Preparation Of Resistant Starch From Early India Rice And The Effect On The Production Of Glucoamylaseby Monascus Purpureus In Liquid Culture

The optimum processing parameters for preparation of Resistant starch (RS) from early indica rice starch or from the high amylose rice starch by autoclaving treatment was established . The prepared RS was also used as sole carbon source for the liquid culture of Monascus purpureus to investigate the effect of RS on production of glucoamylase.The concentration of starch slurry, repeated autoclaving/cooling cycles, autoclaving time for the autoclaving treatment were optimized by orthogonal experiment design, the experimental results showed that optimized parameters for autoclaving treatment were 25% concentration of starch slurry, 11 repeated autoclaving/cooling cycles, retrogradation temperature at 80 C, respectively.The early indica rice starch was pretreated with pullulanase for enhancement of amylose. As high as 49.30% of amylose content in rice starch was achieved by pretreated rice starch with optimum concentration of pullulanase in suitable condition. The effect of the amylose content in rice starch on RS formation by autoclaving treatment was also investigated, the RS formation from the pretreated high amylose rice starch by autoclaving treatment was significantly higher than that from raw early indica rice starch. The more content of amylose, the more yield of RS was achieved.The test for enzymatic digestion of the prepared RS by porcine pancreatic -amylase (PPA) in vitro and biodegradability by M purpureus were conducted respectively. The results showed that the digestion rate for the prepared RS by PPA in vitro was apparently slower than that for raw rice starch, and the degradation rate of the prepared RS was also much slower by M. purpureus fermentation than that of raw rice starch. The results indicated the prepared RS have been achieved both enzymatic resistance and digestion resistance in a certain degree.Selected the early indica rice starch as carbon source, A rotational composite design of quadratic regression experiments was conducted for the optimization of carborn source , inorganic nitrogen source, phosphates in the liquid culture of M. purpureus for theproduction of glucoamylase.Based on the optimized culture medium, the difference in growth and glucoamylase activity between the RS and the rice starch as sole carbon source in liquid culture was investigated comparatively. The result showed that M. purpureus growed at a quicker rate in the RS medium than that in rice starch medium, and also the glucoamylase activity in RS medium is appeared quicker and significantly higher for the whole fermentation process, but the concentration of reduction sugar is much lower in RS medium in early stage of fermentation. The result revealed that the significant difference existed in growth and glucoamylase activity between the prepared RS and the raw rice starch in liquid culture of M purpureus.