食品油炸过程中油脂的吸收机理及其调控机制

Fried food has an important position in traditional and convenience food field because of its special flavor and property. This project is mainly aimed at solving the problems existed in the fried food field, such as the high fat content, obscure fat absorption mechanism, and lack of guideline for reducing fat content. The several kinds of representative fried foods rich in fibre, starch and protein were used as testing material and the new research idea combination of dynamic with static analysis, macroscopic phenomena with microstructure, and qualitative data and quantify were developed in this project. The relationship between the fat absorption and material features, frying procedure and cooling stage were studied and the relationship between the fat absorption and water replacement, pressure drive, capillary pressure and surface-active effect were investigated. The technology system to describe the fat absorption and fat distribution was established. The project could be helpful to explain absorption pathway, distribution characteristic, absorption mechanism and key regulation site of fat absorption, to grasp the fat absorption kinetics during the frying adhesion and drainage, and to establish the regulation mechanism for the representative frying foods. The results would provide the theory basis and scientific guideline for the production of low-fat healthy foods. The project predicted to publish 8-12 papers,including 5 SCI papers, apply for 4-6 patents and cultivate 3-5 postgraduates.

油炸食品因其特有的风味和品质在传统和方便食品中占有重要地位。本课题针对油炸食品含油率高、油脂吸入途径与吸收机理尚未明确、降脂措施缺乏理论指导等现状，以富含纤维、淀粉、蛋白等几类典型油炸食品为试验材料，采取动态分析和静态描述相结合、宏观表象与微观结构相补充、定性观察与定量计算相支撑的新思路，研究油脂吸收与物料特性、油炸过程和冷却过程的内在联系，研究油脂吸收与水分代替、压力驱动、毛细管作用以及表面活性等因素之间深层次联系，建立能够精确描述油脂吸收与分布规律的技术表征体系，系统阐述食品油炸过程中油脂的吸入途径、分布特征、吸收机理及其关键调控点，掌握不同食品体系油脂吸收与沥除动力学规律，建立典型食品油炸过程中油脂吸收的调控机制，为健康低脂食品的生产提供理论依据与科学指导。项目预计发表论文8-12篇，其中SCI论文5篇；申请国家发明专利4-6项；培养研究生3-5人。

油炸食品因其特有的风味和品质在方便食品中占有重要地位。本课题针对油炸食品含油率高、油脂吸入途径与吸收机理尚未明确、降脂措施缺乏理论指导等现状，以富含纤维、淀粉、蛋白等几类典型油炸食品为试验材料，研究了油脂吸收与物料特性、油炸方式和油炸过程的内在联系，研究了油脂吸收与水分代替、压力驱动、毛细管作用以及表面活性等因素之间深层次联系，建立了基于染色法、激光共聚焦显微镜、体视显微镜分析于一体的油炸样品油脂分布评价方法。结果表明：蛋白质的添加可减少油炸样品油脂的吸收，而添加谷朊粉比添加大豆分离蛋白体系的总油脂含量低10.04%~16.69%；样品初始水分含量对最终的油脂含量无显著影响（p>0.05），但显著影响油脂的吸收速率，最终样品的油脂含量与水分蒸发形成的结构更相关，而不是水分本身；随着油炸时间的增加，分布于样品内部的油脂逐渐增多，而外表壳层吸收的油脂始终最多，前8 min，油炸马铃薯片的总孔体积和孔隙率逐渐升高，堆积密度逐渐降低，8~12 min时总孔体积、孔隙率和堆积密度趋于稳定，保持在1.63 cc·g-1、0.42 g·cc-1、68.7%左右，这从结构上解释了油炸时间对油脂吸收的影响；油脂含量随着初始孔径的增大而增大，当穿孔直径为0、0.1、0.2 mm时，油炸马铃薯片的油脂含量无显著差异（p>0.05），当穿孔直径大于0.3 mm时，初始孔径对总油脂含量和结构油脂含量有显著影响（p<0.05），两者均随着初始孔径的增加而增加；通过比较不同类型油脂含量的变化，发现结构油脂含量的变化对总油脂含量变化的贡献率最大；与对照组相比，瓜尔豆胶+甘油涂膜处理使油炸马铃薯脆片的总油脂、表面油脂和表面渗透油脂含量分别降低了39.59%、33.57%和44.30%，组织结构油脂含量没有显著变化（p>0.05），热风干燥、真空微波干燥和红外干燥预处理，分别使油炸马铃薯脆片的总油脂含量降低了30.36%、24.34%和21.95%，表面渗透油脂含量降低了48.59%、42.81%和48.30%。研究发表高水平学术论文12篇，其中SCI论文6篇；申请国家发明专利5项，其中授权专利1项，PCT专利1项；培养研究生4人。