Gatot Trimulyadi Rekso, Centre for Application of Isotopes and Radiation Technology NATIONAL NUCLEAR ENERGY AGENCY Jl. Cinere ,Ps Jumat, PO Box 7002 JKSKL, Jakarta 12070 Fax: 021-7513270, E-mail: gatot28 @ batan.go.id, gatot2811@yahoo.com Radiation processing can modify the molecules weight, hydrophilic and mechanical properties of chitosan resulting in enhanced properties. Radiation processing also provides a simple and fast method for degradation of chitosan for a specific application.

1. STUDY ON IRRADIATION OF CHITOSAN FOR GROWTH PROMOTOR OF RED
CHILI (Capcinum Annum) PLANT
Gatot Trimulyadi Rekso,
Centre for Application of Isotopes and Radiation Technology
NATIONAL NUCLEAR ENERGY AGENCY
Jl. Cinere ,Ps Jumat, PO Box 7002 JKSKL, Jakarta 12070
Fax: 021-7513270, E-mail: gatot28 @ batan.go.id, gatot2811@yahoo.com
ABSTRACT
Studies on irradiation of chitosan as growth promoters of red chili (Capcinum Annum)
plant have been done. Chitosan with 80, 5 % degree of deacetylation was irradiated in dry
solid, wet and aqueous solution at a dose of 50 kGy by gamma ray from Co-60 source. The
irradiated chitosan was dissolved in 300 mL of water. The solution that contains
concentration of 50 ppm chitosan was sprayed to red chili plant three times a week for
each plant. The result showed that irradiation of chitosan in an aqueous solutions give the
highest decreasing of molecule weight from 1. 5740 104 become 0.7450 104 . Irradiation
of chitosan in dry solid conditions gives the highest degree of height growth of plant to
50.2 % and the degree of growth promotion to 92.6 %. The field data of using irradiated
chitosan for red chili plant shows of the increase in production yield was around 60 %
higher than without using irradiated chitosan.
Key words : Irradiation, chitosan, growth promoter, red chili.
INTRODUCTION microbial activity, growth inhibitor of
Chitosan is a linier polysaccharide some pathogens.
derived from chitin, a mayor component
Radiation processing can modify the
of the shell of the crustacean organisms
molecules weight, hydrophilic and
and the second most abundant
mechanical properties of chitosan
biopolymer in nature next to cellulose.
resulting in enhanced properties.
In the last year chitosan has proved to
Radiation processing also provides a
be valuable product for using in
simple and fast method for degradation
different application such as seed
of chitosan for a specific application.
coating, chelating and growth promoters
Radiation-degraded chitosan can induce
etc. Chitosan reported to have various
various kinds of bioactivities such as
biological functions, for instance, anti
growth promotion of plant, suppression

2. of heavy metal that make stress of the hydroxide with liquid and solid ratio of
plant, anti microbial activities. This 20 : 1, at 1000C for 120 minutes.
paper focuses on the irradiation of
conditions chitosan as growth Irradiation of chitosan
promoters for red chili plant The irradiation of chitosan was carried
out in a Co-60- Gamma irradiation
MATERIAL AND EXPRIMENTAL source. The conditions of chitosan for
Preparation of chitin irradiation were solid state, wet and
Chitin extracted from prawn shell liquid (5% chitosan in 1 % acetic acid)
(Penaeus monodon), it was got from the irradiation dose used was 50 kGy
MuaraKarang, North Jakarta. To with a dose rate of 5,1 kGy/hr and
deproteination of the shell, aqueous of 1 parameters measured were molecular
N sodium hydroxide was used to weight and solubility.
remove protein from a known weight of
The effect of irradiated chitosan on the
a particular fraction. The deproteinated
growth of the red chili plant
shell were then demineralized by means
Five series with 2 replicated each were
of 1,0 N hydrochloric acid in order to
done, the experiment was carried out in
remove inorganic salt.
10 plots, the area of the plots was 10 m2
(10 plants). The irradiated chitosan
Preparation of chitosan
were dissolved in water and 300 mL of
Chitosan can be obtained by treating
water that contains concentration of 50
chitin with 50 percen of sodium
ppm chitosan was sprayed to red chili
plant three times a week for each plant.
Figure 1. Preparation of the plots for the experiment of red chili plants on the field
The growth promotion degree (%) of the plant was calculated as follow :

3. Height of the treated - Height of the untreated
Growth of height of the plant degree = x 100 %
Height of the untreated
Evaluation dry weight of the treated - Evaluation of untreated
Growth promotion degree = x100%
Evaluation dry weight of untreated
RESULTS AND DISCUSSION an increasing of the solubility of the
chitosan in 1 % acetic acid.
Effect of irradiation condition of Results concerning of the effect
chitosan on the molecular weight and irradiation conditions of chitosan on the
the solubility. average molecule weight are presented
Gamma-irradiated chitosan showed a in Table 1.
rapid decrease in molecular weight with
Table 1. The effect of different condition of chitosan when irradiated on the average of
molecular weight
Irradiation doses Average molecular weight ( 104)
No (kGy) Condition of chitosan when irradiated
Dry Wet Liquid
1 0 1.5740 1.5740 1.5740
2 50 1.1050 0.9210 0.7450
It was found that upon irradiation, of the condition of chitosan used during
chitosan is actually degradation of any irradiation. Chitosan in the liquid phase
polymer by means of irradiation causes give a lowest of molecular weight than
the chain length of chitosan to become solid and wet conditions. It was
shooter with the formation of shooter because the radiolysis of water during
fragment the molecular size, depend on irradiation occurs.
H2O e-, H•, OH•, H2, H2O2, H3O

4. Furthermore, radical produced by to depolymerization of chain of chitosan
irradiation of water could benefit .
Table 2. The effect of different condition of chitosan when irradiated on the solubility
properties ( in 1% acetic acid)
Solubility (gr/mL)
Condition of chitosan
Irradiation doses Dry Wet
(kGy)
0 0,045 0,580
50 0,120 0,144
It can be seen in Table 2. That the Irradiated chitosan as growth
condition of chitosan during irradiation promoter of red chili plant
gave a significant effect on the
Table 3 illustrated the effect of
solubility of chitosan. The wet
irradiated chitosan at different condition
chitosan give a higher of solubility
of chitosan during irradiation on red
value than dry chitosan . This would
chili plant growth .
tend that low molecular weight of
chitosan give a better solubility.
Table 3. Effect of condition of chitosan when irradiated on height of red chili plants
after 3 month
Condition Height of plants (cm) Average Growth of
No of chitosan Plant number height of height of the
when plants (cm) plant degree
irradiated 1 2 3 4 5 6 7 8 9 10 (%)
at 50 kGy
1 Non 34 36 35 37 33 34 35 39 34 34 35,1 ± 1,34 18,2
irradiated
2 Dry 50 56 58 60 52 53 52 55 52 53 54,1 ± 2,72 82,1
3 Wet 42 48 50 56 57 58 55 52 59 40 51,7 ± 5,96 74,0
4 Liquid 48 42 44 50 42 43 44 40 42 40 43,5 ± 2,40 46,4
Control (without
chitosan ) 32 28 33 29 27 29 29 28 32 30 29,7 ± 1,12 0
The data shows in Table 3 clearly
demonstrated that the irradiated

5. chitosan can effectively help It was because when chitosan irradiated
developing of height of the plants faster in liquid or wet state radical occurs
than that of without irradiation (0 kGy) from radiolysis of water damaged the
and control (without chitosan). In this active side of chitosan .
experiment, chitosan with condition of Table 4. Illustrated the effect of
dry solid state when irradiated was the different condition of chitosan when
most effective as red chili plant growth irradiated as growth promoter for red
compare with wet and liquid chitosan. chili plants .
Table 4. Growth promotion degree of irradiation chitosan on red chili plants
No Condition of Average dry weight of chili plants (g) Growth promotion
chitosan when degree (%)
irradiated at 50
kGy
1 non irradiated 21,2 69,6
2 dry 30,8 146,4
3 wet 27,2 117,6
4 liquid 24,5 96,0
Control (without chitosan): 12,5 0,0
Results in table 4. Showed the the radicals form from radiolysis of
remarkable effect of the growth water damaged the site active of
promotion of the irradiated chitosan on functional group chitosan.
red chili plants. In the dry condition of
The effect of growth promotion for
chitosan when irradiated attained the
plants in field
highest increase of growth promotion
Results in Table 5 showed the
degree (146,4%). The marked lower of
remarkable average effect of the
growth promotion degree of chitosan
growth promotion of the irradiated of
when irradiated in liquid or wet state
dry chitosan on red chili plants 40 days
compare with dry condition, because
age.
Table 5 Growth promotion effect of the irradiated of dry chitosan

6. Average of With out Using irradiated
chitosan of dry chitosan
No Plant characteristic
1 Height of the plant 7 12
(cm)
Amount of root
2 8 19
Length of root (cm)
3 3 8
Amount of leaves
4 4 7
As can be seen in Table 5. The rate than that of without chitosan.
irradiated of dry solid chitosan showed Results of field test showed that by
strong effect of the growth promotion spraying water contents of dry state
on red chili plant at all which roots and irradiated chitosan made the
leaves were found to develop at a faster productivity increase around of 60 %.
Control + chitosan
Control + chitosan
Figure 2. Field test of irradiated dry solid chitosan on yield of red chili
CONCLUSIONS 1. Irradiation of chitosan in dry
solid conditions gives the

7. highest degree of height growth Conference of The Asian
of plant to 50,2 % and the Societies of Cosmetic Scientists,
degree of growth promotion to Bali, Indonesia, 7-9April, 1999.
92,6 %. 5. Gatot Trimulyadi Rekso, N,M
2. The field data of using irradiated Surdia, The Effect of Total
chitosan for red chili plant Irradiation Dose on Graft Co
shows of the increase in polymerization of Acrylic Acid
production yield was around onto Chitin by pre-irradiation
60 % higher than without using Technique, proceeding of The
irradiated chitosan 4thITB-UKM joint seminar on
chemistry, Jogyakarta, 12-13
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