Riddet Institute, Massey University, New Zealand.
Adv Colloid Interface Sci. 2011 Jun 9;165(1):47-57. doi: 10.1016/j.cis.2011.02.001. Epub 2011 Feb 15.
Emulsion forms a major part of many processed food formulations. During the past few decades, the physico-chemical properties of oil-in-water emulsions under various food processing conditions have been extensively studied. However, over the recent years, interest has turned to understanding the behaviour of emulsions during consumption, i.e. physiological processing. In general, on ingestion, an emulsion is exposed to a relatively narrow range of physical (e.g. shear and temperature) and biochemical (e.g. dilution, pH, pepsin, pancreatin, mucins and bile salts) environments as it passes through the mouth into the stomach and then the intestines. There is currently limited knowledge of the physico-chemical and structural changes, which an emulsion may undergo when it passes through the physiologically active regime. A better understanding of the gastro-intestinal processing of emulsions would allow manipulation of physico-chemical and interfacial properties to modulate lipid ingestion, improve bioavailability of lipid soluble nutrients and reduce absorption of saturated fats, cholesterol and trans fats. Food emulsions are commonly stabilised by proteins, as they are not only excellent emulsifiers but also provide nutritional benefits to the product. The effects of digestion conditions on interfacial protein structures are complicated because of potential breakdown of these structures by proteolytic enzymes of the gastrointestinal tract. Studies dealing directly with the behaviour of protein-based emulsions under digestion conditions are very limited. This paper provides an overview of the behaviour of oil-in-water emulsions stabilised with globular proteins, namely lactoferrin and β-lactoglobulin. Recent advances in understanding the interactions between interfacial proteins on oil droplets and various physiological materials (e.g. enzymes and bile salts) in in vitro digestion systems are considered. Major emphasis is placed on the recent work carried out in our laboratory at Massey University on the behaviour of milk protein based emulsions (lactoferrin or β-lactoglobulin) during their passage through the gastro-intestinal tract.
乳液是许多加工食品配方的主要组成部分。在过去的几十年中，已经广泛研究了各种食品加工条件下的水包油乳液的物理化学性质。然而，近年来，人们的兴趣转向了了解乳液在消费过程中的行为，即生理加工。一般来说，摄入时，乳液在通过口腔进入胃然后进入肠道的过程中，会暴露于相对较窄的物理（例如剪切和温度）和生化（例如稀释、pH 值、胃蛋白酶、胰酶、粘蛋白和胆汁盐）环境中。目前，对于乳液在通过生理活性阶段时可能发生的物理化学和结构变化，我们的了解有限。更好地了解乳液的胃肠处理过程，可以操纵物理化学和界面性质来调节脂质摄入，提高脂溶性营养素的生物利用度，并减少饱和脂肪、胆固醇和反式脂肪的吸收。食品乳液通常通过蛋白质稳定，因为它们不仅是出色的乳化剂，而且还为产品提供营养益处。由于胃肠道中的蛋白酶可能破坏这些结构，因此消化条件对界面蛋白结构的影响很复杂。直接研究在消化条件下蛋白质基乳液行为的研究非常有限。本文概述了用球形蛋白（即乳铁蛋白和β-乳球蛋白）稳定的水包油乳液的行为。考虑了在体外消化系统中，界面蛋白与各种生理物质（例如酶和胆汁盐）之间相互作用的最新进展。主要重点是梅西大学实验室在我们实验室最近进行的关于乳蛋白基乳液（乳铁蛋白或β-乳球蛋白）在通过胃肠道时的行为的研究。
