Impact of food processing on the blood cholesterol-lowering effect of cereal beta-glucan

大约60%的人空腹血胆固醇浓度高到足以成为冠心病的危险因素，英国每年有60万人死于冠心病，其中许多是可以通过适当改变饮食和生活方式来预防的。水溶性膳食纤维（SDF）具有许多健康益处；特别是燕麦和大麦β -葡聚糖（BG）在降低血液胆固醇和脂质浓度方面是有效的，这已经被欧洲食品安全局（EFSA）认可。然而，对食物中BG的进一步加工会降低其功效，因此每天至少摄入3g BG的建议摄入量需要每天食用大量（100 - 100克）未加工的谷物，如燕麦和大麦。大多数消费者会觉得这很困难或不美味，因此需要将BG纳入美味的、通常食用的、具有明显降血脂特性的食品中。尽管BG具有明显的健康益处，但其作用机制仍未得到很好的理解。有研究表明，BG降低胆固醇的能力是由这种聚合物和其他类型的SDF干扰脂质消化的各个阶段而触发的，从而减少或延迟脂质摄取。这就扰乱了胆汁盐（肝脏产生的生物表面活性剂，有助于脂质消化）从肠道回到肝脏的循环。胆汁盐是胆固醇的衍生物，因此肝脏中胆汁盐的增加可以降低血浆胆固醇浓度。目前尚不清楚脂质消化的哪些方面受到BG的影响，因此哪些分子特性对其功能至关重要。本建议的目的是确定SDF，特别是BG对脂质消化的作用机制。人们提出了多种机制，它们主要涉及脂质消化和转运过程。因此，体外脂质消化研究将使我们能够详细研究脂质消化的所有不同阶段，包括脂肪酶活性和吸附，胆盐吸附和运输，以及胶束的形成和运输。BG和其他类型SDF的分子和生化特性将使用一系列最先进的技术来确定，包括分析离心，并将允许我们确定哪些特性对功能很重要。基于这些发现，将研究加工对BG的影响，以确定为什么加工会减弱其降低血胆固醇和血脂的能力。这些知识将使我们能够提出一些策略，通过这些策略，SDF可以被纳入美味的加工食品中，并且仍然保持其降低血液胆固醇和脂质浓度的能力。

About 60% of the population have fasting blood cholesterol concentrations high enough to be a risk factor for coronary heart disease, which is responsible for the deaths of >60,000 people annually in the UK, many of which are potentially preventable with appropriate changes to diet and lifestyle. Water soluble types of dietary fibre (SDF), confer many health benefits; in particular, oat and barley beta-glucan (BG) is effective at reducing blood cholesterol and lipid concentrations and this has been recognised by European Food Safety Authority (EFSA). However, further processing of BG in foods can reduce its efficacy, and so a recommended intake of BG of at least 3 g/day requires large quantities (>100g) of unprocessed cereals such as oats and barley to be consumed daily. Most consumers would find this difficult or unpalatable, so approaches are required to incorporate BG into palatable, commonly consumed foods with demonstrable blood cholesterol and lipid lowering properties.Despite the clear health benefits of BG, its mechanisms of action are still not well understood. It has been suggested that the ability of BG to lower cholesterol is triggered by the interference of this polymer and other types of SDF with various stages of lipid digestion, thus reducing or delaying lipid uptake. This then disturbs the recycling of bile salts (bio-surfactants produced by the liver which aid lipid digestion) from the gut back into the liver. Bile salts are cholesterol derivatives, so increased production of bile salts in the liver could reduce plasma cholesterol concentrations. It is not clear which aspects of lipid digestion are affected by BG, and therefore which molecular properties are crucial for its functionality.The aim of this proposal is to determine the mechanisms of action of SDF and in particular BG on lipid digestion. Various mechanisms have been proposed, and they mostly involve the lipid digestion and transport processes. Therefore in vitro lipid digestion studies will allow us to study in detail all the different stages of lipid digestion including lipase activity and adsorption, bile salt adsorption and transport, and micelle formation and transport. The molecular and biochemical properties of BG and other other types of SDF will be determined using a range of state of the art techniques, including analytical centrifugation, and will allow us to determine which properties are important for functionality. Based on these findings, the effect of processing on BG will be studied to determine exactly why processing attenuates its ability to reduce blood cholesterol and lipids. This knowledge will then allow us to propose strategies by which SDF can be incorporated into palatable, manufactured foods and still retain their ability to reduce blood cholesterol and lipid concentrations.