Galacturonic content Pectin Characterization
19 methoxyl content is less than 7, the pectin is categorized as low methoxyl pectin LMP Goycoolea and
Adriana 2003. Methoxyl content of extracted pectin ranged from 4.07-6.43. Based on the value of methoxyl
content, the resulted pectin in this study was relatively low in methoxyl. Graph showing the relationship of microwave power and time of extraction treatment on methoxyl level of pectin can be seen in Figure 13.
The graph showed that the methoxyl content will become higher with increasing microwave power and the length of extraction time.
Figure 13. The relationship between microwave power and extraction time to methoxyl content. Results of analysis of variance showed that the microwave power and extraction time significantly
affected the methoxyl content of pectin, but interaction between microwave power and extraction time was not significantly affect the methoxyl content of pectin Appendix 5b. The highest methoxyl content
was pectin with treatment microwave power of 800 W for 7 minutes, while the lowest methoxyl content was obtained from pectin with treatment microwave power of 600 W for 3 minutes. The range of
methoxyl content from this pectin was 4.07-6.43 which was under 7. Because of the methoxyl pectin was under 7, so the pectin extracted from sugar palm seed was belongs to Low Methoxyl Pectin LMP
category. Methoxyl content of pectin has an important role in determining functional properties of pectin
solution and can affect the structure and texture of pectin gel Constenla and Lozano 2006. High methoxyl pectin forms a gel in the presence of sugar and acid. Conditions required for gel formation is 58-
75 sugar content with a pH 2.8-3.5. Low methoxyl pectin does not have the ability to form gel in the presence of sugars and acids, but it can forms a gel with presence of polyvalent cations Cruess 1958.
LMP on industry can be used as a thickener in manufacturing of low calories beverage, jelly for diabetic, and others healthy food.
The pectin industry normally produces high methoxyl pectin though there are some plants that produce low methoxyl pectin. There are four methods of demethylation including the use of acid, alkali,
enzyme and ammonia in ethanol. Demethylation using acidis commonly used to produce low methoxyl pectin Kertesz 1951. Extraction of high methoxyl pectin is easier to do with lower cost. In addition, most
of the sources of raw materials produce high methoxyl pectin. High methoxyl pectin is more considered to meet the market needs. If the market want slow methoxyl pectin, the high methoxyl pectin can be easily
converted into low methoxyl pectin. But low methoxyl pectin is more difficult to be converted to high methoxyl pectin Kertesz 1951.