Karakteristik pati sagu dengan metode modifikasi asetilasi dan cross-linking
DOI:
https://doi.org/10.5614/jtki.2008.7.3.4Abstract
Sago, one of the main sources of carbohydrate, is commonly used as a substitute material of rice especially in Eastern Indonesia. Sago starch is now finding increasing application in various food products such as sago meals, biscuits, noodles, and desserts. Native sago starch exhibits relatively retrogradation resulting in the formation of a long cohesive gel with increased syneresis. In order to overcome drawbacks of native sago starch, chemical modifications can be carried out to improve its properties. Many types of chemical modification have been applied to starches of various plant sources, including cross-linking and acetylation. The purpose of this research was to study the effect of cross-linking and acetylation modifications to the properties of the sago starch before and after modification. As results, the acetylated starches showed higher swelling power (e.g. increased from 8,3245 to 38,6066 g wet sediment/g initial dry starch) and solubility (e.g. 14,3467 to 33,1876% w/w) and dereased in retrogradation tendencies (16,7399 to 1,3847% separated water) when compared with cross-linking starches and the corresponding native starch. It was observed that the changes in these properties were proportional to the DS achieved by each modification. As for paste clarity, native sago starch showed better characteristic amongst all starches which was shown by the lowest value of absorbance i.e. 0.142.
Keywords: acetylation; cross-linking; characteristics; sago starch
Abstrak
Sagu yang memiliki sumber karbohidrat yang cukup besar dapat digunakan sebagai bahan pangan alternatif. Untuk memperoleh kualitas produk yang diinginkan, karakteristik pati sagu dapat dimodifikasi. Metode modifikasi pati yang digunakan dalam penelitian ini adalah asetilasi dan cross-linking. Prinsip kedua modifikasi ini hampir sama, yaitu mensubstitusi gugus hidroksil pada pati; substitusi dengan gugus asetil pada asetilasi dan substitusi dengan gugus fosfat pada cross-linking. Tujuan dari penelitian ini adalah membandingkan karakteristik pati sagu (solubility, swelling power, freeze-thaw stability, dan paste clarity) yang telah dimodifikasi secara      asetilasi dan cross-linking pada berbagai variasi waktu reaksi serta terhadap pati yang tidak dimodifikasi. Hasil penelitian menunjukkan bahwa karakteristik swelling power, solubility, dan freeze-thaw stability dari pati sagu yang mengalami modifikasi secara asetilasi cenderung lebih tinggi dibandingkan dengan pati sagu yang mengalami modifikasi secara cross-linking maupun pati sagu yang tidak mengalami modifikasi. Karakteristik pati sagu mengalami peningkatan dari 8,3245 g/g menjadi 38,6066 g/g untuk swelling power dan 14,3467% menjadi 33,1876% untuk solubilty. Karakteristik freeze-thaw stability juga mengalami peningkatan yang ditunjukkan oleh semakin sedikitnya jumlah air yang terpisahkan yaitu dari 16,7399 menjadi 1,3847%. Peningkatan ini sebanding dengan kenaikan harga derajat substitusi (DS) untuk masing-masing modifikasi. Untuk karakteristik paste clarity, pati sagu yang tidak mengalami modifikasi menunjukkan karakteristik yang lebih baik dibandingkan pati yang telah mengalami modifikasi; absorbansi untuk pati sagu non-modifikasi adalah 0,142, untuk asetilasi adalah 0,483, dan untuk crosslinking adalah 0,334.
Kata kunci: asetilasi, cross-linking, karakterisasi, pati sagu
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