【作者】 王睿；

【导师】 马晓军；

【作者基本信息】 江南大学 ， 粮食、油脂及植物蛋白工程， 2007， 硕士

【摘要】 本课题旨在研究即食方便米饭的老化机理及其生产工艺的改进。通过研究水分质量分数、贮存时间、支链淀粉链长分布以及几种淀粉酶对即食方便米饭老化、口感的影响和酶处理生产工艺,以获得即食方便米饭的最佳生产工艺条件及成品质量标准。首先,针对即食方便米饭在贮存过程中易老化的问题,先以糊化度为实验指标,研究水分质量分数、贮存时间、淀粉外支链链长分布对其老化的影响。结果显示:水分对糊化度的影响是跳跃性的,在62-65%之间时,4℃保藏后糊化度会有明显变化,而这种变化在三周内已经基本完成;降低淀粉外支链链长,能够在一定程度上抑制淀粉的老化。然后,为了改善即食方便米饭的抗老化性和口感,以糊化度和质构特性为主要实验指标,研究几种淀粉酶对产品及生产工艺的影响。结果显示:麦芽糖淀粉酶能够使即食米饭具有较好的抗老化效果,同时对米饭的质构也有一定的改善作用;最佳的酶处理生产工艺条件确定为:蒸煮时间25min、酶液浓度52 mg/L、酶液浸泡时间15 min、酸液浓度pH4.3、酸液浸泡时间2min。最后,对产品进行感官评定并制定产品的质量标准。最终结果表明:采用本课题得出的最佳工艺制作的样品,贮藏较长时间后,口感虽然仍然比不上新鲜米饭,但是明显要好于同类型的市售产品;产品的质量标准应分三部分:感官指标、理化指标、微生物指标。更多还原

【Abstract】 This study mainly focused on retrogradation of instant rice and improvement of processing. The influence of water content, time, distributions of the chain lengths and amylases on retrogradation and sensory quality of instant rice were investigated in order to get the best processing and quality standard of instant rice.Firstly, in order to control retrogradation during storage, the degree of gelatinization was used to investigate the effects of water content, time, distributions of the chain lengths and amylases on retrogradation of instant rice. The results showed that the degree of gelatinization of sample with 60% water content had an obvious change after storage at 4℃for three weeks, and shortened the chain lengths of amylopectins can restrain retrogradation of it.Secondly, in order to control retrogradation and improve the sensory quality, effects of amylases on instant rice and processing were investigated with the degree of gelatinization and texture profile analysis (TPA). The result indicated that the effect of maltase on retrogradation of instant rice is the best among the three kinds of amylases, and at the same time, the maltase can also improve the texture character of instant rice a little. The best processing were that the cooking time was 25min, the concentration of maltase was 52mg/L, the time of soaking in solution of maltase was 15min, and time of soaking in solution with pH=4.3 was 2min.Finally, the samples were investigated with sensory evaluation, and the quality standard had been made. After a long time storage, the samples made with the best processing tasted better than the product of the same type salting in the market, although their sensory quality were also worse than the fresh cooked rice. The quality standard of product should contain the sensory indexes, physicochemical indexes and microbial indexes.更多还原