Zhang Yun, Zhong Qixin
Department of Food Science, University of Tennessee , Knoxville, Tennessee 37996, United States.
J Agric Food Chem. 2017 Nov 1;65(43):9522-9528. doi: 10.1021/acs.jafc.7b03787. Epub 2017 Oct 18.
There is an established need to deliver lactase in milk to retain activity during storage and hydrolyze lactose after ingestion. In this work, spray-dried lactase powder was encapsulated in solid-in-oil-in-water (S/O/W) emulsions to fabricate delivery systems. The adoption of Span 80 in milk fat and lecithin in protein solution enabled the encapsulation of ∼76% lactase and <400 nm droplets. Additional cross-linking of proteins on droplets by transglutaminase and addition of sodium caseinate effectively reduced the amount of free lactase after spray drying emulsions. Compared to the data for free lactase, encapsulation significantly improved the thermal stability of lactase, reduced the level of lactose hydrolysis during a 14 day refrigeration (from ∼70 to <20%), enabled the gradual release of lactose during the simulated gastric and intestinal digestions, and resulted in the hydrolysis of most lactose during the simulated digestions. Therefore, the studied S/O/W emulsions have the potential to deliver lactase in milk for lactose-intolerant consumers.
在牛奶中添加乳糖酶以在储存期间保持活性并在摄入后水解乳糖，这一需求已得到确认。在这项工作中，喷雾干燥的乳糖酶粉末被包裹在水包油包固体（S/O/W）乳液中以制备递送系统。在乳脂肪中采用Span 80以及在蛋白质溶液中采用卵磷脂能够包裹约76%的乳糖酶并形成直径小于400 nm的液滴。通过转谷氨酰胺酶对液滴上的蛋白质进行额外交联以及添加酪蛋白酸钠，有效减少了喷雾干燥乳液后游离乳糖酶的量。与游离乳糖酶的数据相比，包封显著提高了乳糖酶的热稳定性，降低了14天冷藏期间乳糖的水解水平（从约70%降至<20%），使得乳糖在模拟胃和肠道消化过程中逐渐释放，并导致在模拟消化过程中大部分乳糖被水解。因此，所研究的S/O/W乳液有潜力为乳糖不耐受的消费者在牛奶中递送乳糖酶。
