization
with strong acids; (iii) deproteinization with
alkali medium at 90-1000C; (iv) pigment
removal using solvent extraction or chemical
oxidation [2,3] Unfortunately, this process
often consumes a large amount of chemicals
and water due to the remaining protein
and others from shrimp meat and viscera
Moreover, this organic fraction can cause an
environmental issue
Based on the above problems, it is necessary
to develop a facile and effi cient method for pretreatment of shrimp waste before the production of chitin In this study, a pressing method was used to separate the shrimp head waste into two fractions, solid and liquid, with various solid/liquid ratios The solid fraction contains chitin and small amount of protein and minerals that was used to prepare chitin This pressing step helps to consume smaller amounts of water and chemicals, which were used to produce chitin
II MATERIALS AND METHODS
1 Materials and chitin production
The fresh shrimp heads were collected from a local company (Seafoods-F17, Ltd., Nha Trang, Vietnam) The samples were transported to the laboratory in ice condition and frozen at -200C until use The productive process was presented in Figure 1 and 2 The shrimp heads (10 kg) were pressed at four different solid/liquid ratios of 30:70, 40:60, 50:50, and 60:40 at room temperature The solid fraction was demineralized by 4 wt % HCl and
Trang 2NHA TRANG UNIVERSITY • 59
deproteinized by 4 wt.% NaOH to fabricate
chitin For rough comparison, the collected
shrimp heads were directly used to produce
chitin using the same acid and alkaline
solutions without a pressing step
2 Proximate Analysis
The moisture was measured by the weight
loss during drying the samples at 105oC for 24 h
Ash was determined by burning the samples
at 600oC in a muffl e furnace [1] Protein of
shrimp was measured by Kejldahl method [1]
Protein of chitin was measured by using the
standard micro-Biuret protein assay using
bovine serum albumin as standard Astaxanthin was determined according to the method of Simpson and Haard [6] The degree of deacetylation (DD) was measured according
to Tao and Svetlana [7] Typically, 100 mg chitosan was dissolved in a 20 mL concentrated
H3PO4 solution (85%) at 600C for 40 mins Then, 1 mL above solution was diluted with
25 - 30 mL distilled water (25-30 times) and kept at that temperature for 2h After cooling down to room temperature, samples were measured at 210 nm The DD was calculated according to the following equation (1) and (2):
mM Glc NAc + mM Glc
mM Glc = w - mM Glc NAc * 0.2032 (2)
0.16117 where w is the sample weight (mg) in 1 mL, 0.2032 is the factor to convert the amount of l mol/mL anhydro Glc NAc moiety in the sample into mg anhydro NAc moiety in 1 mL For Glc, this factor amounts to 0.16117 mM Glc NAc was calculated according to standard curve of Glc NAc
Figure 1 The diagram of two productive processes of chitin
Trang 360 • NHA TRANG UNIVERSITY
III RESULT AND DISCUSSION
Table 1 shows the composition of shrimp
head waste, liquid and solid fractions at four
different liquid/solid ratios of 30:70, 40:60,
50:50 and 60:40 The protein, ash and chitin
contents are 55.3, 23.4, and 15.7 wt.% (dry
basis) This is in agreement with previous
published papers on the similar shrimp waste
sources [2, 8-10] By using different pressing
conditions, the compositions of both obtained
liquid and solid fractions were changed In
the liquid fraction, when the liquid/solid ratios
increased from 30:70 (liquid 1) to 60:40 (liquid 4),
the protein content was increased from 58.2
to 60.2 wt.%, respectively Similarly, the chitin content increased from 9.2 to 10.3 wt.%
as increase in the liquid/solid ratio from 30:70
to 60:40, respectively It can be attributed to the crumby of shrimp head waste with small solid pieces presented in the liquid fraction The astaxanthin amount increased signifi cantly from 335.3 to 342.4 ppm as increase of the liquid/solid ratio from 30:70 to 60:40, respectively
On the other hand, in the solid fraction, the moisture content is a range of 68 - 77% which
is lower than that of shrimp head (81,6%) The protein content is approximately 55 wt.% for all samples at different solid/liquid ratios
Figure 2 The diagram of pressing process (1) Feeder, (2, 3) Rollers, (4) Cable-stayed
Table 1 The composition of shrimp head waste, liquid and solid fractions at different pressing processes
# Pressing ratio
(Liquid/Solid) Weight (kg) Moisture (wt.%) Protein (wt.%)* Ash (wt.%)* Chitin (wt.%)* Astaxanthin (ppm)* pH
1 NA 10 ± 0.05 81.6 ± 1.2 55.3 ± 1.4 24.4 ± 0.8 17.5 ± 1.3 155.2 ± 24
2
30/70 3.0 ± 0.03 94.2 ± 0.3 58.2 ± 0.3 23.0 ± 0.5 9.2 ± 0.7 335.3 ± 14 6.9
3 7.0 ± 0.04 77.2 ± 1.4 55.8 ± 0.5 22.8 ± 0.4 18.5 ± 0.5 135.1 ±15
4
40/60 4.0 ± 0.04 93.7 ± 0.5 58.1 ± 0.5 21.0 ± 0.6 9.5 ± 0.6 326.2 ± 20 7.1
6
50/50 5.0 ± 0.02 93.2 ± 0.3 59.0 ± 0.5 20.0 ± 0.4 9.5 ± 0.4 337.7 ± 15 7.3
7 5.0 ± 0.03 70.8 ± 1.7 55.2 ± 0.8 23.1 ± 0.3 19.5 ± 0.5 134.2 ± 16
8
60/40 6.0 ± 0.02 92.8 ± 0.4 60.2 ± 0.7 20.1 ± 0.5 10.3 ± 0.2 342.4 ± 22 7.3
Trang 4Table 2 shows the comparison of total
amount of chemicals and water, which are
used for chitin production from 10 kg of raw
material with and without pressing step In the
demineralization process, the consumed HCl
volumes were 3.7, 3.3, 2.6 and 2.2 L by pressing
at liquid/solid ratios of 30/70, 40/60, 50/50 and
60/40, respectively In the deproteinization
process, the consumed NaOH amounts
were 1.4, 1.2, 1.0 and 0.8 kg by pressing at
liquid/solid ratios of 30/70, 40/60, 50/50 and 60/40,
respectively However, it required 5.4 L
of HCl and 2 kg of NaOH for production of chitin without pressing Therefore, this pressing process can save up to 60% amount
of acid and alkaline In addition, large amount
of water can be saved by using pressing process The consumed water volume were 64.3, 56.8, 45.5 and 38.8 L by pressing at liquid/solid ratios of 30/70, 40/60, 50/50 and 60/40, respectively, which were much lower than that of no pressing (94.6 L)
Table 2 The comparison of amount of chemicals and water used for chitin production
No pressing Pressing 1 Pressing 2 Pressing 3 Pressing 4
Demineralization
VHCl (L) 50.0 ± 0.2 34.0 ± 0.1 30.0 ± 0.1 24.0 ± 0.1 20.5 ± 0.5
H2O (L) 44.6 ± 0.3 30.3 ± 0.4 26.8 ± 0.3 21.4 ± 0.5 18.3 ± 0.3
VHCl 37% (L) 5.4 ± 0.2 3.7 ± 0.1 3.3 ± 0.2 2.6 ± 0.1 2.2 ± 0.1 Deproteinization
VNaOH (L) 50.0 ± 0.5 34.0 ± 0.4 30.0 ± 0.2 24.0 ± 0.4 2 ± 0.5
H2O (L) 50.0 ± 0.5 34.0 ± 0.4 30.0 ± 0.2 24.0 ± 0.4 2 ± 0.5
mNaOH (kg) 2 ± 0.1 1.4 ± 0.1 1.2 ± 0.1 1.0 ± 0.1 0.8 ± 0.1 Table 3 presents the properties of chitin
which was prepared from shrimp head waste
before and after pressing at different liquid/
solid ratios All obtained chitins have the same
light pink color and similar DD (about 9.5 wt.%)
However, the content of protein and ash is
reduced signifi cantly by using pressing step
The protein content is 0.82% for the case
without pressing and it reduces to 0.76, 0.74,
0.70 and 0.68 wt.% at liquid/solid ratios of
30/70, 40/60, 50/50 and 60/40, respectively
The ash content is reduced from 0.76%
(no pressing) to 0.68, 0.65, 0.65 and 0.56% at liquid/solid ratios of 30/70, 40/60, 50/50 and 60/40, respectively On the other hand, when the liquid/solid ratio increased, both the amount
of chemicals used and the size of chitin were reduced so much Based on obtained results, although there is not much different result among samples from pressing processes, the liquid/solid ratio of 50/50 is recommended to get high quantity chitin as well as save amount
of chemicals and water
Table 3 Properties of chitin prepared from different raw materials
Chitin 0 Chitin 1 Chitin 2 Chitin 3 Chitin 4
Appearance Flake, tough Flake, tough Flake, tough Flake, tough Flake, crumby
Protein (wt.%) 0.82 ± 0.1 0.76 ± 0.4 0.74 ± 0.2 0.70 ± 0.3 0.68 ± 0.3
Trang 562 • NHA TRANG UNIVERSITY
IV CONCLUSION
A facile and effi cient pressing method was
developed to separate shrimp head waste into
solid and liquid fractions with different ratios
This step encourages using smaller amounts
of chemicals and water in the production of
chitin The solid/liquid ratio of 50/50 is the most
suitable condition to produce high quantity
chitin This method is potential way to apply in the large scale
ACKNOWLEDGMENT
The authors wish to thank the Ministry of Science and Technology, Vietnam for their kind funding to this research
REFERENCES
1 AOAC, 1990 Offi cial methods of analysis of the Association of Offi cial Analytical Chemistry In: The Association of Offi cial Analytical Chemistry, Washington DC
2 Diaz-Rojas E I., Argüelles-Monal W M., Higuera-Ciapara I., Hernández J., Lizardi-Mendoza J and Goycoolea
F M., 2006 Determination of chitin and protein contents during the isolation of chitin from shrimp waste Macromol biosci., 6, 340-347
3 Gortari M C and Hours R A., 2013 Biotechnological processes for chitin recovery out of crustacean waste:
a mini-review Electron J Biotechnol, 16, 14-14
4 Pham P D T and Tran L T., 2013 Extraction of carotenoprotein from white shrimp heads J Fish Sci Technol., 1, 125-131
5 Sachindra N M., Bhaskar N., Siddegowda G S., Sathisha A D and Suresh P V., 2007 Recovery of carotenoids from ensilaged shrimp waste Biores Technol , 98, 1642-1646
6 Simpson B K and Haard N F., 1985 The use of enzymes to extract carotenoprotein from shrimp waste J Appl Biochem., 7, 212-222
7 Tao W and Svetlana Z., 2008 Determination of the degree of acetylation of chitin and chitosan by an improved
fi rst derivative UV method Carbohydr Polym., 73, 248-253
8 Trang T S., Duong N T H and Pham P D T., 2008 Combining pretreatment by formic acid in shrimp waste processing for improving quality of chitin and chitosan J Fish Sci Technol., 2, 11-16
9 Trang T S., Pham P D T., Minh N C and Linh N T., 2009 Improving the effi ciency of chitin production process from shrimp waste by using formic acid ensilage J Fish Sci Technol., 4, 31-38
10 Trang T S., Vu B N and Pham P D T., 2007 Combining using protease in chitin production from shrimp waste J Fish Sci Technol., 3, 11-17