鲜湿糙米线品质劣变机制与调控研究

Rice noodles are the major and traditional rice production. It is very meaningful and has great significance for the advent of brown rice noodles to prevent the chronic disease, decrease the reduce public health expenditure and improve the health level of residents in China. However, the study on the mechanism of the quality deterioration of brown rice noodle is still in the blank, which is easy to aging, hard to break, bad taste and high cooking loss rate. This project aims to clarify the impact mechanism, which contains three aspects of contents, quality changes of fresh brown rice noodles under different storage conditions, building quality deterioration model of fresh brown rice noodle, and exploring the influence mechanisms of rice bran on the starch retrogradation. Starch structure is determined by Fractal analysis, Solid-State NMR, x-ray diffraction, molecular dynamics simulation, Thermogravimetric Analysis, AFM and SEM. The retrogradation models of fresh rice and brown rice noodles will be established, and the influence of brown rice on the Starch aging kinetics will be studied, for example, Starch nucleation and crystal growth rate. The above study will reveal the deterioration mechanism of fresh rice noodle quality, and the quality of fresh brown rice noodles will be controlled by adjusting the rice milling fineness, damaged starch content, and the water content.

米线是我国最大宗的传统米制品，极具营养价值的糙米线产品的问世对我国预防慢性疾病、减少公共医疗支出、提高我国居民的身体健康水平具有重大意义。然而，鲜湿糙米线容易老化变硬、易断条、口感差、蒸煮损失率高，糙米线品质劣变机制研究目前处于空白。本项目拟通过建立研究不同储藏条件下鲜湿糙米线品质变化规律，构建鲜湿糙米线和精白米线品质劣变模型体系，从淀粉凝胶、淀粉结构、淀粉老化动力学三个方面阐明米糠对淀粉老化性质的影响机理。利用凝胶分型、固体核磁、热重分析、分子动力学模拟、X-射线衍射、原子力电镜等技术表征糙米线淀粉凝胶和淀粉分子结构、构象变化规律；构建鲜湿糙米线和精白米线淀粉老化模型体系，研究分析糠层物质对鲜湿糙米线中淀粉成核与晶体成长速度、老化焓值等淀粉老化动力学的影响规律；通过上述研究揭示鲜湿糙米线品质劣变机制，利用调节糙米磨粉的颗粒细度、损伤淀粉含量、米线水分含量等实现鲜湿糙米线品质的控制。

米线是我国最大宗的传统米制品，极具营养价值的糙米线产品的问世对我国预防慢性疾病、减少公共医疗支出、提高我国居民的身体健康水平具有重大意义。但鲜湿糙米线在储藏过程中容易老化变硬、易断条、口感差、蒸煮损失率高、保质期短等问题，导致其消费和流通受限。本项目通过研究鲜湿糙米线在不同储藏条件下的品质变化规律，从鲜湿糙米线在储藏过程中的淀粉凝胶、淀粉老化动力学和淀粉分子结构等方面解析了其老化回生机理和微生物作用影响其品质的规律，研究发现，鲜湿糙米线在储藏过程中，自由水和强结合水的降低是鲜湿糙米线老化变硬和回生的重要原因；在储藏过程中，白米粉更易发生短期老化，相比未挤压米糠，添加了挤压蒸煮米糠的米粉凝胶更易发生短期老化，但挤压蒸煮米糠对米淀粉长期老化有更强的抑制作用。采用挤压蒸煮米糠、控制磨粉颗粒细度与损伤淀粉、控制水分含量与储藏条件等调控鲜湿糙米线品质，延缓了鲜湿糙米线pH值和水分含量的降低，降低了碘蓝值、蒸煮损失率和自由水的散失，形成了完整和规则的质构特性，获得了品质良好/提升的鲜湿糙米线。通过揭示鲜湿糙米线品质的劣变机理，利用调节糙米磨粉的颗粒细度、损伤淀粉含量、米线水分含量与储藏条件等等实现了鲜湿糙米线品质的调控。本项目对鲜湿糙米线的实际生产具有重要的理论指导意义，有助于米制品产业营养健康及品质改良升级，促进营养健康米制品的消费利用和节粮减损，有利于国家粮食安全。