Characterisation of Physicochemical Properties of Propionylated Corn Starch and Its
Application as Stabiliser

Lee-Fen Hong¹, Lai-Hoong Cheng², Chong Yew Lee¹ and Kok Khiang Peh¹*

¹School of Pharmaceutical Sciences, Universiti Sains Malaysia, USM, 11800 Minden, Penang, Malaysia
²Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, USM, 11800 Minden,
  Penang, Malaysia



Article history: 
Received September 20, 2014
Accepted May 13, 2015



Key words:
starch propionate, degree of substitution, physicochemical properties, oil-in-water emulsion, stabiliser




Summary:
A series of propionylated starches with different degrees of substitution (DS) was synthesised and their physicochemical properties and application as a stabiliser were investigated. Starch propionates with moderate DS were prepared by esterification of native corn starch with propionic anhydride. By varying the reaction times of the esterification process, twelve starch propionates with DS of 0.47 to 0.94 were prepared. FTIR and NMR confirmed the introduction of propionyl groups to the starch. X-ray diffraction pattern showed reduced crystallinity in the starch propionates. The contact angle was found to increase proportionately with the increase in DS. Swelling power results showed that starch propionates were able to swell more than native corn starch at low temperature (40 °C). Oil-in-water (O/W) emulsions prepared using starch propionates (DS of 0.64 to 0.86) showed exceptional stability when challenged by centrifugation stress test. These stable O/W emulsions had viscosities in the range of 1236.7–3330.0 mPa·s. In conclusion, moderately substituted short-chain (propionylated) starches could be a promising cold swelling starch, thickener and O/W emulsion stabiliser in food, pharmaceutical and cosmetic industries.

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