ORGANIC SYNTHESIS OF MAIZE STARCH-BASED POLYMER USING Rhizopus oryzae LIPASE, SCALE UP, AND ITS CHARACTERIZATION

Abstract

The industrial utilization of native starches is limited because of their inherit nature, with characteristics such as water insolubility and their tendency to form unstable pastes and gels. In this investigation, a lipase produced from Rhizopus oryzae was used for modification of maize starch with palmitic acid at a reaction temperature of 45°C for 18 hr in the presence of dimethyl sulfoxide (DMSO). The synthesis of maize starch palmitate was confirmed by Fourier-transform infrared (FT-IR) and ¹H-nuclear magnetic resonance (NMR) spectra with a higher degree of substitution (DS) of 1.68. Thermal gravimetric analysis (TGA) showed that the maize starch palmitate is more stable even up to 496°C as compared to unmodified maize starch (231.4°C). Maize starch palmitate possesses high degree of substitution and thermal properties and thus can be widely used in food and pharmaceutical industry.

Keywords:

• high degree of substitution (DS)
• lipase esterification
• maize starch
• structural characterization

ACKNOWLEDGMENT

The authors gratefully acknowledge financial support from the Ministry of New and Renewable Energy (MNRE). The authors thank Technology Based Incubator, UDSC, and New Delhi for providing the infrastructure support.