Production of maltose syrup by enzymatic conversion of rice starch

An enzymatic process is developed to produce high-maltose syrup and high-protein byproduct simultaneously from materials that contain starch and protein. In the process, the slurry of milled starting material is first liquefied with α-amylase and then centrifuged. The precipitated fraction is recovered as high-protein flour. The supernatant fraction was then saccharified with β-amylase and debranching enzyme (isoamylase or pullulanase) simultaneously to produce high-maltose syrup at various conditions. The yield of high-maltose syrup is affected by temperature, pH, DE values of liquefied starch, different enzyme combinations and varieties of starting materials

Rice starch sample was converted into maltose syrup with comparison to corn starch sample. The conversion was carried out by both liquefaction using α-amylase  and saccharification using β-amylase  and pullulanase .

Production of maltose syrup by enzymatic conversion of rice starch

The morphologies of the rice starch and corn starch samples were characterized by scanning electron micrographs. The results demonstrated that granules size of the rice starch was significantly smaller than that of the corn starch, and the optimum liquefaction time of rice starch was markedly shorter than that of corn starch. The starch conversion to main impurities, such as isomaltose and higher oligosaccharides (maltotriose, maltotetraose, maltoheptaose, and maltohexaose) for rice starch sample were significantly lower than those for corn starch sample (P?<?0.05), and starch conversion to maltose for rice starch sample was equivalent to that observed for the corn starch sample.

It was concluded that the rice starch could be a good alternative to corn starch as raw material for maltose syrup production.