Enhancing delivery of minerals using multifunctional carriers

近年来，由于久坐不动的生活方式导致的能量摄入减少，许多矿物质和维生素的摄入量有所下降。人们还认识到，这些营养素对最佳健康和降低慢性饮食相关疾病风险的需求可能高于为避免缺乏症而建议的水平。在英国等工业化国家，缺铁仍然是一种相对常见的营养障碍，特别是在因生长、失血或老年而需要高需求的个人中。铁、钙、锌和镁等矿物质的吸收通常会因与植酸盐和单宁等其他饮食成分的结合而减少，或者被氧化成不溶的形式，从而严重减少吸收。因此，矿物质的吸收和吸收很大程度上取决于它们所处的形态。因此，如果有可能设计一种系统，在加工、储存和消化的早期阶段(胃)保护矿物质，然后将矿物质释放到小肠，在那里被身体吸收，我们应该能够增强矿物质的摄取。因此，该项目的目的是开发一种对与消化过程有关的pH值变化敏感的新型水溶性矿物质输送结构。这种矿物(在这个项目中我们将重点放在铁)被安置在小的凝胶微珠中(大约。直径0.1 mm)。这些珠子被一层生物聚合物和一层不透水的脂类或蜡层覆盖。生物聚合物是常用的食品配料，如果胶和蛋白质，当组装在这些结构中时，对pH变化变得敏感。我们已经证明，它们在胃中遇到的酸性pH下是稳定的，但当进入与小肠相关的较高pH时，它们会降解。十二指肠中的酶会降解不透水的脂层，从而使铁从微珠中释放出来，从而可被吸收。该项目已被划分为多项任务，以实现以下主要目标。1.创建并表征生物聚合物层的pH值和环境敏感性。使用可以测量这些分子层的质量和组成的技术，我们可以确定这些层如何响应pH的变化并选择合适的系统。2.组装微珠，并在选定的生物聚合物层中进行涂层。在这里，我们将开发一种方法，使我们能够将载铁微珠包裹在不透水的生物聚合物层中。3.测定其稳定性、包封率和释铁性能。我们将测量在典型的加工和储存条件下以及在模拟消化过程中有多少铁从微珠中逸出，以确保它们在适当的条件下释放铁。我们还将使用细胞培养研究，看看释放的铁的形式是否可以被小肠衬里的细胞吸收。4.测定包覆微珠的铁摄取率。研究人员将把含有微珠的食物喂给人类志愿者，并对他们的血浆铁浓度进行监测。这将确切地揭示出这些结构在增强铁的输送方面是多么有效。如果成功，该项目的成果可以应用于其他矿物质和水溶性营养素，在这些地方强化是一个问题。这些方法可广泛应用于各种食物中，从而有助于增加这些重要膳食成分的摄入量。

The intake of many minerals and vitamins has fallen in recent years, due to reduced energy intake associated with a more sedentary lifestyle. It is also recognised that requirements of these nutrients for optimal health and reduction in the risk of chronic diet-related diseases may be higher than those recommended to avoid deficiency disorders. In industrialised countries such as the UK, iron deficiency is still a relatively common nutritional disorder, especially in individuals with a high requirement due to growth, blood loss or in old age. The absorption of minerals such as iron, calcium, zinc and magnesium is often reduced due to binding with other dietary constituents such as phytates and tannins, or oxidation into insoluble forms which severely reduce uptake. Therefore the absorption and uptake of minerals are strongly dependent on the form they are in. Therefore if is possible to design a system that will protect the mineral during processing, storage and the early stages of digestion (stomach), and then release the mineral into the small intestine, where it is absorbed by the body, we should be able to enhance mineral uptake. The aim of this project is therefore to develop a novel delivery structure for water soluble minerals that is sensitive to changes in pH that are associated with the digestion process. The mineral (in this project we will focus on iron) is housed in small gel micro-beads (approx. 0.1mm diameter). These beads are coated in layers of biopolymers and an impermeable layer of lipid or wax. The biopolymers are commonly used food ingredients such as pectin and proteins, and when assembled in these structures, become sensitive to pH changes. We have shown that they are stable at the acidic pH encountered in the stomach, but can degrade when the pass into the higher pH associated with the small intestine. The impermeable lipid layer will be degraded by enzymes in the duodenum, thus enabling the release of the iron from the micro-bead, and thus be available for absorption. The project has been divided up into tasks that will address the following main objectives. 1. Create and characterise the pH and environmental sensitivity of the biopolymer layers. Using techniques that can measure the mass and composition of these molecular layers, we can determine how the layers respond to changes in pH and select suitable systems. 2. Assemble micro-beads and coat in selected biopolymer layers. Here we will develop methods that will allow us to encapsulate iron loaded microbeads in the impermeable biopolymer layers. 3. Determine stability, encapsulation efficiency and iron release properties. We will measure how much iron escapes from the microbeads during typical processing and storage conditions, and during simulated digestion to ensure they will release the iron under appropriate conditions. We will also use cell culture studies to see if the iron that is released is in a form that can be absorbed by cells lining the small intestine. 4. Determine rates of iron uptake from the coated microbeads. Foods loaded with the micro-beads will be fed to human volunteers and their plasma iron concentrations will be monitored. This will reveal exactly how effective these structures are for enhancing the delivery of iron. If successful the results of this project could be applied to other minerals and water soluble nutrients where fortification is a problem. These approaches could be used in a wide range of foods thus helping to increase the intake of these vital dietary components.