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Sago starch (Metroxylon sagu) and Gelose 80 was chemically esterified with Octenyl Succinic Anhydride (OSA) to produce hydrophobically starch which can act as emulsifier in oil-in-water emulsion (O/W). The modification of sago starch and Gelose 80 was conducted in aqueous phase following the optimum parameter: OSA concentration 5.0%, pH 7.20 and reaction time of 9.65 h. The study was conducted to investigate the morphological properties, particle size and surface activity of octenyl succinic anhydride (OSA) modified sago starch. The OSA sago starch had a degree of substitution (DS) of 0.0120. The morphology of starch granule examined by scanning electron microscopy (SEM) showed some rough surface and a few changes in shape of OSA starches. The particle size of both OSA starches significantly (p< 0.05) increased (OSA sago starch = 29.05 µm, OSA gelose 80 = 20.37 µm) due to structural disorder that occurs after modification. OSA sago starch showed an increase in surface tension from 58.40 to 60.80 mN/m with increased in OSA sago starch concentration from 0.01 to 1.0% w/v. The surface tension for OSA gelose 80 was 54.87 mN/m. The modification has improved native sago starch and Gelose 80 becoming surface active molecules which will be useful to be used in emulsion. 

Starch from sago (Metroxylon sagu) was esterified with octenyl succinic anhydride (OSA) in order to regulate its shortcoming by adding amphiphilic properties. The objective of this work is to determine the physicochemical properties of native sago and OSA sago starches. The OSA sago starch was produced according to the optimum condition generated via response surface methodology (RSM) with 5.00 % OSA at pH 7.20 and a reaction time of 9.65 hours. The esterified sago starch gives a degree of substitution (DS) value of 0.012. The physicochemical properties of OSA sago starch was determined by measuring the amylose content, laser diffraction particle size analyzer, scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). The amylose content for OSA sago starch was found to be reduced after esterification reaction. The particle size of OSA sago starch was found to increase significantly (p < 0.05) compared to their native starches. Scanning electron microscopy (SEM) revealed that OSA starch developed slightly rough surface and their edges lost some definition. FT-IR spectroscopy shows that there was appearance of new absorption correspond to ester carbonyl group (1717 cm -1 ) and carboxylate RCOO-(1569 cm -1 ). This study showed that the physicochemical properties of modified starches were influenced not only by DS but also on the botanical origin of the starches.Keywords: physicochemical properties, sago starch, octenyl succinic anhydride, esterification Abstrak Kanji daripada sagu (Metroxylon sagu) telah diesterifikasi dengan oktenil suksinat anhidrat (OSA) sebagai usaha untuk mengawal kelemahan dengan menambah sifat amfifilik. Objektif kajian ini adalah untuk menentukan sifat -sifat fizikokimia kanji sagu asli dan OSA kanji sagu. OSA kanji sagu disediakan mengikut keadaan optima berdasarkan kaedah gerak balas permukaan (RSM) dengan 5.00 % OSA pada pH 7.20 dan masa tindak balas selama 9.65 jam. Esterifikasi kanji sagu memberikan nilai darjah pengantian (DS) sebanyak 0.012. Ciri -ciri fizikokimia OSA kanji sagu ditentukan dengan mengira kandungan amilosa, saiz partikel laser pembelauan analisis, mikroskop imbasan elektron (SEM) dan Fourier transformasi inframerah (FT-IR). Kandungan amilosa untuk OSA kanji sagu didapati berkurangan selepas tindak balas esterifikasi. Saiz partikel OSA kanji sagu didapati meningkat dengan ketara (p < 0.05) berbanding saiz kanji sagu asli. Mikroskop imbasan elektron (SEM) menunjukkan bahawa OSA kanji sagu menghasilkan permukaan sedikit kasar dan kehilangan beberapa sisi definisi. FT-IR spektroskopi menunjukkan bahawa terdapat kemunculan penyerapan baru yang bersesuaian dengan kumpulan ester karbonil (1717 cm -1 ) dan RCOO-karboksilik (1569 cm -1 ). Kajian ini menunjukkan bahawa ciri -ciri fizikokimia kanji diubahsuai bukan hanya dipengaruhi oleh DS tetapi juga berdasarkan pada asal usul botanikal kanji tersebut.Kata kunci: sifat-sifat fizikokimia, kanji sagu, oktenil suksinat anhidrat, esterifikasi