基于亚临界流体的燕麦结构脂适度脱除与淀粉冷水膨胀性能改良的机制

Oats is a whole grain healthy food recognised globally, but its current main product oatmeal does not conform to the dietary habits of Chinese. How to improve the “high fat, no gluten” defect of whole oat flour, to make it suitable for processing Chinese traditional noodles, is the common challenge of cereal industry. In this project, we are focusing on the two key technical bottlenecks: removing oat structured lipids and modifying the oat starch, to improve the adaptability of oat flour. Firstly, we are to confirm the restrictive barriers of removing oat lipid using situ detection means. Then, build a multivariate subcritical solvent system based on its dielectric properties, to find out how the sub-critical solvent breaks the restrictive barrier. And then, moderate remove the oat lipids based on the correlation between structured lipids and the structure, gelatinization and aging properties of starch. Secondly, we are to study the swelling and mass transfer properties of sub-critical ethanol-water solution, and to explore its influence on the crystalline structure of starch granules on molecular level. Then, we modification the starch based on the relationship between its structure and cold water swelling performance. Finally, we are to illuminate the molecules mechanism of removing oat structural lipids and precise modifying of oat starch by sub-critical fluids, and then build the quantitative relationship among solvent composition - subcritical process parameters - microstructure - macro effect (physical properties, and processing adaptability). We hope, eventually to innovate the theory and technology of modifying cereal macromolecular by subcritical fluid, and provide technological support to oat food processing.

燕麦是全球公认的全谷物健康食品，但现有主流产品燕麦片并不符合国人消费习惯。如何改进燕麦全粉“高脂无筋”的不足，使其适于中华传统主食面条工业化加工是杂粮行业面临的共性难题。课题围绕“燕麦结构脂脱除与淀粉改性”两个关键技术瓶颈，首先采用原位探测技术，确定限制结构脂脱除的结构屏障；基于介电特性构建多元亚临界溶媒体系，研究其对结构屏障的破除机制；研究结构脂与淀粉结构、老化特性间的关系，并进行适度脱除。其次，研究亚临界状态下乙醇-水溶液的溶胀与传质特性，从分子水平探讨其对淀粉颗粒内部结晶结构的影响规律；基于淀粉结构与冷水膨胀加工性能的关系，对其进行适度改性。最终，实现多元亚临界溶媒对燕麦结构脂适度脱除与淀粉精准改性机制的分子解析，并构建溶媒组成-亚临界过程参数-微观结构-宏观效应（物理特性、加工适应性）间的量化关联；创建谷物大分子亚临界流体改性理论与方法，为燕麦等杂粮的主食化加工提供支撑。

燕麦是全球公认的健康食品原料，在面制主食加工中具有广阔的应用前景。如何改进燕麦粉“高脂无筋”的不足，使其适于中华传统主食面条的工业化加工是杂粮行业面临的共性难题。项目围绕“燕麦结构脂的脱除、淀粉冷水溶胀性的改善”两个关键技术瓶颈，研究燕麦中结构脂的原位检测方法，探究燕麦结构脂与淀粉的相互作用关系及其脱除屏障；研究燕麦油脂及磷脂的溶出规律，实现对燕麦结构脂可控脱除；采用亚临界乙醇‐水对燕麦淀粉进行改性，阐明燕麦淀粉冷水溶胀性能改善的机制；建立压延式燕麦面条的品质评价方法，并探索适合压延式高添加燕麦挂面的加工工艺，评估脱脂/改性燕麦全粉的面条加工适宜性。研究表明，基于LF-NMR的原位探测技术，可应用于燕麦中结构脂与水分的同时、快速、无损检测；燕麦中的油脂与淀粉分子互作，显著影响了淀粉的结构和理化性质，适度减少燕麦结构脂含量可以调控淀粉的回生。构建了丙烷、丁烷、二甲醚等亚临界多元溶媒体系，通过调整溶媒极性可对燕麦中的油脂与磷脂选择性脱除，极性较强的溶剂（二甲醚）和较高的萃取温度（60 °C）更有利于磷脂的脱除。开发了基于亚临界乙醇-水的燕麦冷水溶胀淀粉制备新技术，在乙醇浓度48%，改性温度95 °C条件下，得到了团粒保持完整、遇冷水可溶胀、常温下能形成凝胶的改性燕麦淀粉，其主要结构特点为表面呈蜂窝多孔状、结晶结构由A‐型转变成V‐型。创新设计 “亚临界乙醇-水”一步法改性技术，得到脱脂和改性的燕麦全粉，改性燕麦粉可显著提升高添加燕麦面带的加工、食用品质及其贮藏稳定性。研究成果完善了燕麦等杂粮中油脂亚临界流体萃取和淀粉改性理论，可为燕麦的主食化、工业化加工产业发展提供了技术支撑。