7 Pectin has a good potential in the pharmaceutical field. Towle and Christensen 1973 stated that it is
been a long time pectin used in treating diarrhea and reduce total blood cholesterol. Pectin that flow through the blood vessels can shorten the blood coagulation time and useful to control bleeding from
injuries. In the pharmaceutical industry, pectin used as an emulsifier for the liquid and syrups preparate, diarrhea medicine for infants and children, the antidote of metals toxic, and as a material to lower the
absorption of various drugs. In addition, pectin also serves as a combination of hormones and work to extend antibiotics and injection materials to prevent bleeding Hoejgaard 2004.
Quality of commercial pectin is determined by the physical properties of pectin. The physical properties are color and flavor, the solubility for solid pectin, the degree of gelation, freezing rate, and
does not contain materials or substances hazardous to health. The physical properties are influenced by the chemical properties of pectin IPPA 2002.
Table 3. Quality specification of commercial pectin FDA of Thailand 1996
Characteristic Value
Moisture content max 12
Ash content max 1
Methoxyl content of HMP min 7
Methoxyl content of LMP max 7
Galacturonic acid content min 35
Degree of esterification min 50
Heavy metal max 0.002
C. Microwave-Assisted Extraction
In the past 20 years, the microwave oven has become an essential appliance in most of kitchen. Faster cooking times and energy savings over conventional methods are the primary benefits. Altough the
use of microwaves for cooking food is widespread, the application of this technology to the extraction process is a relatively new development. The use of microwave energy for processing materials has the
potential to offer similar advantages in reduced processing times and energy saves Thontenson and Chou 1999.
Microwave belongs to the portion of the electromagnetic spectrum with wavelengths from 1 mm to 1 m with corresponding frequencies between 300 MHz and 300 GHz. Within this portion of the
electromagnetic spectrum there are frequencies that used for cellular phones, radar, and television satellite communications. For microwave heating, two frequencies, reserved by the Federal Communications
Commission FCC for industrial, scientific, and medical ISM purposes that commonly using microwave heating. The two most commonly used frequencies are 0.915 and 2.45 GHz. Recently,
microwave furnaces that allow processing at variable frequencies from 0.9 to 18 GHz have been developed for material processing Lauf et al. 1993.
In conventional thermal processing, energy is transferred to the material trough convection, conduction, and radiation of heat from the surface of the material. In contrast, microwave energy is
delivered directly to materials trough molecular interaction with the electromagnetic field. In heat transfer, energy is transferred due to thermal gradients, but microwave heating is the transfer of electromagnetic
energy to thermal energy and energy conversion, rather than heat transfer. This difference in the way energy is delivered can result in many potential advantages of using microwaves for food processing.
Because of microwave can penetrate materials and deposit energy, heat can be generated throughout the volume of the material. The transfer of energy does not rely on diffusion of heat from the surfaces, and it
is possible to achieve rapid and uniform heating of thick material Thontenson and Chou 1999. Recently, dielectric heating or microwave heating becomes attractive technique to improve
extraction yield and quality of pectin from various sources. Application of microwave-assisted extraction was reported by several research groups. Pre-treatment of raw orange peels by microwave was found to
improve extraction yield and quality of pectin Kratchanova et al. 2004. They found that microwave pre- treatment of fresh orange peels led to destructive changes in the plant tissue. The changes resulted in an
8 increase in the capillary-porous characteristic and the water absorption capacity of the plant material. The
heating inactivated the pectin-esterase activity in the oranges. These changes in the plant tissues after a microwave pretreatment gave an opportunity for the considerable increase in the yield of extractable
pectin and improvement of its parameters e.g. DE, molecular mass, and gel strength. Zhandong et al. 2005 also found that the time required for the extracting process is reduced from 1 hour of the
conventional methods to 5 minutes by microwave method by microwave disintegration processing. Bagerian et al. 2011 investigated the effect of microwave power and heating time MAE on the
yield and quality of extracted pectin from grapefruit. The highest total amount of pectin yield was found to be 27.81 ww for 6 min of extraction at 900 W. It was observed that yield, the galacturonic acid
content GalA, and degree of esterification DE increased with an increase in microwave power and heating time. Besides, the molecular weight decreased with an increase in heating time. However, the
effects of power on the molecular weight were more dramatically than heating time. In addition, they also investigated extraction of pectin treated with high-intensity ultrasound UAE and conventional method.
They concluded that microwave assisted extraction improved the quantitative and quantitative characteristics of extracted pectin. These improvements included the considerable increase in the yield of
pectin as well as degree of esterification, galacturonic acid, and viscosity. The yield of MAE is the highest 27.81, whereas UAE and conventional method just 17.92 and 18 respectively. The DE and GalA
of MAE also higher than other method which is 79.35 and 74.86 respectively. UAE just resulted 75.12 for DE and 68.21 for GalA, conventional method only resulted 75.6 for DE and 69.9 for
GalA. Besides, the 2 min microwave heating period was enough to extract the same amount of pectin as obtained from the 90 min conventional extraction period.
9
III. RESEARCH METHODOLOGY
A. Materials and Instruments
1. Materials
Main ingredient that used in this research was sugar palm seed Arenga westerhoutii Griff. that stored under -20
o
C. Chemical that used in the extraction of pectin were HCl 0.25 N, distilled water, and ethanol 95. Chemical that used in the characterization of extracted pectin were ethanol 95, NaCl,
NaOH 0.25 N, NaOH 0.1 N, phenol red indicator, sulphuric acid 98, carbazol solution, HCl 0.25 N, phenolphtalein, methyl red.
2. Instruments
Instruments that used in this research were blender, pH meter, microwave oven, cheesecloth, vacuum evaporator, Whatman 41 paper, oven, buret, electric furnace, crucible, dessicator, burner,
spectrophotometer, beaker glass, flask, volumetric pippet, and viscometer
.
B. Experimental Design
This research was divided into two parts. The first part was extraction of pectin from raw material young endosperm of sugar palm seed using microwave-assisted extraction. The second parts were
characterization of pectin including determination of moisture content, ash content, equivalent weight, galacturonic acid content, degree of esterification, and comparison of extracted pectin to commercial
pectin.
1. Extraction of pectin
Extraction of pectin conducted in order to get pectin for characterization and to determine the combination effect of microwave power and extraction time on the resulting pectin. The stages on pectin
production consist of:
a. Sample preparation
Sugar palm seed that stored under -20
o
C was thawed using running water. This process usually took time around 2 hours until the ice was completely gone.
b. Extraction
Sugar palm seed was weighed and crushed using blender for 2 min with addition 600 mL of distilled water. Adjustment of pH was done by adding hydrochloride acid 0.25 N until pH
reaches 1.5. Extraction was performed on microwave oven with microwave power and time varies as treatments.
Microwave power used in this study was 600 W and 800 W. While the extraction time used in this study was 3 min, 5 min, and 7 min. Extracted solution was filtered by using a thick
cheesecloth and was squeezed to separate the filtrate from the pulp. Then the solution was concentrated on rotary evaporator until the volume became half of its original volume by heating
at 80
o
C.
c. Precipitation isolation
The evaporated filtrate was cooled in the room temperature then pectin precipitation was performed by adding 95 ethanol that had been acidified adding 2 mL concentrated
hydrochloride acid per one liter of ethanol. The ratio of filtrate with ethanol added is 1:1.5. Precipitation process was done for 12 hours. Pectin precipitate was filtered using Whatman 41
paper to separate the precipitated pectin from ethanol solution.
